Chasing satellites usually means one person, one antenna and a few minutes at the right time of day. SatNOGS turns that around. It is an open source, participatory project that links amateur ground stations around the world into one network, so that anyone can schedule an observation of a satellite and have a station somewhere else do the listening. This guide explains what SatNOGS is, how its Network and its database fit together, what the public numbers show, what kind of stations take part, and how a radio amateur can use or join it. The description comes from the project websites, and the numbers come from their public interfaces on 27 October 2026.

What SatNOGS Is

The SatNOGS website describes itself as an open source global network of satellite ground stations, with three main parts: the Network, a global network of ground stations designed as an open participatory project; the DB, a machine-readable crowdsourced satellite information database; and the documentation, with detailed information on building your own ground station or adding an existing station to the network. The name is short for Satellite Networked Open Ground Stations. The documentation says that project development spans hardware, software and data processing, and that it aims to create and use a distributed network of ground stations around the globe. The database footer credits the Libre Space Foundation.

The idea is attractive for several reasons. A satellite in low Earth orbit is in range of any single station for only a few minutes per pass, but a network of many stations can listen to it many times a day from different places. The result is far better coverage than any one person could achieve, and a shared record of what each satellite transmitted and when. For a general introduction to hearing and working satellites yourself, read our guide to getting started with amateur radio satellites.

The Network: Observations on Demand

According to the SatNOGS Network page, the Network is a global management interface that facilitates multiple ground station operations remotely. An observer can take advantage of the full network of SatNOGS ground stations around the world. The network is open to anyone, so any observer can use all available ground stations and communicate with satellites. All observation results are public, and all data are distributed freely under the Creative Commons Attribution-Share Alike license. The page invites people to join, whether as owners of ground stations, as builders, or as developers who can help with the satnogs-network web application, which is written in Python and JavaScript.

An observation works like this. You choose a satellite and a transmitter from the database, pick a ground station and a time window when the satellite passes over it, and schedule the observation. The station records the signal, the network stores the audio and waterfall, and the result is published for anyone to see. For many satellites the data include decoded telemetry, so a student or a satellite builder can look at the health of a small satellite without owning an antenna. Because every observation is public, the community can also check whether a satellite is alive, which is useful after a launch when new satellites need to be identified.

The Database

The SatNOGS DB is a crowdsourced and machine-readable catalog of satellites and their transmitters. Its home page lists new satellites and satellites close to decaying, along with decoder versions and a count of observations of each satellite. On 27 October 2026 its public interface listed 2,841 satellites, of which 1,774 were in orbit, 1,026 had re-entered the atmosphere and 41 were planned for the future. These counts show how fast the field is changing: many satellites in the database are small spacecraft with a short life, and many new ones are added after every launch. Each satellite has an identifier, a NORAD number where available, a launch date, countries and a list of transmitters with their frequencies and modes.

The database is also where operators of small satellites can check what the community has learned about their own spacecraft, and where hams can find the downlink frequency and mode for a satellite they want to receive. If your interest is in amateur satellites that you can work, rather than only listen to, the Gpredict tracking guide and our article on contacting the International Space Station cover the operating side.

What the Network Looks Like in Numbers

The public interface of the Network gives a picture of the community. Please read these figures as a snapshot from 27 October 2026, because they change daily.

The gap between registered stations and recently active ones is worth understanding. Many registered stations were set up for tests or by people who later moved on, so only a fraction of the list is active. Even so, hundreds of stations were seen in the previous week, and the total number of observations is in the millions. That is a remarkable amount of data for a volunteer project. The station list also shows what hobbyists build: the antenna entries on the registered stations include cross Yagis, plain Yagis, verticals, turnstiles, quadrifilar helix antennas and dipoles, mostly for the VHF and UHF bands, with some on L band and S band.

What a SatNOGS Station Looks Like

A typical station is small. It has an antenna suited to the band of interest, often a cross Yagi or a turnstile for the 137 MHz, 144 MHz or 435 MHz ranges, an inexpensive software defined radio, a low-noise amplifier and a small computer such as a Raspberry Pi. The computer runs the SatNOGS client, which contacts the Network, downloads the schedule, controls the radio during each pass and uploads the recordings. For beginners with a USB SDR dongle the entry cost is low, and the project provides documentation on hardware and software setup. Our guides to SDR options for hams and Raspberry Pi shack projects are good background for the equipment.

The station owner also chooses how much to automate. A simple station accepts any scheduled observation on its bands; a more careful one limits observations to satellites of interest, sets a minimum elevation angle to avoid noisy low passes, and publishes a description of its equipment. The station list shows these choices, including minimum horizon settings and target utilization, so you can see which stations are suitable for an observation.

A Sample Pass, Step by Step

To see how the pieces fit, imagine that you want to know whether a small satellite launched last week is transmitting. You open the database and search for the satellite by name or by its catalogue number. If it is new, it may appear in the list of new satellites on the home page. You look at its transmitters: a frequency in the VHF or UHF range and a modulation type. You then go to the Network, choose the satellite and the transmitter, and the interface lists upcoming passes over stations that can hear that band. You pick a station with a high elevation pass, schedule the observation and wait.

After the pass, the observation page shows a waterfall, an audio recording and, if a decoder is available, the decoded frames. A clean line in the waterfall that moves smoothly in frequency, bending as the satellite approaches and recedes, is the Doppler curve; you can confirm that the satellite is alive without a single piece of equipment of your own. If the waterfall is empty, you can try another station or another pass before concluding that the satellite is silent, because a low pass, local noise or a poor antenna can hide a real signal. This simple routine is the basis of many community checks on new satellites.

Limits and Good Manners

Like any shared resource, the network works best when people are considerate. Station owners donate their time, power and bandwidth, and they decide how many observations they accept. Do not schedule large numbers of unneeded observations, and be patient if a station is offline: the public interface itself shows that most registered stations are not active at a given moment. Remember too that the data you see depend on equipment of widely different quality. A weak signal on one station may be strong on another, so compare several observations before drawing conclusions. If you notice a problem in the database, such as a wrong frequency, report it through the proper channel so that the correction helps everyone.

Using SatNOGS as a Ham Without a Station

You do not need to own any equipment to take part. As an observer, you can create an account on the Network, choose a satellite and schedule an observation on a station with a good pass. The most useful uses for amateurs include:

• Checking whether a satellite is working. If a satellite you want to use has not been heard recently, the observations will show it.
• Finding frequencies and modes. The database lists transmitters, so you do not need to search through scattered web pages.
• Learning what signals look like. The recorded waterfalls show what telemetry bursts and beacons look like, which helps when you try to receive them yourself.
• Studying Doppler shift. The waterfall of a pass makes the frequency change clearly visible.
• Teaching. A class can see a real satellite signal without any equipment, using public data.

Be mindful of the difference between listening and transmitting. SatNOGS stations are receive-only ground stations for monitoring satellite downlinks. If you want to make contacts through an amateur satellite, you need your own transmitting station and the appropriate licence, and the SatNOGS data will help you choose the best time and frequency.

Joining the Network With Your Own Station

1. Read the documentation. The project’s documentation explains the hardware options and software installation, and it points to a wiki for how to use the network and build a station.
2. Choose an antenna that matches your goal. A simple turnstile or cross Yagi suffices for many low-orbit satellites on VHF and UHF.
3. Get a receiver and a computer. A USB SDR and a small computer are the usual combination.
4. Register your station. You enter the location, the antenna description and the minimum elevation, and the network assigns a station number.
5. Check your results. View the recorded observations and see whether the passes show a clear signal.
6. Improve step by step. Add a preamplifier or a better antenna, change location of the antenna away from noise, and keep the client software updated.

The client software version is another sign of how a project matures: the public station list shows versions such as 1.8.1, 2.1.2 and 1.6 in use, which means that stations run a range of releases. If you join, use the current recommended version from the documentation.

Contributing Without Building Anything

SatNOGS is a volunteer project, and it welcomes people who do not own ground stations. You can improve the database by correcting transmitter information when you have a verified source, help decode telemetry by contributing to the decoders, write documentation or translate it, and report bugs in the web applications. The Network page specifically asks for people fluent in Python or JavaScript to help with the web application and points to the source code and issue tracker. For many hams, the easiest contribution is to check a satellite pass with their own receiver and report what they hear, which gives the database a human confirmation.

The Bottom Line

SatNOGS is an open, volunteer network that shares satellite ground station capacity across the world. The Network schedules and stores observations, the database catalogs thousands of satellites and their transmitters, and all data are public under a Creative Commons license. On 27 October 2026 hundreds of stations were active, and millions of observations were on record. You can use it without owning anything, or add your own low-cost receive station with an SDR and a small computer. Either way, it is one of the best learning tools for anyone who is curious about satellites.

Frequently Asked Questions

What does SatNOGS stand for?

Satellite Networked Open Ground Stations. It is an open source project that links amateur ground stations into a global network.

Do I need a license or equipment to use it?

To schedule observations and look at the data you only need an account. Owning a receive-only ground station requires a receiver, an antenna and a computer; transmitting through a satellite requires an amateur licence.

Is the data free?

Yes. The Network says observation results are public and distributed under the Creative Commons Attribution-Share Alike license.

What is the SatNOGS DB?

A crowdsourced, machine-readable database of satellites and their transmitters. On 27 October 2026 it listed 2,841 satellites, of which 1,774 were in orbit.

What equipment do stations use?

Mostly VHF and UHF antennas such as cross Yagis, turnstiles and quadrifilar helices, plus a software defined radio and a small computer running the SatNOGS client.

How many stations are active?

On 27 October 2026 the public interface showed 4,541 registered stations, of which 610 had been seen in the previous 30 days.

Walk into any ham radio supplier and you will find a wall of black and grey rings, clamps and beads, each labeled with a puzzling number: 31, 43, 61, 77. Those numbers are the ferrite mix, the material recipe, and choosing the wrong one is one of the most common reasons a homemade choke fails to cure RFI or a transformer runs hot. This guide explains what the mix numbers mean, what the main types are used for, how core names are built, how to think about turns and heat, and how to match a mix to a job such as a common mode choke, a balun or an unun. The figures here are the typical ranges quoted for ham use, so always confirm with the manufacturer’s data sheet for the exact core you buy.

What a Ferrite Mix Is

A ferrite is a ceramic-like magnetic material made from iron oxide combined with other metals. The Wikipedia article on ferrite magnets explains that soft ferrites, the type used in radio work, are generally made from either manganese and zinc or nickel and zinc. Manufacturers vary the recipe to change how the material responds at different frequencies, and they label each recipe with a mix number. Two cores of the same size but different mix behave differently, and you cannot tell them apart by looking at them, so the label matters.

The two families have different personalities. Manganese-zinc (MnZn) materials have high permeability and are most effective at lower radio frequencies, but they conduct a little electricity and so are used with care in high-frequency windings. Nickel-zinc (NiZn) materials have much higher electrical resistivity and work at higher frequencies. In both cases the useful result at RF is an impedance that combines inductance and loss. For a choke, the loss is what you want: the ferrite converts unwanted RF current into a little heat. For a transformer, loss is what you do not want, because it wastes power and warms the core.

The Main Mixes and What Hams Use Them For

The table lists the mixes you will meet most often. The frequency ranges are the typical values that ham sources quote, and the data sheet for a given core is the final authority.

If you remember only one rule, make it this: use a lossy mix (31 or 43) when you want to block current, and a low-loss mix (61, or sometimes 43) when you want to transfer power through a transformer. Mixing up the two roles is the root of many failures. A choke made of the wrong mix can do almost nothing at the frequency that matters, and a transformer made of a lossy mix can overheat at power levels that a low-loss mix handles easily.

Powdered iron cores, usually identified by codes such as -2 and -6 on cores that begin with T, are a different material, not ferrite. They are used for tuned circuits, filters and matching networks where stable inductance matters more than loss, and they look like colored rings. Do not mistake them for ferrite when you buy parts for a choke.

How Core Names Are Built

Many ham cores follow a naming convention that includes the shape, the size and the mix. A name such as FT-240-31 means a ferrite toroid, FT, with an outside diameter of 2.40 inches, 240 in hundredths of an inch, made of mix 31. FT-140-43 is a smaller toroid of mix 43, and FT-114-61 a mid-size core of mix 61. Clamp-on cores, also called snap-on or split cores, are sold by dimension and mix and are designed to be added to an existing cable without cutting it. Beads and sleeves are simple tubes that slip over a wire, as described in the Wikipedia article on ferrite beads. Different makers use different naming schemes, so check the specification, not only the name.

Size matters for three reasons. A bigger core has more material, so it offers more impedance for a given number of turns. A bigger window lets you pass thicker coax, which gives you the option of a larger choke, and a larger core can handle more heat before it saturates or overheats. For common mode chokes on a typical station feedline, many hams use a large toroid or several smaller ones stacked together.

Common Mode Chokes: Choosing Mix and Turns

A common mode choke is a coil of coax, or a group of wires, passed through a ferrite core so that common mode current on the outside of the cable sees a high impedance while the wanted signal inside the coax is unaffected. Our guide to common mode chokes explains why this matters for RFI. For the HF bands, mix 31 is the usual first choice because it offers a high, resistive impedance over a wide range of frequencies. For VHF, mix 43 or 61 is common, because mix 31 loses effectiveness as frequency rises.

Turns are the second variable. More turns raise the impedance, up to a point: as you add turns, stray capacitance between them creates a resonance, and above that frequency the choke becomes less effective. A short coil with a few turns is good at high frequencies and a longer coil is better at low ones, which is why some designs use several different chokes in series. As a practical guide, a choke of a modest number of turns on one large core, or several cores along the cable, is typical on HF. The best test is to measure the choke with an antenna analyzer or a NanoVNA, or to check the actual effect on noise, because published numbers refer to ideal conditions.

• Do not pack turns tightly if you can avoid it. Spacing the turns can reduce capacitance and widen the useful range.
• Keep input and output leads apart. Leads that run close together reduce the effect of the choke.
• Use the right cable. The choke has to fit the diameter of your coax, so choose the core by the window size.
• Place the choke where the problem is. At the antenna feedpoint to keep current off the line, and near the equipment to stop noise from entering it.

Baluns and Ununs: Choosing Mix for Transformers

Baluns and ununs are transformers, and for transformers the loss in the core should be low. Our guide to baluns and ununs explains the roles. For wideband HF transformers, hams use mix 43 or mix 61 depending on the impedance ratio, the power and the frequency range. A 49:1 unun for an end-fed half-wave wire, like those in our end-fed half-wave antenna guide, usually uses a toroid of mix 43 or 61, and a 9:1 unun for a random wire, described in our random wire guide, is often wound on mix 43. The choice involves a trade-off: mix 43 gives good performance at the low end of HF, while mix 61 loses less power at the high end and handles more power without heating.

Heat is the way a poor choice shows itself. If a transformer core gets hot to the touch after a few minutes of transmission, it is turning part of your power into heat. Reduce the loss by using a lower-loss mix, a larger core or more cores, or reduce the power. If the SWR shifts as the core warms, the permeability of the material is changing with temperature, which is another reason to choose a conservative design. Do not use a high-permeability lossy mix, such as 31, in a high-power transformer: it is designed to absorb RF.

Heat, Power and Saturation

Ferrite cores have two limits that matter to hams. The first is heating. A choke that is doing its job converts some of the common mode energy to heat, which can be significant at high power or when the common mode current is large. At QRP levels this is rarely an issue, but at hundreds of watts a small bead can get very warm. The second is saturation, where the magnetic field in the core is too strong for the material and it stops behaving as an inductor. Saturation is rare in RF chokes handling only common mode current, but it can happen in transformers that carry the full power of the transmitter, especially at low frequencies.

In practice, you manage both limits by using more core material than you think you need. Stack two cores instead of one, use a bigger toroid, and keep the winding spread out so heat can escape. If a core is hot, feel for the trend after a few minutes at full power with the intended mode; a very warm core is a sign to improve the design, and a core that is too hot to touch should be fixed before further use.

Practical Uses at a Typical Station

• Feedline choke at the antenna: several turns of coax on a large mix 31 toroid, or a string of clamp-on cores, to keep current off the shield.
• Choke on computer and USB cables: a snap-on core of mix 31 or 43 near the equipment to reduce noise in and out. For tracing noise sources in your home, see our guide to finding and killing RF noise.
• Power leads: beads or a toroid on DC supply wires to stop switching noise.
• Wideband transformers: mix 43 or 61 for 9:1 and 49:1 ununs and 1:1 or 4:1 baluns.
• VHF chokes: mix 43 or 61 beads or cores on the coax near a VHF antenna.

A Simple Way to Test a Choke at Home

You do not need laboratory equipment to see whether a choke does its job. If you own a NanoVNA or an antenna analyzer, wind the choke, connect a short wire through it with the instrument leads at each end, and sweep the HF range. A good choke shows a high impedance, with a large resistive part, across the bands you care about. Compare a choke with a few turns, one with more turns and one with a different mix, and the differences become obvious: one may peak on 40 meters and fall away on 10, another may be flat but lower overall. Our guide to the NanoVNA antenna analyzer explains the calibration needed for reliable readings.

The second test is the one that counts: does it reduce the problem? If you added the choke to stop noise on receive, listen on the affected band before and after, watching the S-meter or the noise level. If you added it to stop RF in the shack on transmit, check for the original symptoms, such as audio buzz or a computer that resets, while transmitting at the usual power. Change one thing at a time. If you add three chokes at once and the problem goes away, you will not know which one mattered, and you may have spent money you did not need to spend.

Finally, keep notes. Write down the mix, the core size, the number of turns, the position on the cable and the effect. A small notebook of such results becomes a very personal guide to your own station, and it is far more reliable than general rules, because every antenna, feedline and house is different.

Buying Cores and Avoiding Fakes

Because the mix cannot be seen, the main risk is buying a core that is not what the label says. Buy from reputable suppliers, avoid unbranded bargain lots with no specification, and keep the original packaging or a note of the mix with each core. If you are unsure, an inexpensive test with an analyzer can show whether a core behaves like the mix claimed, by comparing the impedance of a known number of turns across the frequency range with the manufacturer’s data. Always label your finished chokes with the mix and the number of turns, so you can repeat or repair them later.

The Bottom Line

The mix number tells you what a ferrite core will do. Mix 31 is the lossy workhorse for HF common mode chokes, mix 43 is the general-purpose NiZn for upper HF, VHF chokes and wideband ununs, mix 61 is the low-loss choice for transformers and VHF work, and mix 77 serves low frequencies. Use lossy mixes to block current and low-loss mixes to transfer power, add more core instead of more heat, label what you build, and check the data sheet before you rely on a number.

Frequently Asked Questions

What does the number in FT-240-31 mean?

FT means ferrite toroid, 240 is the outside diameter in hundredths of an inch (2.40 inches) and 31 is the mix.

Which mix is best for HF common mode chokes?

Mix 31 is the usual choice for the HF bands because it gives a high, lossy impedance over a wide range. Use mix 43 or 61 for VHF.

Which mix should I use for a 49:1 or 9:1 unun?

Mix 43 is the common choice, and mix 61 is used where lower loss and higher power handling matter. Follow the design you are building.

Why does my transformer core get hot?

The core material is absorbing some of the power as loss. Use a lower-loss mix, a larger core or several cores, or reduce power.

Is powdered iron the same as ferrite?

No. Powdered iron cores, such as types -2 and -6, are a different material, used for tuned circuits and filters rather than for lossy chokes.

Can I tell the mix by looking at the core?

No. Different mixes look alike, so rely on the label, the supplier and the data sheet.

Before FT8 took over the HF bands, a family of slower weak-signal modes did the same job. JT65 and JT9, joined by JT4, were the workhorses of early digital weak-signal work, and they are still part of WSJT-X today. This guide explains how those legacy modes work, what separates them, how they compare with FT8 and Q65, and where they are still useful. The details come from the WSJT-X 3.0 User Guide, which describes them in its modes overview, in the VHF features chapter and in the protocol specifications.

The Family in One Paragraph

The WSJT-X User Guide says that JT65 was designed for EME on VHF and higher bands and is mostly used for that purpose today. JT9 was designed for the HF bands and lower, and its submode JT9A is 1 dB more sensitive than JT65 while using less than 10 percent of the bandwidth. JT4 offers a wide variety of tone spacings and has proven highly effective for EME on microwave bands up to 24 GHz. All three use one-minute timed sequences, so a minimal QSO takes four to six minutes: two or three transmissions by each station, one sending in odd UTC minutes and the other in even minutes. For background, the Wikipedia article on JT65 gives the history of the mode.

How They Compare With FT8 and Q65

The table puts the older modes next to the modern ones, using figures from the guide. FT8 is four times faster than the one-minute modes, with 15-second sequences, but it is less sensitive by a few decibels, according to the guide. Q65 offers a range of sequence lengths and tone spacings for fast-fading signals.

The difference between 72 and 77 bits is not just a number. The 72-bit modes use two 28-bit fields for callsigns and a 15-bit field for a grid locator, report or acknowledgment, plus one bit that flags free text of up to 13 characters. The 77-bit modes add five bits to flag special message types, such as nonstandard callsigns, contest exchanges and FT8 DXpedition mode. That is why contest messages exist for FT8 and FT4 but not for JT65 or JT9.

JT65 in Detail

The protocol specification gives the technical profile. JT65 uses a Reed-Solomon (63,12) error-control code to convert 72-bit user messages into sequences of 63 six-bit symbols. These are interleaved with another 63 symbols of synchronization information according to a pseudo-random sequence. Modulation is 65-tone frequency-shift keying at 2.692 baud. The tone spacing equals the keying rate for JT65A and is two and four times larger for JT65B and JT65C. The guide’s EME section says that digital EME has mostly used JT65A on 50 MHz, JT65B on 144 and 432 MHz and JT65C on 1296 MHz.

JT65 includes special messages for EME. The signal report OOO is sometimes used instead of a numerical report, and shorthand messages for RO, RRR and 73 dispense with the sync vector entirely and use pairs of alternating tones for 1.486 seconds. With VHF features enabled, the decoder responds to these formats automatically; you generate them for transmission by checking the shorthand box. The guide recommends checking Single decode for VHF operation, since only one or a few signals normally appear in the receiver passband, and not using the two-pass decoding option. Deep search, averaging and AP decoding can be enabled from the Decode menu.

The signal-report range of JT65 is limited. The guide says reports are constrained to lie between -30 and -1 dB and are significantly compressed above about -10 dB, which is why reports for strong signals do not look very precise. For a wider view of weak-signal reporting, see our guide to WSPR, which uses a different message structure.

JT9 in Detail

JT9 uses a strong convolutional code with constraint length 32 and rate one half, which gives an encoded message of 206 information-carrying bits. Modulation is nine-tone frequency-shift keying at 1.736 baud. Eight tones carry data, so three bits are conveyed by each symbol, and one tone is used for synchronization. A transmission needs 85 channel symbols. For JT9A, the tone spacing equals the keying rate of 1.736 Hz, and the total occupied bandwidth is 9 times 1.736, or 15.6 Hz. This narrow footprint is what the guide means by less than 10 percent of the bandwidth of JT65, and it is why JT9 can fit many signals into a small slice of an HF band.

JT9 supports a wider range of signal reports than JT65, from -50 to +49 dB, and assigns more reliable numbers to relatively strong signals. The guide also mentions faster JT9 submodes, E through H, which are designed for meteor scatter and similar short-lived propagation along with MSK144; these use sequence lengths of 5, 10, 15 or 30 seconds. If you want to see how meteor scatter works in practice, our MSK144 guide covers the operating side.

JT4 in Detail

JT4 is built for EME on the microwave bands, 2.3 GHz and above. It uses the same convolutional code as JT9 and four-tone frequency-shift keying at 4.375 baud. Each symbol carries one information bit and one synchronizing bit. The submode selector sets the tone spacing, and wider spacings are used on the higher bands to cope with larger Doppler spreads; the guide gives JT4F as the usual choice for EME on 5.7 and 10 GHz. As with JT65, some operators use single-tone short messages for EME QSOs, generated by the Sh box, with Tx6 producing a 1000 Hz tone to help the other station find the signal and 1250 Hz to indicate readiness to receive. The Deep option on the Decode menu, averaging and deep search are all recommended for JT4.

Messages in the 72-Bit Modes

The 72-bit message format has some quirks that explain why these modes feel different from FT8. A standard message has two 28-bit fields for callsigns and a 15-bit field for a grid locator, report, acknowledgment or 73. One additional bit flags a message that contains arbitrary free text of up to 13 characters. Special cases allow other information, such as add-on prefixes like ZA/K1ABC or suffixes like K1ABC/P, to be encoded. In the 72-bit modes, compound callsigns come in two types: Type 1 uses one of about 350 common prefixes and suffixes, which you can display from the Help menu, in place of the third word of the message, and Type 2 handles other prefixes (one to four characters) and suffixes (one to three characters) when the message begins with CQ, DE or QRZ. In both cases a message that carries a compound callsign cannot carry a locator or report in the usual place, which is one reason traveling stations were often seen as awkward in the early days of the modes.

Directed CQ messages are another feature. The compression algorithm supports messages that begin with CQ AA through CQ ZZ, which are encoded internally as if they were the callsigns E9AA through E9ZZ and converted back for display. This lets a station call CQ for a particular region or group without needing a separate field in the message. The same structure was carried forward into the 77-bit modes, which is why directed CQ calls appear in FT8 as well.

Averaging, Deep Search and Depth

JT4, JT65 and Q65 offer message averaging, which sums successive transmissions that convey the same message and allows decodes at signal-to-noise ratios several decibels below the threshold for a single transmission. JT4 and JT65 also allow Deep Search decoding, in which the decoder hypothesizes messages containing known or previously decoded callsigns and tests them for reliability using a correlation algorithm. Decoded lines show a letter d when Deep Search was used and a confidence indicator from 0 to 9. These options are on the Decode menu, and the guide recommends Deep for most weak-signal work. The cost is processing time, but modern computers handle one-minute sequences easily, so there is rarely a reason to leave these options off when you are working at the edge of the noise.

For an EME operator these options are practical tools. A first echo of your own signal or a weak partner’s message may not decode in a single minute, but after a few repeats the averaged signal rises above the threshold. That is why EME schedules often involve repeating the same message several times, and why consistent timing and frequency matter: averaging only works if the successive transmissions line up.

Why Q65 and FT8 Replaced Them

The guide says that digital EME was done mostly with JT65A on 50 MHz, JT65B on 144 and 432 MHz and JT65C on 1296 MHz until the advent of Q65, and that on the higher microwave bands the typical choices were JT65C, wider JT4 submodes or QRA64. It now recommends a suitable Q65 submode for EME on any VHF or higher band, and says Q65 has replaced QRA64. For HF, FT8 made the one-minute modes less attractive by offering four times the speed. Many operators prefer faster QSOs and a bigger audience on FT8, while JT65 and JT9 activity on HF has dwindled.

Even so, the legacy modes are still in WSJT-X, and the 3.0 release extends the modern conveniences to them. According to the guide, auto-sequencing, filters, reply-to-CQ and the wait features are now available for all WSJT-X QSO modes, including the 72-bit modes JT4, JT9 and JT65. That means you can run JT65 on 6 meters EME with the same filters and wait options as FT8, which helps if you work moonbounce on schedule.

Where the Legacy Modes Still Make Sense

• EME on VHF and UHF: JT65 is still used where the activity group has not moved to Q65.
• Microwave EME: JT4 remains a proven choice on bands up to 24 GHz.
• Narrow HF segments: JT9 uses very little bandwidth, so it suits quiet corners of the band.
• Experimentation and learning: the slower pace makes the structure of weak-signal QSOs easy to follow, and the waterfall for each mode has a distinctive look.
• Rare regional activity: some local nets and beacons use the older modes, so a decoder that includes them lets you listen in.

If you are planning to try the legacy modes, check which mode the active stations use before you transmit. Our guide to digital modes beyond FT8 helps you compare, and the EME beginners guide shows what stations use today.

Setting Up JT65 or JT9 in WSJT-X

1. Choose the mode on the Mode menu. For JT65 pick the submode (A, B or C) that matches the band and the local convention.
2. Check your clock. One-minute sequences are timed to UTC, and an error of more than a second or so hurts decoding; our guide to FT8 time sync applies equally.
3. For VHF operation, enable the VHF and submode features on the General settings tab, check Single decode and avoid two-pass decoding.
4. Select Deep on the Decode menu if your computer can handle it, and add averaging, deep search or AP if you are working at the limit.
5. Remember that transmit periods alternate: one station sends in odd minutes and the other in even minutes.

The Bottom Line

JT65, JT9 and JT4 are the one-minute weak-signal modes that came before FT8. JT65 serves EME on VHF and above, JT9 was built for HF with a very narrow signal, and JT4 is a microwave EME mode with a choice of tone spacings. They are slower than FT8 and use a 72-bit message format with no contest messages, but they are still decoded by WSJT-X, and in version 3.0 they gain the same auto-sequencing, filters and wait features as the newer modes. Use them where activity exists, and use Q65 or FT8 where it does not.

Frequently Asked Questions

Which is more sensitive, JT9 or JT65?

According to the WSJT-X guide, JT9A is 1 dB more sensitive than JT65 while using less than 10 percent of the bandwidth.

How long does a JT65 QSO take?

The one-minute modes need four to six minutes for a minimal QSO, with two or three transmissions by each station.

What is JT4 used for?

JT4 is designed especially for EME on the microwave bands, 2.3 GHz and above, and has been effective up to 24 GHz.

Are JT65 and JT9 still in WSJT-X?

Yes. WSJT-X 3.0 still includes JT4, JT9 and JT65, and extends auto-sequencing, filters and the wait features to them.

Why do FT8 and Q65 have more message types?

They use a 77-bit payload, with five extra bits that flag special message types such as nonstandard callsigns and contest exchanges, whereas JT4, JT9 and JT65 use 72 bits.

Should I use JT65 or Q65 for EME?

The guide recommends a suitable Q65 submode for EME on any VHF or higher band, but check which mode the stations you want to work are using.

Anyone who watches an FT8 screen long enough will see tiny codes at the end of some decoded lines: a2, a3, a7, sometimes followed by a question mark. They are the visible trace of a clever idea in the decoder. AP decoding, short for a priori decoding, lets WSJT-X use what it already knows about a message to pull a signal out of the noise. This guide explains the idea in plain language, how the decoder uses it in FT8, FT4, FST4, JT65 and Q65, what each code means, why some lines end with a question mark, and how to treat a decode that depends on AP information. Everything below follows the WSJT-X 3.0 User Guide.

The Idea Behind A Priori Decoding

The WSJT-X User Guide describes AP decoding as a set of procedures that use naturally accumulating information during a minimal QSO. When you decide to answer a CQ, you already know your own callsign and the callsign of your potential partner. The software therefore knows what to expect for at least 57 bits of the next message: 28 bits for each of two callsigns plus one or more bits for the message type. The decoder’s task is reduced to determining the remaining 15 bits and ensuring that the result is reliable.

The decoder starts by setting the AP bits to the hypothesized values, as if they had been received correctly, and then tests whether the remaining message bits and the parity bits are consistent with those assumed values, with a specified level of confidence. The standard decoder for these modes uses a strong error-correcting code of the low-density parity-check type, described in the Wikipedia article on LDPC codes, and AP information is a way of giving that code a head start. The guide says that this increases the decoder’s sensitivity by up to 4 dB, at the cost of a slightly higher rate of false decodes.

Where AP Is Used

The documentation lists the modes whose decoders include AP procedures: FST4, FT4, FT8, JT65 and Q65. The rules differ by mode:

• FT8 and JT65: AP is optional, and you can switch it on or off from the Decode menu.
• Q65: AP is always enabled.
• FT4 and FST4: AP is always enabled when the decode depth is Normal or Deep.

The practical consequence is that FT8 operators have a choice, while users of the other modes get AP automatically at their usual depth. Our guide to setting up WSJT-X for FT8 shows where the decoder options sit in the program, and our article on JTDX versus WSJT-X compares how two popular programs approach decoding.

The a1 to a8 Codes

A successful AP decode is labeled with an end-of-line indicator of the form aP, where P is a single digit that tells you what information the decoder assumed. For FT4, FT8 and FST4 the guide lists these types:

The guide explains that, for example, a2 indicates that the successful decode used MyCall as hypothetically known information. Types a7 and a8 are used only in FT8. The FST4 table is the same, except that it omits the decoding attempts for AP types 4 and 5 to save time. JT65 has its own list, with a1 to a7, including types that include the DX grid, such as MyCall DxCall DxGrid and CQ DxCall DxGrid.

Which AP Types Are Tried When

WSJT-X tracks six QSO states in its auto-sequencer and attempts different AP types depending on the state. For FT4 and FT8 the guide lists them as follows:

• Calling station: types 2 and 3.
• Report: types 2 and 3.
• Roger report: types 3, 4, 5 and 6.
• Rogers: types 3, 4, 5 and 6.
• Signoff: types 3, 1 and 2.
• Calling CQ: types 1 and 2.

The logic is natural. When you are calling CQ, the only things the program can assume are the word CQ and your own callsign, so it tries types 1 and 2. When you are in the middle of a QSO and waiting for a final RRR or 73, it can assume both callsigns and the likely end of the message. This is why a weak final acknowledgment is decoded so often in practice: the program has strong expectations about what it will say.

The Question Mark

If the decoder finds a codeword that it judges to have a high but not overwhelmingly high probability of being correct, a question mark is appended to the line. The guide notes that, to avoid misleading spots from occasional false decodes, messages marked this way are not forwarded to PSK Reporter. In the documentation’s table of notations, a question mark means decoded with lower confidence, the letter a means decoded with the aid of some a priori information, and the digit following it is the AP type. An additional character after P means that the decode was obtained by averaging a number of previous messages, so q34 in Q65 would mean a Q65 decode with AP type 3 from 4 messages, and an asterisk indicates that 10 or more prior messages contributed.

For a ham, the message is simple: a decode with aP and a question mark deserves a second look. If the callsign is one you were not expecting, the report seems odd, or the station does not repeat in the next period, treat it as unconfirmed. Our guide to PSK Reporter explains how the spots that do get uploaded show up on the map.

Reading a Decoded Line From Left to Right

The guide explains that the information accompanying decoded messages generally includes the UTC time, the signal-to-noise ratio in dB, the time offset DT in seconds and the audio frequency in Hz. Some modes add more, such as frequency offset, drift or distance. Between the audio frequency and the message there is a mode character, and the guide lists them: a backtick for FST4, a plus sign for FT4, a tilde for FT8, a dollar sign for JT4, an at sign for JT9, a hash for JT65, a colon for Q65 and an ampersand for MSK144. After the message come the end-of-line codes. A question mark means lower confidence, the letter a means AP was used, the letter d means Deep Search, the letter f means the Franke-Taylor or Fano algorithm, and C is a confidence indicator for Deep Search.

Putting this together, a line that ends with a3 tells you the decoder was expecting a message from the station you were working and found it; a line that ends with a1 tells you the program matched a CQ pattern; and a line with no code at all was decoded without any assumptions. This is why strong stations rarely show AP codes: they decode without help, and the codes appear mostly on weak signals, near the limit of the decoder.

A Worked Example

Imagine that you have called a station and the band is noisy. Your computer’s auto-sequencer is in the state where it expects a reply, so the decoder tries AP types 2 and 3: first assuming a message addressed to your callsign, then assuming a message with both callsigns. The other station sends a signal report, but the signal is well below what an ordinary decode would manage. Because the program already knows 57 bits of the 77-bit message, it needs to resolve only the report and the parity checks; the decode succeeds, and the line ends with a3.

You then send your own report with R. In the next period the program is in the Roger-report state and tries types 3, 4, 5 and 6, since an RRR, RR73 or 73 may follow. Even a very faint RR73 can be decoded with a6 because the program assumes both callsigns and the ending. The contact is complete, with a few decibels of help from the decoder at each step. Without AP, you might have needed several repeats, and in a marginal case the QSO might have failed.

Now consider the opposite case: a line ends with a2 and a question mark, and the message names your callsign together with a station you never called. That is a classic warning sign. The decoder assumed your callsign, found a codeword that fit this pattern in the noise, and produced a plausible but wrong message. If you see this, do not answer; wait for the next period and see whether the station calls again. The guide’s decision to withhold question-marked decodes from PSK Reporter shows that the developers treat these cases with caution too.

Q65 and the q-Codes

Q65 has its own end-of-line codes, qP, listed in a separate table: q0 for no assumed information, q1 for CQ, q2 for MyCall, q3 for MyCall and DxCall, q4 for MyCall, DxCall and a blank, RRR, RR73 or 73, and q5 for MyCall and DxCall with a maximum drift of 50. They work in the same way as the a-codes, and because AP is always enabled for Q65, they appear whenever the decoder had help. The Q65 decoder takes advantage of the AP information that accumulates as a QSO progresses, from your own callsign and the word CQ at the start to the DX callsign and perhaps its four-digit grid later. If you are interested in the mode, read about the fast-fading uses of Q65 in our EME and scatter guides.

What AP Does Not Do

• It does not invent signals. The decoder still needs a real signal and a codeword that fits; AP only lowers the threshold.
• It does not replace the operator. The guide states that auto-sequencing is an operator aid and not an operator replacement.
• It does not help with a station you have never heard. For a first decode of a CQ from a stranger, only the most basic AP type is available, and the gain is smaller.
• It does not fix a bad clock or a bad audio level. Check your computer clock first; our guide to FT8 time sync explains why a one-second error hides signals completely.

Should You Turn AP On in FT8?

There is no universal answer, but the facts help you choose. AP adds up to 4 dB of sensitivity to your decoder, which is real: it is the difference between decoding a weak station and missing it. The cost is a slightly higher rate of false decodes. In a quiet band, those false decodes are easy to spot and ignore. In a crowded band with many callsigns, a false decode can look like a real contact and mislead you, especially if the program is waiting for an answer from the station you called. Many operators leave AP on for normal operation and treat any decode with a question mark with caution, which is consistent with the documentation, since the program flags the uncertain ones for you.

If you operate in a contest, where a false QSO in your log is costly, you may prefer a conservative approach. A real QSO is confirmed by a complete exchange from the other station, and the usual rules still apply: do not log a contact until you have received the final message. Keep a simple habit of reading the end of each line, and you will quickly learn how often the decoder uses AP on your band.

The Bottom Line

AP decoding gives WSJT-X a head start by assuming the parts of a message that you already know, such as your own callsign, the callsign of your partner and the usual endings. The result is up to 4 dB more sensitivity in FT8, FT4, FST4, JT65 and Q65, with a slightly higher chance of false decodes. Learn to read the a1 to a8 and q0 to q5 codes, treat question marks as a warning, and confirm contacts with the next message.

Frequently Asked Questions

What does a2 or a3 at the end of a line mean?

The decode used a priori information: a2 means MyCall was assumed, and a3 means both MyCall and DxCall were assumed.

How much does AP decoding help?

The WSJT-X guide says it increases sensitivity by up to 4 dB, at the cost of a slightly higher rate of false decodes.

Is AP always on?

It is optional in FT8 and JT65, always on for Q65, and always on for FT4 and FST4 when the decode depth is Normal or Deep.

What does a question mark mean?

The decode was judged to have a high but not overwhelming probability of being correct. Such messages are not forwarded to PSK Reporter.

Which AP types are FT8-only?

Types a7 and a8. Type a7 uses information from the previous receive sequence, and a8 is similar to a3 but uses a different list-decoding algorithm.

Does AP work for a station I have never called?

Only in a limited way. For an unexpected CQ the decoder can assume little more than the word CQ, so the sensitivity gain is smaller than during a QSO.

WSJT-X is the program behind most FT8 contacts in the world, and each major release changes the way many operators work. This guide walks through WSJT-X 3.0 as described in the version 3.0.0 User Guide on the project site. It covers the features that change daily operation (band buttons, filters, the Wait features and audible alerts), the technical additions (parallel FT8 decoding, full duplex mode, the Transceiver Control Interface and the SWR cutoff), and what to check before you upgrade. I use only what the documentation says, so if you run a different version, compare with its own guide.

Where the New Version Comes From

The WSJT-X 3.0.0 User Guide begins with an introduction explaining that WSJT-X is an open-source program designed to facilitate basic amateur radio communication using very weak signals. The name stands for Weak Signal communication by K1JT, and the program started as an extended branch of the earlier WSJT, first released by Joe Taylor, K1JT, in 2001. The guide credits a long list of contributors, including the core development team, and states that WSJT-X provides flexible rig control for nearly all modern radios, automatic Doppler tracking for EME and lunar echo testing, and analysis of received passbands up to 5 kHz wide on Windows, Macintosh and Linux. The installer filenames in the guide include wsjtx-3.0.0-win64.exe for 64-bit Windows.

The guide also explains the version numbering: major, minor and patch numbers separated by periods, with release candidates such as 2.7.0-rc1 issued ahead of a general-availability release, and a rule that release candidates should be used only during a defined testing period and not on the air after the general-availability release with the same number. That is useful advice for anyone tempted to run pre-release software during a contest.

What Is New in Version 3.0

The section “New in Version 3.0” lists the main developments, which I summarize here in the order the guide gives them. The table groups them by what they change for the operator.

Band Buttons and the Interface

Band Buttons can be enabled from the View menu, and the guide says they appear as a top row of controls under the decoded text windows. Two sets are available. One is oriented to HF and covers the bands from 160 meters to 70 centimeters; the other covers VHF and higher, from 8 meters to 24 GHz. Clicking a button changes the dial frequency, which is a faster alternative to opening the frequency list or typing on the radio. Combined with a logging program that follows the radio, it takes the guesswork out of band changes during a contest or a DX chase.

The guide also notes improvements for large screens: high-resolution monitors are supported with better scaling of fonts and widgets, and the user interface is available in many languages. You can start WSJT-X in a particular language from a command prompt, for example with wsjtx –language es for Spanish or –language ja for Japanese. OpenSSL is now installed automatically with WSJT-X, with manual intervention needed only if an incompatible version is already on the computer.

Filters: Hide What You Do Not Need

Filters limit what is displayed in the Band Activity window. You define filtering categories on the Filters tab of the settings, and you can switch many of them on or off from the Filters menu of the main window. According to the guide you can specify up to four territories for which hiding messages can be switched on or off, hide messages from a specific continent, or hide stations worked before on a band. There are entry fields for a Blacklist, a Whitelist and an Always Pass list, and they can be used in combination.

• Blacklist: suppress decodes from unwanted stations, contest messages or other unwanted content. You can enter whole callsigns, parts of callsigns or keywords.
• Whitelist: show only messages with certain grids, calls or keywords. Everything else is suppressed, except what the Always Pass list allows.
• Always Pass: display decodes from specific stations even if their country or continent is hidden.
• Ignore List: a click on the Ignore button adds the callsign in the DX Call box to the list, and such stations are ignored when you use the CQ options or Wait and Reply.

When any filter that limits the display is active, the status label changes from green “Receiving” to cyan “Receiving, Filters on”, so you do not forget that something is hidden. The guide adds that filters are disabled automatically for special operating modes, so you do not miss a station by accident, and that a BP (bypass) checkbox shows all decoded messages. If you currently use outside tools to filter decodes, compare them with our guides to GridTracker and JTAlert, which add maps and wanted-DXCC alerts on top of WSJT-X.

The Wait Features

Version 3.0 offers three wait-to-transmit features: Wait and Reply, Wait and Call and Wait and Pounce. You enable them with a checkbox near the bottom of the General settings tab. When they are enabled, the DX Call field and the Enable Tx button turn yellow to warn you that an automatic transmission may occur when a specified condition is met. The guide tells you to be alert and take any necessary precautions.

Wait and Reply continues your QSO when the station in the DX Call field sends you a message. For example, you may have called K1ABC, received no reply and stopped transmitting when K1ABC answered someone else; if K1ABC then calls you, your QSO resumes automatically, and a second RR73 is sent if your first one was not answered. It works in all modes where auto-sequencing is available. The guide suggests clearing the DX Call field after each QSO, using the F4 key or a right-click on the DX Call button.

Wait and Call is for a station that disappears in a deep fade. When you click the DX Call label, which turns red if a callsign is present, the program calls the station automatically up to three times after decoding it again sending CQ, RR73, RRR or 73. Pressing Halt Tx or Stop disables it.

Wait and Pounce answers a CQ from a station that meets selection criteria. With the DX Call box empty, you choose a CQ category from the drop-down list, right-click Enable Tx so that it turns orange, and in your next transmit sequence the program replies to a CQing station that matches. With Max Dist, Max dB or Min dB the program prevents working dupes by consulting the wsjtx.log file; the guide warns not to erase the file wsjtx_log.adi, which is your primary logbook. Wait and Pounce works together with the filters, so you can wait for a particular prefix, grid, callsign or keyword.

Remember that the wait features do not remove the human from the loop. The guide says clearly that auto-sequencing is an operator aid, not an operator replacement, and that WSJT-X will not make consecutive fully automated QSOs. Some contests and awards also require attended operation, so check the rules; our FT8 DXpedition mode guide explains related behavior with Fox and Hound stations.

Audible Alerts

WSJT-X can play a sound when a decoded message has specific content. This requires access to at least two audio output devices: one for the transmitted audio, selected on the Audio tab, and a different one for alerts, which are always played on the default audio device, usually the computer’s speaker. You turn on alerts by checking the desired boxes on the Alerts menu and clicking Enable Audio Alerts. Categories above the dividing line in the menu need the option to show DXCC, grid and worked-before status to be enabled on the General tab, and the Colors tab shows what triggered an alert. A callsign in the Ignore list is silent unless you check BP, and you can mute the alerts for one callsign with a click on the Ignore button.

Full Duplex, TCI and the SWR Cutoff

Full Duplex Mode lets WSJT-X transmit and receive at the same time. The guide says it is useful for satellite operation, where the audio source is normally set to the transponder downlink, and for monitoring your own transmitted signal by using a web SDR as the audio input. The Transceiver Control Interface (TCI) is a software layer that allows control, data transfer and synchronization between hardware devices and applications, and WSJT-X 3.0 supports it for both rig control and audio input and output.

Transmitted power and SWR can now be displayed in a status bar label, as reported by the radio, and transmission can be stopped automatically if the SWR exceeds 2.5, for example if you accidentally select the wrong antenna. The guide says these features work with most modern radios controlled through Hamlib or FLRig. Our guide to rig control with Hamlib explains the control path, and the Hamlib project is where radio support is developed. A right-click on the Tune button can also start ATU tuning on some radios with an internal ATU, again through Hamlib.

Other Additions Worth Knowing

• Band hopping for FT8, FT4 and MSK144: checkboxes allow sequential reception intervals on the main sub-bands, or on up to eight dial frequencies that you specify.
• Saved audio: files can be set to delete automatically after 30 days, which keeps disk usage under control.
• Features for all QSO modes: auto-sequencing, filters, reply-to-CQ and the wait features are available for the 72-bit modes JT4, JT9 and JT65 as well as the 77-bit modes FST4, FT4, FT8, MSK144 and Q65.
• SuperHound and SuperFox: SuperHound operators can activate Wait and Call for a SuperFox callsign even if SuperFox has not yet been decoded, but blind calling is prevented; Fox operators get a warning if another Fox seems to be on the same frequency.
• EME improvements: easier selection of dial frequencies within an EME sub-band, offsets of an integer number of megahertz between transmit and receive, buttons for Echo mode and six popular Q65 submodes, and CALL3.TXT downloads.
• Logging: support for an ADIF field type for satellite QSOs and a “Log automatically” option when not in contest mode.

Before You Upgrade

1. Back up your log and settings. Copy wsjtx_log.adi and your configuration before installing.
2. Read the system requirements. The 3.0 guide lists a computer with a modern Windows, macOS or Linux, audio at 48000 Hz and 16 bits, and a way to synchronize the clock to UTC within one second.
3. Do not upgrade the day before a contest. Test the new interface and your rig control first.
4. Re-check your setup. Our WSJT-X and FT8 setup guide lists the audio, CAT and clock settings to verify after any change.
5. Try the new features one at a time. Enable filters first, then alerts, then the wait features, and notice how each changes your operating.

The Bottom Line

WSJT-X 3.0 adds quality-of-life features that matter every day: band buttons, flexible filters, wait options that save you from useless transmissions, audible alerts and an SWR cutoff that protects the transmitter. It also adds technical features for specialists, including full duplex, TCI, band hopping and EME improvements. Read the relevant sections of the guide, back up your files, and adopt the features gradually so that you stay in control of every contact.

Frequently Asked Questions

What are the Wait features?

Wait and Reply, Wait and Call and Wait and Pounce are options that help you make QSOs under difficult propagation conditions while minimizing useless transmissions. Enabled features turn the DX Call field and Enable Tx button yellow.

Can WSJT-X 3.0 stop transmitting if the SWR is high?

Yes. Transmitted power and SWR can be shown in the status bar, and transmission can be stopped automatically if SWR exceeds 2.5, with most radios controlled through Hamlib or FLRig.

What are the band buttons?

Two sets of buttons, enabled in the View menu: one for HF from 160 m through 70 cm, and one for VHF and up from 8 m through 24 GHz.

Do audible alerts need special hardware?

They need at least two audio output devices: one for transmitted audio and the default device for the alerts.

Is the interface available in other languages?

Yes. The user interface is available in many languages, and you can start the program in a chosen language with a command line option.

Does 3.0 still support the older modes?

Yes. The guide lists JT4, JT9 and JT65 together with FST4, FT4, FT8, MSK144, Q65, WSPR, FST4W and Echo mode.

When a magazine headline says that a severe geomagnetic storm is on its way, what should a radio amateur actually expect? The answer is easier to find if you know the code used by forecasters. The NOAA space weather scales turn complicated physics into numbered levels, much like the categories for hurricanes and earthquakes, and each level comes with a description of likely effects. This guide explains the three scales published by the NOAA Space Weather Prediction Center: G for geomagnetic storms, S for solar radiation storms and R for radio blackouts. It focuses on what each means for HF, VHF aurora and polar paths, how often the events occur, and how to use alerts when planning a session.

What the Scales Are

The NOAA Space Weather Scales page explains that the scales were introduced to communicate to the general public the current and future space weather conditions and their possible effects on people and systems. Many Space Weather Prediction Center products describe the space environment, but few described the effects that can be experienced as a result of disturbances, and the scales fill that gap. They describe disturbances for three event types: geomagnetic storms, solar radiation storms and radio blackouts. Each scale has numbered levels, from 1 for minor to 5 for extreme, analogous to the scales for hurricanes, tornadoes and earthquakes, with a list of possible effects, a physical measure and the average frequency of events.

The frequency column is given per solar cycle of 11 years, so it tells you how often to expect each level over a full cycle. That is useful to keep in mind with our article on solar flux, A-index and K-index, which covers the daily values that sit underneath these levels. The scales are the plain-language layer on top.

The G Scale: Geomagnetic Storms

Geomagnetic storms are disturbances of the Earth’s magnetic field. They are measured with the planetary K-index (Kp), and the G scale maps Kp to levels. The effects listed by NOAA for HF radio are the most relevant for amateurs.

The table reproduces the HF and aurora entries from the NOAA page; the page also lists effects on power systems, spacecraft, satellite navigation and pipelines at each level. For radio amateurs the main message is that the higher the G level, the more the HF bands are disturbed, the lower in latitude the aurora can be seen, and the better the chances for radio aurora on VHF. Our guide to radio aurora on VHF explains how to use those events.

The S Scale: Solar Radiation Storms

Solar radiation storms are bursts of energetic particles from the Sun, measured by the flux of particles at energies of 10 MeV or more. The S scale runs from S1 to S5. Their main effects on radio are on paths that cross the polar regions. According to NOAA, S1 has minor impacts on HF radio in the polar regions, S2 gives small effects on HF propagation through the polar regions, S3 gives degraded HF propagation through the polar regions, S4 is likely to blackout HF radio through the polar regions, and S5 can cause a complete blackout of HF communications through the polar regions.

• S1 (minor): about 50 events per cycle; minor impacts on HF in the polar regions.
• S2 (moderate): about 25 per cycle; small effects on polar HF propagation.
• S3 (strong): about 10 per cycle; degraded polar HF propagation.
• S4 (severe): about 3 per cycle; blackout of HF radio through the polar regions for several days is likely.
• S5 (extreme): fewer than 1 per cycle; complete HF blackout through polar regions possible.

The practical meaning for hams is that radio contacts that go over the pole, such as paths from Europe to the west coast of North America or to Japan, may suffer during radiation storms even if the rest of the bands seem normal. Stations at high latitudes feel the effect most. If you use a path predictor, you can check the radiation storm level before blaming your antenna.

The R Scale: Radio Blackouts

Radio blackouts come from solar flares. The R scale uses the peak X-ray flux of the flare, measured in the GOES X-ray classes, to define levels from R1 to R5. The effects occur on the sunlit side of the Earth and last for minutes to hours, which matches the time the flare keeps the lower ionosphere heavily ionized. NOAA lists the physical measure and the frequency per cycle for each level.

• R1 (minor), X-ray class M1: about 2000 events per cycle (about 950 days); weak degradation on the sunlit side, with occasional loss of radio contact.
• R2 (moderate), M5: about 350 per cycle (about 300 days); limited blackout on the sunlit side, with loss of contact for tens of minutes.
• R3 (strong), X1: about 175 per cycle (about 140 days); wide-area HF blackout and loss of contact for about an hour.
• R4 (severe), X10: about 8 per cycle (about 8 days); blackout on most of the sunlit side for one to two hours.
• R5 (extreme), X20: fewer than 1 per cycle; complete HF blackout on the entire sunlit side for a number of hours.

A flare blackout is sudden and short-lived, and it only affects the sunlit hemisphere, so a contact between stations in darkness may continue normally. We cover the mechanism and the D-Region Absorption Prediction in our guide to HF radio blackouts, which is a useful companion to this article.

How Forecasts and Alerts Reach You

The scales are used in the watches, warnings and alerts that the Space Weather Prediction Center issues. A watch means conditions are possible in the coming days, a warning means they are expected or beginning, and an alert reports that a threshold has been reached. The alert text names the scale level, for example a geomagnetic storm watch at G2 or an alert for an R1 radio blackout, so once you know the scales you can read an alert at a glance. Many hams follow these messages through the NOAA website, through apps and through space weather feeds that scroll in logging software.

One practical habit is to separate the forecast from the observation. A forecast of G3 tells you to be ready, but the observed Kp tells you what happened. If the storm arrives and Kp rises to 7, check the bands on that day and make a note. Over a season you will see how closely the prediction and the experience match for your own antennas and paths.

Planning Around Space Weather

Experienced DXers keep a simple plan for disturbed days. On the first day of a geomagnetic storm, when the bands are unsettled, they often switch to lower frequencies, because the higher bands tend to suffer most when the F2 layer is depressed. On the following day, as the ionosphere recovers, they look for enhanced propagation on certain paths. Contest operators watch the K-index in the hours before a major event and decide whether to emphasize low bands or high bands at the start. Portable operators who plan to operate near the poles, for example on a polar expedition or in a high-latitude park, check the S scale before they go, since a radiation storm can close the very paths they are trying to use.

It is also worth remembering that space weather conditions change on a timescale of hours. The scales do not tell you what will happen next week, only what is expected now and in the next few days. Combine them with the daily solar flux and your own listening, and you will have a better picture than any single number can give you.

Comparing the Three Scales

The three scales describe different physical processes, and they do not always occur together. A big flare can cause an R3 blackout, and a few hours or days later a coronal mass ejection may cause a G3 storm, and in some cases a solar radiation storm at the same time. In other cases only one of the three occurs. For a radio amateur, this means checking all three before you decide what is wrong with the bands. A good rule is to look at the R scale for sudden loss of signals, at the G scale for several hours or days of poor or unusual conditions, and at the S scale when your path crosses the polar region.

Using the Scales in Practice

1. Check the current levels before a contest or DXpedition chase. The NOAA page and the SWPC alert feeds list the current events and the forecast.
2. Match the symptom to the scale. Sudden fade-out in daylight: R. Several days of flutter, noise and unusual openings: G. Polar-path trouble: S.
3. Use bad days for different activities. A G3 storm is a bad day for HF DX on high-latitude paths, but a good day to listen for aurora on 6 and 2 meters, and to try low-band contacts that are sometimes enhanced.
4. Do not panic about the headlines. A G1 or R1 event occurs often and has minor effects on most stations; the levels marked as extreme are rare.
5. Keep a record. Note the conditions and what you observed; over time you will learn how your own station responds.

For general reading about the broader topic, the Wikipedia article on geomagnetic storms provides historical examples and the physics behind the numbers. To see how disturbance depends on the position in the 11-year cycle, our guide to HF propagation explains why quiet and disturbed days both matter.

Common Misunderstandings

• “G5 means the end of radio.” NOAA says HF radio propagation may be impossible in many areas for one to two days at G5, which is serious but temporary, and G5 events are very rare.
• “Every flare ruins the bands.” Many flares are small, and R1 and R2 events typically cause short degradations on the sunlit side only.
• “A storm always means no DX.” Geomagnetic storms reduce some paths and improve others, and they can open VHF aurora paths that are otherwise closed.
• “The scales predict the next hour exactly.” They describe levels and likelihoods; forecasts can be wrong, and the real event may arrive early or late.

The Bottom Line

The NOAA space weather scales give the plain-language levels of three types of disturbance: G for geomagnetic storms (measured by Kp), S for solar radiation storms (important for polar paths) and R for radio blackouts (sudden daytime fade-outs after solar flares). Each runs from level 1 to 5, and NOAA lists how often each level occurs per 11-year cycle, from about 1700 G1 storms down to fewer than one R5 or S5 event. Use the scales to decide whether a bad day is due to space weather, to pick the right band or activity, and to avoid blaming your station for something that comes from the Sun.

Frequently Asked Questions

What do G, S and R stand for?

G is for geomagnetic storms, S for solar radiation storms and R for radio blackouts. Each has five levels, from 1 (minor) to 5 (extreme).

Which scale affects HF the most?

All three can. R causes sudden daytime blackouts on the sunlit side, G causes disturbed conditions for hours or days, and S affects polar paths.

What Kp level is a G1 storm?

Kp 5. G2 is Kp 6, G3 is Kp 7, G4 is Kp 8 including a 9-, and G5 is Kp 9.

How often do the strongest events occur?

NOAA lists G5 storms at about 4 per 11-year cycle, R5 blackouts at fewer than 1 per cycle and S5 radiation storms at fewer than 1 per cycle.

Does a geomagnetic storm help VHF operators?

It can. Stronger storms push the aurora to lower latitudes, so radio aurora contacts on VHF become possible in places that rarely see them.

Where can I see the current levels?

On the NOAA Space Weather Prediction Center website, which publishes the scales together with current conditions and forecasts.

Operating from a park or nature reserve is one of the most popular ways to enjoy portable amateur radio, and more than one program exists to organize it. WWFF, short for World Wide Flora and Fauna in Amateur Radio, is the international one, with a motto that fits in four words: make nature your shack. This guide explains how WWFF works for people who go out to operate (activators) and for those who sit at home working them (hunters). It covers the references, the 44-QSO rule, the logging fields that matter, the LogSearch database, and the main awards, using the information published on the WWFF website. Check the site for current details before you plan an activation.

What WWFF Is

The WWFF website describes the program as encouraging licensed ham radio operators to leave their shacks and go outside, operating portable in Protected Flora and Fauna areas (PFF) all over the world. More than 40,000 PFF areas are registered in the WWFF Directory, and hunters and activators can apply for awards globally and nationally. The About page adds that the aim is to draw attention to the importance of protected nature areas: amateur operators set up in designated nature parks and PFF areas, which generates attention for those places while giving the ham community an interesting activity to contact.

WWFF is an international, non-commercial program run by the WWFF team in cooperation with national coordinators of many national flora and fauna programs. Both the global program and the national programs are run by volunteers. That structure explains why you will see reference numbers with national prefixes, and why the details of what counts as a protected area depend on the national coordinator.

References and the Directory

Every protected area in the program has a reference number made of a program prefix and a number. Examples on the website include KFF-3774, in the United States program, and the awards page uses GFF-0001, GMFF-0001 and DXFF-0001 as illustrations. The Directory page lists the programs by prefix, with entries from all continents; for example, the list of prefixes includes LYFF, which is the Lithuanian program. You look up your park in the directory, note its reference, and use that reference in your logs and announcements.

The directory and the rest of the site are the place to check whether your intended location qualifies. Not every park is registered, and the program has a process for proposing new references through the national coordinators. If you want to activate a place that has no reference, ask the national coordinator before you go.

Activators and Hunters

An activator is the operator who goes to the reference, sets up a station and calls CQ. A hunter is a station that calls the activators, usually from home, and wants to log as many references as possible. Both are needed, and the program awards both sides. Like other portable programs, WWFF encourages QRP and simple equipment, and the same planning ideas apply: a lightweight antenna, a reliable power source and a plan for the weather. Our guides to battery and power options for portable operation and QRP operating cover those points, and the same techniques used for Summits on the Air work well in a park.

If you already take part in Parks on the Air, you can often use the same operating session to count for both programs when the location is registered in both, as long as you follow the rules of each. The logs are submitted separately, and the references are different.

Getting Started: Registering

The website uses a login with manual approval. The login page says to always use your callsign as the username, and that all other applications are rejected. The Rules and FAQ page lists the topics a new member needs: the WWFF rules and how to activate a park, how to use the forum, how to confirm an activity and send in a log, what to do if you change callsign, how to complete your profile and change your password, how to use LogSearch and apply for awards, and how to confirm with eQSL correctly for portable activations. Read those pages before your first activation, because they set out what counts as a valid activation.

The 44-QSO Rule and Activation Logs

The awards page contains an important rule for some awards: activations must be logged in the WWFF global database, with a minimum of 44 QSOs logged per activity, to count toward certain certificates. In practice, most activators plan to reach 44 contacts at each reference. It is a useful target, because it is enough to be worth the trip and low enough to achieve in an hour or two on a good day. The WWFF Points award uses a similar rule of thumb, where each completed block of 44 QSOs from a reference earns a point.

The ADIF fields matter for confirmation and for the park-to-park (P2P) award. The awards page says that for your activation log you should always include MY_WWFF_REF with the activated WWFF reference, using the official ADIF 3.1.3 fields. For a park-to-park contact you also include WWFF_REF with the worked reference. Older, unofficial fields exist: MY_SIG set to WWFF and MY_SIG_INFO with the reference, plus SIG and SIG_INFO for the worked reference. For a P2P credit to be confirmed, the two logs must match on callsign, reference, date, band and mode. Our guide to POTA logging apps shows tools that export these fields, and the awards page mentions FLE and Ham2K Polo as software with special options for logging P2P QSOs directly in ADIF.

LogSearch and Awards

The awards are free. The global awards page says certificates are available in electronic format (PDF or JPG) at no charge, and that all awards are based on QSO information in the WWFF LogSearch database. Other sources, including QSL cards, LoTW and eQSL, are not accepted. Awards are claimed in two categories, activators and hunters.

The steps on the References activator award are set out on the page: below 440 references in steps of 11, between 444 and 862 in steps of 22, and above 888 in steps of 44. The hunter and P2P awards use steps beginning at an entry level of 10 references, then steps of 44 up to 444, then 100 up to 4,444, then 200 up to 8,444 and 400 above that. The WWFF Points award, launched on 1 January 2020, has an entry level of 10 points. The page includes a worked example: a station that makes 32 contacts in a first activation earns no point, and reaching a total of 44 contacts earns one point; 132 contacts in a single reference give three points; and a DX expedition with 542 contacts earns ten points. Study the rules before you start so you can plan activations to gain the most value.

A Sample Activation Day

Planning is easier with a concrete timeline. Suppose you choose a registered nature reserve about an hour from home. The week before, you check the directory for its reference, read the reserve’s rules on access and antennas, and write the reference on the first page of your logbook. The evening before, you pack the radio, a battery, a simple wire antenna with a light support, a notebook for backup logging, water and a rain cover. On the day, you arrive early, set up away from paths and sensitive areas, and test the antenna with an analyzer before calling.

When you are ready, you post a spot or an announcement so that hunters know your reference and frequency, then call CQ with your callsign and the reference. The first contacts usually arrive within minutes if the announcement is visible. Keep exchanges short, repeat the reference for new hunters, and log each contact immediately. After 44 contacts, you can decide whether to keep going, move to another band, or switch to a different mode to give other hunters a chance. When you pack up, check the area, remove every piece of equipment and rubbish, and go home to upload the log. A day like this gives an activator the best of both worlds: the enjoyment of a portable operation and a log that counts toward awards.

Community, Marathon and Further Reading

The WWFF site is more than a database. It has a forum with a 24-hour help desk, news and monthly summaries called the WWFF Monthly Pulse, categories for park-to-park and activation stories, and pages for the WWFF Marathon with its rules and standings. These pages show how active the community is, and they are a good place to read first-hand accounts of activations before you plan your own. The site also notes that WWFF is supported by volunteers who work on the directory, the LogSearch software, statistics and the award processing, and invites people to look at the vacancies page if they want to help.

It is a good idea to read a few of the activation stories on the site before your first trip. They show what real activators do about antennas, access, noise and the weather, and they tend to include small tips that are not found in the rules, such as where to stand to avoid a noisy power line or how to handle a pileup with a low-power station.

Equipment Checklist for a Park Activation

• A radio and a power source with enough capacity for the planned operating time, plus a spare.
• An antenna that you have tested at home, and a way to support it without damaging trees or park property.
• A logging method, ideally with the ADIF fields for WWFF, and a paper backup.
• A way to announce your activity, such as a phone with a data connection or a friend who can post a spot for you.
• Weather protection for you and the equipment, and a first-aid kit.
• A copy of the park rules and the permit, if one is required.

Practical Tips for Activators

• Find the reference and the park rules. Check access, permits and any restrictions on antennas, vehicles and noise.
• Announce yourself. Use the WWFF website’s spotting and the DX cluster resources it links to, so hunters know where you are.
• Aim for at least 44 contacts. This is the number that counts for several awards.
• Log carefully. Use the official ADIF fields from the start and check your log before you upload it.
• Leave no trace. The aim of the program is to draw attention to protected areas, so respect them.

Practical Tips for Hunters

• Watch for spots. The site links to a DX cluster page for the program; add the alerts you want.
• Work different references and entities. Variety is what the awards measure.
• Keep your log accurate. Your contacts must match the activator’s log for confirmation.
• Be patient with small stations. Activators often run QRP and low antennas; clear calling helps them.

The Bottom Line

WWFF is a volunteer-run, worldwide program that turns protected nature areas into places to operate portable. Find a reference in the directory, register with your callsign, aim for at least 44 contacts per activation, log with the official ADIF fields, and use the free awards to measure your progress as an activator or as a hunter. If you already enjoy POTA or SOTA, WWFF is an easy addition that gives your trips a second purpose.

Frequently Asked Questions

What does WWFF stand for?

World Wide Flora and Fauna in Amateur Radio. Operators set up in Protected Flora and Fauna (PFF) areas.

How many references are there?

The website says that more than 40,000 PFF areas are already registered in the WWFF Directory.

Are the awards free?

Yes. Certificates are available in electronic form at no charge, and they are based on the WWFF LogSearch database rather than on QSL cards or LoTW.

How many contacts do I need per activation?

Certain awards require a minimum of 44 QSOs logged per activity. Plan to reach at least that number at each reference.

Which ADIF field marks my activated reference?

MY_WWFF_REF with the reference. For a park-to-park contact, add WWFF_REF with the worked reference.

Can I log WWFF contacts with other programs at the same time?

Many operators activate a location that is registered in several programs, but each program has its own logging and rules, so submit logs to each one separately.

Every August, hundreds of radio amateurs leave their shacks and set up beside lighthouses and lightships all over the world. They put up a wire antenna, switch on a transceiver and call everyone they can hear. The event is the International Lighthouse Lightship Weekend, usually shortened to ILLW, and it is one of the friendliest operating events in amateur radio. This guide explains what the ILLW website says about the event: what it is, when it takes place, why it is deliberately not a contest, how close to the light you have to be, what counts as a lighthouse, how to call CQ, and how to register. Always read the organizers’ current guidelines before you plan an operation.

What the ILLW Is

The ILLW website explains that August has become the international month for lighthouses. In the United States, August 7 is National Lighthouse Day, and during the first week of August American amateurs set up portable stations at lighthouses in an activity known as US National Lighthouse Week. In Britain the Association of Lighthouse Keepers runs the International Lighthouse Heritage Weekend on the same weekend as the ILLW, to encourage managers, keepers and owners to open their lighthouses to the public. The ILLW itself began in 1998 as the Scottish Northern Lights Award run by the Ayr Amateur Radio Group, and it has since grown into an event that the site says attracts over 500 lighthouse entries located in over 40 countries. The site also states that more than 90 countries have taken part over the years.

The purpose is stated clearly in the guidelines: to promote public awareness of lighthouses and lightships and their need for preservation and restoration, and at the same time to promote amateur radio and foster international goodwill, while remembering the dedication of those who served as lighthouse keepers. In other words, it is half radio and half heritage, and the public relations side is as important as the contacts. For background on the structures themselves, the Wikipedia article on lighthouses is a good reference.

Dates

The event is normally held on the third full weekend in August. For the next event, the site lists 00:01 UTC on 21 August 2027 to 24:00 UTC on 22 August 2027, which is 48 hours. The site also has entrants lists for 2026 and 2027, so you can see which lights are registered for which year, and reports from earlier years. If you read this guide months before the event, you have plenty of time to find a lighthouse and arrange permission, which is often the longest part of the planning.

Why It Is Not a Contest

The guidelines are firm on this point: the ILLW is not a contest. There are no prizes, certificates or other enticements to participate, and for that reason participation is free. Each station’s operators decide how they will operate in terms of modes and bands, within the terms of their amateur licence. Participants are not committed to being on the air for the entire period, only for as long as they can manage. There are no restrictions on antennas or power. The organizers ask that stations take time to work other lighthouses and lightships, as well as slow operators, newly licensed stations and QRP stations.

That attitude changes the way you operate. Instead of rate and multipliers, the aim is a friendly conversation and a chance to explain what you are doing. If you are used to the pace of a contest, our guide to the special event station gives a good model of the more relaxed approach that suits events like this one.

How Close to the Light Do You Have to Be?

The guidelines require that the station must be at or adjacent to the light. Adjacent means next to or as close as possible. Because space in many lighthouses is limited, the activity does not have to take place inside the tower itself: a field-day-type set-up at the light or in a building next to it is fine. The idea is that the station should have a visible presence for passing members of the public who visit the lighthouse over the weekend. Permission to operate from a lighthouse or lightship should be obtained from the relevant authorities, and the guidelines discourage operation from imitation lighthouses or lights on poles.

What Counts as a Lighthouse or Lightship

The definition is stricter than many newcomers expect. A lighthouse is generally a structure that is or has been listed officially as an aid to navigation in a recognized publication and that falls into the classic concept of a lighthouse: a substantial tower with an internal staircase, a revolving lens and a designated keeper at some point. Lighthouses moved to museums for historic reasons are also permitted. Being listed in an official document does not automatically qualify a structure; range lights, channel markers and breakwater lights are examples that may not qualify. Lightships are those that are or have been listed officially as floating aids to navigation, and lightships used as restaurants or other commercial operations are not acceptable. Faux lighthouses that were never an active aid to navigation are discouraged.

The site has a page of examples of lights that were submitted and rejected. If you are unsure whether your chosen light qualifies, read the guidelines page at illw.net guidelines before you register.

Frequencies, Modes and Calling CQ

Because the event is not a contest, you may operate on any authorized frequency and mode allowed by your licence. The organizers do not list particular frequencies, because more than 50 countries are involved and each has its own band plan. Digital modes are allowed. The guidelines say the main purpose is to show the public what amateur radio can do by making voice contacts with other lighthouse stations, and that an HF transceiver and a wire antenna tell the story best. They add that if you want to use FT8 there are no restrictions: these are guidelines, not rules. If you choose a digital mode, our guide to setting up WSJT-X for FT8 covers the basics.

To help other stations identify you, the site asks CW operators to add LT for lighthouse or LS for lightship when calling, and other operators to add the word LIGHT, LGT, LIGHTHOUSE or LIGHTSHIP after their call. Some stations also obtain a callsign with the letter L in the suffix to help others recognize them. A typical phone call would be “CQ lighthouse weekend, this is” followed by your callsign, then “lighthouse” again. If you are unsure how to give a clear callsign, the phonetic alphabet guide is useful.

Lighthouse Numbers

The organizers have compiled a list of lights that have taken part, with an identifying number for each. These numbers are there for use when conditions make it hard to understand the name of the lighthouse over the air. The list is not a definitive list of all lighthouses, and if your light is not in it you can leave the number field blank on the registration form; a number will be allocated after your entry is received, provided the structure complies with the guidelines. The numbers are mainly for use during the event. You can use any other reference number if a contact is chasing an award that requires a qualifying number.

Registering Your Station

Registration is optional, but it helps other people know which lighthouses will be on the air. The guidelines ask that multiple entries with different callsigns not normally be accepted unless there is a valid reason, though other callsigns can be used on the air. It is not unusual for a second registration to be submitted by a different group for the same lighthouse, and the organizers do not refuse it in the hope that the two groups can coexist. If you want to take part, review the registration form and the lights list on the website, choose a light that meets the guidelines and send your entry in good time.

Planning an Operation

1. Choose and approach the light. Contact the owners or managers early and explain what you plan to do and who will come.
2. Plan power and shelter. Lighthouses are often windy and exposed. Our guide to battery and power options for portable operation will help you choose a power source.
3. Prepare for visitors. A poster, a few printed handouts and an operator who can talk to the public turn the weekend into a public event.
4. Prepare a QSL. Many chasers want a card or an electronic confirmation, and our article on QSL card design shows what to include.
5. Log carefully. Record the lighthouse number and name with each contact so that later requests are easy to answer.

Tips for Talking to the Public

The guidelines make clear that one of the aims is publicity, and that the organizers invite the press and, where the site allows, the public. That changes what a good operating position looks like. Put the table where visitors can see it, keep a headset spare so a child can listen to a real contact, and use a simple sign explaining that you are an amateur radio station taking part in an international event. A short written explanation of what you are doing, the name of your club and a way to contact it, will turn casual curiosity into an interested new member.

Keep the demonstration concrete. Visitors respond to hearing a station from another country, or from another lighthouse a few hundred kilometers away, much more than to technical explanations. If propagation is poor, a local VHF contact with another lighthouse group is a reasonable alternative, as long as it is within your licence and the spirit of the event. Always remember the weather: lighthouses are exposed, and a sudden change can make operating uncomfortable or unsafe, so have a plan for packing up quickly.

Common Mistakes

• Registering a light that does not meet the guidelines, such as a replica or a minor channel marker.
• Operating too far from the structure, so the public cannot see the station.
• Forgetting to obtain permission from the relevant authorities.
• Treating the weekend as a contest and rushing contacts, instead of giving attention to slow or new operators.
• Not logging the lighthouse number or name, which makes later QSL requests hard to handle.

How to Chase Lighthouses

You do not have to be at a lighthouse to enjoy the event. Many hams spend the weekend at home working as many lights as they can, using the entrants list to see which are active. The organizers invite you to give extra attention to the less experienced stations. If you also enjoy other portable programs, you may find the approach familiar from our guides to Parks on the Air and Islands on the Air, which also reward finding and working special locations.

The Bottom Line

The International Lighthouse Lightship Weekend is a free, relaxed, 48-hour event on the third full weekend of August in which amateurs operate at or next to lighthouses and lightships and everyone else tries to work them. It is not a contest, so there are no prizes, no mandatory frequencies and no power or antenna restrictions. Pick a qualifying light, get permission, register if you wish, call with LT, LS or LIGHT after your callsign, and make the most of the chance to show the public what amateur radio can do.

Frequently Asked Questions

When is the ILLW held?

Normally on the third full weekend in August. The site lists 21 to 22 August 2027 for the next event, running 48 hours from 00:01 UTC on the Saturday.

Is the ILLW a contest?

No. There are no prizes, certificates or other enticements, and participation is free.

Do I have to be inside the lighthouse?

No. The station must be at or adjacent to the light, and a field-day-style set-up next to the lighthouse is acceptable.

Which modes and frequencies can I use?

Any authorized frequency and mode under your licence. The organizers prefer voice demonstrations but state that FT8 and other modes are allowed.

How do I identify myself as a lighthouse station?

CW stations add LT for lighthouse or LS for lightship, and others add LIGHT, LGT, LIGHTHOUSE or LIGHTSHIP after the callsign.

Is registration required?

No, but it is encouraged because it lets other stations know which lighthouses will be on the air.

At 10 GHz the wavelength is only three centimeters, antennas are small dishes, and a signal usually needs a line of sight between hilltops to reach its destination. That makes it a very different sport from HF contesting, and one weekend pair each year is devoted to it. The 10 GHz and Up contest, run by the ARRL, invites North American amateurs to work on the microwave bands from 10 GHz all the way up to light. This guide explains what the official page says about the dates, the operating limit, the objective of working many different locations, how logs are submitted, and what a beginner needs to know about equipment and operating practice before trying the microwave bands for the first time.

What the Contest Is

According to the ARRL contest page, the objective is for North American amateurs to contact as many amateur stations as possible, in as many different locations as possible in North America, on bands from 10 GHz through light. Amateurs are encouraged to operate from more than one location during the event. That is unusual, because most contests reward staying at one fixed station. Here the scoring philosophy rewards moving: a rover who drives to several hilltops gets more distinct locations to work and more distinct stations to contact, and a fixed station gains by working them.

The phrase “through light” refers to optical communication. Microwave enthusiasts experiment with modulated light beams, including lasers and high-power LEDs, for line-of-sight contacts over many kilometers. Few operators try this, but the contest recognizes it as part of the same family of experiments. Most activity is on 10 GHz, with fewer stations on the higher bands.

Dates and Operating Limits

The contest has two weekends. The page gives the dates as the third full weekend of August and September, and lists August 15-17, 2026 and September 19-21, 2026. Each weekend begins at 0900 UTC on Saturday and runs through 0759 UTC on Monday. Participation is limited to 42 hours of operating time in each of the two contest weekends, so you can pace yourself within the long window instead of staying up for the whole period. The page also notes that the start and end times changed from earlier years, when they were expressed in local time, and reminds participants to log all contacts in UTC.

The 42-hour limit is a good example of how a microwave contest differs from HF. Propagation on these bands changes slowly, equipment is carried to a hilltop and set up by hand, and the best conditions often occur at dawn and after sunset. You can plan to operate at the best times, and spend the other hours on travel, rest and moving between locations. If you plan to take part, check the hours in your own time zone, because 0900 UTC is early morning in North America and the Sunday-to-Monday transition falls in the night.

Why Locations Matter

The emphasis on different locations is not an accident. A contact is a path between two points, and on 10 GHz the path must usually be unobstructed. A station at a good hilltop can see far more of the horizon than a station in a valley. The same station operating from three different places can work three different groups of other stations. The contest page links to detailed rules on restrictions, so read them before you plan a multi-location route.

It helps to understand how far the signals can go. The geometric limit for line of sight depends on antenna height, a subject that we cover in our guide to the radio horizon. On microwave bands, the practical range is often a little more than line of sight because of atmospheric refraction, and longer distances are possible with tropospheric ducting, a mode we describe in our guide to tropospheric ducting. Rain scatter is another mode that microwave operators use: a heavy rain cell at the right distance scatters energy toward the other station, which opens contacts that are impossible by line of sight.

Narrowband and Wideband Operation

Microwave stations come in two broad types, and both take part in the contest.

The wideband stations are the easiest way to start; older designs were built around a Gunn diode oscillator, and newer modules use synthesized sources. They are easy to start with because a small kit can be built in a weekend and is cheap enough to use for experiments. The narrowband stations use a transverter, which converts the microwave frequency to an intermediate frequency such as 144 MHz or 432 MHz, so that an ordinary SSB and CW transceiver can be used. A narrowband station needs a stable oscillator and good frequency reference, because at 10 GHz even a small error is a large frequency offset. The narrowband calling frequency on 10 GHz is generally found near 10.368 GHz, but check the current convention in your region before you rely on it.

Equipment Basics

A basic 10 GHz station has four parts: a dish antenna, a feed, a transverter or transceiver module, and a way to point and power it. Dishes are small. Because the wavelength is only three centimeters, a dish of modest size gives high gain, and the beam is very narrow, so pointing accuracy matters. A small error in aiming can lose the signal completely. For that reason, operators carry a compass, a map or a smartphone, and often use a visible light source or a mirror to align dishes at long range.

Waveguide and coaxial connectors are another special feature of microwave work. Ordinary coax loses a large share of the power at 10 GHz, so builders keep the feedline very short and often mount the transverter directly at the feed. Connectors are typically SMA or N type, and waveguide flanges and adapters appear on the more serious stations. Weatherproofing is a concern, and cables and connectors should be sealed carefully; our guide to weatherproofing coax connectors explains the basic methods.

It is also useful to learn about the nearby bands. Many operators start on 1296 MHz and 2.3 GHz and move up, using the same techniques and the same transverter ideas at each step. Our 23 cm band guide is a good introduction to the first of those steps.

Safety, Weather and Practical Logistics

Microwave contesting means hiking or driving to exposed places, so plan for the conditions. Check the forecast before you leave, carry water and warm clothing, and tell someone where you are going. A dish is a sail, so secure it firmly against wind, and never set up near power lines. At the frequency of 10 GHz, the beam from a transmitting dish is narrow but can be strong in front of it, so keep people out of the beam and do not look into the feed while transmitting. Follow the RF exposure guidance that applies in your country, as you would for any amateur station.

Power is another practical matter. Portable stations need batteries that last for the whole session, and a transverter can draw a surprising amount of current compared with a simple FM module. Our guide to weatherproofing coax connectors helps with the outdoor side, but a checklist is also useful: batteries charged, compass, map, headlamp, logging device, spare cables and a notebook for paper backup. Write down your grid square at each location before you transmit, because a wrong grid in the log can cost you contacts at the checking stage.

Why the Microwave Bands Matter

The microwave bands give amateur radio a place for experimentation that is not available at lower frequencies. The antennas are small enough for one person to carry, the bandwidth available is large, and the techniques learned here are the same ones used in commercial links and satellite communications. The contest also keeps these allocations active, which matters because spectrum that is not used is spectrum that can be questioned. Taking part, even with a basic station and a few contacts, is a contribution to that activity and a good way to learn a branch of radio that most hams never see.

How Operating Works

Contacts are made by arrangement far more often than by calling CQ. A typical sequence is for stations to announce their location and times on a local chat group or on a calling frequency, then to set up a schedule, point their dishes at each other and exchange callsigns, grids and reports. Grid squares are the standard way to describe location in this activity. If you are not sure how they work, our guide to grid squares and the Maidenhead locator system explains the notation.

Because the beams are so narrow, the usual practice is to find the other station using a more tolerant band first, usually 144 or 432 MHz, and to use that contact to give directions: “I am at the northwest corner of the parking area, please point at azimuth 135”. Then both stations swing to the microwave band and make the contact. This technique saves a great deal of time and is a good reason for a microwave operator to keep a VHF radio next to the transverter.

Logging and Submitting Your Entry

Logs are due no later than 30 days after the second weekend ends. Logs may be submitted online or by mail, but electronic Cabrillo logs are the preferred method; the ARRL web app for 10 GHz and Up submissions is described on the contest page. If you submit on paper, you mail a completed summary sheet and log sheets, postmarked before the deadline, and the ARRL recommends a delivery method with a tracking number. A conversion tool for Cabrillo files is available through a link on the page. The ARRL also states that suitable certificates will be awarded online for exceptional operating efforts.

For the full rules, including how scoring works and which restrictions apply, download the PDF linked from the page. This article does not reproduce the scoring formula, because the details can change between years and the PDF is the definitive source. If you plan to take part more broadly in ARRL VHF-and-up events, our guide to the ARRL VHF contests gives the schedule and grid-based scoring.

A Beginner’s Plan for the Next Event

1. Start with one band. Build or buy a 10 GHz setup and test it at short range with a friend.
2. Find local activity. Ask local clubs or VHF groups who is active on microwaves, and ask to join a field session.
3. Choose a good hilltop. Use a map and the radio horizon calculation to pick a location with a clear view in several directions.
4. Prepare a log. Record the UTC time, band, callsign and grid for each contact.
5. Keep the 42-hour limit in mind. Plan your operating time around the best hours for the path and keep a record of the hours you use.
6. Take care with safety. Microwave transmitters can be hazardous at close range, so never stand in front of a dish that is transmitting, and observe the RF exposure rules for your country.

The Bottom Line

The ARRL 10 GHz and Up contest is two long weekends, each starting at 0900 UTC on Saturday and ending at 0759 UTC on Monday, with a limit of 42 operating hours per weekend, and it rewards working many different locations on the microwave bands from 10 GHz to light. A small wideband station is a cheap way in, a narrowband transverter station is a better long-term goal, and success depends mostly on a good hilltop and careful dish pointing. Read the rules PDF, plan your locations, log in UTC and submit a Cabrillo file within 30 days after the second weekend.

Frequently Asked Questions

When is the 10 GHz and Up contest?

On the third full weekend of August and the third full weekend of September. The page lists August 15-17 and September 19-21 for 2026.

How long is each weekend?

Each weekend begins at 0900 UTC Saturday and runs through 0759 UTC Monday, with a limit of 42 hours of operating time per weekend.

Which bands are included?

Bands from 10 GHz through light, for contacts in North America.

Why operate from several locations?

The objective is to contact as many stations in as many different locations as possible, and amateurs are encouraged to operate from more than one location.

How do I submit my log?

Electronically in Cabrillo format through the ARRL web app, which is preferred, or by mail on paper. Logs are due 30 days after the second weekend.

Do I need narrowband equipment?

No. The contest accepts any equipment, but narrowband SSB and CW stations with transverters generally reach farther than simple wideband FM modules.

Bouncing a signal off the Moon and back is still one of the most dramatic things an amateur can do, and one contest is built entirely around it. The ARRL EME Contest invites stations to work as many others as possible via the Earth-Moon-Earth path on any authorized amateur frequency above 50 MHz. This guide summarizes the official ARRL page: the dates of the four weekends, the exchange and how it doubles as the multiplier, how to log contacts correctly, the deadline, and some practical advice from the WSJT-X documentation on submodes for each band. The third weekend of the 2026 event starts today, so the timing is good for anyone curious about listening.

What the Contest Is

The ARRL EME Contest page gives the objective as working as many amateur stations as possible via the Earth-Moon-Earth path on any authorized amateur frequency above 50 MHz. The contest exchange is a station’s four-digit Maidenhead grid square locator, and the grid square also serves as the score multiplier. Analog stations, such as CW operators, may optionally send a signal report in any mutually understood format if station size or propagation prohibits exchanging grid squares.

That last sentence says a lot about the nature of the activity. On the Moon path, signals are extremely weak and fade rapidly, so some stations, especially small ones, cannot complete a full exchange on every contact. If you are new to the whole idea, our EME moonbounce guide for beginners explains how the path works and what equipment people use. For the physics, the Wikipedia article on Earth-Moon-Earth communication is a good reference.

The Four Weekends

The contest is organized as four full weekend periods, each running 48 hours from 0000 UTC on Saturday through 2359 UTC on Sunday. The weekends are split by band group, so you work the weekends that match your equipment. The ARRL lists these dates for 2026:

The split exists because moonbounce conditions differ by band group. Microwave stations tend to be small and need the Moon at a good position, while the lower bands need large arrays and operate at times when the Moon’s declination and distance suit them. Planning a weekend means checking the Moon’s rise and set at your location and the times when the Moon is closest to Earth, since a nearer Moon gives a slightly stronger echo. WSJT-X includes an astronomical data window for exactly this purpose.

Grid Squares as the Exchange and the Multiplier

In most contests the multiplier is a country or a zone. Here it is the grid square, which rewards variety of locations around the world. To make the scoring work, your log must record the four-digit grid from which you made the QSO and the four-digit grid of the station you contacted, in the sent and received information of every QSO line, regardless of what was actually sent over the air. If you need a refresher on locators, read our guide to grid squares and the Maidenhead system.

Portable stations deserve special attention. The ARRL gives examples of a station that operates from its home grid on one day and from another grid on the next, and then returns home for the November weekend. Each QSO line carries the grid that was used at that moment, so the checker credits the right multipliers. If you plan to operate from a rare grid, treat that as a selling point to announce in advance, because other stations will want the new multiplier.

Choosing a Mode and Submode

The contest allows any mode. In practice, digital modes dominate on most bands, with CW and SSB used by large stations. The WSJT-X User Guide describes how digital EME has evolved: until the arrival of Q65, it was mostly done with JT65A on 50 MHz, JT65B on 144 and 432 MHz and JT65C on 1296 MHz, with JT65C, wider JT4 submodes or QRA64 on the microwave bands. The guide now recommends a suitable submode of Q65, which has replaced QRA64, for EME on any VHF or higher band, and gives these examples:

• 50 and 144 MHz: Q65-60A.
• 432 MHz: Q65-60B.
• 1296 MHz and 2.3 GHz: Q65-60C.
• 3.4 and 5.7 GHz: Q65-60D.
• 10 GHz: Q65-60D or E.
• 24 GHz and higher: Q65-60E.

The pattern is the one you would expect: higher bands bring larger Doppler spread, so the tone spacing grows from A to E. The guide also notes that JT4, JT65 and Q65 offer message averaging, which sums successive transmissions that carry the same message and allows decodes several decibels below the threshold for a single transmission. JT65 and Q65 also offer a priori decoding that uses information accumulated during a QSO. All of these options are selected from the Decode menu. For further background on the mode, see the WSJT-X User Guide.

Doppler, Offsets and Echo Mode

Doppler shift is a major factor in moonbounce, particularly on the microwave bands. With a CAT-controlled radio, WSJT-X can compensate for changing Doppler shift, even during a CW EME QSO. The guide explains how: put the radio in CW mode, set the mode option in the Radio settings to None so that the program does not try to change it, and use the Tune button to switch between receive and transmit. No tones are transmitted, because the radio is in CW, but the program knows when you are transmitting and adjusts the dial frequency for each state.

WSJT-X 3.0 also supports large offsets between receive and transmit frequencies, for example to allow EME QSOs between countries that have amateur allocations at 2304 and 2320 MHz. In the guide’s example, a station receives on 1296 MHz and transmits on 1298 MHz using a transmit shift of +2 MHz. Finally, Echo mode lets you hear your own echo and measure it. The Echo transmission is a fixed 1500 Hz tone lasting 2.048 seconds, and the program records the lunar echo about 2.5 seconds later, computes its spectrum and displays it. Each cycle takes 6 seconds. It is a very good way to test your station before you try a contact, because if you cannot hear your own echo, the other stations will not hear you either.

Why EME Signals Are So Weak

The Moon is roughly 384,000 kilometers away, and its surface reflects only a small fraction of the energy that reaches it, scattering the rest in all directions. The total path loss for a round trip at 144 MHz is on the order of 250 dB, which is why moonbounce stations use large antenna arrays, low-noise preamplifiers and, on the lower bands, high power. The path loss grows with frequency, which is partly why the microwave weekends are separate: stations on 10 GHz use dish antennas and have to deal with high pointing accuracy and large Doppler shift, while stations on 50 MHz need very large arrays of long-boom Yagis because the wavelength is long.

The echo is also affected by libration fading, the slow rocking of the Moon as seen from Earth, which makes the reflected signal flutter, and by Faraday rotation on the lower bands, which changes the polarization of the signal as it passes through the ionosphere. These effects explain why careful stations use circular or switchable polarization and why the Q65 submodes have wider tone spacing at higher frequencies. You do not have to master the theory to operate, but knowing why a signal comes and goes helps you decide whether to keep calling or wait for a better moment.

Operating Practice and Etiquette on the Moon Path

EME operating practice is different from that on HF. Because contacts are slow and signals weak, most operators agree schedules in advance, often on a chat page that lists who is calling, on which band and when. The conventional calling period structure is that one station transmits in the first period and the other in the second, switching according to the odd and even minutes or the agreed sequence length, so both stations must be accurately timed. Do not call on top of an active QSO, and do not transmit continuously when you are not in a scheduled contact: the bands are quiet and each period is valuable.

Contest weekends bring out stations that are rarely heard at other times. If you are a beginner with a modest station, listen to find the large stations, and when you do call, send clean, correctly timed messages. Keep your total power within the limits of your licence and make sure you do not cause interference to terrestrial weak-signal operators nearby. If you have a good local VHF community, ask for a skilled operator to help you with a first test, because a first echo is much easier with a guide. The skills you learn there carry over to every other weak-signal mode.

Logging and Log Submission

The ARRL says that logs are due no later than 30 days after the final weekend of the contest ends at 2359 UTC. Logs must be submitted through the ARRL web app, and only online submission is accepted. Submissions must contain your complete log from all weekends you operated. If your logging software exports an ADIF or Cabrillo file with the required fields, including WSJT-X, you can submit it directly. For Cabrillo conversion help the ARRL points to a conversion tool, and certificates are available for download online.

The ARRL lists the ADIF fields that must be present. These fields are exported automatically by WSJT-X. If you use another ADIF-compliant program, the following are recommended:

• call: the call of the station worked (required).
• gridsquare: the grid of the station worked (optional, because it is determined during log checking).
• mode and submode: such as FT8, CW, SSB or MSK (mode is required).
• rst_sent and rst_rcvd: signal reports (optional).
• time_on or time_off, and qso_date or qso_date_off: the time and date of the QSO, with the end time preferred (required).
• band and freq: for example 2M, 70CM, 23cm or 3cm, and the frequency in MHz (both required).
• station_callsign and my_gridsquare: your callsign and your own grid square (required).

Missing fields cause rejected logs, so test your export before the weekend by making a dummy log entry and reading the resulting file.

Getting Ready as a Beginner

Most stations in the contest have large antenna arrays, but many people take part as listeners or with modest setups on 6 meters. Our 6 meter band guide explains the band where small EME stations most often begin. The 2 meter band guide and 70 cm band guide cover the layout of the bands where many serious EME stations operate.

1. Listen first. Set WSJT-X to Q65 with the submode listed above for your band and watch for decodes on the contest weekends.
2. Check your clock and your Doppler setup with Echo mode before the Moon is high.
3. Prepare a log with the correct fields, including your own grid.
4. Arrange schedules with other stations. Many EME contacts are made by agreement in advance using chat groups.
5. Be patient. Contacts take a long time, and the Moon is only above the horizon for part of each day.

The Bottom Line

The ARRL EME Contest runs over four 48-hour weekends, two for 2.3 GHz and up and two for 50 to 1296 MHz, and uses the four-digit grid square as both exchange and multiplier. Use the Q65 submode recommended for your band, let WSJT-X handle Doppler, test with Echo mode, record both grids on every QSO and submit a complete ADIF or Cabrillo log within 30 days of the last weekend. Even if you only listen this time, you will learn what a real moonbounce signal looks like.

Frequently Asked Questions

What is the exchange in the ARRL EME Contest?

Each station’s four-digit Maidenhead grid square locator, which is also the multiplier. Analog stations may optionally send a signal report if grid squares cannot be exchanged.

When are the 2026 weekends?

August 8-9 and September 5-6 for 2.3 GHz and up, and October 31 to November 1 and November 28-29 for 50 to 1296 MHz.

Which frequencies can I use?

Any authorized amateur frequency above 50 MHz.

Which WSJT-X mode should I use?

The WSJT-X guide recommends a suitable Q65 submode for EME on any VHF or higher band, for example Q65-60A on 50 and 144 MHz and Q65-60B on 432 MHz.

How do I submit my log?

Through the ARRL web app, as a Cabrillo or ADIF file containing all weekends you operated, no later than 30 days after the final weekend ends.

Do I need a huge station?

Big arrays help, but the contest allows any mode, and the page notes that analog stations may skip the grid exchange when station size or propagation prohibits it.

Every transceiver data sheet lists a sensitivity figure, and almost every operator has wondered what it really means. Is a lower number always better? Does a preamplifier help? Why does a radio with a “worse” figure sometimes hear better on the air? The answers lie in a small amount of arithmetic and one idea: sensitivity is not about how much a receiver amplifies, but about how much noise it adds. This guide explains receiver sensitivity in practical terms, covering the thermal noise floor, bandwidth, noise figure, the minimum discernible signal (MDS), how those numbers relate to the S-meter, and when sensitivity matters on HF and on VHF.

What Receiver Sensitivity Really Measures

A receiver can only detect a signal that is stronger than its own noise. Amplification does not help, because noise is amplified along with the signal. Sensitivity is therefore the weakest signal level at which a receiver can still produce a usable result. Manufacturers define “usable” in different ways. For SSB and CW, the figure is often the minimum discernible signal (MDS), which is the signal power equal to the receiver’s noise power, so that the output rises by 3 dB when the signal is applied. For FM, the specification is usually written in microvolts for a given signal-to-noise-and-distortion ratio, such as 12 dB SINAD. These are different tests with different units, so comparing numbers from different radios requires care.

The related minimum detectable signal concept is used in many fields. For ham radio, the practical definition is simple: MDS is the signal level that gives the same audio output as the receiver noise alone. Anything below the MDS is hidden in the noise, and anything well above it is easy to hear. Levels are normally given in dBm, which is decibels relative to one milliwatt, so that very small numbers become convenient negative values.

The Thermal Noise Floor: -174 dBm per Hertz

Every resistor, every antenna and every piece of matter at room temperature produces thermal noise, described in the Johnson-Nyquist noise article. At a standard temperature of 290 kelvin, the available noise power is about -174 dBm in every hertz of bandwidth. To find the noise in the bandwidth of your receiver, add 10 times the logarithm of the bandwidth in hertz. A bandwidth of 1000 Hz adds 30 dB, giving -144 dBm; a bandwidth of 100 Hz adds 20 dB, giving -154 dBm. This is the best possible noise floor for that bandwidth: a perfect, noiseless receiver cannot do better.

Two consequences follow immediately. First, narrowing the filter lowers the noise floor and improves the MDS: halving the bandwidth improves it by 3 dB, and reducing from 2400 Hz to 240 Hz improves it by 10 dB. This is why a CW operator with a narrow filter hears signals that an SSB operator cannot. Second, the noise floor is set by the bandwidth you choose, not by the radio’s maximum capability. A CW signal in a 500 Hz filter is easier to hear than the same signal in a 2400 Hz filter even if the radio and antenna are identical. Our guide to receive filter bandwidth explains how to choose the width.

Noise Figure: How Much Noise the Receiver Adds

A real receiver adds noise of its own. The noise figure is the number of decibels by which the receiver degrades the signal-to-noise ratio compared with the ideal case. A noise figure of 10 dB means the receiver’s own noise is 10 dB above the thermal floor. Adding it to the thermal noise gives the practical formula: noise floor in dBm equals -174, plus 10 times the logarithm of the bandwidth, plus the noise figure. The noise figure article gives the formal definition.

The values come directly from the formula. They show that bandwidth matters as much as noise figure: going from 2400 Hz to 250 Hz improves the noise floor by about 10 dB, the same as improving the noise figure from 15 dB to 5 dB. Many modern HF transceivers have noise figures in the range of roughly 5 to 15 dB depending on band and preamp settings, but check the data for your own radio, because this varies and manufacturers do not always publish it. Independent lab reports often list the MDS at a stated bandwidth, and those numbers are comparable between radios if the bandwidth is the same.

Relating dBm to the S-Meter and to Microvolts

The usual convention for HF is that S9 corresponds to a signal of 50 microvolts across 50 ohms, which is -73 dBm. Each S-unit below S9 is 6 dB, so S8 is -79 dBm, S7 is -85 dBm, and S1 is -121 dBm. Above S9 the meter reads in decibels over S9. A noise floor of -130 dBm in a 2400 Hz bandwidth is therefore about 9 dB below S1, which is why a good receiver with the antenna disconnected shows no S-meter movement at all, and why a signal that barely lifts the meter can still be perfectly readable on CW. Many real radios do not follow the convention exactly, particularly at VHF, where the convention is different, so treat the S-meter as relative.

The same logic gives a link between dBm and microvolts: 1 microvolt across 50 ohms is -107 dBm, 0.5 microvolt is -113 dBm and 0.2 microvolt is -121 dBm. So the common FM specification of about 0.2 microvolt for 12 dB SINAD corresponds to a very weak signal, similar in level to the S1 reference point, although the two numbers measure different things.

When Sensitivity Matters and When It Does Not

This is the most important practical point. On the lower HF bands, external noise from the atmosphere, the Sun and human-made sources is far above the thermal floor. On 80, 40 and 20 meters in a typical residential area, noise from power lines, switching supplies and electronics often sets the limit, by tens of decibels. If the noise that arrives at your antenna is 30 dB above the thermal floor, a receiver with a noise figure of 10 dB adds hardly anything to it, and making the receiver quieter has no effect on the signals you can hear. Adding a preamplifier on those bands only amplifies noise and adds the risk of overload, a point we cover in our guide to the HF preamp and attenuator.

The opposite is true at VHF and above. External noise is lower, so the receiver and the feedline can dominate. A long run of coaxial cable ahead of the receiver adds its loss directly to the system noise figure: 3 dB of loss in the cable means 3 dB more noise. That is the reason for mast-mounted preamplifiers on weak-signal VHF and UHF stations, covered in our mast-mounted preamplifier guide. For EME and other weak-signal work, every decibel matters, and the noise figure of the first amplifier is one of the main design choices.

• Low HF bands (160 to 40 meters): external noise dominates; bandwidth and antenna quality matter more than noise figure.
• Upper HF bands (20 to 10 meters): external noise is lower in quiet locations, and a quiet receiver can help, but only if your local noise is also low.
• VHF and UHF: receiver noise figure and feedline loss are important; a good preamplifier at the antenna is a common upgrade.
• Weak-signal modes: the same arithmetic applies, with long integration acting like a very narrow bandwidth.

If you suspect that local noise is the real limit, the right step is to find the source. Our guide to finding and killing RF noise explains the process, and removing a source of 20 dB of noise has a larger effect than any change to the radio.

Worked Example: Comparing Two Radios

Suppose a data sheet quotes an MDS of -138 dBm for radio A in a 500 Hz bandwidth and -132 dBm for radio B, in a 250 Hz bandwidth. At first glance radio A looks better by 6 dB, but the bandwidths differ. Narrowing radio A from 500 Hz to 250 Hz would lower its floor by 3 dB, giving about -141 dBm, so radio A is really 9 dB better. Now suppose both specifications use 500 Hz, and radio A quotes -138 dBm while radio B quotes -137 dBm. The 1 dB difference is far smaller than the variation you will see from the antenna, the band and the time of day, and you should ignore it when making a purchase.

The same reasoning applies to a preamplifier. If it improves the system noise figure by 3 dB, the noise floor falls by 3 dB, which matches the effect of halving the filter bandwidth. Doing both gives 6 dB. Whether this is worth the cost depends on whether noise from the radio or noise from outside is the limit on your band. If it is outside noise, neither change matters; if it is the radio, both will help. Always decide using the dummy load test above, not the data sheet alone.

The same arithmetic explains why digital modes such as FT8 work with such weak signals. A decoder that integrates over several seconds behaves like an extremely narrow filter, so the effective noise floor falls far below what a normal SSB filter allows. The standard reference bandwidth for WSJT-X signal reports is 2500 Hz, and signals decode at levels well below -20 dB in that reference bandwidth. The thermal floor is the same, but the processing gain lets the software reach much deeper into it.

A Simple Test You Can Do at Home

You can check your own receiver without special equipment. Set the radio to a quiet band, set the mode and filter width you normally use and turn off the preamplifier and the noise reduction. Connect a dummy load in place of the antenna and note the audio level or the S-meter reading, then reconnect the antenna. If the noise rises noticeably with the antenna connected, external noise is above the receiver’s own noise and sensitivity is not the limit on that band. If the noise stays the same, your station is limited by the radio, and a preamplifier or a quieter receiver might help. This simple test is the rule of thumb behind much of the advice in the amateur literature, and it is quick enough to try on each band.

For a more careful measurement you need a calibrated signal generator and a way to read the audio output level. With the generator connected to the antenna input at a known level, you adjust the level until the output rises by 3 dB compared with the noise alone, and read off the MDS. This is how laboratories do it, and it requires a generator accurate at very low levels. Most hams will not need to do this, but it helps to know how published numbers are produced.

Common Misunderstandings

• “More gain is better sensitivity.” Gain raises noise and signal alike. Only a lower noise figure or a narrower filter improves the signal-to-noise ratio.
• “A lower MDS number is always better, whatever the bandwidth.” MDS must be compared at the same bandwidth; a figure for 500 Hz cannot be compared with one for 2400 Hz.
• “Sensitivity decides how far I hear.” On HF, propagation and external noise decide most of it.
• “Dynamic range is the same thing.” Dynamic range describes the span between the noise floor and the strongest signal the receiver can handle; see our article on receiver dynamic range.
• “A preamp always helps.” It helps only when the receiver noise, not the external noise, is the limit.

The Bottom Line

Receiver sensitivity is set by three things: the thermal floor of -174 dBm per hertz, the bandwidth you select, and the noise figure of the receiver and feedline. Narrowing the filter and cutting feedline loss are the cheapest ways to improve it. On the lower HF bands, external noise swamps the receiver’s own noise, so a quieter radio or a preamplifier will not help; on VHF and above, the noise figure is a real design choice. Use the formula, check bandwidths when comparing radios, and look for noise sources at home before spending money on gear.

Frequently Asked Questions

What does MDS mean?

Minimum discernible signal: the signal level at which the output equals the receiver’s own noise, so the audio rises by 3 dB when the signal is applied. It is usually quoted in dBm at a stated bandwidth.

What is the thermal noise floor?

About -174 dBm per hertz of bandwidth at 290 kelvin. Add 10 times the logarithm of the bandwidth in hertz to get the noise in your filter.

Does a narrower filter improve sensitivity?

Yes. Halving the bandwidth lowers the noise floor by 3 dB, so a 250 Hz CW filter has a noise floor about 10 dB lower than a 2400 Hz SSB filter.

What is the noise figure?

The number of decibels by which the receiver degrades the signal-to-noise ratio compared with a perfect receiver. A lower number means a quieter receiver.

Do I need a preamplifier on HF?

Usually not on the lower bands, where external noise is much higher than receiver noise. It may help on the highest HF bands in a quiet location, and more often at VHF and UHF.

How many dBm is S9?

By the usual HF convention, S9 is 50 microvolts across 50 ohms, or -73 dBm, with 6 dB per S-unit below it.

Build a Yagi, and you soon discover a puzzle: the directional gain you wanted comes with a driven element that looks nothing like a 50 ohm load. The currents induced in the reflector and directors pull the feedpoint impedance far below what a plain half-wave dipole would show, and connecting coax directly gives a poor match. The classic cure is a small matching system at the feedpoint, and the three most common are the gamma match, the T-match and the beta match, also called a hairpin match. This guide explains why a matching system is needed, how each type works in plain language, how to tune it with an antenna analyzer, and how to choose the right one for your project.

Why a Yagi Needs a Matching System

A half-wave dipole in free space has a feedpoint impedance of roughly 73 ohms, close enough to 50 ohm coax that a direct connection gives a modest standing wave ratio. When you add a reflector and one or more directors, the mutual coupling between elements changes the current distribution, and the driven element’s impedance falls, often to somewhere between about 20 and 30 ohms, depending on the design. A Yagi optimized for gain or front-to-back ratio usually ends up with a low feedpoint impedance. A 50 ohm line connected to a 25 ohm load gives an SWR of about 2:1, and a design pushed harder gives more. Our guide to what an SWR meter tells you explains what that number means in practice.

The matching system has two jobs. It must raise the impedance seen by the coax to about 50 ohms, and it must cancel the reactance that appears when the driven element is cut slightly off resonance, which is common in Yagi design. The general theory is called impedance matching, and the three systems described here are simply convenient mechanical ways to do it with metal tubing at the feedpoint. The background on the antenna itself is in the Wikipedia article on the Yagi-Uda antenna.

The Gamma Match

The gamma match is probably the most popular feed system for home-built and commercial Yagis, particularly for VHF and for HF beams with a metal boom. A gamma match is built around these parts:

• The driven element, usually connected directly to the metal boom at its center. The center of a half-wave element is a point of zero RF voltage, so the element can be bolted to the boom without insulators.
• The gamma rod, a short piece of tubing or rod running parallel to the driven element, close to it, offset to one side of the center.
• A shorting strap or clamp, connecting the outer end of the gamma rod to the driven element at a chosen distance from the center.
• A series capacitor, placed between the inner end of the gamma rod and the center conductor of the coax. The coax shield connects to the boom or the center of the driven element.

The name comes from the shape, which resembles the Greek letter gamma. In principle, the feed current flows into the gamma rod, across the short strap and into the driven element, and the offset from the center steps up the impedance, much as moving a tap along a transformer winding does. The gamma rod adds inductance, so the series capacitor is used to cancel it. Moving the shorting strap changes the impedance step-up; adjusting the capacitor changes the reactance. The two adjustments interact, so you need to repeat them in turn.

The gamma match is an unbalanced feed. The coax shield connects to the boom, and currents can flow on the outside of the coax, which can distort the pattern and let noise enter the receiver. Many builders add a choke at the feedpoint or a few turns of coax or ferrite beads on the feedline. Our guides to baluns and ununs and to common mode chokes explain how to do that.

The T-Match

The T-match is a close relative of the gamma match and could be described as two gamma matches placed back to back. The driven element is split at the center, and two short rods run parallel to it, one on each side of the center, joined to the element by shorting straps. The feedline connects across the center of the two rods, which forms the crossbar of a letter T. Because the matching is symmetrical, the T-match is a balanced arrangement. This means it works best when it is fed through a balun, or when the capacitors are placed in each arm so that the coax can be connected directly.

The advantage of the T-match is symmetry, which tends to give a cleaner pattern than a single-sided gamma, and it can handle higher impedance step-ups. The disadvantage is mechanical: the element is split at the center, so it must be insulated from the boom, and the extra parts take more care to weatherproof. In practice, T-matches are widely used on commercial VHF and UHF antennas, where the parts are small and the balun can be built into the housing.

The Beta Match and Hairpin Match

The beta match, often called the hairpin match, works on a different principle. The driven element is deliberately made slightly shorter than resonant length, so that it is capacitive at the operating frequency. A U-shaped loop of tubing, the hairpin, is connected across the split center of the element and acts as a shunt inductor. The hairpin cancels the capacitive reactance of the element, and it also steps up the low impedance of the driven element to a level close to 50 ohms. The feedline connects across the hairpin, often through a 1:1 balun.

The hairpin match is attractive for several reasons. It has no capacitor, so there are fewer parts to fail in the weather. It is a DC short across the feedpoint, which gives some protection against static buildup. It is also easy to adjust: you slide the connection points along the hairpin until the SWR is lowest. The driven element must be isolated from the boom, as with a T-match, and it needs a balun for a balanced feed. Many commercial HF and VHF Yagis use a hairpin match for these reasons.

Comparing the Three Matches

The table gives general tendencies, not strict rules. A good builder can make any of the three work, and a poorly built one will perform badly whatever its type. The usual way to pick is to start from the mechanical design of your boom and the materials you have on hand. If your boom is a metal tube and you want to avoid insulators, the gamma match is the natural choice. If you want fewer weather-sensitive parts and do not mind a balun, the hairpin is the cleanest.

How to Tune a Gamma Match

Tuning the gamma match is the part that most builders find intimidating, but a methodical routine works. You need an antenna analyzer or a NanoVNA, and our guide to the NanoVNA antenna analyzer explains how to calibrate it and take a sweep. Follow these steps.

1. Mount the antenna at working height, or a realistic height away from the ground and metal objects. The environment changes the match, and a bench measurement on the ground can mislead.
2. Set the shorting strap to the position given in the design or the manufacturer’s instructions, and set the capacitor to mid-range.
3. Sweep the band and look at the resonance and SWR. Note the frequency of minimum SWR and the SWR at that point.
4. Adjust the capacitor first to bring the resonance to the desired frequency and reduce the reactance. Then move the strap a little to improve the impedance. Repeat in small steps, noting each result.
5. Stop when the SWR is as low as you need across the part of the band you use. A value under 1.5:1 is good for most purposes.
6. Lock the settings by tightening the hardware and sealing the capacitor against moisture, then re-check the SWR.

Remember that the gamma match interacts with the element length. If the driven element is too long or too short, you will find that the capacitor and strap run out of range. Check the element lengths against the design before adjusting the match. For designing and checking a Yagi before you build it, our antenna modeling walkthrough shows how to simulate the feedpoint impedance, which tells you in advance what step-up the match must provide.

Practical Construction Tips

• Use compatible metals. Aluminum tubing with stainless steel hardware is usual; avoid contact between dissimilar metals that corrode in the weather.
• Keep the gamma rod parallel and rigid. A flexing rod changes spacing and shifts the match in the wind.
• Weatherproof the capacitor. Many builders use a fixed or variable capacitor in a sealed housing, or a coaxial capacitor made from a rod and a sleeve with an insulator between them.
• Add a choke. A few turns of the feedline, or ferrite cores, near the feedpoint reduce unwanted currents on the outside of the coax.
• Record the final settings. Note the strap position and capacitor value so that you can repeat the build or restore it after maintenance.

If you are still deciding on the type of beam, our comparison of Yagi and hex beam antennas may help you decide, since a hex beam avoids the matching problem by using a different geometry.

Which One Should You Build?

The decision usually comes down to the band, the boom and the builder’s tools. For a VHF Yagi on a metal boom, a gamma match made from a short piece of tubing is a very common first choice, because a few millimeters of adjustment are enough to reach a good match and the parts cost little. For a UHF antenna, where the elements are small and the tolerances tight, the T-match or a printed or molded matching structure is often better. For an HF beam on a long boom where weather and corrosion are the main enemies, a hairpin match avoids the variable capacitor, which is the part most likely to fail over the years.

Whatever you choose, remember that matching does not change the pattern of the antenna; it only changes how well the feedline is connected. A beam that has been matched well still has the same gain and front-to-back ratio as before, but one that is poorly matched wastes power as heat in the feedline or radiates it from the coax shield. If you are building from published plans, use the matching method and dimensions the designer used, because the element lengths and spacings were chosen together with the matching in mind.

Finally, put the result into practice. After the match is finished, check the SWR on several frequencies across the band, then check again after a rain and after a week of weather. A match that holds its value across those conditions is a match you can trust, and you will know that the effort at the workbench was worthwhile.

Common Mistakes

• Assuming that a low SWR proves a good antenna. The match only means that power reaches the antenna.
• Adjusting the strap and the capacitor at the same time. Change one, measure, then change the other.
• Tuning on the ground. A beam on a short stand can look very different from the same beam on a tower.
• Forgetting to deal with common-mode current on a gamma-matched feed.
• Using the wrong element length. A gamma match cannot repair a driven element that is much too long or too short.

The Bottom Line

A Yagi’s driven element usually has a low feedpoint impedance, so it needs a matching system. The gamma match is the most common choice for a metal boom, the T-match gives a balanced arrangement popular on VHF and UHF, and the beta or hairpin match removes the capacitor and uses a shortened element and a balun. Whichever you use, measure with an analyzer at working height, adjust one control at a time, and deal with common-mode current. With patience, any of the three will give you a low SWR and a good-looking pattern.

Frequently Asked Questions

Why does a Yagi need a matching system?

The reflector and directors lower the feedpoint impedance of the driven element, often well below 50 ohms, so a matching system is used to transform it and to cancel any reactance.

What is the difference between a gamma match and a T-match?

A gamma match feeds one side of the driven element with a single rod and capacitor and is unbalanced. A T-match uses two rods, one on each side, and is symmetrical and balanced.

Is the hairpin match the same as the beta match?

Yes, the names are used for the same arrangement: a shortened driven element with a shunt inductor, in the form of a hairpin, across the feedpoint.

Do I need a balun with a gamma match?

The gamma match is unbalanced, so a choke or common mode filter on the feedline is recommended to prevent current on the outside of the coax.

How do I tune a gamma match?

Use an antenna analyzer at working height. Adjust the series capacitor and the shorting strap in small steps, one at a time, until the SWR is lowest at the frequency you want.

Can I use a gamma match on an HF beam?

Yes. Gamma matches are widely used on HF Yagis with a metal boom, although the parts are larger and the capacitor must be rated for the power and the weather.

Between the busy 2 meter band and the crowded 70 centimeter band sits a stretch of spectrum that many VHF operators never use: the 222 MHz band, also known as the 1.25 meter band. It covers 222 to 225 MHz in the ARRL band plan, only three megahertz wide, and it has a character of its own: less crowded than 2 meters, with a well-defined weak-signal segment, FM repeaters on a standard split, and a place for packet and links. This guide walks through the ARRL band plan segment by segment, explains what each part is for, and shows how the band connects with VHF contesting and moonbounce. The band plan details come from the ARRL’s published band plan page.

Where the Band Sits and Who Can Use It

The 1.25 meter band is a Region 2 allocation in the international scheme, meaning the Americas. In many other parts of the world there is no amateur allocation at 222 MHz, so the band is mainly relevant to operators in the United States, Canada and some other countries of the Americas. Always check the allocation and licence conditions of your own country. In the United States, the band is open to Technician licensees and above, according to the FCC rules, but verify the current rules if you plan to operate. The Wikipedia article on the 1.25-meter band gives the general background.

The ARRL band plan page notes that the 222 MHz band plan was adopted by the ARRL Board of Directors in July 1991, and the ARRL band plan is the reference this guide follows. Band plans are voluntary agreements, not law, but they work because most operators follow them. If you operate on a frequency that the plan reserves for repeater inputs, you may interfere with a repeater and with people you never hear.

The ARRL 1.25 Meter Band Plan

The plan divides 222 to 225 MHz into functional blocks. The table summarizes them from the lowest frequency to the highest.

The pattern is easy to remember. The bottom 150 kHz is for weak-signal work, the middle of the band is a block of FM simplex, digital and control channels, and the top is divided between repeater inputs, in the lower half, and repeater outputs, in the upper half. If you compare the FM input block (222.25 to 223.38 MHz) with the output block (223.85 to 224.98 MHz), the two are separated by 1.6 MHz, which is the standard repeater offset on this band; this follows simply from the arithmetic of the plan.

The Weak-Signal Segment

Like other VHF and UHF bands, 222 MHz keeps its lowest portion for CW and SSB. The plan marks 222.0 to 222.025 MHz for EME, 222.05 to 222.06 MHz for propagation beacons and 222.1 MHz as the SSB and CW calling frequency. Calling frequencies work the same way as on 2 meters and 70 centimeters: you call on the calling frequency, agree on a QSY frequency within the weak-signal range, and move off so that others can use the calling channel. If you are used to the layout of the 2 meter weak-signal range, the 2 meter band guide shows the equivalent segments.

Weak-signal operating on 222 MHz is usually done with horizontal polarization and a Yagi, as on 2 meters, and it benefits from the same propagation modes: tropospheric ducting, meteor scatter, aurora and sporadic-E on rare occasions. Our guide to tropospheric ducting explains the mode that carries most long-distance VHF contacts in summer and autumn. Because the band is so lightly used, a station that calls CQ on the calling frequency with a good antenna may find that nobody is listening, so most contacts are arranged in advance on a regional chat or at a scheduled time.

FM Repeaters and Simplex

The FM portion of the band is where most casual operators will find activity. Repeater inputs sit between 222.25 and 223.38 MHz, and outputs between 223.85 and 224.98 MHz, with the 1.6 MHz offset between them. FM simplex lives between 223.40 and 223.52 MHz, and the segment from 223.71 to 223.85 MHz is left to the local frequency coordinator, who can decide whether it hosts simplex, packet or repeater outputs. Because of the local option segments, always check with your regional coordinator or your local club before programming a radio.

Operating on a 222 MHz repeater is just like operating on a 2 meter or 70 centimeter repeater. You need the output frequency, the offset direction and the CTCSS tone, if used. Our guides to VHF and UHF simplex and repeater operating and to CTCSS tones explain the programming steps. Radios that cover this band are less common than 2 meter and 70 centimeter radios, so be sure that your radio covers 222 to 225 MHz before you rely on it.

Digital, Packet and Links

The plan sets aside 223.52 to 223.64 MHz for digital and packet use, and 223.64 to 223.70 MHz for links and control. Packet activity is much lower than in the past, and many of these frequencies are now used for experiments or for point-to-point data links. Links and control channels are used to connect repeaters and to control remote bases, so they should be treated with special care. Do not transmit on a link frequency unless you are the coordinator’s assigned user.

The 222 MHz and Up Distance Contest

The band has its own contest. The ARRL’s 222 MHz and Up Distance Contest takes place on the first full weekend of August; the page lists August 1-2, 2026. It begins at 1800 UTC Saturday and ends at 1759 UTC Sunday. The objective is to work as many stations as possible on the 222 MHz through 241 GHz bands using any allowable mode. A station in a specific grid locator may be contacted from the same location only once on each band, regardless of mode, so the contest rewards variety of grids and bands rather than repeat contacts with the same station.

Logs are due within fourteen days after the event and must be submitted in Cabrillo format through the ARRL’s web app. Certificates are awarded for top single-operator fixed, multi-operator fixed, rover, club, small team and large team scores in each of the 18 contest regions. The regions are based on groups of US states and Canadian provinces, with region 18 covering DX, Alaska, Hawaii, US possessions and maritime mobile. If you want to take part in the wider VHF contest calendar, our guide to the ARRL VHF contests explains how the January, June and September events are scored by grid squares.

Compared With 2 Meters and 70 Centimeters

The three VHF and UHF bands have a similar structure, which is why the 222 MHz band feels familiar to anyone who has used the others. On 2 meters, the ARRL plan lists EME at 144.00 to 144.05 MHz, a national calling frequency at 144.200 MHz and the national simplex calling frequency at 146.52 MHz. On 70 centimeters, EME is at 432.00 to 432.07 MHz, the calling frequency is 432.100 MHz and the national simplex frequency is 446.00 MHz. On 222 MHz the weak-signal calling frequency is 222.100 MHz. The main differences are practical: far fewer stations and fewer commercial radios on 222 MHz, and a smaller band that fills up quickly in a contest weekend.

The antennas are small and cheap, and a home-built design is a very good first project. A quarter-wave on this band is about 33 centimeters, so even a simple ground plane or a short Yagi is easy to build. For a general introduction to antennas at this size, our article on 2 meter antenna options describes designs that you can scale to 222 MHz by using the shorter wavelength.

Equipment and Station Notes

Equipment is the main hurdle on this band, because the choice is smaller than for 2 meters or 70 centimeters. Some FM mobile radios and a few multimode transceivers cover 222 to 225 MHz, and many operators who are active on the band use a transverter with an HF or 2 meter radio for weak-signal work. A transverter converts between the 222 MHz band and an intermediate frequency in the radio you already own, which lets you reuse its SSB and CW modes. Check the specification of any used radio before you buy; our checklist for buying used ham radio equipment applies here.

Feedline loss matters more at VHF than at HF. At 222 MHz a long run of thin coaxial cable can waste a large part of your power, which is why VHF operators use low-loss cable and keep the run as short as practical. A mast-mounted preamplifier can help a weak-signal station, but only if the feedline loss is large and the receiver is the limiting factor. Antenna height also counts more than power: raising a small Yagi above nearby obstacles often gives a bigger improvement than any amplifier.

Polarization is a simple but important choice. FM repeaters and simplex use vertical polarization, so a vertical antenna such as a ground plane or collinear is the usual choice there. Weak-signal operation on SSB and CW uses horizontal polarization, so a horizontal Yagi is the standard. If you want to do both, some operators install two antennas on the same mast and use a coaxial switch. Whatever you choose, keep the ARRL band plan in mind so that you are using the right antenna for the right part of the band.

Operating Tips for a Quiet Band

• Announce yourself. Because there are so few stations, call on the calling frequency at a time that you have announced on a local chat group or a club net.
• Use schedules. Arrange regular contacts with a friend. Many operators find that regular skeds keep the band alive.
• Take part in contests. The VHF contests and the August 222 and Up weekend bring stations out who are otherwise silent.
• Listen for beacons. The 222.05 to 222.06 MHz propagation beacon segment is a good place to check whether a path is open.
• Ask the coordinator. Local option segments differ between regions, so ask before setting up a net or a repeater.

Getting Started on 222 MHz

1. Check that your licence and country allow operation on 222 to 225 MHz, and read the current rules rather than relying on an older article or a friend’s memory.
2. Find out which repeaters and simplex channels are in use in your area by asking your local club or frequency coordinator.
3. Choose a radio that covers the band. Some multiband mobile radios do, many do not.
4. Build or buy a simple antenna, and check the SWR before transmitting.
5. Listen on 222.100 MHz and the simplex block, and set up a time with a friend to try a first SSB or FM contact.

The Bottom Line

The 222 MHz band is a small and quiet corner of VHF with a clear structure: weak-signal and EME at the bottom, FM repeaters with a 1.6 MHz split at the top, and simplex, digital and control channels in the middle. It rewards operators who like to build antennas and experiment, and it has its own August contest. Follow the ARRL band plan, check your regional coordination before choosing a frequency, and make sure your radio and licence cover the band before you plan your first contact.

Frequently Asked Questions

What frequencies does the 222 MHz band cover?

The ARRL band plan covers 222 to 225 MHz, also known as the 1.25 meter band.

Where is the weak-signal calling frequency?

The SSB and CW calling frequency in the ARRL band plan is 222.100 MHz, with weak-signal CW and SSB in 222.10 to 222.15 MHz.

What is the repeater offset?

The plan places repeater inputs at 222.25 to 223.38 MHz and outputs at 223.85 to 224.98 MHz, which is a separation of 1.6 MHz.

Is the band available worldwide?

No. It is an allocation in Region 2, so it is mainly available in the Americas. Check your own country’s rules.

When is the 222 MHz and Up Distance Contest?

On the first full weekend of August, from 1800 UTC Saturday to 1759 UTC Sunday. The ARRL page listed August 1-2 for 2026.

Can I use FM simplex on 222 MHz?

Yes. The plan sets aside 223.40 to 223.52 MHz for FM simplex, plus a local option segment from 223.71 to 223.85 MHz.

For the last few years HF operators have enjoyed some of the best conditions in a generation, with 10 and 12 meters open for long stretches and 6 meters waking up far from the usual season. That raises an obvious question: where are we now in Solar Cycle 25, and how fast will the good conditions fade? This guide answers it with real numbers. It uses the NOAA Space Weather Prediction Center (SWPC) pages and its published observed and predicted cycle data, as available on 27 October 2026, and translates them into practical advice for amateur radio. The short version: the maximum has passed, activity is declining, and the decline will be gradual enough that the higher HF bands will still produce good days for a while.

What the Solar Cycle Is and Why Hams Track It

The Sun’s activity rises and falls in a cycle of roughly 11 years. The NOAA SWPC Solar Cycle Progression page shows the observed and predicted cycle in two forms: the sunspot number, and the F10.7 cm radio flux. Both numbers matter to radio amateurs. Sunspot number is a count of spots and groups on the solar disc. F10.7 is the radio noise from the Sun measured at a wavelength of 10.7 cm, in solar flux units, and it is closely related to the ionization of the upper atmosphere that supports HF propagation. Higher flux generally means a more strongly ionized F layer and better support for the higher HF frequencies. Our guide to solar flux, A-index and K-index explains how to read the daily numbers.

The cycle matters for planning, not just for curiosity. If you know that conditions will decline over the next years, you can decide when to chase DXCC entities on 10 and 12 meters, when to invest in low-band antennas, and what to expect from contests. The SWPC page itself says that the prediction gives a rough idea of the frequency of space weather storms of all types, from radio blackouts to geomagnetic storms to radiation storms, and is used by industries to gauge the expected impact in the coming years.

The Cycle 25 Record So Far

SWPC publishes the observed cycle indices as a data file. The values below come from that file and show the yearly averages of the monthly mean sunspot number for the years around the peak. The 2026 value covers January to September only.

A few more details from the same file. The smoothed sunspot number was only 1.8 in December 2019, which marks the minimum between Cycles 24 and 25. The highest monthly mean sunspot number of the cycle so far was 216.0 in August 2024, and the highest smoothed value was 160.9 in October 2024. The highest monthly F10.7 was 245.6 in August 2024, and the highest smoothed F10.7 was 194.5 in October 2024. The latest complete month in the file is September 2026, with a monthly sunspot number of 60.3 and F10.7 of 105.41. These are real observed values, but remember that the smoothed numbers need several months of data after a given month, so the most recent months have no smoothed value yet.

How the Forecasts Compared

The SWPC page describes two predictions. The first came from a NOAA, NASA and ISES panel convened in 2019, which received nearly 50 distinct forecasts from the scientific community and synthesized them. It predicted a maximum of 115 in July 2025, with error bars of 105 to 125 and a peak between November 2024 and March 2026. The second is an updated prediction that SWPC describes as a re-calibration based on new observations; it was made available as an experimental product in October 2023 and replaced the panel prediction on the website in February 2025. The panel prediction can still be displayed from a drop-down menu.

The observed numbers show how much the cycle exceeded the 2019 forecast. The smoothed maximum in the data file was 160.9, far above 115, and it occurred in October 2024, within the window the panel allowed for the timing but not for the size. That is a useful lesson for anyone who relied on early forecasts: cycle predictions can be wrong by a large margin, especially in amplitude, and the right approach is to follow the observations and the monthly updates.

What the Current Forecast Says

The SWPC predicted cycle file, which begins in April 2026, gives a monthly value for the smoothed sunspot number and F10.7, together with bands of uncertainty. Sampling it each October gives a clear picture of the decline:

• October 2026: predicted smoothed sunspot number 87.9 and F10.7 125.9.
• October 2027: 65.9 and F10.7 103.8.
• October 2028: 38.7 and F10.7 85.1.
• October 2029: 20.2 and F10.7 75.3.
• October 2030: 9.3 and F10.7 70.8.

The SWPC page also notes that Solar Cycle 26 is expected to begin some time between January 2029 and December 2032, and that SWPC does not yet produce a prediction for it. The shaded regions on the page show uncertainty derived from earlier cycles: there is roughly a 25% chance that the smoothed sunspot number will fall within the darkest shaded region at a given time, a 50% chance for the medium region and a 75% chance for the lightest. In other words, the numbers above are central estimates and not promises.

What It Means for the HF Bands

Treat the following as rules of thumb, not guarantees. When the daily solar flux is high, the F2 layer supports higher frequencies, so 10, 12 and 15 meters open widely. As the flux falls toward 100 and below, the highest bands open less often and for shorter periods, and the center of activity shifts down to 20 and 17 meters. Around solar minimum, 20 meters still opens, while 15 and 10 meters can be nearly dead for days. The forecast above suggests a smooth slide: by late 2027 the predicted F10.7 is around 104, which is still capable of good 15 and 17 meter days, but by 2029 it is near 75, a value typical of quiet years.

• 10 and 12 meters: expect fewer and shorter openings each year. Our 10 meter band guide describes how to catch what remains.
• 15 and 17 meters: still the best daytime DX bands for several more years; see our 15 meter guide.
• 20 meters: the stable workhorse through the decline.
• 40, 80 and 160 meters: the low bands are often said to improve at solar minimum because daytime absorption falls, so keep your low-band antennas in good shape.
• 6 meters: sporadic-E openings do not follow the solar cycle in the same way, so summer openings will continue, but F2 openings on 6 meters will become rare.

Why Declining Does Not Mean Dead

A declining cycle still has strong days. Solar activity is noisy: a single large active region can lift flux for a week even when the monthly average is falling, which is why the data file shows a jump to 101.8 in May 2026 after 79.0 in April. Looking only at the trend line loses those opportunities. For planning, use the daily solar flux and a tool such as VOACAP, which takes the smoothed sunspot number as an input to predict which bands will be open on a given path and hour.

The decline also brings a different kind of risk: geomagnetic storms and flares continue throughout the declining phase of a cycle, and radio blackouts can still interrupt HF contacts. Our guide to HF propagation explains how the main drivers of HF conditions work.

Why Smoothed Numbers Lag Behind

When you look at cycle charts you will see two kinds of values: the monthly mean and the smoothed value. A smoothed value is an average that runs across many months around the date in question, so it cannot be computed for a month until the following months have been observed. That is why the latest months in the SWPC file carry a placeholder instead of a smoothed value, and why the peak of a cycle can only be named with confidence long after it has happened. The monthly values are noisier, but they are available at once and show real swings. In the file, for instance, the monthly sunspot number fell from 114.8 in October 2025 to 91.7 in November, then rose to 124.2 in December 2025, while the smoothed number moved slowly the whole time.

For daily operating decisions neither of these numbers is the right tool. The monthly and smoothed values describe the trend. The daily flux and the geomagnetic indices describe what is happening today, and the ionosphere responds to the day’s numbers within hours. A practical habit is to use the trend for your annual plan and the daily values for your weekend.

Planning Contests and DX Chasing During the Decline

A declining cycle changes the way experienced operators plan. Contests that were dominated by 10 meters in 2024 will increasingly be decided on 15 and 20 meters, and the multipliers on the highest bands become more valuable because fewer stations can work them. If you chase DXCC entities, the sensible approach is to use the remaining high-band openings on the countries that are hardest to hear on 20 meters, and leave the easy entities for later. Our guide to long path DX shows another way to find openings when the direct path is closed.

It is also a good moment to look at your station as a whole. High bands are forgiving, because a modest antenna and low power can still reach far when the F2 layer is strongly ionized. As activity falls, antenna gain and height count for more on every band. Improving the low-band antennas and receive systems pays off over a longer period than any single season of good conditions.

Finally, keep your expectations realistic about forecasts. The forecast values in this article are SWPC’s central estimates from its published file. The uncertainty shown on the page grows with time, and the actual numbers will differ. When the next month’s data arrive, the forecast moves, and this article’s figures will be out of date. That is the nature of the cycle, and part of the pleasure of following it.

How to Follow the Cycle Yourself

1. Visit the SWPC Solar Cycle Progression page once a month to see the new data points and how they compare with the prediction. The page says the prediction is updated every month as more observations become available.
2. Check the daily flux and A and K indices before an operating session or contest, since they tell you today’s conditions rather than the long-term trend.
3. Keep a short log of which bands opened to which regions. After a year you will have your own record that is more useful than any average.
4. Use the Wikipedia article on Solar Cycle 25 for the background story of how the cycle compared with earlier ones.

The Bottom Line

Solar Cycle 25 peaked in 2024, well above the 2019 panel forecast, and has been declining since. Yearly average sunspot numbers fell from 154.5 in 2024 to 123.5 in 2025 and 85.3 so far in 2026, and NOAA’s current forecast takes the smoothed sunspot number from about 88 this month to about 66 in October 2027 and below 10 by October 2030. Use the high bands while they last, keep an eye on daily flux, and prepare your low-band antennas for the years when the upper bands go quiet.

Frequently Asked Questions

Has Solar Cycle 25 peaked?

In the SWPC data the highest smoothed sunspot number was 160.9 in October 2024, and activity has declined since. Smoothed values for the most recent months are not available yet.

What is F10.7?

F10.7 is the radio flux from the Sun at a wavelength of 10.7 cm, measured in solar flux units, and it is a standard indicator for HF propagation conditions.

How good was the original forecast?

The 2019 panel predicted a maximum of 115 in July 2025. The observed smoothed maximum was 160.9 in October 2024, so the cycle was stronger and earlier than that forecast.

When will Cycle 26 start?

SWPC says Solar Cycle 26 is expected to begin some time between January 2029 and December 2032 and does not yet produce a prediction for it.

Will 10 meters still open in 2027?

Yes, on good days. The forecast F10.7 in October 2027 is about 104, so openings will be less frequent but not gone.

Where do I find the data?

On the NOAA SWPC Solar Cycle Progression page, which also links to the observed and predicted data files.

Some on-air events are about points, multipliers and rate. Kids Day is about something simpler: giving a child a microphone, a friendly voice on the other end, and the thrill of hearing a stranger in another state say their name back. The ARRL runs it twice a year as an event designed to promote amateur radio to young people. This guide explains what the ARRL says about the event: when it takes place, how long it lasts, what to say during a contact, which frequencies the ARRL suggests, and how to plan a session so that the children enjoy it and the adults enjoy helping. Always check the ARRL page for the current details, since this event has no scoring and few formalities, but dates and notes can change.

What Kids Day Is for

According to the ARRL Kids Day page, the event is offered twice a year to promote amateur radio to young people. You are invited to share the excitement with your kids or grandkids, a Scout troop, a church group or the general public. The goal is to give young people on-the-air experience and hopefully foster interest in getting a license of their own. It is also intended to give older hams a chance to share their station and their love for the hobby with the next generation.

That focus shapes everything else. The page describes no scoring system and no contest-style log deadline, and there is no penalty for operating for ten minutes or for five hours. The ARRL’s wording is that you operate as much or as little as you like. If you have been looking for a low-pressure way to bring a child to the radio, this is the easiest entry point on the calendar. For general background on the hobby itself, the Wikipedia article on amateur radio is a good starting point for parents. Our guide to introducing children to amateur radio offers activities for before and after the event.

Dates and Times

The page says Kids Day is generally held on the first Saturday in January and the third Saturday in June, and that current dates are listed in the ARRL contest calendar. By that rule the next January event would fall on January 2, 2027 and the June event on June 19, 2027, but confirm both on the calendar before you announce anything. The event always runs from 1800 UTC through 2359 UTC, which is six hours. Convert that to local time for your area and remember that the UTC date can differ from your local date in the evening.

A fixed six-hour window works well for children. You can run a morning or lunchtime session if the UTC window falls in your daytime, you can take breaks for food, and you can plan a short time for each child instead of a long vigil at the radio. In the Americas, the UTC window falls during the afternoon and evening. In Europe it falls in the evening and night, so parents and organizers in Europe should plan accordingly, or run an earlier local demonstration and listen for stations later.

The Exchange: Name, Age, Location and Favorite Color

The suggested exchange is deliberately simple: name, age, location and favorite color. It is easy for a child to remember and it gives the other operator something to say. The page also says to be sure to work the same station again if an operator has changed. In other words, when a different child sits in front of the microphone, call the same friendly station again so that each child gets a contact. To draw attention, call “CQ Kids Day”. A typical contact might sound like this:

1. The child calls: “CQ Kids Day, CQ Kids Day, this is [callsign].”
2. The answering operator gives the callsign and says: “Hello, my name is John, I am 62, I am in Texas and my favorite color is green.”
3. The child answers with name, age, location and favorite color, and the two sign off with thanks and the callsigns.

The experienced operator should slow down, speak clearly and avoid jargon. The child may read the exchange from a card, and a pause is fine. It helps to review the phonetic alphabet before the event so the child can spell a callsign or a town name; our guide to the ham radio phonetic alphabet includes the standard words.

Suggested Frequencies

The ARRL suggests these frequency ranges so participants can find each other. Using them is not mandatory, but sticking to them keeps the event concentrated where people are listening.

You can also use your favorite repeater, with the permission of the repeater’s sponsor. The ARRL also reminds participants to observe third-party restrictions when making DX QSOs. That is important if a child is speaking to a station in another country: not every country allows third-party communications, so check the rules before you let a child talk to an overseas station. If you are unsure which sideband to use on these bands, our guide on USB versus LSB gives the usual convention.

Planning a Station for Young Operators

The best Kids Day stations are simple. A radio that the child can understand, a microphone within easy reach, a comfortable chair and a clear card with the exchange are more important than a big signal. The ARRL page gives a good example of a successful local event in an account from an Indianapolis Red Cross disaster radio group: they began setup and testing early in the week before, held a code-practice area so children and parents could see Morse code, gave each child a log sheet, and ran five stations, one each on 10, 15 and 20 meters and two on 2 meters. Twenty-four kids made 58 contacts. The page also mentions a station in Hawaii that made 125 contacts one January.

From those examples, a few good habits follow:

• Test everything beforehand. Set up the antenna and radio the week before, and make a test contact so you know the band you plan to use is open.
• Prepare a log sheet for each child. Seeing their own callsign and a list of contacts gives the child something to keep.
• Have more than one position. One station for HF and one for VHF means that waiting children can still do something.
• Keep the licensed control operator close. In most countries an unlicensed child may speak over the radio under the supervision of a licensed operator; check the rules where you live and ask your national society if you are unsure.
• Have a plan for noise and propagation. If a band is closed, move to another or switch to a VHF simplex contact with a nearby ham.

If your radio club is looking for a venue, ask about libraries, community centres and Scout halls. The page suggests sharing the excitement with a Scout troop, and our guide to Jamboree on the Air explains another event that connects scouting and radio.

Making the First Contact Easy

Children often feel nervous when the radio crackles and a stranger answers. A few steps make the first contact smoother. Let the child listen for a few minutes first, and show how the waterfall or the dial moves. Practice the exchange aloud with a parent or an older ham before going on the air. Explain that the person on the other end has volunteered to be there and is excited to hear from them. Keep the microphone technique simple: press the push-to-talk, speak after a short pause, and let go to listen. A few simple instructions beat a long lecture. Our first QSO guide shows what a basic contact sounds like, and it applies to children and adults alike.

Experienced operators who want to help can do so without a station of their own. Listen on the suggested frequencies during the event, answer any call that sounds like a child, and play along with the exchange. If you hear a child struggling, slow down and give them time. The page asks that you work the same station again if the operator has changed, which means a single friendly operator can give several children a contact in one session.

Kids Day for Clubs and Schools

A radio club can turn Kids Day into a small public event. Choose a location where parents and children can walk in, such as a library room or a club shack with open doors, and display a simple poster that explains what is happening. Put one volunteer at the door to welcome visitors, one at the radio to help with the exchange, and one at a table with log sheets, coloring pages or a Morse code practice area. The Indianapolis account on the ARRL page shows the value of that structure: children and parents moved between stations at their own pace, and the club members had time to explain what they were doing.

Think about the day as a demonstration that leaves something behind. A card with the club’s meeting time, a short list of websites about getting a license, and a printed certificate of participation give families a reason to follow up. Many hams remember a single contact from childhood as the start of their interest, and a friendly invitation to the next club meeting can turn a one-day event into a lasting connection.

Using VHF and Repeaters

If propagation is poor on HF, a VHF station provides a back-up. The ARRL page allows the use of a favorite repeater with the permission of the repeater’s sponsor, so a local net can help children make contacts even when the HF bands are closed. Ask the repeater owner in advance, announce the session on the club net, and keep the traffic short so that others can use the repeater. Local contacts are also the best way to let a very young child practice, because the signal is strong and the other operator is nearby if help is needed.

Reporting, Photos and Certificates

The ARRL encourages all participants to post their story and thumbnail photos on the Kids Day Soapbox page and to tell the world who they talked to. It also invites high-resolution photos, 500 KB to 3 MB, of youth in action, such as operating, setting up antennas and having fun, sent by email to contests@arrl.org. The ARRL notes that it must have a release form for photos of anyone younger than 18 before the pictures can be used in publications such as QST. All participants are eligible for a colorful certificate of participation that can be downloaded and completed with the participant’s name and the date of the contact. There is also a short survey asking for the number of participants by age group and the number of contacts.

Common Mistakes to Avoid

• Making the session too long. Short turns keep children interested.
• Using jargon such as Q codes and abbreviations with a child. Plain language works best.
• Forgetting to ask about third-party rules before a child speaks to a DX station.
• Forgetting a photo release form for children under 18 if you plan to send photos to the ARRL.
• Choosing a band that is closed at that hour, so the radio is silent. Check propagation first.

The Bottom Line

Kids Day is a six-hour ARRL event held generally on the first Saturday in January and the third Saturday in June, built around a simple exchange of name, age, location and favorite color. There is no scoring, only the experience of the first contact. Prepare a simple station, test it, use the suggested frequencies, keep a licensed operator nearby, and give each child their own short turn. If you are an experienced ham without a child to host, answer the calls you hear: your friendly voice could be the reason someone becomes a ham.

Frequently Asked Questions

When is Kids Day?

Generally the first Saturday in January and the third Saturday in June. It always runs from 1800 UTC through 2359 UTC, and the ARRL contest calendar lists the current dates.

What is the Kids Day exchange?

The suggested exchange is name, age, location and favorite color. Call “CQ Kids Day” to attract attention.

Does the child need a license?

The ARRL page is about giving young people on-the-air experience. Rules for unlicensed participants differ by country, so a licensed control operator should be present and local regulations must be followed.

Which frequencies are suggested?

For example 28.350 to 28.400 MHz on 10 meters, 14.270 to 14.300 MHz on 20 meters and 7.270 to 7.290 MHz on 40 meters. You can also use a repeater with the sponsor’s permission.

Is there a score or a prize?

The ARRL page describes no scoring. All participants can download a certificate of participation.

Can I talk to stations in other countries?

The ARRL asks participants to observe third-party restrictions when making DX QSOs, so check the rules for the country involved first.

Most contest talk is about CW and SSB, but one weekend a year belongs to the computer modes. The ARRL Digital Contest, formally the ARRL International Digital Contest, invites amateurs worldwide to exchange four-digit grid squares using any digital mode except RTTY, which in practice means FT8 and FT4 for nearly everyone. This guide summarizes the official ARRL page and the WSJT-X documentation: when the contest runs, who can work whom, what counts as legal operation, how the unusual off-time rule works, which sub-bands the ARRL recommends, and how to set up your software so that the exchange is generated for you.

What the Contest Is

According to the ARRL contest page, the objective is for amateurs worldwide to contact and exchange QSO information with other amateurs using any digital mode, excluding RTTY, that supports the four-digit grid square exchange. Operation must be attended. The bands are 160, 80, 40, 20, 15, 10 and 6 meters, and any station may work any other station. In the US, Technician licensees are limited by FCC rules to the 10 and 6 meter bands. Each station may be worked once per band, regardless of mode.

Notice what is missing: there is no separate score for each mode, because one contact per band is all you get. That keeps the contest simple, and it places the emphasis on activity and on covering as many bands as possible. The exchange itself is the grid square, so if you are unsure what that means, our guide to grid squares and the Maidenhead locator system is a good starting point, and the Wikipedia article on the Maidenhead Locator System gives the background.

Dates and Contest Period

The contest runs on the first full weekend of June. It begins at 1800 UTC on Saturday and ends at 2359 UTC on Sunday, a period of 30 hours. The ARRL page links to the contest calendar for the exact dates each year. The rules are maintained as a single downloadable document, the complete ARRL International Digital Contest rules in PDF form, which also contains the scoring rules; read it before your first contest, because this article does not reproduce the scoring formula.

Attended Operation Only

The most important rule for FT8 operators is that automated operation is not permitted. Each claimed contact must include contemporaneous direct initiation by the operator on both sides of the contact. In plain language, you must be at the keyboard and you must start your own contact. Letting software call CQ and work stations unattended does not count. WSJT-X is designed with this in mind, because its documentation says that auto-sequencing is an operator aid and not an operator replacement, and that the program will not make consecutive, fully automated QSOs.

The same principle is the reason for caution with any scripts or helper programs. If the program replies to a station without you pressing a button or choosing a message, ask yourself whether that is direct initiation. When in doubt, follow the rules in the PDF and the intent behind them: both operators are actively making the contact.

The Unusual Off-Time Rule

The contest period is 30 hours, but a single-operator station may operate only 24 of them. Multi-operator stations may operate all 30. After the first QSO, up to 6 hours of off time may be taken in one or two breaks before the final QSO is logged. Each off time must be at least 60 minutes long. The log-checking software counts the two longest breaks in your log and uses those as your two off times; additional breaks and breaks shorter than 60 minutes are ignored. The time before your first QSO and after your last QSO does not count as off time.

The log is then checked and scored over the first 24 hours of operating time. You may keep operating after that without penalty, and those QSOs still count for the other operators, so the ARRL asks you not to delete any QSOs after the 24-hour limit. The intent of the two-break rule is to add a strategic element: you cannot take many short breaks, so you have to decide based on local propagation and sleep.

The first three rows are examples taken from the ARRL’s own list of plans that satisfy the rules. If you have never planned rest for a long event, our guide to rest and time management in 24 and 48 hour contests offers a routine that suits these windows.

FT8 and FT4 Sub-bands Recommended by the ARRL

The page lists recommended sub-bands for FT4 and FT8, as of June 2022. Technician licensees in the US are limited to the 10 and 6 meter sub-bands. The recommendations are:

• FT4 (MHz): 1.836-1.840 (avoid WSPR operation on 1.840), 3.580-3.590, 7.080-7.090, 14.080-14.090, 21.080-21.090, 28.080-28.090 and 50.330-50.340.
• FT8 (MHz): 1.840-1.844 (avoid WSPR on 1.840), 3.590-3.600 (no digital above 3600), 7.090-7.100, 14.090-14.100, 21.090-21.100, 28.090-28.100 and 50.340-50.350.

The advice for choosing a frequency is practical. Set the radio dial at the bottom of the sub-band and run your QSOs on audio frequencies within the radio passband, typically 2.5 to 4 kHz wide. If a sub-band becomes crowded, move the dial up in 2 kHz increments, for example 7.080, 7.082, 7.084, 7.086 and 7.088 MHz for FT4. This keeps everyone in the same place so stations can find each other, instead of spreading across the band.

Setting Up WSJT-X for the Contest

WSJT-X handles the exchange for you. The User Guide says that FT4, FT8 and MSK144 support special messages for NA VHF and EU VHF contests, and that FT4 and FT8 also support messages for ARRL Field Day, FT Roundup, WW Digi and the ARRL International Digital Contest. The decoders recognize and decode these messages at any time. To have the program generate the correct messages and do the matching auto-sequencing, select a supported operating activity on the File | Settings | Advanced tab.

The model QSO for the NA VHF Contest and the ARRL International Digital Contest looks like this:

1. CQ TEST K1ABC FN42
2. K1ABC W9XYZ EN37
3. W9XYZ K1ABC R FN42
4. K1ABC W9XYZ RRR
5. W9XYZ K1ABC 73

Either callsign may have /R appended to indicate a rover in a VHF contest. You can use RR73 in place of RRR, and the final 73 is optional. Every message carries only the callsigns and the grid squares, so a contact is quick. Contest messages are not supported for compound callsigns, which is explained in our guide to nonstandard callsigns in WSJT-X, so if you operate with a prefix or suffix, check how your messages are generated before the contest starts.

Before any contest, make sure the computer clock is accurate and your audio levels are right. Our guide on FT8 time sync covers the clock, and keeping ALC action off your transmit audio is part of good practice.

What a Typical Hour Looks Like

An hour in this contest is quieter than an hour in an SSB contest, and it is easy to underestimate how much work it still takes. You select a band, set the dial to the bottom of the recommended sub-band, and watch the decodes scroll in 15-second periods for FT8 or 7.5-second periods for FT4. Each time you see a station you have not worked on this band, you double-click the decode and the program starts the exchange. A complete contact has about five messages, so with FT8 you can finish roughly one contact per minute, but only if both stations answer promptly and no one else is transmitting on top.

That rhythm explains why the FT4 recommendation exists. FT4 uses 7.5-second sequences and, as the WSJT-X guide says, is especially well suited to radio contesting, so contacts are about twice as fast when the band is quiet. FT8 has more stations on the air and is more sensitive by a few decibels, which helps when conditions are poor. Many operators begin the contest on FT8 for the larger audience and switch to FT4 on a band that has a good number of active stations. Because a station can only be worked once per band regardless of mode, there is no point in working the same call on both modes on the same band.

Station Requirements and Common Problems

You do not need a large station. The modes were built for weak signals, so a modest antenna can bring in many contacts, but there are a few details that decide whether the weekend is pleasant:

• Clock accuracy: a clock that is more than a second or so off means your decodes shrink to almost nothing. Sync before the contest and recheck during it.
• Transmit audio: keep the level low enough that your radio shows no ALC action, because a distorted signal splatters across the narrow sub-band and annoys neighbours.
• Power: awards separate QRP and Low Power, so running high power is not the only way to win an award. Check the PDF rules for the exact power levels and categories.
• Computer load: logging, decoding and a browser on the same machine can slow the decoder. Close what you do not need.
• Dupes: WSJT-X helps you avoid working the same station twice on a band when you use its filter and wait features, but the final check is your own logging program.

Another common problem is not being in the log of the other station. The WSJT-X guide points out that contest QSOs are generally treated as invalid when they appear in one station’s log and not the supposed partner’s, so a contact that you think is complete but the other station never confirmed may be lost. A sensible habit is to wait for the final RRR or RR73 before you start calling someone else.

Logs, Deadlines and Awards

Logs are due within seven days after the end of the event. They must be submitted online, in Cabrillo format, through the ARRL web app at contest-log-submission.arrl.org; paper logs are not accepted. If your software does not export Cabrillo, the ARRL page points to a conversion tool at b4h.net/cabforms where you enter your log data and receive a Cabrillo file. Our guide to Cabrillo logs and the UBN process explains what the checker looks for.

Certificates are awarded to the top QRP and Low Power single-operator scorers, and to the top QRP and Low Power multi-single scorers, in each ARRL/RAC section and each DXCC country other than W and VE. Plaques, if sponsored, are awarded to the top QRP and Low Power entrants in each category overall, in each ARRL division, in Canada and in each DXCC country other than W/VE. The International Digital Contest is also one of the ten ARRL contests designated as Affiliated Club Competition events, so your club can combine members’ scores. Questions go to contests@arrl.org.

Strategy for a First Entry

• Pick a band plan before the start. A 20 meter and 40 meter combination with a switch to 15 or 10 meters when open is a safe base. Remember that 6 meters is part of this contest and can open suddenly in June.
• Use the two-break rule. Plan your sleep for the hours when the bands are weakest where you live, and schedule the two longest breaks there.
• Work every band you can. A station is worth one contact per band, so changing band is often better than calling the same stations again.
• Be present. Because automated operation is not allowed, steady attended operation is what the contest rewards.
• Check your category. Our article on contest categories explains QRP and Low Power, which matter for awards here.

The Bottom Line

The ARRL International Digital Contest is a 30-hour June weekend for FT8, FT4 and other grid-exchanging digital modes, with attended operation only, one contact per band per station, and a two-break off-time rule that limits single operators to 24 hours. Follow the ARRL’s recommended FT4 and FT8 sub-bands, let WSJT-X generate the contest messages from the Advanced settings, submit a Cabrillo log within seven days, and read the rules PDF for scoring. It is a good first contest for anyone who already enjoys digital modes.

Frequently Asked Questions

When is the ARRL Digital Contest held?

On the first full weekend of June, from 1800 UTC Saturday to 2359 UTC Sunday.

Which modes are allowed?

Any digital mode except RTTY that supports the four-digit grid square exchange, such as FT8 and FT4.

Can I let my software run unattended?

No. Automated operation is not permitted; each claimed contact needs contemporaneous direct initiation by the operator on both sides.

How many hours can I operate?

A single operator may operate 24 of the 30 hours, with up to 6 hours of off time in one or two breaks of at least 60 minutes each. Multi-operator stations may operate all 30 hours.

How do I submit my log?

Upload a Cabrillo file through the ARRL web app within seven days after the contest ends. Paper logs are not accepted.

Which bands are used?

160, 80, 40, 20, 15, 10 and 6 meters. US Technician licensees are limited to 10 and 6 meters by FCC rules.

Sooner or later every FT8 operator sees a decode with angle brackets, such as <PJ4/K1ABC> or a mysterious <…>, and wonders what is going on. The answer lies in how WSJT-X compresses messages, and in what happens when a callsign does not fit the compact pattern. This guide explains nonstandard callsigns: what counts as standard, how compound callsigns such as PJ4/K1ABC and special event calls such as YW18FIFA are handled in FT8, FT4, FST4, MSK144 and Q65, what the angle brackets mean, and what you give up when you use one. All details come from the WSJT-X 3.0 User Guide.

Why FT8 Cares About the Shape of a Callsign

The WSJT-X User Guide explains that all QSO modes use structured messages that compress human-readable information into fixed-length packets. A standard message consists of two 28-bit fields normally used for callsigns, and a 15-bit field for a grid locator, report, acknowledgment or 73. In the modes with 77-bit payloads (FST4, FT4, FT8, Q65 and MSK144) the five extra bits flag special message types for nonstandard callsigns, contest exchanges, FT8 DXpedition mode and a few other possibilities.

The arithmetic is worth seeing, because it shows why some callsigns do not fit. A standard amateur callsign has a one- or two-character prefix, at least one of which must be a letter, followed by a digit and a suffix of one to three letters. Within those rules the number of possible callsigns is 37 x 36 x 10 x 27 x 27 x 27, or somewhat over 262 million. Since 2 to the power 28 is more than 268 million, 28 bits are enough to encode any standard callsign uniquely. Similarly, there are 180 x 180 = 32,400 four-digit Maidenhead grid locators, fewer than 2 to the power 15 (32,768), so a locator needs 15 bits. Anything that does not follow the pattern, such as a call with a country prefix in front or a long suffix, needs a different treatment. Our guide to callsign prefixes shows how varied real callsigns are, and the Wikipedia overview of amateur radio call signs explains the international prefix system that standard patterns are built on.

What Counts as Nonstandard

For the 77-bit modes the guide says that compound callsigns, such as PJ4/K1ABC or K1ABC/3, and special event callsigns, such as YW18FIFA, are supported for normal QSOs but not for contest-style messages. Compound and nonstandard callsigns are recognized and handled automatically by special message types. Most operators never think about it, because WSJT-X generates the right messages by itself. The knowledge matters when something looks odd on the screen or when you plan to operate from abroad or under an unusual call.

The rules for these messages are specific:

• One nonstandard callsign and one standard callsign may appear in most messages, provided that one of them is enclosed in angle brackets.
• If the message includes a grid locator or a numerical signal report, the brackets must enclose the compound or nonstandard callsign. Otherwise the brackets may be around either call.
• Angle brackets mean that the enclosed callsign is not transmitted in full but as a hash code using fewer bits.
• A receiving station displays the full nonstandard callsign if it has been received in full recently. Otherwise it shows the placeholder < . . . >.

These restrictions are honored automatically by the algorithm that generates default messages for minimal QSOs. If you click on decodes and let auto-sequencing do its work, you will not break them.

A Model QSO With a Compound Callsign

The guide gives a model contact between a station operating as PJ4/K1ABC and a station W9XYZ. In the order the messages are sent:

1. CQ PJ4/K1ABC
2. <PJ4/K1ABC> W9XYZ
3. W9XYZ <PJ4/K1ABC> +03
4. <PJ4/K1ABC> W9XYZ R-08
5. <W9XYZ> PJ4/K1ABC RRR
6. PJ4/K1ABC <W9XYZ> 73

Look at how the brackets move. The first call is sent in full so that listening stations learn the full call before a hash stands in for it. After that, whichever call is the nonstandard one is bracketed when a report or locator is sent, and the standard one is bracketed when the roles require it. The point is that each message contains only one full call and one hash, and the receiver fills in the hash from what it has heard before. If your decoder never heard the full call, you see <…> instead.

What You Give Up With a Nonstandard Callsign

The documentation is frank about the cost. Using a nonstandard callsign restricts the types of information that can be included in a message. In particular, it prevents including your locator in standard messages, which impairs tools such as PSK Reporter that rely on grid locators to map your signal. There is also no support for two nonstandard callsigns to work each other, except for the special cases involving /P or /R used in VHF contesting. And contest-style messages are not supported for compound calls.

In practice, this means that a /P or a foreign prefix is not a disaster, but it does make you slightly less visible. If your licence allows you to operate with your normal call (for example, under rules that do not require a prefix), many operators prefer that on FT8. If your authority requires the prefix or suffix, use it; the guide notes that operators with a compound callsign use its full form when calling CQ and possibly also in a 73 transmission, as may be required by licensing authorities. For the legal background see our guide to CEPT licences and operating abroad and our article on portable callsign suffixes.

The Older 72-Bit Modes: Type 1 and Type 2 Compound Calls

The older modes JT4, JT9 and JT65 use a 72-bit payload, and they handle compound callsigns in two ways. Type 1 compound callsigns involve one of about 350 of the most common prefixes and suffixes, which you can display from the Help menu. A single compound callsign of this kind takes the place of the third word of a message, which normally would be a locator, report, RRR or 73. Valid examples are CQ ZA/K1ABC, CQ K1ABC/4 and G0XYZ K1ABC/4. A message that contains a Type 1 compound callsign cannot have a third word, so ZA/K1ABC G0XYZ -22 would be sent without the report.

Prefixes and suffixes that are not on the list use Type 2 compound callsigns. The compound callsign must be the second word of a two- or three-word message, and the first word must be CQ, DE or QRZ. Prefixes can be 1 to 4 characters and suffixes 1 to 3 characters. Valid examples are CQ W4/G0XYZ FM07, QRZ K1ABC/VE6 DO33 and DE W4/G0XYZ 73. A second callsign is never allowed in these messages. In a Type 2 QSO the operators typically send the full compound call when calling CQ and then use the base call and standard structured messages for the rest.

The guide also mentions an option on the File | Settings | General tab, called Message generation for type 2 compound callsign holders, which lets you experiment if you use such a call. For modern FT8 operation most of this detail is behind the scenes, but it explains why old software versions behaved differently.

Practical Settings and Habits

Let the software generate messages

Use the standard message buttons and auto-sequencing. WSJT-X will automatically put the brackets in the right places for the call you entered in Settings. Typing messages by hand is where mistakes happen, such as putting brackets around the wrong call or including a locator that cannot be sent.

Avoid the slash in free text

The guide advises you to avoid the character / in free-text messages, because the program may try to interpret your construction as part of a compound callsign. Free-text messages are limited to 13 characters, including spaces, and are meant for short words such as “TNX ROBERT 73”. WSJT-X is not designed for rag-chewing.

Check your callsign in Settings

Enter your callsign exactly as you will use it on the air. If you are visiting another country, set the full compound callsign before you start. Operators who forget this either transmit a callsign that is not valid in the country they are in or make life harder for the station that is trying to log them.

Expect <…> in busy periods

If you see <…> in place of a callsign, it only means your computer has not recently heard that station transmit its full callsign. Waiting a few periods usually reveals the call. This also explains why a DX station that has just started operating may not appear correctly in your list until you have received a full-callsign message.

A Worked Scenario: Operating From a Holiday Location

Suppose you are licensed in your home country and plan to operate FT8 from a holiday cottage abroad under a reciprocal arrangement that requires a prefix. Before you leave, open File | Settings | General and enter the full compound callsign, including the prefix, exactly as the licensing authority requires. Check that your computer clock is accurate, because a clock error is the most common reason for no decodes, and read the message generated in the first transmit slot to confirm it contains the callsign you expect. WSJT-X shows your outgoing message in the status bar exactly as another station would receive it, which makes this check easy.

When you call CQ you will notice that your grid locator is missing from the standard message, and that replies may show your call with brackets in later messages. Do not be alarmed. Stations that decoded your first transmission will log the full callsign, and stations that join late may only see a placeholder until you transmit again. If the band is busy, you may find that fewer stations answer than at home, and that is a normal consequence of the restrictions rather than a fault in your station. Keep your messages short, log each contact with the callsign you actually transmitted, and upload to your logbook service using that call. If you want to understand how PSK Reporter shows your coverage, remember that spots without a locator are shown with less detail.

The same approach applies if you use a long special event callsign, or a callsign with a suffix like /P that you add for a portable activation. In each case, the software adapts, and your job is to enter the call correctly, leave the message generation alone, and avoid overriding it with hand-typed text.

Special Event Callsigns

Special event callsigns often break the standard pattern, with numbers and many letters, as in the guide’s example YW18FIFA. They work for ordinary QSOs under the same rules as compound calls, but they will not work with contest exchanges, so a special event station that wants to join a contest on FT8 may need to use its regular call in the contest. Our guide to running a special event station explains how these callsigns are obtained and promoted.

Common Mistakes

• Manually removing the angle brackets or adding your own to a message, which makes the message invalid.
• Expecting your grid locator to appear on PSK Reporter when you transmit with a compound callsign.
• Trying to work another nonstandard station in a normal QSO and wondering why the exchange fails; the software does not support two such stations except for /P and /R in VHF contests.
• Using a slash in a free-text message and causing the program to read it as a compound call.
• Assuming that <…> means a problem. It simply means the full call has not been received recently.

The Bottom Line

A standard callsign fits into 28 bits. Anything else, including compound calls with a country prefix or a portable suffix and special event calls, uses special message types and a hash in angle brackets. The result is a working QSO, but without your locator in standard messages, without contest exchanges and without a second nonstandard station on the other end. Let WSJT-X generate the messages, enter your callsign correctly, avoid slashes in free text, and use the full form when your licence conditions require it.

Frequently Asked Questions

What do the angle brackets in an FT8 message mean?

They mean the enclosed callsign is not sent in full but as a hash code with fewer bits. Your computer shows the full call if it has received it recently, otherwise it shows a placeholder.

Which modes handle nonstandard callsigns this way?

The modes with 77-bit payloads: FST4, FT4, FT8, MSK144 and Q65. The older 72-bit modes JT4, JT9 and JT65 use Type 1 and Type 2 compound callsigns instead.

Can I use a compound callsign in a contest on FT8?

The guide says compound callsigns are supported for normal QSOs but not for contest-style messages.

Why does my locator not appear on PSK Reporter?

Using a nonstandard callsign prevents the locator from being included in standard messages, which impairs tools like PSK Reporter.

Can two nonstandard stations work each other?

WSJT-X offers no support for that, except for the special cases involving /P or /R used in VHF contesting.

Should I put a slash in a free-text message?

No. The guide recommends avoiding the slash because the program may try to interpret it as part of a compound callsign.

Most contests are won by big stations with tall towers. The School Club Roundup is different: it exists to give students, teachers and school radio clubs a friendly on-air event where they are the people everyone wants to work. Run by the ARRL, it takes place twice during the school year and lasts five days each time, so a school can fit it into a normal timetable instead of giving up a weekend. This guide summarizes the official rules on the ARRL page: the dates, the exchange, how points and multipliers work, which bands and frequencies are allowed, and how a school or individual can take part. Always check the ARRL page before each event, because details can change.

What the School Club Roundup Is

The ARRL School Club Roundup page describes an event that encourages contacts with any class of station, especially school stations. Anyone can take part: schools, clubs and individuals. School stations are those operated at a school during the operating period, including any group formed for the purpose of participating, from kindergarten to university. The aim is to give young people real operating experience and to give experienced operators a reason to call a student who may be on the radio for the first time.

If you are just starting out in contesting, this is one of the gentlest events on the calendar, in the same family as the ARRL Rookie Roundup, but spread over a school week. Our contest calendar guide shows where it fits among other events.

Dates and Operating Limits

There are two School Club Roundups during each school year, in October and February. Each event runs Monday through Friday, from 1300 UTC on Monday to 2359 UTC on Friday, a period of 107 hours. The October session is held during the third full school week of October and the February session during the second full school week of February. The ARRL page lists February 9-13 and October 19-23 for 2026, so use the page to see the date for the next session.

The operating limits are designed for school days. A station may operate no more than 6 hours in any 24-hour period, and no more than 24 hours of the 107-hour event in total. Clearly marked breaks of at least 10 minutes may be taken and do not count toward operating time. That rule keeps the event from becoming a marathon and lets a club share one callsign among many students, each operating a short shift.

Bands, Frequencies and Simplex Rules

All amateur bands except 60, 30, 17 and 12 meters are permitted. Repeaters are not to be used; only recognized simplex frequencies may be used. The ARRL gives US examples: 144.90 to 145.00 MHz, 146.49, 146.55 and 146.58 MHz, and 147.42, 147.45, 147.48, 147.51, 147.54 and 147.57 MHz. The national calling frequency of 146.52 MHz may not be used, and similar restrictions apply in other countries. The page also suggests HF segments to make finding school stations easier:

• Phone (MHz): 1.855-1.865, 3.850-3.880, 7.225-7.255, 14.250-14.280, 21.300-21.330 and 28.440-28.460.
• CW (MHz): 1.800-1.810, 3.530-3.540, 7.030-7.040, 14.030-14.040, 21.130-21.140 and 28.130-28.140.

These are suggestions, not requirements; rules in your country about which segments are legal for your licence class still apply. If you are not sure which sideband or which segment to use, our guide on USB versus LSB explains the conventions by band.

Entry Classes and the Exchange

The event uses three single-transmitter entry classes, and the exchange is built around them. The exchange has four parts: your call sign, a signal report, your class and your location. The class is the letter I (individual or single operator, non-club), C (club or multi-operator group, non-school) or S (school club or group, grades K-12, colleges and universities). The location is your US state, Canadian province or territory, or DXCC country or entity. Multi-operator groups must choose one call sign for the whole operating period.

A full exchange has to be sent and received over the air. Because of that rule, only digital modes that support the full exchange are allowed. A typical phone contact on 20 meters is therefore “CQ School Club Roundup” and an answer along the lines of “59 S, Ohio”, which already gives the receiving station the signal report, school class and location.

How Scoring Works

You may contact each station once per band and mode, with phone, CW and digital counted as the three modes (packet, RTTY, PSK and similar modes count as digital). Phone QSOs score 1 point and CW or digital QSOs score 2 points. Repeater contacts are not allowed, except satellite and real-time digital contacts, which may include the use of digipeaters and network nodes but not store-and-forward bulletin boards or mailboxes.

The multiplier is the number of US states plus Canadian provinces and territories plus DX countries or entities, plus 2 times the number of clubs contacted, plus 5 times the number of schools contacted. Alaska and Hawaii count as US states, while other US possessions and territories, including Puerto Rico and the US Virgin Islands, count as DX entities. The final score is the QSO points multiplied by the multiplier. Because every school is worth five multiplier points, a school is the most valuable contact you can make. That is deliberate, and it explains why experienced operators gladly slow down and call a student station.

Preparing a School Station

The ARRL page links teachers’ advice for organizing a successful activity, and a few practical points follow from the rules. Plan a shift schedule so that no single callsign breaches the 6-hour limit, and keep a written list of operating times. Prepare a small card with the exchange so that a student can read it aloud without stress. Decide in advance which bands the school can reach: with a modest HF setup and a simple wire, 20 and 40 meters are usual choices, and 10 meters can be excellent when it is open. If you are building a school station from scratch, our guide to teaching children amateur radio collects activities that help students prepare, and our first QSO guide shows what a normal contact sounds like.

Remember licensing. Students who are not licensed can operate under the supervision of a licensed control operator in some countries, but rules on third-party operation differ, so ask your national society before the event. If your students will contact DX stations, observe the restrictions that apply to communicating with other countries.

Logging and Submitting Your Entry

You can log on paper, using the SCR paper log form and summary sheet, or on a computer. The ARRL page lists GenLog version 7.48 or later, N1MM Logger+ and N3FJP version 1.2 or later, and says that other popular logging programs may also support the event. If you use a Cabrillo file, the ARRL provides a Cabrillo specification sheet, version 0.96. Our guide to Cabrillo logs and UBN explains what the format looks like.

Entries must be submitted online or postmarked no later than 15 days after the end of the operating period. The online form is the simplest route. Log contents used to determine final scores and awards are available to the public. For questions, the ARRL gives the contest address, contests@arrl.org.

Certificates and Categories

All entries receive an award certificate in PDF format. The entry categories for certificates are elementary, middle or junior high school, senior high school, and college or university. Non-school clubs, multi-operator groups and individuals are also eligible for a certificate, and DX entries are listed separately at the end of the US entries in each category. Results from October 2013 onward are available online at the ARRL contest site, and the page mentions that LBJ High School Radio Club (K5LBJ) ranked first in the high school category in both 2006 and October 2010, a reminder of what a motivated school club can do.

A Sample Operating Session

To see how the rules fit together, imagine a school club with one transceiver and a simple wire antenna that plans a 30-minute lunchtime shift on Wednesday. A student sets the radio to the suggested 14.250-14.280 MHz phone segment, listens for a clear spot and calls, “CQ School Club Roundup, this is the school club station.” A club station answers with a signal report, the letter C and its state. The student records the call sign, the report, the class and the location in the log, and the contact scores 1 point. Because it is a club, it also adds 2 to the multiplier the first time it is worked.

A few minutes later a school station answers from another state. That contact scores 1 point in phone and adds 5 to the multiplier, as well as its own state if that state is new. By the end of the shift, the student has a handful of contacts, a feel for how an exchange sounds, and a log that is easy to check. If the school later moves to CW or a digital mode, the same contacts can be worked again on the new mode for 2 points each, since stations may be worked once per band and mode.

Planning around these rules makes a difference. A school with only a few students operating each day gets most of its score from variety, not volume: more states, more clubs and more schools raise the multiplier faster than extra contacts with the same people.

Why the Event Works for Education

The event teaches a lot in a short time. Students learn how to speak clearly on the air, how to use phonetics, how to read a map to understand where a station is, and how propagation changes with the time of day and the band. Teachers can link the event to lessons about geography, electronics and communication. The five-day format also means a class can follow the whole event, compare which bands were open in the morning and afternoon, and discuss why. The general idea of competitive operating is described in the Wikipedia article on contesting, and the School Club Roundup is a gentle introduction to it.

Clubs that support a school can help by lending equipment, setting up an antenna, and acting as the licensed control operators. Even a short visit to explain how to log a contact is valuable. Keep the tone encouraging, and let the students do the calling and logging themselves whenever the rules in your country allow it.

Tips for Experienced Operators

• Listen first. School stations often have small antennas and a modest signal, so be patient and call with clear, slow speech.
• Give a clean exchange and repeat it if asked. A student may be writing it down for the first time.
• Do not use repeaters or the national calling frequency; stay on proper simplex frequencies on VHF.
• If you are a club, send the letter C so schools know you are in the right category and can count the multiplier.
• Say thank you and encourage the operator. A friendly contact can be the reason a student becomes a licensed ham.

The Bottom Line

The School Club Roundup is a five-day, twice-yearly ARRL event built around schools, clubs and new operators. The exchange (call, report, class I, C or S, and location) is short, scoring is simple (1 point for phone, 2 for CW or digital, multiplied by locations plus club and school bonuses), and the operating limits keep it manageable on a school schedule. Check the ARRL page for the next dates, prepare a shift plan and an exchange card, and make a point of calling any school station you hear.

Frequently Asked Questions

When is the School Club Roundup held?

Twice each school year: the third full school week of October and the second full school week of February. Each event runs from 1300 UTC Monday to 2359 UTC Friday.

Can individuals who are not in a school take part?

Yes. Individuals and non-school clubs can enter and are eligible for a certificate, and they are encouraged to contact school stations.

What is the exchange?

Your call sign, signal report, class (I for individual, C for club or S for school) and your US state, Canadian province or territory or DXCC country or entity.

How many hours can a station operate?

No more than 6 hours in any 24-hour period and no more than 24 hours of the 107-hour event. Marked breaks of at least 10 minutes do not count.

Which bands are not allowed?

The 60, 30, 17 and 12 meter bands are not permitted. All other amateur bands may be used, but repeaters may not.

When are logs due?

Entries must be submitted or postmarked no later than 15 days after the end of the operating period.

If you have only used FT8 and FT4, FST4 may look like a familiar name with a very different purpose. The WSJT-X User Guide says so directly: do not confuse FST4 with FT4. FST4 is designed primarily for making weak-signal two-way contacts on the LF and MF bands, where signals are slow, stable and extremely weak, and where transmit sequences can last many minutes. Its sibling FST4W does the beacon-like job that WSPR does on other bands. This guide explains how both modes work, what the documentation says about frequency stability and decoder controls, and how to start on the 2200 m and 630 m bands.

What FST4 Is and Where It Fits

The WSJT-X User Guide lists eleven modes in WSJT-X 2.7, and the same set carries on in version 3.0. FT8 uses 15-second sequences for fast HF contacts, FT4 uses 7.5-second sequences and is well suited to contesting, and FST4 is designed especially for LF and MF. Like the other QSO modes it uses the same 77-bit message structure, so a normal exchange of callsigns, grid locator, report and 73 works exactly as in FT8.

The big difference is time. FST4 offers T/R periods from 15 seconds up to 1800 seconds, which is half an hour. On a very quiet, stable channel, the longer you integrate a signal, the weaker it can be and still decode. That is the logic behind the mode, and it is also its main limit, as the next section explains.

Sequence Lengths and Frequency Stability

FST4 sequence lengths are 15, 30, 60, 120, 300, 900 and 1800 seconds, and submodes are named FST4-60, FST4-120 and so on. The guide gives an important warning: longer sequences provide better sensitivity only if the transmit and receive frequency instability and the channel Doppler spread are small enough that signals stay phase coherent over several symbols. In general, frequency changes during a transmission and Doppler spread must each be small compared with the symbol keying rate.

The guide’s own example is FST4-1800, which has a keying rate of 0.089 baud, so successful operation requires frequency stability better than around 0.05 Hz, and Doppler spread below that. A transmission consists of 160 symbols, so the keying rate for any submode is simply 160 divided by the sequence length. The table works that out for each period.

The keying rates in the table come from simple arithmetic, not from a table in the documentation, apart from the FST4-1800 figure. The practical lesson is that the longest sequences are not for everyone. A radio with a free-running oscillator may drift too much, and a stable receiver clocked from a GPS-disciplined reference is a typical aid on these bands.

How the FST4 Signal Is Built

FST4 appends a 24-bit cyclic redundancy check to the 77-bit message payload, creating a 101-bit message-plus-CRC word. Forward error correction uses a (240,101) low-density parity check code. A transmission consists of 160 symbols: 120 information symbols of two bits each, mixed with five groups of eight predefined synchronization symbols. The modulation is 4-tone frequency-shift keying with Gaussian smoothing of the frequency transitions (4-GFSK).

These details matter because they explain how FST4 ends up sensitive. The CRC keeps the false-decode rate low, the strong code corrects many bit errors, and the spread-out sync symbols let the decoder lock onto a signal that is invisible on the waterfall.

FST4W: The WSPR Alternative for LF and MF

FST4W is used in the same way as WSPR, but it has significant advantages on the 2200 m and 630 m bands. According to the guide, WSPR with its two-minute sequences can be decoded at signal-to-noise ratios as low as -31 dB in a 2500 Hz bandwidth, while FST4W offers optional sequence lengths as long as 30 minutes and reaches sensitivity thresholds as low as -45 dB. If you know how WSPR works, you already know the concept: transmit a short message with a callsign, grid and power level, and let receiving stations around the world report it.

FST4W has a scheduling option that WSPR does not. By default the receive frequency is 1500 Hz and the frequency tolerance is 100 Hz, so the active decoding range is 1400 to 1600 Hz, but you can choose other centre frequencies and tolerances. A drop-down control offers a round-robin mode: if three operators agree in advance to select 1/3, 2/3 and 3/3, their transmissions occur in a fixed sequence with no two stations on the air at once. For WSPR-like random scheduling you choose Random. As with WSPR, reception reports can be uploaded automatically to the WSPRnet database, which provides mapping and archives.

Decoder Controls You Should Know

The guide describes several controls that matter more on LF and MF than on HF:

• F Low and F High: these spin boxes set the lower and upper frequency limits of the FST4 decoder, marked by dark green angle brackets on the Wide Graph. Keep the range fairly small, because QRM and transmissions in other modes or sequence lengths slow down decoding.
• Single decode: on the File | Settings | General tab, this limits the range to F Tol either side of Rx Freq.
• Noise blanker (NB): the percentage sets how many of the largest-amplitude samples are zeroed before decoding. Most users find settings between 0% and 10% work best. A setting of -1% makes the decoder try 0, 5, 10, 15 and 20% in turn, and -2% loops through 0, 2, 4 and up to 20%, but only for candidates within 20 Hz of the receive frequency to save time.
• Decode depth: a priori (AP) decoding is always enabled for FST4 and FT4 when the depth is Normal or Deep. The FST4 AP table is the same as FT8’s except that it omits two types to save time.

Noise is the main enemy on these bands, particularly in towns, where switching supplies and lighting produce broadband interference. Our guide to low band receive antennas explains the kinds of antennas that improve the signal-to-noise ratio before the software ever sees the audio.

Trying FST4 With the Sample File

The documentation includes a sample exercise that is worth doing before you transmit. Select FST4 on the Mode menu, set T/R to 60 s and Decode to Deep, and set NB to 0%. In the Wide Graph, try Bins/Pixel 2 and N Avg 4, set the start frequency below 1000 Hz and the width to include 1400 Hz, set F Low to 1000 and F High to 1400, then open the sample wave file from the save\samples\FST4+FST4W folder. For FST4W the guide’s example uses T/R 1800 s, Bins/Pixel 1, N Avg 150 and Start 1200 Hz. After decoding you will see a single decode, even though the signal is essentially invisible on the Wide Graph spectrogram, which is the best demonstration of what the mode can do.

Getting on the Air on 2200 m and 630 m

The two bands are the home of FST4. The 630-meter band and 2200 m band are allocated to amateurs in many countries, but power limits, permitted segments and licence conditions differ, so check your own regulator before building a station. Our 630 and 2200 meter band guide covers the practical side of antennas and transmitters.

A typical beginner path is to start by receiving. Set up WSJT-X in FST4W mode with an audio connection from a receiver, decode what other stations transmit, and watch the reports appear. Receiving costs nothing in terms of licence or antenna, teaches you the noise environment, and shows you whether your location is workable. When you are ready to transmit, an FST4W schedule is a polite way to start, because it behaves like a beacon and does not tie up the band while stations work out a QSO.

For QSOs, agree on a sequence length and a calling frequency before you start. Long sequences make a normal exchange slow: a complete contact with six messages needs a few periods of 120 or 300 seconds, and much longer with 1800 s. That is part of the charm of these bands, but it means you must plan your time, and it means any clock error shows up quickly, as discussed in our 160 m guide for a related low-band mindset.

Station Requirements Beyond the Software

The software side of FST4 is simple compared with the station side. WSJT-X needs the usual things: a computer clock synchronized to UTC within one second, audio input and output at 48000 Hz and 16 bits, and a way to key the transmitter. On LF and MF the real challenges are different. Antennas are electrically tiny at these wavelengths, which means low efficiency and high losses in loading coils and ground systems. Many stations use a vertical or inverted-L wire with a large ground screen, and an inverted-L is also a favourite on the neighbouring bands; our inverted L antenna guide explains the geometry.

Because efficiency is low, power limits and legal conditions matter. Some countries allow only modest power on these bands, and the allowed segments are narrow. This is where a long, very sensitive mode helps: you can be heard at levels that would be useless in SSB or CW. Even so, an hour spent reducing local noise or improving the ground system will often be worth more than any amount of fiddling with decoder settings.

Choosing Between FST4W, WSPR and FT8

The three modes overlap in purpose, so it helps to compare them by what you want to find out. If you want a quick two-way contact on a busy HF band, FT8 is the right choice. If you want to probe propagation on HF or VHF with a low-power beacon, WSPR is the traditional tool and has the largest network of receivers. If you want the same on 2200 m or 630 m, FST4W is designed for that job, and its longer sequences let you work down to lower signal levels than WSPR allows. For actual QSOs on those bands, FST4 is the matching two-way mode.

A sensible routine for a new LF station is to run FST4W for a few days, study the reports to see which stations hear you and at what signal-to-noise ratios, adjust the antenna or the transmitter power, and then arrange schedules with a regular partner for FST4 contacts. This feedback loop is slow, but every step teaches you something concrete about your own station.

Common Mistakes

• Picking the longest sequence on the first day. If your oscillator is not stable enough, a long sequence performs worse, not better.
• Setting the decode range too wide, which slows the decoder and invites decodes of other modes.
• Treating FST4 as a faster FT4. They are different modes with different purposes.
• Forgetting that FST4W is a beacon mode, not a QSO mode; there is no exchange of reports.
• Ignoring noise at home. A good receive antenna usually does more than another decibel of transmit power.

The Bottom Line

FST4 and FST4W are WSJT-X modes built for the slow, stable world of LF and MF: sequences from 15 to 1800 seconds, strong error correction, and sensitivity to match the long integration times. Learn the stability requirements, keep the decode range tight, use the noise blanker sensibly, and begin by receiving FST4W reports before you transmit. Once you understand your own noise floor and oscillator, the longer sequences become a tool instead of a risk.

Frequently Asked Questions

Is FST4 the same as FT4?

No. The WSJT-X User Guide warns against confusing them. FT4 is a fast mode with 7.5-second sequences, well suited to contesting, while FST4 is designed primarily for weak-signal QSOs on LF and MF.

Which sequence lengths does FST4 support?

15, 30, 60, 120, 300, 900 and 1800 seconds, named FST4-15 through FST4-1800.

What is FST4W?

FST4W is a beacon-style mode used in the same way as WSPR, but with advantages on 2200 m and 630 m, including sequence lengths up to 30 minutes and sensitivity as low as -45 dB according to the guide.

How stable must my radio be?

The guide’s example is FST4-1800: frequency stability better than around 0.05 Hz is required, along with Doppler spread below that. Shorter sequences are more forgiving.

Can I upload FST4W spots?

Yes. Users with internet access can automatically upload WSPR and FST4W reception reports to WSPRnet, which provides mapping and archival storage.

Does FST4 use AP decoding?

Yes, AP decoding is always enabled for FST4 when the decode depth is Normal or Deep.

Most people meet WSJT-X through FT8, a mode designed for crowded HF bands. Q65 mode belongs to the other side of the program: it was built for signals that are not only weak but also unstable, the kind you get from moonbounce, rain scatter, ionospheric scatter and trans-equatorial paths. This guide explains what the WSJT-X User Guide says about Q65, how its sequence lengths and submodes fit together, why a priori decoding gives it an edge, and how to configure and operate it. All technical details below come from the WSJT-X 3.0 documentation, so check the current guide if you use a newer release.

What Q65 Is Designed For

The WSJT-X User Guide describes Q65 as a mode designed for fast-fading signals: EME, tropospheric scatter, rain scatter, ionospheric scatter, trans-equatorial propagation (TEP) and similar paths. A fast-fading signal rises and falls in strength within a single transmission, which defeats decoders that assume a steady carrier. Q65 uses a strong error-correcting code and a wide choice of tone spacings so that the decoder can still recover the message when the signal is smeared in frequency or time.

The guide also states that on VHF and higher bands, QSOs with the weak-signal modes are possible at signal levels 10 to 15 dB below those required for CW. Q65 sits in that family, which is why it is widely used for 6 m, 2 m and microwave moonbounce. If you are new to the idea of bouncing signals off the Moon, read our EME moonbounce beginner guide first, then return here for the settings.

Sequence Lengths and the Q65 Submode Names

Every Q65 submode name has two parts: a number for the length of the transmit/receive sequence in seconds and a letter for the tone spacing. According to the protocol specification in the guide, Q65 offers T/R sequence lengths of 15, 30, 60, 120 and 300 seconds, and submodes A to E have tone spacings of 1, 2, 4, 8 and 16 times the symbol rate. So Q65-60A is a 60-second sequence with the narrowest tone spacing, and Q65-120C is a 120-second sequence with tone spacing four times the symbol rate.

The occupied bandwidth is 65 times the tone spacing. The guide gives the extremes: 19 Hz for Q65-300A and a maximum of 1733 Hz for Q65-15C, Q65-30D and Q65-60E. From the 1733 Hz figure for Q65-60E you can work out the rest of the 60-second family, because each step up in letter doubles the spacing. The table shows that arithmetic.

The right-hand column is a guideline, not a rule from the documentation. The guide only says that Q65 offers a range of tone spacings for different propagation conditions. In practice, the activity group for your band and path decides which submode everybody uses, and the sensible approach is to follow that convention rather than invent your own.

How the Q65 Message Is Built

Q65 uses the same 77-bit message structure as FT8, FT4 and FST4, so you can use the same standard exchange of callsigns, grid locator, report and 73. The error correction is a specially designed (65,15) block code with six-bit symbols. Two symbols are punctured, meaning they are computed but not transmitted, which leaves an effective (63,13) code: 13 information symbols carried by 63 channel symbols. The punctured symbols hold a 12-bit CRC computed from the 13 information symbols, and the CRC keeps the false-decode rate very low.

A 22-symbol pseudo-random sequence spread through the transmission is sent as tone 0 and used for synchronization. Adding the two parts gives 63 + 22 = 85 channel symbols in every Q65 transmission. You do not need these numbers to operate the mode, but they explain why Q65 tolerates drift and fading: the synchronization is spread through the whole sequence instead of sitting at the start.

Why A Priori Decoding Matters in Q65

The Q65 decoder uses a priori (AP) information, which means it makes use of what it already knows about the message. At the start of a QSO it knows your own callsign and the word CQ. As the QSO progresses, the available AP information grows to include the callsign of the station you are working and perhaps its four-digit grid locator. The decoder uses whatever is available at that moment.

The guide notes that AP decoding raises decoder sensitivity by up to 4 dB at the cost of a slightly higher rate of false decodes, and that for Q65 it is always enabled. Decoded lines show the type of AP information with a code of the form qP, from q0 (no assumed information) through q1 (CQ), q2 (MyCall), q3 (MyCall and DxCall) and q4 (MyCall, DxCall and a final RRR, RR73 or 73) to q5. If the decode was averaged over several periods, a further digit shows the number of messages, so q34 means a Q65 decode using AP type 3 from four messages, and an asterisk means ten or more.

Seeing a q-code on a line is useful because it tells you how much trust to place in it. A decode that appears only because the program was already expecting your callsign is not the same as a decode of a CQ from a stranger. WSJT-X also marks lower-confidence decodes with a question mark and does not forward them to PSK Reporter, which keeps occasional false decodes out of the spots. Our PSK Reporter guide shows how those reports are used.

Where Q65 Is Used

EME on 6 m and up

The guide illustrates Q65 with a Q65-60A sequence received by EME on 6 meters, with several stations decoded over the Earth-Moon-Earth path. It also describes the single-tone short messages that some operators use for Q65 EME contacts on the microwave bands. Checking the box labeled Sh generates these messages, and selecting Tx6 produces a single tone at 1000 Hz to help the other station find you; switching Tx6 to 1250 Hz tells them you are ready to receive messages. These short-form messages are not decoded automatically and auto-sequencing will not respond to them, so you interpret them yourself.

If you want background on the path itself, the Wikipedia article on Earth-Moon-Earth communication explains why echoes are so weak and why the Moon’s motion causes Doppler shift and fading. That fading is exactly the problem the wider Q65 tone spacings were made for, and it is why moonbounce stations on higher bands choose wider submodes than stations on 6 m.

Ionospheric scatter on 6 m

Another example in the guide is a 6 m ionospheric-scatter signal over a 1155 km path, received using submode Q65-30A and barely audible most of the time. That example shows the practical appeal of the mode: a contact that would be nearly impossible by ear or with CW becomes routine when the computer can integrate the signal. If you are curious about the band, our 6 meter band guide covers the openings in more detail.

Tropo, rain scatter and TEP

Tropospheric ducting, rain scatter and trans-equatorial propagation all produce signals that fade and flutter. Our guides to tropospheric ducting and transequatorial propagation describe these paths. The Q65 mode is simply the digital tool that suits them, since the longer sequences let the decoder collect more signal energy than FT8 can in 15 seconds.

Setting Up Q65 in WSJT-X

Setup follows the same pattern as other WSJT-X modes. Choose Q65 on the Mode menu, then select the sequence length and submode your activity group uses. WSJT-X 3.0 adds buttons for quick access to six popular Q65 submodes and to Echo mode, and the guide notes that the experimental 15A, 15B and 15C submodes can be decoded with EME delay. For EME work, the 3.0 release also makes it easier to pick dial frequencies within an EME sub-band and to offset your transmit frequency by a whole number of megahertz from the receive frequency to match different regulatory allocations.

Before your first Q65 QSO, check these points:

• Clock accuracy: the guide requires a means of synchronizing the computer clock to UTC within one second, and the longer the sequence, the more important a steady clock is for averaging. Our FT8 time sync guide applies equally here.
• Radio control: use CAT control through Hamlib so that WSJT-X can set the dial frequency and handle split operation.
• Audio level: keep the transmit audio low enough that the radio does not show ALC action, exactly as you would for any digital mode.
• Repeat transmissions: WSJT-X offers a general option, MSK144/Q65: Tx until 73 is received, which keeps sending until it receives a 73 when copy is marginal. The guide says a maximum of ten attempts is made before it times out.

MAP65 and QMAP for Serious EME Stations

For serious moonbounce, WSJT-X installs a companion program called QMAP. The guide describes it as a program that uses a single polarization channel and only the Q65 mode, covering a 90 kHz sub-band at a time and working together with WSJT-X to provide automatic Doppler compensation and other EME features, especially on 1296 MHz and higher bands. Its older relative MAP65 handles JT65 as well and can use two orthogonal polarization channels for automatic polarization-matched reception. Both are installed with WSJT-X, although MAP65 only on Windows. Most beginners will never need them, but it is useful to know that the Q65 ecosystem extends beyond the main window.

Q65 Compared With FT8 and FST4

FT8 uses 15-second sequences and is built for busy HF bands where speed matters more than the last decibel. FST4 is designed primarily for LF and MF, with sequence lengths up to 1800 seconds. Q65 occupies the middle ground for VHF and above: sequence lengths from 15 to 300 seconds and tone spacings chosen to match how much the signal spreads. If you want a broader overview of other modes, our article on digital modes beyond FT8 puts them side by side.

Reading the Decoded Lines

A Q65 decode line looks like any other WSJT-X line, with the UTC time, signal-to-noise ratio in dB, time offset DT in seconds and audio frequency in Hz, followed by the message. The mode character for Q65 is a colon, and the end-of-line information carries the q-code described above. Signal reports are expressed as signal-to-noise ratio in a standard 2500 Hz reference bandwidth, so a report of -22 means the signal power was 22 dB below the noise power in that bandwidth, a level far below what you can hear. When you work a station on a long sequence, expect a QSO to take many minutes, and use the waiting time to check your frequency, your clock and your antenna pointing rather than to retune the radio.

Common Mistakes

• Choosing a submode on your own instead of following the convention for the band and path, so that nobody hears you.
• Forgetting that sequences are timed to UTC: stations transmit in alternating periods, and starting in the wrong one means you transmit when your partner does.
• Reading too much into a q-coded decode. Treat a decode that depends heavily on AP information as likely, not certain, until the next period confirms it.
• Running too much power or overdriving the audio. Weak-signal modes reward clean signals, not loud ones.
• Expecting results from a poor receive system. Q65 can pull a signal out of the noise, but a low-noise receive setup still decides how far you can go.

The Bottom Line

Q65 is the WSJT-X mode for signals that fade, flutter and drift: EME, scatter, ionospheric paths and TEP. Learn the submode naming (period in seconds plus a tone-spacing letter), follow the convention used by activity on your band, keep your clock and audio levels in order, and let the AP decoder help you without trusting it blindly. Start with a sequence length and spacing that matches published activity, listen for a few periods to see what the decoded lines look like, and then make your first call.

Frequently Asked Questions

What does the name Q65-60A mean?

The number is the T/R sequence length in seconds and the letter is the tone spacing. Submodes A to E use tone spacings of 1, 2, 4, 8 and 16 times the symbol rate, so Q65-60A is a 60-second sequence with the narrowest spacing.

Which sequence lengths does Q65 offer?

The WSJT-X documentation lists 15, 30, 60, 120 and 300 seconds.

Is Q65 only for EME?

No. The guide lists EME together with tropospheric scatter, rain scatter, ionospheric scatter and trans-equatorial propagation, as well as other fast-fading signals on VHF and higher bands.

Does Q65 use AP decoding?

Yes. A priori decoding is always enabled for Q65 and can raise sensitivity by up to 4 dB, with a slightly higher chance of false decodes. Decoded lines carry a q-code that shows what information the decoder assumed.

Can I use the same message format as FT8?

Yes. Q65 uses the same 77-bit message structure as FT8, FT4 and FST4, so the standard exchange of callsigns, grid, report and 73 works.

What is QMAP?

QMAP is a companion program installed with WSJT-X that decodes Q65 over a 90 kHz sub-band using a single polarization channel and works with WSJT-X for Doppler compensation. It is aimed at EME, especially on 1296 MHz and above.

A weather station on the roof is one of the oldest ways for amateurs to combine radio, electronics and a useful public service. A CWOP APRS weather station goes a step further: it reports its measurements automatically, and the data may end up in the same systems that feed weather forecasts. CWOP, the Citizen Weather Observer Program, began with amateur radio operators experimenting with packet radio, and it still has strong ties to APRS. This guide explains what CWOP is, how the data travel from a backyard sensor to the National Weather Service, what role APRS and the internet play, how to place the sensors so that the readings are worth sharing, how quality control works and how to join. The facts come from the reference article on the Citizen Weather Observer Program and from the program’s own site.

What CWOP Is

According to the reference, CWOP is a network of privately owned electronic weather stations, concentrated in the United States but also located in more than 150 countries. Volunteers with computerized weather stations send automated surface weather observations to the National Weather Service through the Meteorological Assimilation Data Ingest System, known as MADIS. The data are then used by forecast models, and the observations are also redistributed to the public. The article reports that as of September 2026 more than 13,000 stations worldwide report regularly to the network.

The program’s own website, wxqa.com, describes CWOP as a public-private partnership with three goals: to collect weather data contributed by citizens, to make those data available for weather services and homeland security, and to give the contributors feedback so that they have the tools to check and improve their data quality. The address stands for weather quality assurance, which tells you something about the priority. The site says that the number of North American stations sending data over a few days is normally more than 7,000, sending 50,000 to 75,000 observations every hour, and that over 800 different organizations use the CWOP data.

How the Data Travel

The data path is easy to follow once you separate the radio part from the internet part.

1. The station measures. Sensors for temperature, humidity, pressure, wind and rain feed a data logger or a small computer.
2. The station reports. The report is formatted as an APRS weather packet. It is either transmitted by radio through an APRS modem or sent directly over the internet.
3. An IGate or direct internet connection passes it on. The reference explains that numerous IGates, meaning internet gateways, receive broadcast APRS packets from the radio network and forward them via APRS-IS to the FindU servers. Packets can also originate directly from computers on the internet without being broadcast on the radio waves.
4. FindU forwards to MADIS. The wxqa.com site says that every five minutes, the data are sent from the findU server to the NOAA MADIS server.
5. Quality checks and distribution. The MADIS system integrates weather observations from many sources and applies temporal and spatial consistency checks. Quality flags are stored with the data so that users can obtain the most trustworthy data possible. From MADIS, the CWOP data are redistributed to other users.

The amateur radio connection, as the reference notes, makes it inexpensive and simple for an individual to install consumer-level weather sensors at a point of interest, connect them to a radio transmitter through a simple APRS modem and start sharing weather reports. Solar power and radio transmission make it possible to place self-contained weather stations at unattended and wireless sites, which allows a dense set of measurements. If you are new to the packet system itself, read our article explaining APRS, IGates and digipeaters first.

Radio or Internet?

CWOP began as an amateur radio experiment, but it now includes both amateur radio APRS stations and internet-only stations. The two options suit different people, and the table compares them.

The program’s member lists show that the identifiers differ by type. The site allows searches of the member list by ham, CW or DW call sign, which reflects that licensed amateurs report under their call signs and others use a program-assigned identifier. If you are a ham, your call sign with a suffix forms the station identity; otherwise you apply for the assigned identifier when you sign up.

The Radio Side: Packets on VHF

If you choose the radio path, the report goes out on the standard APRS frequency in your region, through a TNC or a sound card modem, and is picked up by IGates and digipeaters. A software modem running on a small computer is enough for many stations. Our article on Direwolf, a soundcard packet TNC explains how to build one with a sound interface, and the guide to Raspberry Pi ham radio projects shows how a single-board computer can run it all day. The APRS reference article lists weather reports as one of the standard packet types, alongside positions, messages and telemetry.

Keep the transmissions modest. Weather reports are short, and a station only needs to send them every few minutes. A weather station that sends a packet every few seconds would waste airtime and annoy other users of the channel. Follow the reporting interval recommended by the program, and use the lowest power that reaches your IGate. A fixed station on a good antenna rarely needs more than a few watts.

Siting the Sensors

A weather station is only as good as its location. The CWOP goal of giving contributors the tools to improve their data would be pointless if the sensors were placed carelessly. The following points reflect standard meteorological practice, and the program’s own resources give more detail on station setup.

Temperature and Humidity

Mount the sensor in a ventilated radiation shield, in the shade, away from walls, roofs, chimneys and air-conditioner exhausts. A sensor in direct sun or next to a hot wall reads too high, and a sensor on a roof reads differently from one over grass. A height of a couple of meters above the ground, over natural ground cover, is the usual target.

Wind

The anemometer and vane need open exposure, high enough to clear obstacles. Trees and buildings disturb the flow, so readings from a sensor next to the house are biased. The reference photograph shows a typical station with a mast supporting the wind vane and anemometer while the rain gauge and other sensors are close to the ground, which reflects the usual compromise.

Rain and Pressure

The rain gauge should be level, in an open area away from overhanging trees and the roof edge, so that it catches rain the way the ground does. Pressure sensors can sit indoors, but the reading must be configured correctly for the station’s elevation, because forecast systems compare station pressure with models. Confirm the setting against a nearby official observation.

Lightning and Grounding

A mast carrying sensors and an antenna is a lightning target. Protect the station with proper grounding and surge protection on the cables, as described in our guide to station grounding and lightning protection. Use waterproof connectors on every outdoor joint.

Data Quality and Feedback

One reason CWOP is respected is its attention to data quality. The reference says that MADIS applies temporal and spatial consistency checks and stores quality flags with the data. The wxqa.com site offers pages for data quality and for checking the packets that stations send, which allows contributors to find problems such as a stuck sensor, a bad pressure setting or a time error. A good habit is to compare your readings with those of nearby stations, particularly when a front passes or after a rain, and to fix any consistent offset at its source rather than adjusting the numbers.

Time is another common problem. Weather observations are valuable because they are timely, so the clock on your logger or computer should be correct and the reports should use the right time reference. Our article on UTC time in ham radio explains the standard time that weather and radio services use.

Typical Equipment

Most CWOP stations are built around a consumer weather station sold for home use, with an outdoor sensor array, an indoor console and a way to read the data into a computer. The outdoor array normally combines temperature and humidity, wind speed and direction, and a rain gauge, and a separate barometer is built into the console or the logger. A small always-on computer, such as a single-board computer, reads the data and runs the software that formats and sends the reports. For a radio station, add a VHF transceiver, an antenna with a clear path to the nearest IGate or digipeater, and a modem, either a hardware TNC or a sound card with software. For an internet-only station, the same computer sends the reports directly. Whichever route you choose, keep the cable runs short, use shielded cable for the sensors where the manufacturer recommends it, and label every connector so that you can service the station without guessing.

Plan for maintenance as well. Rain gauges clog with leaves and insects, radiation shields collect dust and spider webs, and anemometer bearings wear out. A visit every few months to clean and inspect the sensors keeps the readings honest, and a station that suddenly changes behaviour after a storm is a good reason to climb the mast and look.

Joining the Program

The wxqa.com site provides sign-up pages for CWOP and for a snow-observation variant. The general steps are as follows, though you should follow the instructions on the program’s current pages because they are updated from time to time.

1. Install and test the station until the readings are stable and sensible, and place the sensors correctly.
2. Choose your reporting path: APRS by radio with a licensed call sign, or internet only.
3. Read the program’s information pages and the recommended reporting interval.
4. Complete the sign-up form with your location, the station type and your contact details, and wait for your identifier.
5. Configure the software to send reports to the servers listed on the program’s pages, using the identifier you were given.
6. Watch the quality pages for a few days and fix any problems that they show.

Why Hams Take Part

For radio amateurs, the appeal is practical. A weather station gives your APRS setup a purpose beyond a symbol on a map, and the data have a real use: the reference notes that CWOP observations feed forecast models. For emergency-minded hams, local weather data complements storm spotting. Our guide to the high altitude balloon and APRS tracking shows another way that APRS reports atmospheric data, this time from a platform that rises through the sky. Both projects teach the same skills: sensors, packets, gateways and checking your data against the real world.

The Bottom Line

CWOP lets a backyard weather station contribute to the same data stream that supports forecasts. Hams can report with APRS through IGates and the internet servers, and others can report over the internet alone, and the data go from FindU to NOAA’s MADIS every five minutes for quality checking and distribution. Good sensor siting, a correct clock and attention to quality feedback matter more than expensive equipment. Choose your path, place the sensors carefully, sign up on the program’s pages, and keep an eye on the quality reports.

Frequently Asked Questions

What is CWOP?

The Citizen Weather Observer Program is a network of privately owned weather stations that send automated observations to the National Weather Service through MADIS, where they feed forecast models and are redistributed to the public.

Do I need a ham license?

Not for internet-only reporting. A license is needed to send APRS packets by radio, which is how the program began.

How often is the data forwarded?

The program’s site says the data are sent from the findU server to the NOAA MADIS server every five minutes.

What is MADIS?

It is the Meteorological Assimilation Data Ingest System, which integrates weather observations from many sources and applies consistency checks, storing quality flags with the data.

How many stations take part?

The reference article reports more than 13,000 stations worldwide as of September 2026, in over 150 countries, with the site reporting normally more than 7,000 in North America.

Where should I put the sensors?

Use a shaded, ventilated shield for temperature, an open mast for wind, a level open spot for the rain gauge and the correct elevation setting for pressure.

People who ask about two-way radio often meet four different names in the first hour: ham radio, CB, GMRS and FRS. They all let you talk without a phone network, and they are often sold in the same shops, but they are different services with different rules, tools and communities. This guide compares ham radio vs CB radio, and sets GMRS and FRS beside them, so you can see which one fits your situation. It covers the frequencies, the licenses, the power limits, the range you can expect, the use of repeaters and the questions about which service is best for travel, family use, emergency preparation and a lifelong hobby. The descriptions follow the reference articles on citizens band radio, the General Mobile Radio Service and the Family Radio Service. Radio rules change and differ by country, so check your own regulator before you buy or transmit.

The Four Services in One Paragraph Each

Amateur (Ham) Radio

Amateur radio is a licensed service for people who are interested in radio as a hobby and as a technical skill. You pass an exam, receive a call sign and gain access to many frequency bands from HF through microwaves, with the freedom to build and modify your own equipment, use higher power than the personal services and communicate across the world. Our guide to getting your amateur radio license explains the usual exam classes.

Citizens Band (CB)

The reference defines CB as a land mobile radio system that allows short-distance, one-to-many voice communication among individuals, using two-way radios operating near 27 MHz, the 11 meter wavelength. It is distinct from the other personal radio services such as FRS, GMRS and the amateur radio service. In many countries CB does not require a license and may be used for business or personal communications. Radios share a single channel, only one can transmit at a time, and users take turns. The channel plan is the familiar 40 channels, with variations in some countries.

General Mobile Radio Service (GMRS)

The reference describes GMRS as a land-mobile FM UHF radio service for short-range two-way voice communication, authorized in the United States under Part 95 of the FCC rules. It requires a license in the United States, although some compatible equipment can be used license-free in Canada. It operates near 462 and 467 MHz, and it shares that band with FRS.

Family Radio Service (FRS)

FRS is a walkie-talkie system authorized in the United States since 1996. It uses channelized frequencies around 462 and 467 MHz in the UHF band, it uses frequency modulation rather than the amplitude modulation common on CB, and it needs no individual license. The reference notes that radios approved for FRS are not legal to operate anywhere in Europe, because exact allocations differ between countries.

Side-by-Side Comparison

The table below compares the services using the figures in the reference articles, which are mainly about the United States. Check the current rules of your country before relying on any number.

License and Identification

The biggest practical difference is the license. In the United States, CB has not needed an individual license since 28 April 1983, and the reference notes that in earlier years many users ignored the rules for call signs and licenses. In the UK, CB was deregulated in December 2006 and is now license-free, though the rules on approved equipment and power levels still apply. GMRS in the United States requires a license that is issued to individuals who are at least 18 years old. No exam is required, and the license covers the licensee’s immediate family. Each GMRS station must identify with its FCC-assigned call sign at the end of a transmission or series of transmissions, and at least once every 15 minutes during a long exchange. FRS needs no license for the individual.

Amateur radio sits at the other end of the scale. The license requires an exam, and in return it grants a call sign and wide privileges. Identification is part of the culture and the rules, and a call sign is how stations know each other. If you are interested in the hobby side of radio rather than just in a tool, the exam is the entrance fee. It is a good investment because you learn the fundamentals of electronics, antennas and operating practice.

Power and Range

Higher power is often assumed to mean longer range, but the reference articles are more cautious. For CB with a vertical antenna, the reference quotes a typical range of about 5 to 30 kilometers, depending on terrain, for line-of-sight communication, with propagation conditions sometimes permitting contacts over much greater distances because 27 MHz is in the shortwave region. For GMRS, which is UHF, the reference says reliable range is line-of-sight, and estimates about one or two miles between handhelds on flat ground. A repeater with a high antenna can extend the usable range to about 20 miles, and higher power does not give much increase in range, although it can improve reliability at the limit of line-of-sight distance.

The same point applies to amateur VHF and UHF. The horizon limits the range of any UHF or VHF radio, and antenna height is more important than output power. Our guide to the radio horizon explains how to estimate the distance. Where ham radio goes beyond the personal services is the HF bands: a licensed amateur with a modest wire antenna can make contacts across oceans, something that CB can do only occasionally and unpredictably.

Repeaters and Linking

Repeaters extend the range of handhelds by receiving a signal and retransmitting it from a high place. Amateur radio has thousands of repeaters, and many of them are linked, including over the internet, so that a handheld in one country can talk to a handheld in another. Our guides to EchoLink and to VHF and UHF simplex and repeater operating describe how that works. GMRS licensees may establish repeaters, but according to the reference they cannot be linked together over the internet or connected to the telephone network, and FRS rules prohibit repeaters altogether. CB radios generally work directly between the radios on a channel.

Many FRS and GMRS radios include sub-audible tone squelch codes, which are often called privacy codes. The reference explains that they offer no protection from eavesdropping and exist only to reduce unwanted audio when sharing busy channels. The same tones are used on amateur repeaters for access control, as described in our article on CTCSS tones and DCS codes.

Equipment Rules and Warnings

• FRS radios must be certified and have attached antennas. The reference says that equipment is not certified if it exceeds power limits, has a detachable antenna or allows selection of frequencies outside the designated channels. The limitation is meant to keep the range modest, so that many users can share the channels.
• Combination FRS/GMRS radios are restricted. The reference notes that since 30 September 2019 it has been unlawful in the United States to import, manufacture or sell radio equipment capable of operating under both GMRS and FRS. This does not apply to amateur radios that are not certified under Part 95, and many handhelds sold for amateur use can also transmit on the FRS and GMRS frequencies, although that does not make it legal to use them there without following the rules of those services.
• Illegal amplifiers are a CB problem. The reference notes that illegal amplifiers to increase range are common on CB and that using equipment or power above the permitted limits risks fines or confiscation in countries such as the UK.
• Export radios are not CB radios. The reference warns that radios sold in the US as 10 meter amateur transceivers can be used only on amateur bands by licensed amateurs, because they are not type-certified for other services and usually exceed authorized power limits.

The practical lesson is to buy equipment that is approved for the service you intend to use and to follow the rules of that service. An amateur handheld is a flexible tool, but only licensed amateurs may transmit with it, and only on the amateur bands.

Which One Should You Choose?

The right service depends on what you want to do.

Family Trips and Events

If the goal is to keep a family or a small group in touch at a festival, campsite or ski slope, FRS or a combined GMRS arrangement is the simplest. The radios are small, the setup is minimal and there is no exam. The range is short, so the radios work best when the group stays within a few hundred meters to a kilometer or two.

Vehicles on the Road

CB is the traditional choice for truck drivers, off-road convoys and farm vehicles. It works without infrastructure, an external antenna on the vehicle gives a range of a few kilometers, and the channel is open to everyone. It is noisy and busy in some areas, and it offers little privacy. If you drive in a convoy and want a reliable link, a GMRS or amateur VHF or UHF mobile radio with a good antenna can be cleaner.

Emergency Preparedness

For household emergency planning, a few licensed or license-free handhelds can be useful for neighbourhood communication. For real resilience, amateur radio offers more: the exam teaches the skills, the bands include long-distance HF, and the community includes emergency organizations. See our articles on ARES and RACES and the ham radio go kit if you want to see what that looks like.

A Hobby That Grows

If you enjoy tinkering, building antennas, making contacts in distant places, taking part in contests or using satellites, only amateur radio offers that range. Many people start with a personal service and later take the exam when they discover what else is possible. The transition is easy because the first radio you buy as a ham, a dual-band handheld, can already do the same short-range job on the amateur bands and much more.

The Bottom Line

CB, GMRS and FRS are practical tools for short-range, simple communication, with limited power and few options for experimentation. GMRS needs a license in the United States and allows more power and repeaters, FRS is license-free and limited to low power and fixed antennas, and CB works near 27 MHz with a power cap of 4 watts on AM and FM and 12 watts PEP on SSB in the countries covered by the reference. Ham radio requires an exam, but it offers many more bands, modes and freedoms, including the ability to talk around the world. Choose the personal services for convenience and the amateur service for skills and reach, and always follow the rules for the service and the country where you use the radio.

Frequently Asked Questions

Is ham radio the same as CB radio?

No. CB is a personal radio service near 27 MHz with strict equipment and power limits, while amateur radio is a licensed hobby service with many bands, modes and much more freedom.

Do I need a license for CB?

In many countries, including the United States and the United Kingdom, no individual license is needed. Rules vary, so check your national regulator.

Do I need a license for GMRS and FRS?

In the United States, GMRS requires a license with no exam, valid for 10 years and covering immediate family members. FRS needs no individual license.

How much power can CB use?

The reference gives 4 watts on AM and FM and 12 watts PEP on SSB in the US, Canada, the EU and the UK.

Can I use a ham handheld on FRS or GMRS?

The radio may be able to transmit on those frequencies, but using it there without meeting the rules of those services is not legal. Amateur equipment is for the amateur bands.

Which is best for emergencies?

Simple FRS or GMRS handhelds help with local communication, but amateur radio offers the skills, the bands and the volunteer organizations needed for a wider response.

Small, battery-powered boards that send text messages across hills and forests without a cell tower have become a common sight at hamfests and field days. Most of them run Meshtastic, an open-source mesh messaging system built on LoRa radio. Many hams own one, but the relationship between Meshtastic and ham radio is not obvious: the system is designed to work without a license, yet it can also be configured for amateur bands under a license, and the two ways of operating come with different rules. This guide explains what Meshtastic and LoRa are, how a message hops across a mesh, what the documentation says about regions, licensed mode and encryption, what the node roles do, how far the signals really go and where the technology fits next to APRS, AREDN and Winlink.

What Meshtastic Is

The reference article on Meshtastic describes it as a LoRa-based mesh networking protocol and software platform. The main goal is low-power, long-range communication over ISM radio bands, at power levels that do not require a license to use, and it is designed around exchanging text messages and data in off-grid environments. Each device connects with a single phone, and messages hop from node to node to extend the reach. The project was created by Kevin Hester in early 2020, it is open source, and it is run as a community effort with many contributors.

The hardware is simple. Meshtastic runs on development boards based on microcontrollers such as the ESP32 and the nRF52840, equipped with a LoRa radio and Bluetooth, and optionally with a GNSS receiver and Wi-Fi. The reference lists several manufacturers of compatible boards and says that the project maintains an official list of supported devices. The user normally pairs the node with a phone app by Bluetooth, writes a message on the phone, and the node transmits it over LoRa.

What LoRa Is

LoRa, from long range, is a proprietary radio communication technique based on spread spectrum modulation. According to the reference article on LoRa, it uses license-free sub-gigahertz bands, for example 433 and 868 MHz in Europe and 915 MHz in North America, and it enables long-range transmission with low power consumption. Data rates are low, from about 0.3 to 27 kilobits per second depending on the spreading factor. The spreading factor is a selectable parameter: a lower value gives a higher data rate but worse sensitivity, and a higher value gives better sensitivity at a lower data rate, with the cost that the signal stays on the air longer.

That trade-off is the heart of LoRa. A signal that is very slow can be decoded when it is much weaker than the noise, so it travels far, but it takes a long time to send. For short text messages this works well. For anything that needs speed, such as voice or pictures, it does not. The same principle is familiar to hams who use weak-signal modes such as FT8 and WSPR, where a slow, narrow signal is traded for sensitivity. Our guide to digital modes beyond FT8 compares the HF modes that follow this approach.

Licensed or License-Free: Regions Matter

This is where the ham question becomes specific. In Meshtastic, every node must be told which region it is operating in. The LoRa configuration page says that you must set the region, so that the device operates within the legal limits for your area, and that as long as it is unset, the node displays a message and does not transmit. The regions include license-free ISM allocations, for example the European 868 and 433 bands and the 915 band in North America.

The documentation also lists regions that correspond to amateur allocations, named ITU region 1, 2 and 3 for the 2 meter band, and 70 centimeter and 1.25 meter variants for the regions where those bands exist. It states that these regions can only be selected in licensed mode, that you must not use them without an amateur radio license, and that you should review the privileges and restrictions of operating under an amateur license first. It lists two concrete consequences: encryption is not permitted, and you must transmit your call sign. The documentation adds that the listed power limit is the ceiling that the firmware applies and not your national limit, so you should check your national band plan before you transmit.

The documentation also describes an advanced option for licensed operators. When enabled, it ignores the normal channel calculation and uses a frequency you set, which allows out-of-band operation, and the page asks users to respect local laws, to enable the ham mode if they are licensed and to turn off encryption. The wording is a reminder that these settings are meant for people who know the rules. If you are unsure, stay on the license-free configuration for your region until you have read your own country’s regulations.

In practice, the sensible approach for most hams is to treat the two modes as separate tools. Use the license-free region for casual messaging, hiking and community networks that include non-hams. Use licensed mode only when you want to take advantage of amateur-band privileges, and when you accept the amateur rules on identification and encryption. Do not mix the two on a single node, and do not transmit on an amateur band with settings that do not meet the amateur rules.

How the Mesh Works

The reference explains that Meshtastic forms a mesh by rebroadcasting messages. A node that hears a message that it has not seen rebroadcasts it, so that the message spreads outward from the sender, and a limited number of hops stops it from circulating forever. The practical effect is that nodes that cannot hear each other directly can still exchange messages through nodes in between. Reliability depends on having several nodes in the area. The article also notes that the system needs line of sight between devices, so buildings, trees, hills and mountains can block links. For a refresher on why VHF and UHF links depend on the horizon, see our guide to the radio horizon.

Two settings must match for nodes to hear each other: the region and the modem preset. The LoRa configuration page explains that presets are pre-defined combinations of bandwidth, spreading factor and coding rate that trade range against speed, and that nodes need the same preset to hear each other. The default preset provides a mixture of speed and range for most users. Faster presets use more bandwidth, shorten the time on air and reduce the range, and some of the widest presets are not legal in all regions.

Node Roles

Each node has a role that determines how it behaves on the mesh. The reference article describes the main ones. The client role is the default and is considered best for typical users: the node announces itself, sends telemetry and rebroadcasts messages that have not been repeated by a neighbour. Client mute is similar but does not rebroadcast other people’s messages, and the reference recommends it for additional nodes, such as a small node in a pocket, because several client nodes in the same place can cause other users’ messages to reach a dead end. Client base prioritizes rebroadcasting messages from nodes marked as favourite, and suits a well-placed node on a roof or in a tree. Router and repeater roles are for infrastructure and rebroadcast all messages once, and the router appears in other users’ node lists while the repeater does not.

The lesson for new users is that more nodes do not always mean a better network. A pocket node set to client can add traffic without adding reach, and a well-placed infrastructure node on a hill can do far more than ten nodes on the ground. Start with the default role, add a mute role for a second node, and consider infrastructure roles only for fixed locations.

Realistic Range

The numbers quoted for LoRa range can be misleading. The LoRa reference states that the range can reach 330 kilometers in perfect conditions, which is a record-style figure from the project’s own range tests, and approximately 10 kilometers in practical conditions. The Meshtastic range test page lists a ground-to-ground record of 331 kilometers, set with a slow, long-range preset at 868 MHz, a high-gain antenna and a clear line of sight between two high points. That record shows what is possible from hilltop to hilltop. It says little about what a handheld node in a town will do.

In everyday use, expect a few kilometers in the open and much less in cities and forests, and expect your antenna and its height to matter more than the board. As with VHF and UHF in general, a better antenna in a higher place beats more power. Our article on the handheld antenna upgrade applies to these small nodes too, because the stock antenna on a pocket board is usually a compromise.

Limits You Should Know

Meshtastic is not a replacement for either the internet or for amateur voice and data systems. The reference article points out that it is limited to text messaging and cannot serve as an internet replacement, and that bandwidth limits cause congestion when many users try to communicate at once. It cites the example of the 2024 Hamvention, where the network crashed after excessive traffic from a single user’s MQTT bridge, and describes the specialized firmware that developers later created for events with thousands of nodes. In Europe, the duty cycle limit means that a node that reaches its hourly limit stops transmitting until it is allowed again, according to the configuration page.

Security matters too. The ISM configuration offers encryption of messages, and the amateur configuration does not, because amateur rules prohibit it. Be careful about what you send on a mesh in licensed mode: all of it is public. The project’s own legal page states that the devices have not been tested by regulatory organizations and should be considered experimental, so do not depend on them for safety-critical communication.

Where It Fits With Other Ham Systems

A Meshtastic node is one tool among several for off-grid and emergency communication, and each tool has its own strengths.

• APRS reports positions and short messages over VHF through digipeaters and internet gateways. The LoRa reference lists LoRa APRS as a variation of the Automatic Packet Reporting System that uses LoRa. Our article on APRS explains the standard system.
• AREDN builds a high-speed amateur mesh on Wi-Fi hardware and carries real data, not just text. See our AREDN guide.
• Winlink sends email over HF and VHF through gateways. Read about it in our guide to Winlink over HF.
• Voice on VHF and UHF remains the fastest way to coordinate a team, and a handheld with a repeater or simplex net needs no phone.

For hams in emergency communication groups, Meshtastic can be a useful supplement for quick text messages between team members in terrain where other links are weak, and for people who are not hams. It should not replace the training and procedures of an organization such as ARES. See our go kit guide for the equipment that a team normally carries.

Getting Started Safely

1. Choose hardware from the official compatibility list for your region’s frequency band, and buy one with a decent antenna.
2. Set the region first before the node transmits, and use the license-free region unless you plan to operate under your amateur license.
3. Keep the default role and the default preset until you know what the neighbouring nodes use.
4. Read the legal page and the LoRa configuration page before enabling any amateur settings.
5. Find your local mesh community and ask which preset and channel they use, so that your node can hear theirs.
6. Test your range with a second node before you rely on it on a hike.

The Bottom Line

Meshtastic is a LoRa mesh for short text messages that works without a license on ISM bands, and it can also be used on amateur bands in licensed mode, where encryption is not permitted and your call sign must be transmitted. The range depends mostly on the antenna and the terrain, with 10 kilometers a practical figure and 331 kilometers a record from hilltop to hilltop. Set the region first, keep the defaults, understand the roles, and treat the system as a supplement to your amateur radio skills, not a replacement.

Frequently Asked Questions

Do I need a ham license for Meshtastic?

Not for the license-free ISM regions at the power levels the project uses, although national rules vary. You do need an amateur license for the amateur-band regions, which can only be selected in licensed mode.

Can I encrypt messages in licensed mode?

No. The documentation states that encryption is not permitted in the amateur regions and that you must transmit your call sign.

How far does Meshtastic reach?

About 10 kilometers is a practical figure, and the published ground record is 331 kilometers under ideal conditions. Terrain, antenna and preset change the result a lot.

What is the difference between LoRa and Meshtastic?

LoRa is the radio modulation technique. Meshtastic is the mesh networking software that uses LoRa to rebroadcast text messages between nodes.

Why does my node not transmit?

The region may be unset. The documentation says that until you set a region the node shows a message and does not transmit.

Is Meshtastic suitable for emergency communication?

It is useful for short text messages and tracking, but it is limited to text and can become congested, and the project describes the devices as experimental. Use it as a supplement to established amateur radio methods.

FM satellites are where most people start, because a handheld and a small beam are enough to talk through them. But the quieter and more rewarding side of amateur satellite operating is the linear transponder satellite. Instead of a single FM channel, it relays a whole slice of spectrum, so many stations can make SSB and CW contacts at the same time, each on its own frequency, and every signal keeps its natural sound. The price is a little more skill: you have to tune two frequencies, correct for Doppler shift and listen to yourself coming back from space. This guide explains how a linear transponder works, why full duplex is so useful, how Doppler affects your tuning, what AO-7 can teach a beginner, and which habits keep a crowded passband pleasant for everyone.

What a Linear Transponder Is

The ARRL guide to amateur radio satellites describes the difference simply. Linear transponder satellites retransmit an entire slice of spectrum, typically SSB and CW, rather than a single fixed channel. Multiple stations can be on the transponder at once, at different frequencies inside the passband, and the experience is similar to tuning across a band rather than using one repeater channel. The reference article on amateur radio satellites adds that since 1965 most OSCAR satellites have carried a linear transponder for two-way communication in real time, and that amateur satellites may act as repeaters, as linear transponders and as store-and-forward digital relays.

Inside the satellite, the transponder receives a block of frequencies on the uplink band, amplifies them, shifts the whole block to the downlink band and retransmits it. Because the whole block is shifted together, a signal that is 5 kHz above the bottom of the uplink passband appears at a fixed offset in the downlink passband, and two signals keep their spacing relative to each other. Voice stays voice, and CW stays CW. That is the reason it is called linear: the transponder does not demodulate anything, and its output is a faithful copy of its input.

FM Repeater Satellites Compared

The two types of satellite behave very differently for the operator. The table compares them.

The amateur satellite reference notes that frequency modulation is more tolerant of Doppler shift than single sideband, and that FM is much easier to tune manually. Linear satellites are more demanding for that reason. If you have not yet made your first FM satellite contact, start with our introduction to amateur radio satellites, and come back here when you are comfortable with tracking a pass.

Why Full Duplex Matters

On a linear transponder you transmit on one band and listen on another at the same time. If your radio can do this, you hear your own signal coming back from the satellite, a few moments after you speak or send. That is very valuable, because it tells you three things at once: that your signal is reaching the satellite, how strong it is compared with others in the passband, and whether you are on the frequency you intended. The ARRL notes that linear satellites require full-duplex operation, transmitting and receiving simultaneously to hear yourself through the transponder, and more careful tuning, which makes them a natural second step once FM satellite basics are comfortable.

Full duplex can be done with two radios, with a single dual-band transceiver that supports satellite mode or with a receiver and a transmitter that are separate. Use headphones in all cases, because a speaker near the microphone causes feedback and picks up your own audio. If your station is limited to half duplex, CW makes it practical: you can listen between elements, but the experience is harder, and you must tune by calculation rather than by hearing yourself.

Doppler Shift on a Linear Pass

The satellites move at high speed, and the frequencies you hear and the frequencies you must transmit on change during every pass. The amateur satellite reference explains the pattern. While the satellite is moving toward the ground station, the downlink frequency appears higher than normal, so you must tune your receiver higher. At the same time, the satellite receives your uplink at a higher frequency than normal, so your transmitted frequency must be lower for it to arrive at the correct place. After the satellite passes its closest point and begins to move away, the process is reversed. The downlink appears lower and the uplink must be adjusted higher.

The amount of correction depends on the band. Doppler shift is proportional to frequency, so it is larger on 70 cm than on 2 m, and larger on 2 m than on 10 m. On a linear transponder, even a small error moves you away from the station you want to talk to or onto somebody else’s conversation. The reference points out that these corrections are normally calculated by tracking software, and that many modern transceivers have a computer interface that allows automatic Doppler correction. Manual correction is possible, but it is difficult to stay precisely near the right frequency. Our guide to Gpredict, tracking and Doppler control shows how to connect software and radio so that this is done for you.

A Simple Manual Method

If you are tuning by hand, a common technique is to choose the downlink frequency you want to listen to and to leave it where it is on the dial, adjusting only the uplink to keep your signal on the right spot. Another approach is to fix the uplink and tune the downlink. Either way, the principle is the same: tune one, correct the other, and check yourself by listening. Practice on a high-elevation pass in daylight, with the radio, the logging and the tracking all set up before the satellite rises.

AO-7: The Oldest Linear Satellite

For many operators, the first linear satellite is AMSAT-OSCAR 7, usually called AO-7. According to the reference article on AO-7, it is the oldest operational satellite, whether government, scientific, military or commercial, and it carries two amateur radio transponders. The Mode A transponder has an uplink on the 2 meter band and a downlink on the 10 meter band. The Mode B transponder has an uplink on the 70 centimeter band and a downlink on the 2 meter band. It also has beacons on the 10 meter, 2 meter and 70 centimeter bands.

The reference gives details that matter for planning. AMSAT reported AO-7 still operational in 2015, after a period of 21 years during which it was silent, and the satellite has reliable power only from its solar panels. It is eclipsed on every orbit during the northern summer and autumn, and during the rest of the year it is in continuous sunlight and alternates between mode A and mode B. In other words, whether you can use AO-7 on a given day depends on its schedule, so check the current mode before you plan a pass.

The same article explains an interesting regulatory point for United States operators. The Mode B uplink around 432.1 MHz predates the 1979 international allocation of 435 to 438 MHz to the Amateur Satellite Service. The reference says that the IARU band plan marks the 432.1 MHz range as weak signal in all three Regions, and that accessing the Mode B uplink is permitted in the United States under a waiver from the FCC. If you operate from another country, check your national rules for the uplink segment before you transmit. Our article on the 70 cm band summarizes the band plan basics for that part of the spectrum.

Power and Etiquette

A linear transponder has a limited output power, shared among all the signals in the passband. If one station transmits a strong uplink, its downlink can take a disproportionate share of that power and suppress weaker stations. The result is a transponder that sounds crowded with a few loud signals and many that cannot be heard. The widely accepted practice among satellite operators is to use only as much power as it takes to hear yourself at a level no louder than the satellite beacon or the average signal in the passband. If your downlink is louder than the beacon, you are using too much power.

These other habits make a passband a pleasant place to operate:

• Listen first. Spend a minute or two tuning across the passband before you transmit, to find a clear space and to hear the style of operating.
• Keep contacts short. A pass lasts only a few minutes, and a brief exchange of call signs and grid squares lets more people make contacts. Our article on grid squares and the Maidenhead system explains the locator that is usually exchanged.
• Use CW if you can. CW signals are narrow and can be copied through noise and interference that would defeat SSB, and they take less of the transponder’s power.
• Avoid calling CQ on top of others. Move away from an active conversation and leave a gap between stations.
• Respect the beacon. Do not transmit near the beacon frequency at the edge of the passband.
• Log carefully. Record the satellite name, mode, time in UTC, call sign and locator of the other station.

The split between transmit and receive frequencies on the same radio is related to the technique of split operation used on HF pileups. If you want a refresher on the controls involved, read our article on split operation, VFO A/B, RIT and XIT.

Station Requirements

A linear satellite station can be modest. A multimode radio capable of SSB and CW on the downlink band, another for the uplink or a dual-band radio with a satellite mode, a pair of small Yagis or other directional antennas, a way to point them and tracking software cover the basics. The antennas need not be large, but they need to be directional at the higher bands, and many operators use handheld Yagis held by hand or small antennas on a rotator. Circular polarization on the antenna, which is common for satellite work because it reduces fading as a satellite rotates, is helpful, although many stations work with linear antennas and live with the fades. Keep the feed lines short, the connectors weatherproof and the preamplifier close to the antenna if you use one on the downlink band.

The mode and the band combination will determine the equipment. A satellite with a 70 cm uplink and a 2 m downlink, such as AO-7 in Mode B, needs a UHF transmitter and a VHF receiver. A satellite with a 2 m uplink and a 10 m downlink, such as Mode A, needs a VHF transmitter and an HF receiver with a suitable antenna for 10 meters. The geostationary option is different, because it does not move; see our guide to the QO-100 geostationary satellite if you prefer an antenna that stays fixed.

Your First Linear Pass: A Checklist

1. Update the satellite elements in your tracking software and check the pass time, the maximum elevation and the current transponder mode.
2. Set the radios to the correct modes, using the sideband that suits the transponder. Check whether the transponder is inverting or non-inverting, because that changes the direction of tuning.
3. Connect headphones, test the microphone or key and confirm that the tracking software controls the radio frequencies.
4. Start listening a minute before the satellite rises, find the beacon and tune across the passband.
5. When you hear stations, transmit a short call on the uplink at low power and find your own signal on the downlink.
6. Reduce power until your downlink is comparable to the others and make a short contact.
7. Log the contact, and note the time, the satellite and the settings that worked.

The Bottom Line

A linear transponder satellite relays a whole passband of SSB and CW signals, which makes it feel like a small band in space. To use it well, listen to yourself in full duplex, correct for Doppler shift with software or a clear manual routine, and keep your uplink power low enough that your downlink is no louder than the beacon. AO-7 is a historic first satellite for many operators, but check its current mode and your national rules for the uplink. Start with a short, well-prepared pass, and your next contacts will be easier.

Frequently Asked Questions

What is a linear transponder satellite?

It is an amateur satellite that retransmits a whole slice of spectrum, typically SSB and CW, so that many stations can use it at once at different frequencies within the passband.

Do I need full duplex?

It is strongly recommended. Hearing your own signal through the satellite confirms that you are reaching it and lets you adjust your frequency and power.

How does Doppler shift affect me?

The downlink frequency appears higher as the satellite approaches and lower as it leaves, and the uplink must be corrected in the opposite direction. Tracking software or a radio with computer control can do the correction automatically.

Which bands does AO-7 use?

Mode A has a 2 meter uplink and a 10 meter downlink. Mode B has a 70 centimeter uplink and a 2 meter downlink. The satellite alternates between the modes during part of the year.

How much power should I use?

Use the least power that lets you hear your downlink at a level no louder than the beacon or the average signal. A louder signal takes power from other stations.

Can I use a handheld radio?

For FM satellites, yes. For linear satellites you need SSB or CW capability, full duplex and better antennas, so a handheld alone is not usually enough.

Most amateur radio antennas are simple about polarization: a dipole hung horizontally gives horizontal polarization, and a vertical gives vertical. Satellite operators speak a different language. Their antennas are described as RHCP or LHCP, their feed lines go through phasing harnesses, and their preamplifiers switch between two senses. This guide explains what circular polarization in ham radio actually is, why the two directions of rotation are called right-hand and left-hand, why the definition itself is a source of confusion, what happens when linear and circular antennas meet, and which antennas produce a circular wave. The physics follows the standard reference article on circular polarization, and the practical notes tie it to amateur satellite work.

What Circular Polarization Means

Polarization describes the orientation of the electric field of a radio wave. In a linearly polarized wave, such as the one from a horizontal dipole, the electric field oscillates back and forth along one line. In a circularly polarized wave, the reference explains, the electric field has a constant magnitude at each point and rotates at a constant rate in a plane perpendicular to the direction of the wave. If you could follow the tip of the electric field vector as the wave travels, it would trace a helix along the direction of propagation, like a corkscrew.

The reference gives the condition for circular polarization: the two orthogonal components of the electric field must be of equal magnitude and out of phase by exactly 90 degrees, which is one quarter of a wavelength. It is this quadrature relationship that creates the helix. If the components are not equal, or the phase difference is not 90 degrees, the result is elliptical polarization, of which circular and linear polarization are the two limiting cases. Real antennas never produce a perfect circle, and the closeness of the ellipse to a circle is called the axial ratio. The nearer to 1, or 0 dB, the better the circular polarization.

RHCP and LHCP

A circularly polarized wave can rotate in one of two senses. The reference defines right-handed circular polarization, abbreviated RHCP, as the case where the electric field vector rotates in a right-hand sense with respect to the direction of propagation, and left-handed circular polarization, LHCP, as the case where it rotates in a left-hand sense. Which way is which depends on where you stand, and that is where the confusion comes in.

Two Conventions

The reference points out that two opposing historical conventions exist. In the first, polarization is defined from the point of view of the source: you point your right or left thumb away from the source, in the direction of propagation, and the curl of your fingers shows the rotation of the field with time. This convention conforms to the IEEE standard and is generally used by the engineering community, as well as by quantum physicists and radio astronomers. In the second convention, polarization is defined from the point of view of the receiver, and it is used in many optics and chemistry textbooks. The same wave is called right-handed in one convention and left-handed in the other.

For amateur radio, the practical rule is to follow the engineering definition. When a satellite or an antenna manufacturer says RHCP, it normally means the IEEE sense, as seen looking in the direction of propagation. The reference recommends specifying the point of view when there is any doubt, and that is good advice if you build or buy antennas from different sources. It also gives a helpful fact about helical antennas: a right-handed helix radiates a right-handed circularly polarized wave under the IEEE definition, and a left-handed helix responds to left-circular polarization.

What Happens at a Mismatch

Polarization matters because a receiving antenna picks up only the matching component of the wave. The combinations are easy to remember with the table below. The loss values for linear against circular are standard results; real antennas deviate from them, particularly when the axial ratio is poor.

The last two rows explain the appeal of circular polarization. A circular receiving antenna does not care about the orientation of a linear transmitting antenna, and the price is a loss of about 3 dB compared with a perfect match. A linear-to-linear link can be perfect or terrible depending on rotation. That is why circular polarization is used where the orientation of one end is unknown, changing or both. Our article on vertical and horizontal polarization describes the linear case, where cross-polarized links lose a lot of signal and where ground reflections can complicate the picture.

Why Satellites Use It

Amateur satellites are the main place where hams meet circular polarization. A satellite in low Earth orbit tumbles or spins, moves across the sky and changes its position relative to you in a few minutes. A linearly polarized antenna on the satellite would present a constantly changing orientation to the ground station, and the received signal would swing from strong to weak as the angle changes. Circular polarization removes most of the sensitivity to orientation, so the signal is steadier. The reference article on AMSAT-OSCAR 7, notes that it carried a circularly polarized, canted turnstile VHF and UHF antenna system, an example of the technique at work in an early amateur satellite.

The ionosphere gives another reason. A linearly polarized wave passing through the ionosphere can have its plane of polarization rotated, a phenomenon known as Faraday rotation, and the effect is larger at lower frequencies. A circularly polarized wave is not affected in the same way, because rotation of the reference plane does not change a circle. That is one more reason why circular antennas are favoured for links that pass through the ionosphere.

Geostationary satellites do not tumble, but they still use circular polarization in some cases. In our guide to the QO-100 satellite, the uplink is described as right-hand circular, while the downlink is linear. Do not assume that every satellite link uses the same scheme; check the specification for the satellite and the band you plan to use. If you are getting started with satellite operating, read our introduction to amateur radio satellites first.

Reflections Reverse the Sense

The reference explains an effect that matters for anyone who bounces signals off something. The handedness of polarized light is reversed when it is reflected off a surface at normal incidence. The rotation of the plane of polarization of the reflected light is identical to that of the incident field, but because the propagation direction is now opposite, the same rotation that was called right-handed for the incident beam is called left-handed for the reflected one. Right circular polarization reflected from a smooth conductor at normal incidence comes back as left circular polarization. This principle holds strictly at normal incidence only; at other angles the reflected wave generally becomes elliptical.

For hams, this has several consequences. Reflections from buildings, hills or the ground can arrive with the opposite sense, and a circularly polarized antenna of the original sense will reject them to a degree, which can reduce multipath interference. It is also the reason why a signal bounced off a surface, such as a reflector dish, needs to be understood in terms of the reversal when you choose the sense of a feed. For example, a dish with a circular feed may need the opposite sense from that of the direct wave. Always check the documentation of the feed and the dish if you work with one.

Antennas That Make Circular Polarization

The reference lists the standard ways to produce a circular wave, quoting an antenna textbook. They fall into three families, and each is used by amateurs.

Crossed Dipoles and Crossed Yagis

Two crossed dipoles provide the two orthogonal field components. If the two dipoles are identical and fed with a 90 degree phase difference, the polarization along the axis is circular. One way to get the phase difference is to feed one of the two dipoles with a transmission line that is a quarter wavelength longer or shorter than that of the other. This is the principle behind the crossed Yagi, which satellite operators use at VHF and UHF: two sets of elements are mounted at right angles on one boom, and a phasing line gives the quadrature feed. The sense of rotation depends on which dipole is fed with the longer line, so changing the phasing harness changes between RHCP and LHCP. Many satellite stations include a switch so that they can select the sense that matches the satellite, or the one that reduces fading.

The Helical Antenna

The helix is the simplest mechanical circular antenna. For axial-mode operation, the textbook quoted in the reference gives an optimum circumference of about one wavelength and a spacing of about a quarter of a wavelength between turns. The helix radiates along its axis, and its handedness is fixed by the direction in which it is wound. It is popular for satellite work at UHF and microwave frequencies because it is broadband and has a single feed, with no phasing network. Our article on the Gpredict satellite tracking guide shows how to point such antennas with a rotator and track the Doppler shift.

Patch Antennas

For microwave bands, a patch antenna can produce circular polarization when two orthogonal modes are excited with a 90 degree time-phase difference. For a square patch, the easiest way is to feed it at two adjacent edges through a 90 degree power divider. Patch antennas are found in small, flat designs for GPS and for some satellite receive systems.

Practical Tips for Satellite Operators

• Check the satellite specification. Know whether the downlink and uplink are linear or circular, and which sense. The conventions differ between sources, so follow the IEEE definition unless told otherwise.
• Use a switchable sense if you can. A relay or a phasing switch lets you select RHCP or LHCP. If the signal fades, try the other sense, because reflections and the satellite’s orientation can change what works best.
• Do not expect miracles from a handheld antenna. A linear antenna such as a handheld whip or a small Yagi works, but the signal will fade as the satellite moves. Holding the antenna at an angle or rotating it slowly can compensate, and some operators tilt the antenna to find the best angle during a pass.
• Account for the 3 dB. A circular antenna on a linear signal gives up about 3 dB, which is acceptable for a strong signal and visible for a weak one.
• Keep the feed line short and low-loss. At UHF and above, feed line loss matters, and a preamplifier at the antenna may be required.
• Test the antenna. Use a receiver and a known signal to compare the two senses before you rely on the antenna for a pass.

The same ideas apply to other circular systems that amateurs use, including EME at higher frequencies and some ATV and microwave links. If you operate from the International Space Station using a handheld, see our guide to ISS contacts with ARISS for the typical antenna choices.

The Bottom Line

Circular polarization is a wave whose electric field rotates at a constant rate, produced when two perpendicular components of equal strength are 90 degrees apart. RHCP and LHCP describe the direction of rotation, and the engineering convention looks along the direction of travel from the source. A circular antenna picks up any linear signal with about 3 dB of loss, which is why satellite links use it. Reflections reverse the sense, and crossed Yagis, helices and patches are the common ways to build the antennas. Know the sense your satellite uses, bring a way to switch it and keep the 3 dB in mind when you work the weak signals.

Frequently Asked Questions

What is circular polarization?

It is a polarization state in which the electric field of the wave has constant strength and rotates at a constant rate in a plane perpendicular to the direction of travel, tracing a helix along the path.

What is the difference between RHCP and LHCP?

They are the two senses of rotation. In the IEEE engineering convention, the sense is defined from the point of view of the source, looking in the direction of propagation. Optics textbooks often use the opposite convention.

How much do I lose if I receive a linear signal with a circular antenna?

About 3 dB, regardless of the orientation of the linear signal. That is the trade-off for not having to match the orientation.

Why do satellites use circular polarization?

Their orientation relative to the ground station changes constantly, and a circular antenna avoids the deep fades that a fixed linear polarization would cause. It also avoids the effect of Faraday rotation in the ionosphere.

What happens when a circular wave is reflected?

At normal incidence the handedness reverses, so a right-hand wave comes back as a left-hand wave. At other angles the reflected wave tends to become elliptical.

Which antennas make circular polarization?

Crossed dipoles or crossed Yagis fed with a quarter-wave phase difference, helical antennas in axial mode and patch antennas fed at two points with a 90 degree divider.

The ordinary half-wave dipole is the first antenna most amateurs build, and it works well. A folded dipole antenna looks like a small modification: add a second wire parallel to the first and join the two ends. Yet that one change quadruples the feed-point impedance, widens the bandwidth and turns the antenna into something that matches cheap 300 ohm twin lead almost perfectly. This guide explains how the folded dipole works, why the impedance is about 292 ohms, how the number of wires changes the figures, how to build a practical version for an HF band and where the design has limits. The technical description follows the standard reference article on the folded dipole.

What a Folded Dipole Is

The reference defines a folded dipole as a half-wave dipole with an additional parallel wire connecting its two ends. If the extra wire has the same diameter and cross-section as the dipole, two nearly identical radiating currents are produced. The far-field radiation pattern is therefore nearly identical to that of a single-wire dipole, with the same figure-eight shape and the same low gain, but at resonance the feed-point impedance is four times higher.

The reference also gives a useful way to think about the shape. A folded dipole is technically a folded full-wave loop antenna, in which the loop has been bent at opposing ends and squashed into two parallel wires in a flat line. Its broad bandwidth, high feed-point impedance and high efficiency are characteristics more like those of a full loop, even though its radiation pattern looks like an ordinary dipole. Since it is easier to understand a half-wave dipole than a loop, both full loops and folded dipoles are often described as two half-wave dipoles in parallel, joined at the ends.

If you want to remind yourself of the basics first, our guide to your first HF antenna covers the simple dipole and its alternatives.

Why the Impedance Is Four Times Higher

The reason is current. Imagine that the antenna must radiate a fixed amount of power. The total radiating current, which is the sum of the currents in both wires, is twice the current in each wire taken separately, and so it is also twice the current at the feed point. The power radiated depends on that total radiating current and on the radiation resistance of a simple half-wave dipole. The power delivered at the feed point depends on the current in the fed wire, which is only half of the total, and on the feed-point resistance. Setting the two powers equal shows that the feed-point resistance must be four times that of the single dipole.

With the textbook value of about 73 ohms for a resonant half-wave dipole in free space, the folded dipole presents roughly 292 ohms. In real installations the figure changes with height above ground, the surroundings and the wire thickness, so treat 292 ohms as the starting point. Our article on dBi and dBd also uses the half-wave dipole as the reference antenna, which is why its properties matter beyond simple wire antennas.

A Natural Match for 300 Ohm Line

A feed-point impedance of about 292 ohms is very close to the 300 ohm characteristic impedance of flat twin-lead ribbon cable. The reference notes that the folded dipole is therefore well matched to 300 ohm balanced transmission lines. That is why it appears in so many everyday antennas. Half-wave folded dipoles are often used as FM radio antennas, and the versions made of twin lead that hang on a wall are often supplied with FM tuners. They are also widely used as the driven element in rooftop Yagi television antennas, where the high impedance of the driven element is useful because the parasitic elements lower it.

For amateur use, there are two common feeding methods. The first is to connect 300 ohm twin lead directly to an antenna tuner or to a transceiver through a matching network that can handle balanced lines. The second is to use a 4:1 balun at the feed point, which transforms the roughly 300 ohm balanced impedance to about 75 ohms unbalanced, close enough to 50 ohm coax that the SWR is moderate on the design frequency. A balun also isolates the feed line from the antenna and helps to keep common-mode current off the coax. Our guide to baluns and ununs explains the types and when to use each, and it is worth reading before you choose one.

Wider Bandwidth

The second advantage is bandwidth. According to the reference, a folded dipole has a wider bandwidth than a single dipole. The usable range of frequencies, defined by an acceptable SWR, is wider because the antenna behaves partly like a loop and the two conductors share the current. You can see it on the analyzer: the SWR curve of a folded dipole is broader and flatter around resonance than that of a single wire of the same thickness. On the lower HF bands, such as 80 and 40 meters, where a plain dipole may cover only part of the band, a folded dipole can cover a bigger portion without retuning.

The reference adds that the antenna can be used to transform the value of the input impedance over a broad range of step-up ratios by changing the thickness of the conductors on the fed side and the folded side. In other words, a designer can adjust the impedance ratio by using wires of different diameters. For most amateurs building a wire antenna, using two identical wires is easiest, and the four-to-one ratio comes automatically.

More Wires, More Impedance

If two wires multiply the impedance by four, more wires multiply it by more. The reference explains that adding a third parallel wire raises the feed-point impedance to nine times that of a single-wire dipole, which is 658 ohms, a good match for open-wire feed line, and broadens the resonant band further. In general, the radiation resistance is approximately n squared multiplied by 73 ohms, where n is the number of parallel half-wave wires side by side, connected at their ends. The table summarizes the pattern.

The reference also describes a variant in which each parallel wire is slightly too short by the same amount, and a capacitive loading wire, usually dangling, is connected at each end to restore resonance. That design achieves nearly as good performance as the full flattened-loop version in a shorter space.

Building a Twin-Lead Folded Dipole

A folded dipole made from 300 ohm twin lead is cheap and quick to build. The steps below are a general guide; adjust the details for your band and your installation.

1. Choose the band and calculate the length. The starting length of a half-wave dipole in feet is about 468 divided by the frequency in megahertz, but twin lead has a velocity factor that shortens the electrical length, and the exact figure depends on the cable. Cut a little long, and plan to trim. Our article on velocity factor explains why cable and wire lengths do not match the free-space numbers.
2. Join the two conductors at both ends. The two wires of the twin lead are shorted together at each end, which forms the loop. Solder the connections and seal them against moisture.
3. Cut one conductor at the center. The feed point is a gap in one of the two wires at the center of the antenna. The two cut ends connect to the feed line.
4. Attach the feed line. Connect either a 300 ohm twin lead feed line or a 4:1 balun at the center. Use a strain relief so that the weight of the line does not pull on the joint.
5. Hang it up. Support the ends with insulators and keep the antenna clear of metal objects. Keep it as high and as straight as practical.
6. Measure and trim. Use an antenna analyzer to find the resonant frequency and shorten the antenna evenly at both ends if it is too low in frequency. If you do not have an analyzer, see our guide to the NanoVNA antenna analyzer, which shows how to take a sweep.

Twin lead is light and flexible, but it has weaknesses. Rain and ice change its characteristics, and the plastic can deteriorate in sunlight over the years, so inspect it regularly and replace it when it cracks. If you need a more durable version, you can make the antenna from two separate wires held apart by spacers, or from ladder line, which is less affected by weather. The article on ladder line versus coax compares the feed line types.

Where Folded Dipoles Are Used

The reference lists several of the best-known uses. The folded dipole is used as an FM broadcast receiving antenna, as the driven element of rooftop television Yagis and in many other broadband antennas. It is also the basis of at least one amateur design. The T2FD antenna is a folded dipole with a resistor added on the second wire, opposite the feed point, which produces a very wideband antenna at the cost of some efficiency. We cover it in our guide to the T2FD antenna.

In Yagi design, the folded dipole is a popular driven element because the parasitic elements around it reduce its impedance. When the impedance falls by a factor, the folded design brings it back toward a convenient value. That is why many commercial VHF and UHF Yagis use a folded dipole in the driven position.

Limits to Keep in Mind

The folded dipole is not a miracle antenna. It does not add gain over a regular dipole at the same height, because the radiation pattern is nearly the same as that of the single-wire version. The extra wire adds weight, wind load and complexity, and the high impedance means that you need a matching device or a balun when you use coax. It is also normally resonant on one band; on other bands the feed-point impedance changes in a complicated way, and while a tuner and balanced line may allow multiband use, that is a different approach from the single-band design discussed here.

Height and surroundings matter as they do for any horizontal wire. A folded dipole mounted low over poor ground will have a different impedance and pattern than one mounted at a half wavelength. If you want to understand how height changes things, read our article on antenna height and takeoff angle. Common-mode current on the feed line can also distort the pattern and bring noise into the receiver, so a good balun or choke at the feed point is worth installing.

The Bottom Line

A folded dipole is a half-wave dipole with a second parallel wire joined at both ends. The pattern stays the same as that of a simple dipole, but the feed-point impedance rises to about 292 ohms, the bandwidth increases, and 300 ohm twin lead or a 4:1 balun can feed it without trouble. Add a third wire and the impedance rises to about 658 ohms, and in general it grows with the square of the number of wires. It is an inexpensive project for a single band, a useful driven element for a Yagi and the starting point for broadband designs such as the T2FD.

Frequently Asked Questions

What is the impedance of a folded dipole?

About 292 ohms at resonance, which is four times the roughly 73 ohms of a simple half-wave dipole. The exact value changes with height, wire thickness and surroundings.

Does a folded dipole have more gain?

No. The radiation pattern is nearly the same as that of an ordinary dipole, so the gain is similar. The advantages are the higher impedance and the wider bandwidth.

How do I feed a folded dipole with coax?

Use a 4:1 balun at the feed point. It transforms the balanced impedance of about 300 ohms to about 75 ohms unbalanced, which is close to 50 ohm coax.

Can I make one from 300 ohm twin lead?

Yes. Short the two conductors together at both ends, cut a gap in one conductor at the center for the feed point, and trim the length with an analyzer. Allow for the velocity factor of the cable.

What happens with three wires?

The impedance rises to nine times that of a single dipole, about 658 ohms, which suits open-wire feed line, and the resonant bandwidth broadens further.

Is a folded dipole good for multiband use?

Not by itself. It is designed for one band, although a tuner and balanced feed line can make it usable on others with some loss.

Some antennas are famous because they are easy to build, and some are famous because they are enormous. The rhombic antenna belongs to the second group. It is a diamond of four horizontal wires, each one to several wavelengths long, strung from poles or towers high above the ground, and for decades it was one of the main tools for long-distance shortwave communication. Few amateurs have the land to build one, but the design is still worth understanding, because it shows how a directional antenna can be wideband, why traveling-wave antennas are terminated, and what the real costs of high gain look like. This guide explains how a rhombic works, what a terminated and an unterminated version do, what the advantages and disadvantages are, and whether a radio amateur might ever consider one. The technical description follows the standard reference article on the rhombic antenna.

What a Rhombic Antenna Is

The reference defines a rhombic antenna as a type of radio antenna made of four sections of wire suspended parallel to the ground in a diamond or rhombus shape. All four sides are the same length, and the length is not critical. It is typically from one to two wavelengths for each side, and for any chosen length and frequency, there is an optimum angle at which the sections should meet at the acute vertices. The reference mentions about 42 degrees at the fed end and at the far end as a typical figure, but the correct angle depends on the design.

A horizontal rhombic radiates horizontally polarized waves at a low elevation angle, off the pointed end of the antenna that is opposite the feed point. Its main advantages are simplicity, high forward gain, wide bandwidth and the ability to operate over a wide range of frequencies. It is fed at one of the two acute vertices, through a balanced transmission line or a coaxial cable with a balun. The opposite vertex is either left open or terminated with a non-inductive resistor. That one choice, open or terminated, changes the antenna’s behaviour completely.

How It Works

The easiest way to think about a rhombic is as four long wires that each radiate a pattern with main lobes at an angle to the wire. A long wire does not radiate evenly like a short dipole; with a length of a wavelength or more, the pattern splits into lobes that point toward the wire’s ends at angles that depend on its length. The diamond shape is chosen so that one of the main lobes from each of the four sides points in the same direction, and the four contributions reinforce each other. The reference illustrates this with a diagram of the radiation patterns of each segment, and states that using the correct vertex angle makes the lobes line up and increases the gain.

That geometry explains two things. First, it explains why the correct angle depends on the length and the frequency: the lobes of a long wire move as the electrical length changes, and the angle must be chosen so that they remain aligned. Second, it explains why the antenna has useful performance over a wide frequency range. As the frequency changes, the lobes shift only slowly, so the alignment degrades gradually rather than collapsing. The reference notes that the input impedance and the radiation pattern are relatively constant over a 2:1 range of frequencies, and that the impedance can be kept fairly constant over a range of 4:1 or more, with the forward gain increasing at about 6 dB per octave.

If you want to refresh the terms used for lobes and beamwidth, our article on the antenna radiation pattern explains them.

Terminated or Open?

The termination decides whether the rhombic is a one-way antenna or a two-way antenna.

The Terminated Rhombic

When the wires meeting at the far vertex are joined by a non-inductive resistor, the antenna becomes a traveling-wave antenna. The current wave that flows along the wires from the feed point is absorbed at the end instead of reflecting back. With the reflection removed, the radiation pattern is unidirectional, with the main lobe off the terminated end. That end of the antenna is oriented toward the intended receiving station or region. The cost is power. A resistor that absorbs the wave also absorbs energy that could have been radiated, and in a transmitting antenna it must be able to dissipate a large part of the transmitter’s power.

The Unterminated Rhombic

When the far end is left open, a reflected wave travels back along the wires. The rhombic then radiates in both directions, with two opposite lobes off the two acute ends, although the reference points out that it is not perfectly bidirectional. This version is simpler and wastes less power in a resistor, but it gives up some of the cleanliness of the pattern and the broadband behaviour of the terminated antenna.

Amateurs who have built Beverage antennas for low-band receiving will recognize the principle. A Beverage is also a terminated traveling-wave wire, and the resistor at the far end is what gives it a clear direction. Our article on low band receive antennas describes how that works in practice, and the reference article on the Beverage antenna gives the formal definition. A rhombic can be thought of as a high-gain, diamond-shaped relative of that family.

Improving the Efficiency With a Stub

The reference mentions an interesting way to recover some of the lost power. It is possible to improve the low efficiency and gain of unidirectional rhombics by replacing the termination resistor with a low-loss, balanced, resonant stub transmission line. The stub reflects the power that would have been wasted in the resistor back into the antenna with the correct phase to reinforce the excitation from the transmitter. According to the reference, this arrangement can increase the radiation efficiency of transmitting antennas to the 70 to 80 percent range, at the cost of increased complexity. The picture in the article shows a horizontal three-wire rhombic terminated with a resonant stub, not a resistor, for this purpose.

A Short History

The reference says that the rhombic antenna was designed in 1931 by Edmond Bruce and Harald Friis, and that it was most commonly used in the high-frequency or shortwave band as a broadband directional antenna. Before World War II, it was one of the most popular point-to-point high-frequency antenna arrays. After the war it largely fell out of favour for shortwave broadcasting and point-to-point communication, and it was replaced by log-periodic antennas and curtain arrays. Large log periodics provide wider frequency coverage with comparable gain, and curtain arrays give a cleaner pattern, the ability to steer in elevation and azimuth, much higher efficiency and higher gain in less space.

The rhombic has not disappeared, however. The reference notes that it remains useful where the combination of high forward gain and large operating bandwidth cannot be achieved by other means, or where a directional antenna is needed but construction and installation costs must be kept low. It is also used for reception, and the article gives the example of a monitoring station in the United Kingdom with three rhombics aligned for reception at three different azimuths. If you want to see a more modern wideband directional antenna that hams can build, read our guide to the log periodic dipole array.

Advantages and Disadvantages

The rhombic’s advantages are the reasons it was used so widely. It is simple, with no moving parts and no complicated phasing network. It is reliable, because it is mostly wire and poles. It handles considerable transmitter power, because the voltage and current distribution along the wires is essentially uniform. It is wideband, so one antenna can serve a range of frequencies. And several rhombics can be connected end to end in the arrangement known as a MUSA, a Multiple Unit Steerable Antenna, which was used for receiving long-distance shortwave signals.

The disadvantages are just as real. A rhombic requires a large area of land, especially if several antennas are installed to serve different directions or regions, or to cover widely different frequencies. It suffers from efficiency problems because of earth losses under the antenna, spurious lobes that waste power, losses in the termination and the inability to maintain constant current along the conductors. The reference gives a typical radiation efficiency of 40 to 50 percent, and says that the low efficiency significantly reduces the gain for a given main lobe beamwidth compared with other arrays of the same beamwidth. In other words, a rhombic is not the most efficient way to produce a given amount of gain, but it can be one of the cheapest and simplest.

How Big Is It at HF?

The size is the first obstacle, and it is easy to calculate. The wavelength in meters is roughly 300 divided by the frequency in megahertz. At 14.2 MHz the wavelength is a little more than 21 meters, so a rhombic with each side two wavelengths long has legs of about 42 meters, roughly 138 feet, for a total of four legs. At 7.1 MHz, the same design has legs of about 84 meters, or 277 feet. Even at 28 MHz, where the wavelength is about 10.7 meters, a two-wavelength leg is about 21 meters or 70 feet. The antenna also needs supports at all four vertices, and those must be high enough to give the right takeoff angle, which depends on the height above ground compared with the wavelength. Our guide to antenna height and takeoff angle explains why height matters.

The reference says that the rhombic can radiate at elevation angles close to the horizon or at higher angles, depending on its height above the ground relative to the operating frequency and on its physical construction. A low radiation angle is useful for skywave propagation, in which the waves directed toward the horizon reflect from the ionospheric layers and come back far beyond the horizon. That is why rhombics were so popular for long-distance circuits. A beam of this kind, pointed at one region and giving a low angle of departure, is what a DX operator wants.

Could a Radio Amateur Use One?

For nearly all amateurs, a classical rhombic is impractical. The land requirement alone rules it out for suburban lots, and a multiband station would need several different rhombics or a compromise design. The antenna is fixed, so it points in one direction without a rotator, and that is a strength for a circuit that always works the same region and a weakness for a station that wants to work the world.

That said, there are situations where the idea makes sense. A club with access to a large field could build a rhombic for a single band and a single region, perhaps for a special event or a receiving project. A DXpedition team, or a station on a farm or at a remote site, could consider a smaller design for a single band. Others will be better served by a Yagi, a quad or a log periodic. Our comparison of the Yagi and the hex beam shows how a more compact directional antenna compares. If you do plan any large wire antenna, model it first, as described in our guide to antenna modeling with EZNEC and 4nec2, because the lobes and the termination values depend on the exact geometry.

Practical Cautions

• Mind the safety clearances. A rhombic is supported by tall poles or towers, and a wire that falls across a power line is a serious hazard. Read our article on tower safety before working at height.
• Use a proper termination. The resistor must be non-inductive and rated for a large part of the transmit power. An underrated resistor will fail quickly.
• Plan the feed system. The feed point impedance is high compared with 50 ohm coax, so a matching network or a balanced line with a balun is needed.
• Check local rules. A large wire structure may need permission from the landowner and from local authorities.

The Bottom Line

A rhombic antenna is a diamond of four equal wires that combine four long-wire lobes into one strong beam off the far end. A terminated rhombic is unidirectional, wide in bandwidth and simple, but it wastes a large part of the power in the termination, and its typical efficiency is only 40 to 50 percent. It needs a great deal of land and tall supports, which explains why log periodics and curtain arrays replaced it in many professional services. For amateurs it is mostly a teaching example and a rare project for people with a field, but it explains traveling-wave antennas, wideband design and the trade-off between gain and efficiency better than almost any other antenna.

Frequently Asked Questions

What is a rhombic antenna?

It is an antenna made of four wires of equal length suspended horizontally in a diamond shape. It gives high forward gain and wide bandwidth, and it radiates horizontally polarized waves at a low elevation angle.

Why is a rhombic terminated with a resistor?

The resistor absorbs the wave at the far vertex so that it does not reflect back. This makes the pattern unidirectional, with the main lobe off the terminated end, at the price of wasted power.

How efficient is a rhombic antenna?

The reference gives a typical radiation efficiency of 40 to 50 percent because of earth losses, spurious lobes and termination losses. A resonant stub in place of the resistor can raise it to the range of 70 to 80 percent.

Which bands can it cover?

The input impedance and the pattern are relatively constant over a 2:1 frequency range, and can be held over a 4:1 range or more, so one rhombic can cover several nearby bands, though the best performance is at the design frequency.

Why did the rhombic fall out of use?

After World War II it was replaced in many services by log-periodic antennas and curtain arrays, which offer wider coverage or more gain and efficiency in less space.

Can I build one at home?

Only if you have a very large area and tall supports. For most amateurs, a Yagi, a quad or a log periodic is a more practical way to get a directional HF antenna.

On the first day of every year, a different kind of event takes over the CW portions of the HF bands. Straight Key Night is not a contest, nobody keeps score, and the goal is simply to sit down with a straight key, or perhaps an old bug, and have a relaxed conversation in Morse code. This guide explains what the ARRL says about the event, when it takes place, how the exchange differs from a contest exchange, how the voting for Best Fist and Most Interesting QSO works, and how to prepare your key and your sending so that you enjoy it. All the event details come from the official ARRL page; check it before January 1 in case anything has changed.

What Straight Key Night Is

The ARRL page for Straight Key Night describes it as a 24-hour event that is not a contest, but a day dedicated to celebrating our CW heritage. Participants are encouraged to get on the air and make enjoyable, conversational CW contacts. The use of straight keys or bugs to send is preferred. There are no points scored, and the ARRL says that all who participate are winners.

That description is the whole point. In a contest, the aim is to exchange the minimum information at the highest rate. On Straight Key Night the opposite applies: slow down, make your own Morse sound human, and talk about the weather, your station, the key you are using and the radio you built in 1978. If you have ever wished that CW contacts were more than a string of 599 and a serial number, this is the day for you. Our guide to ragchewing includes ideas for keeping a conversation going.

When and Where

Straight Key Night is held every January 1 from 0000 UTC through 2359 UTC. Because it is defined in UTC, the event starts in the evening of December 31 in North America and runs until the evening of January 1, so a New Year’s Eve party and the first hours of the event overlap in some time zones. In 2027, January 1 falls on a Friday.

The ARRL says that all authorized amateur frequencies may be used, but activity has traditionally been centered on the HF bands. In practice, you will find stations on the CW sub-bands of 80, 40 and 20 meters and sometimes on 160 meters, with the best band depending on time of day and propagation. Tune across the CW segments, listen for slow, deliberate sending and answer someone who sounds like they are having fun.

Straight Key, Bug or Paddle?

The ARRL prefers straight keys or bugs, because the event is about the human hand. The table below summarizes the most common keys you will meet, and the general reference article on the telegraph key describes how these devices developed.

If you only own a paddle, you can still join the fun, and you will find that many operators on the air are friendly toward newcomers. But if you can borrow or buy an inexpensive straight key, the experience is much closer to the intention of the event. Our guide to CW keys compares the types in more detail and shows what to look for when you buy one.

The SKN Exchange

There is no required exchange, but there is a tradition that tells other operators that you are taking part. The ARRL’s article on the event explains that, when participating, you should send the letters SKN before sending the signal report, instead of sending only the RST. That tells passers-by who may be tuning across the band that Straight Key Night is still going strong, and it lets participants recognize each other. A typical call might be CQ SKN, followed by your call sign, and a reply with the other station’s call sign, SKN, the signal report, your name and your location.

After that, the conversation can go anywhere. Common topics include the key you are using, your station, your age and how long you have been licensed, the weather at your location, and how the year is starting. The abbreviations are the ordinary ones used in CW conversation, which you will find in our guide to CW abbreviations and prosigns. If you want a refresher on reports, see our explainer on RST signal reports.

Voting for Best Fist

The one competitive element is a pair of votes. According to the ARRL, after Straight Key Night you send the Contest Branch a list of the stations you contacted, plus your vote for the best fist you heard. The vote does not have to be for a station you worked, because it is meant to reward good sending that you heard on the band. You can also vote for the most interesting QSO you had or that you monitored. The votes for Best Fist and Most Interesting QSO are tabulated and included in the results.

Entries must be received by January 31. You can send your information by email to the address shown on the ARRL page or by mail to the ARRL at its Newington address. Because the event uses a simple list rather than a Cabrillo file, you do not need contest software, and a plain text list is sufficient. The ARRL also invites you to post comments and photographs on its contest soapbox page, which becomes an online collection of stories and pictures. The terms of entry say that log contents are available to the public, all entries become the property of the ARRL, and entrants agree to follow the regulations of their national licensing authority.

What Makes a Good Fist

A fist is the individual character of a person’s Morse sending. A good one is not about speed. It is about rhythm, spacing and clarity, and the operators who win votes are usually those whose code is easy to copy and pleasant to listen to. If you want yours to be one of them, work on these habits before January 1:

• Keep the timing consistent. A dah should be about three times the length of a dit, and the gaps between letters and words should be even. The commonest fault with a straight key is rushing the spaces. Practicing with a metronome or with a code practice program helps.
• Send at a speed you can control. A steady 12 or 15 words per minute sounds better than a hurried 25 with errors. Beginners often copy this speed more easily too.
• Leave a clear word space. Many listeners can copy individual letters but lose the words if you run them together.
• Do not hold the key down. A relaxed hand and wrist produce a smoother rhythm than a tense one.
• Listen to yourself. Record your sending and play it back. You will hear problems that you do not notice in real time.

If you need help with speed and technique, our article on learning Morse code and building CW speed offers a practice plan.

Adjusting Your Key

A straight key is a simple mechanical device, but small adjustments change how it feels. The two main ones are the contact gap and the spring tension. If the gap is too wide, your hand has to travel further for every element, which tires you and slows your sending. If it is too narrow, the contacts may chatter or close by accident. Spring tension has a similar trade-off: too light and the lever feels floppy, too heavy and the hand tires. Start with the manufacturer’s setting, then adjust a little at a time until the key feels comfortable for a long conversation.

Mount the key on a heavy base or a piece of wood so that it does not slide on the table, and place the whole arm on the desk so that you are not lifting it. A good chair and a sensible height matter more than most people expect. If you use an older key, clean the contacts and check that the wiring is secure. Finally, make sure that the radio’s keying circuit is set up correctly for a plain key line, and check how your transceiver’s break-in or semi-break-in delay is set, because a poorly set delay will clip the first or last element. See our article on full break-in and QSK for the settings.

Vintage Radios and Home-Built Gear

The ARRL’s story about the event notes that the number of entries has grown, and that many participants use it to test and show off vintage equipment. Some plug in their old bugs and join, and others simply enjoy the relaxed, CW-enriched setting. If you have an old transmitter, a restored receiver or a home-built rig, this is the day to put it on the air. Be careful with older gear, though: check that it is stable, that the signal is clean and that it does not splatter or drift beyond the band edge. Our article on key clicks and a clean signal explains what to listen for, because hard keying on older transmitters can produce clicks that disturb neighbouring stations.

Low power is welcome, too. Many straight key enthusiasts also like QRP, and a few watts into a simple wire can make contacts across continents when conditions are good.

Making the Most of the Day

Because the event lasts a full UTC day, you do not need to sit at the radio for 24 hours. A few simple choices make it enjoyable.

• Pick a time when you are fresh, and operate for an hour or two rather than forcing a marathon.
• Call CQ SKN at a slow speed, and answer calls at the speed of the caller.
• Keep a short note of the stations you work and any interesting details of the conversation, because you will want them for your vote.
• Take photographs of your key and your station for the ARRL soapbox if you like.
• Invite a friend who is learning CW to listen along.

Tips for Beginners

If you have only recently learned the code, Straight Key Night is one of the best days of the year to make your first CW contacts, because the operators on the air are there to talk rather than to race. Do not be afraid to say that you are new. Many experienced operators will slow down for you, repeat what you missed and enjoy being asked about their key. Keep a pad and pencil next to the radio, write down the call sign first, and ask for a repeat with a question mark if you did not copy something. Short exchanges are fine: a call sign, a name, a location and a thank-you is a complete and satisfying contact, and you can add more as your confidence grows. The most common mistakes are sending too fast, running words together and forgetting to listen before transmitting, and each of them is easy to correct once you know about it.

The Bottom Line

Straight Key Night is a 24-hour, no-score celebration of hand-sent Morse on January 1, from 0000 to 2359 UTC. Use a straight key or a bug if you can, send SKN before the report to show you are taking part, have a real conversation, and vote for the best fist you heard and the most interesting QSO. Send your list and votes to the ARRL by January 31. Work on your timing and your key setup beforehand, and the day will be as much fun for you as it is for the person who hears your sending.

Frequently Asked Questions

Is Straight Key Night a contest?

No. The ARRL describes it as a day dedicated to celebrating CW heritage. No points are scored, and the emphasis is on conversational contacts.

When does it take place?

Every January 1, from 0000 UTC to 2359 UTC. Check your local time, because the UTC day starts on December 31 in the evening in the Americas.

Which bands can I use?

All authorized amateur frequencies are allowed, although activity has traditionally been centered on the HF bands.

What does SKN mean in the exchange?

Participants send the letters SKN before the signal report so that others know they are taking part in Straight Key Night.

Can I use a paddle?

You can join with any key, but the ARRL prefers straight keys or bugs because the event is about hand-sent CW.

How do I vote and report?

Send the ARRL a list of the stations you contacted, your vote for the best fist you heard and your vote for the most interesting QSO, so that it is received by January 31.

The first full weekend of January brings one of the friendliest events for anyone who enjoys keyboard modes: the ARRL RTTY Roundup. It is a 30-hour contest in which every contact is made on Radioteletype, the stations are spread across five HF bands, and the exchange is short enough to learn in a minute. This guide covers the dates, the rules about modes and bands, the exchange for W/VE and DX stations, the way the score is calculated, the unusual 24-hour off-time rule, the categories and the log submission steps. The rules described here come from the official ARRL contest page and the rules document published by the ARRL, so check the current version before the contest, because rules are revised from time to time.

What the ARRL RTTY Roundup Is

The ARRL contest page describes the event as one in which amateurs worldwide contact and exchange QSO information with other amateurs using only the RTTY mode on the 80, 40, 20, 15 and 10 meter bands. Any station may work any other station, so unlike some ARRL events there is no split between domestic and DX stations. The event is popular because it invites newcomers to digital contesting: the signals are narrow, the software is mature, and a modest station with a good computer can make a lot of contacts.

Two rules set the tone. First, only RTTY counts. The ARRL created a separate International Digital Contest for people who want to use other digital modes, and the RTTY Roundup page makes the distinction clear. Second, automated operation is not permitted. The ARRL states that each claimed contact must include contemporaneous direct initiation by the operator on both sides of the contact, so unattended robots do not count.

Dates and Times

The contest runs on the first full weekend of January, but never on January 1. It begins at 1800 UTC on Saturday and ends at 2359 UTC on Sunday, which makes a 30-hour contest period. In 2027, January 1 falls on a Friday, so the first full weekend is 2 and 3 January. The official dates are maintained in the ARRL contest calendar, and you can also compare them with the independent contest calendar before you plan the weekend.

The timing is useful. The Saturday start at 1800 UTC gives European stations the evening and North American stations the afternoon. By the time darkness reaches the middle of North America, the lower bands open, and the second half of the contest moves into the Sunday daytime when 20, 15 and sometimes 10 meters are busy.

Bands, Mode and Contact Rules

The rules limit the bands to 3.5, 7, 14, 21 and 28 MHz. Use only RTTY, and log your contacts with the RY mode abbreviation in the Cabrillo file. You may contact each station once per band, regardless of mode, so you can work the same station again on another band. The 160, 30, 17 and 12 meter bands are not used, which concentrates the activity on the five allowed bands.

The ARRL RTTY Roundup is not the only RTTY event of the year, and the operating practice has much in common with other contests. If you are new to the mode, our RTTY contesting guide describes the software and tuning basics, and our Fldigi setup guide shows how to set up a sound card interface and macros if you prefer that program.

The Exchange

The exchange has two parts, and what you send depends on where you are.

• W/VE stations, meaning stations in the United States and Canada, send a signal report and their US state or Canadian province.
• DX stations send a signal report and a serial number that begins with 1.

In RTTY contests the signal report is 599. A typical contact shown in the ARRL rules goes like this: W1PY calls CQ RU, K9CT answers, W1PY sends K9CT 599 CT, K9CT replies 599 IL, and W1PY closes with TU. A DX station would send a serial number in place of the state, for example 599 428. The rules point out that the answering station does not need to send the CQing station’s call sign before the exchange unless there is confusion.

A tip for DX stations: the serial number must start at 1 and increase with each contact. Your logging software normally does this automatically, but check the setting before the contest, because a serial number that does not increase is easy to get wrong when you restart the program.

Scoring

The scoring is simple. Each contact counts for one QSO point. To calculate the final score, multiply the total QSO points by the number of multipliers. The multipliers are the DXCC entities, not including the US and Canada, plus the US states and the District of Columbia, plus the Canadian provinces and territories, including Labrador. Each multiplier counts once, not once per band. Hawaii and Alaska count as DXCC entities. The ARRL provides a contest multipliers list with the abbreviations.

Because every contact is worth only one point, the multipliers drive the score more than the QSO count does. The multiplier is counted once and not per band, so the first contact with a new state is a bonus on any band. The second contact with that state on another band adds a QSO point but not another multiplier. This is different from contests where multipliers are counted on each band, and it changes how you spend your time. Look for new multipliers first, then add contacts on the band you are already using.

The 24-Hour Off-Time Rule

The rule that surprises newcomers is the off-time requirement. Single-operator stations may operate up to 24 hours of the 30-hour period. Multioperator stations may operate the entire 30 hours. After your first contact, you may take up to six hours of off time in one or two breaks, and each break must be at least 30 minutes long. The log checking software counts the two longest breaks in your log and treats those as your two off times. Additional breaks and breaks shorter than 30 minutes are ignored. The time before your first contact and after your last one does not count as off time.

The ARRL page gives examples that satisfy the rules. You could start at 1800 on Saturday and operate 24 hours straight. You could start an hour late at 1900, take two two-hour breaks, and end at 2300, an hour early. Or you could start at 1800, operate 12 hours, sleep 5.5 hours and finish at 2330. If you take several 30-minute breaks, only the first two are counted toward the required six hours.

The checking process calculates your score over the first 24 hours of operating time. You are encouraged to keep operating after that, because there is no penalty and the stations you contact still get credit for the contact. Do not delete those contacts from your log. The ARRL explains that the intent is to add an element of strategy: you cannot simply take many short breaks, so you must decide when to sleep based on propagation and your own stamina. For more on planning rest, see our article on rest and time management in 24 and 48-hour contests.

Categories and Power Levels

The rules list Single Operator in all power categories and Single Operator Unlimited in all power categories. Multioperator entries can be Single Transmitter, with low and high power, Two Transmitter with high power, or Multitransmitter with high power. The power sub-categories are the standard ARRL definitions: QRP is 5 watts PEP output or less, low power is 100 watts or less, and high power is 1500 watts or the limit set by your national licensing authority, whichever is less. For more detail on what categories mean in practice, see our guide to contest categories explained.

The rules include a Limited Antennas Overlay. Any Single Operator or Single Operator Unlimited entrant can enter with it if they use only single-element antennas, such as a single vertical, an end-fed wire or a single dipole, no more than 50 feet above ground at its highest point. Multiband verticals and dipoles with fan or trap constructions are acceptable. The overlay is a good option for stations with a simple wire antenna that want a fair comparison.

Operating Tips for RTTY

RTTY contesting has its own habits. The ARRL does not tell you how to tune, but the practices below are widely used by contesters and fit the rules.

Set Up the Software Before the Contest

Choose your decoding program and test it with the radio, the sound card interface and your logging program. Amateur RTTY normally uses 45.45 baud with a shift of 170 Hz, and most contest software is preconfigured for that. Create macros for CQ, the exchange and the thank-you message, and confirm that the exchange fields are correct for your location. A mistake in a macro is repeated hundreds of times.

Keep the Signal Narrow and Clean

RTTY is a constant-carrier mode, so the transmitter works hard for the entire transmission. Reduce the drive level so that the amplifier and the radio stay within their duty cycle, and avoid overdriving the audio, which creates extra products that disturb neighbouring stations. Our article on keeping your signal clean includes the general principles.

Chase Multipliers Early

Since multipliers count only once, early in the contest every new state is valuable. A common approach is to run a frequency while the rate is good and tune the band for new multipliers when it slows. When the multipliers run out, stay on the band that gives the best rate.

Use Time Zones to Your Advantage

If you are in Europe, expect strong openings toward North America in the late afternoon and evening, and use the earlier hours on 20 and 15 meters for Asia and the Pacific. In North America, the lower bands offer long-path and European openings in the evening and at night. Plan your off time during the slowest period at your location.

Logs and Awards

Logs are due within seven days after the contest ends at 2359 UTC. Electronic Cabrillo logs are the preferred method and must be uploaded through the ARRL web application. Paper logs can be mailed, but the ARRL recommends a delivery method with a tracking number. If you need to convert a log to Cabrillo, the ARRL page points to a conversion tool. The ARRL notes that for all ARRL and IARU HF contests beginning 30 September 2026, only online log submission will be accepted, so plan to upload your file. Our Cabrillo and UBN guide explains the file format and the log checking process.

Certificates are awarded to the top high power, low power and QRP single-operator scorers, and to the top high power and low power multioperator scorers, in each ARRL or RAC section and DXCC entity other than W/VE. If plaques are sponsored, they go to the top low and high power entrants in each category overall, in each ARRL division and in Canada. The RTTY Roundup is also one of the ten ARRL events designated as an Affiliated Club Competition, so you can contribute your score to your club by selecting the club name when you upload the log. The detailed conditions are in the official RTTY Roundup rules document.

The Bottom Line

The ARRL RTTY Roundup is a short, well-defined contest: RTTY only, five HF bands, 599 plus a state, province or serial number, one point per contact and a multiplier for every state, province and DXCC entity. The unusual part is the 24-hour limit for single operators, which turns your sleep schedule into strategy. Prepare your software and macros, learn the off-time rule, chase multipliers early, and upload a Cabrillo log within seven days.

Frequently Asked Questions

When is the ARRL RTTY Roundup?

It is held on the first full weekend of January, but never on January 1. It starts at 1800 UTC on Saturday and ends at 2359 UTC on Sunday.

Which bands and modes are allowed?

Only the 3.5, 7, 14, 21 and 28 MHz bands and only the RTTY mode. Contacts are logged with the RY mode code in the Cabrillo file, and automated operation is not permitted.

What do I send in the exchange?

W/VE stations send a signal report and their state or province. DX stations send a signal report and a serial number that starts at 1.

How is the score calculated?

Each contact is worth one point. The total is multiplied by the number of multipliers, which are DXCC entities other than the US and Canada, US states and DC, and Canadian provinces and territories. Each multiplier counts once, not once per band.

Can a single operator work all 30 hours?

You can keep operating, but only 24 hours count toward your score. Off time must be taken in one or two breaks of at least 30 minutes each, and the log checker uses the two longest breaks.

How do I submit my log?

Upload a Cabrillo log through the ARRL web application within seven days after the contest. The ARRL notes that from 30 September 2026 only online log submission is accepted for ARRL and IARU HF contests.

Every December, the quietest and most demanding band in amateur radio gets a weekend of concentrated activity. The ARRL 160 meter contest is a CW-only event on 1.8 MHz, and it is one of the few contests where a modest antenna, a dark winter evening and a good receiver can matter more than raw power. This guide explains the dates and hours, the exchange, how the points and multipliers work, the categories, the log rules and the practical choices that decide a score on Top Band. Everything about the rules comes from the official ARRL contest page and the rules document published there; check the current version before you operate, because the details are revised from time to time.

What the Contest Is

According to the ARRL 160 Meter contest page, the objective is for amateurs worldwide to exchange information with W/VE amateurs on 160 meter CW. That wording matters, because it sets up an unusual structure. W/VE stations, meaning stations in the continental United States and Canada, may work anyone. DX stations may work only W/VE stations. A contact between two DX stations does not count for contest credit, however good the signal was.

The contest uses only the 1.8 MHz band and only CW. There is no phone section and no digital section. It is a good first step if you want to see how a contest feels at a slower pace than the big 48-hour events, but the band itself is not forgiving, which is why the event has a loyal following among operators who enjoy low-band challenges. If you are new to the band, our practical guide to 160 meter DXing covers the propagation basics.

Dates and Operating Hours

The contest is held on the first full weekend in December. It begins at 2200 UTC on Friday and ends at 1559 UTC on Sunday, a period of 42 hours. In 2026 the first full weekend of the month falls on 5 and 6 December, so the contest starts on Friday 4 December at 2200 UTC. The ARRL maintains the official dates in its contest calendar, and the independent contest calendar lists the same weekend alongside other events, so confirm the dates there before you plan your station time.

There is no operating time limitation in any category. You can operate all 42 hours if you wish, and many serious entrants concentrate their effort on the dark hours at their location and at the DX end, which is the part of each night when the band comes alive. Because the contest spans two nights in the northern hemisphere, it includes two sunsets and two sunrises, and those are the periods when signals tend to be strongest and the gray line can give an advantage on long paths.

The Exchange

The exchange is short. W/VE stations send a signal report and their ARRL or RAC section. DX stations send only a signal report. In practice the report is always 599 in CW contests, which is covered in our article on cut numbers and CW contest exchanges. A typical contact between a W1 station and a W/VE caller sounds like this: the station calling CQ sends the caller’s call sign, then 599 and the section, for example CT, and the caller replies with 599 and a section such as EMA.

Maritime mobile stations, and aeronautical mobile stations outside W/VE, also send their ITU region. Canadian stations in Yukon, Northwest Territories and Nunavut send TER as their section, as the ARRL page points out. The list of abbreviations is published by the ARRL as the contest multipliers list, and you should load it into your logging program or keep it beside the radio. Your logging software should already know the sections, but check that it is up to date before the weekend.

Who Works Whom

The structure creates three different experiences depending on where you are.

• W/VE stations can contact other W/VE stations and DX stations. Both count.
• DX stations can contact only W/VE stations. They can work every section, and there is no benefit to calling another DX station.
• Overseas and non-contiguous US territories are special. Alaska (KL7), Hawaii (KH6), the Caribbean US possessions (KP1 to KP5) and the Pacific territories (KH0 to KH9) count as ARRL sections and can work both domestic and DX stations. Make sure your logging software accepts these contacts, as the ARRL advises on its page.

The rules also say that the 1830 to 1835 kHz window is no longer reserved for W/VE-to-DX contacts in this contest. Older articles about the event sometimes mention a DX window, so be careful with advice that predates the current rules.

Scoring: QSO Points and Multipliers

The scoring has two parts. Each contact between W/VE stations counts for two QSO points. Each contact with a DX station counts for five points. The final score is the total of the QSO points multiplied by the number of multipliers.

• W/VE stations count ARRL and RAC sections, plus the northern territories, plus DXCC entities.
• DX stations count ARRL and RAC sections only.

Each multiplier counts once, because there is just one band. The ARRL page notes that the list of 85 multipliers is the same as the one used in Sweepstakes and Field Day. The table below summarizes the structure.

The point values tell you something about strategy. A DX contact is worth two and a half times a domestic one, and every new DXCC entity adds a multiplier, so a W/VE station gains much more from one new country than from several more domestic contacts in a section it has already worked. A DX station, on the other hand, has a fixed set of multipliers to chase, which is the list of sections, and its challenge is to be heard in each part of North America.

Categories and the Limited Antennas Overlay

The rules offer three main categories. Single Operator is for one person who does all the operating, logging and station adjustments, with no spotting assistance. Single Operator Unlimited allows spotting assistance. Multioperator, Single Transmitter allows several operators, also with spotting assistance, but only one transmitted signal at any time. Within the single-operator categories there are three power levels, defined in the rules as QRP at 5 watts PEP output or less, low power at 100 watts or less and high power at 1500 watts or the national limit, whichever is less. The multioperator category has low and high power. For a broader view of how categories work in all contests, see our guide to contest categories explained.

The rules also include a Limited Antennas Overlay. Any Single Operator or Single Operator Unlimited entrant can enter with it. Operation is limited to single-element antennas, such as a single vertical, an end-fed wire or a single dipole, no more than 50 feet above ground at its highest point. A multiband vertical or a dipole built with a fan or trap design is acceptable. This overlay is especially useful on 160 meters, where many stations cannot erect a large array. It lets a station with a simple wire compete against others with similar antennas rather than against a farm of towers and Beverages.

Spotting Assistance

The difference between the single-operator categories comes down to spotting assistance. In the Single Operator category, any technology that identifies a call sign or multiplier on a signal is prohibited. The rules define this widely: it includes telnet clusters, DX spotting websites, packet, automated multichannel decoders such as CW Skimmer, reverse beacon networks, and arrangements with other people such as alerting nets or chat rooms. The Single Operator Unlimited and multioperator categories may use them, with spotting information taken from sources open to the general public.

If you are unsure which category fits, ask whether anything outside your own ears and your own station helped you find a station. If it did, you belong in the Unlimited category. Our explainer on the reverse beacon network and CW Skimmer describes the tools that count as assistance.

Antennas and Receiving on Top Band

The 160 meter band has a reputation for punishing small antennas, and a contest highlights the problem. A full-size half-wave dipole on this band is more than 250 feet long, so most operators use a vertical, an inverted L or a loaded wire, with a radial system or other ground. Our guide to the inverted L antenna explains one of the most popular choices.

The bigger issue is often reception rather than transmission. Local noise can make an otherwise good signal impossible to copy, and in a CW contest a weak signal in the noise may be lost altogether. Many top operators use separate low-band receiving antennas such as Beverages or small loops, and the improvement in the signal-to-noise ratio can be dramatic. If you want to hear stations that others cannot, read our article on low band receive antennas.

For a typical home station, here are the preparation steps that pay off most:

• Check the SWR across the CW part of the band. Top Band antennas are narrow, and an antenna tuned for 1.83 MHz may be poor at 1.85 MHz.
• Walk around the house with a portable receiver and find the sources of noise before the contest, not during it.
• Test your ground system and radials after the autumn weather.
• Confirm that the section list and DXCC data in your logger are current.
• Keep the station powered and warm. Winter operating conditions are harsh on feed lines and connectors.

Operating Strategy

A 42-hour contest on one band rewards patience. A few ideas are worth considering.

Concentrate on the Dark Hours

Signals on 160 meters depend heavily on darkness along the path. The best conditions at your station will normally be around local sunset through sunrise, with enhanced openings around the grayline periods at either end. The daytime hours are typically slow, which makes them a natural time to rest, eat and repair. Our guide to rest and time management in long contests can help you plan your sleep.

Decide Between Running and Searching

With only one band, the main choice is how much time to spend calling CQ and how much to spend tuning. A strong station can run a frequency and let the callers come, while a weaker station is usually better off tuning across the band to find multipliers and answering them. Mixing the two is common: run when the rate is good, then search for new sections or countries when the rate falls.

Keep the Exchange Clean

The exchange is short, which means errors in call signs are the main way to lose points. Log checking removes any contact with a busted call sign or a contact that is not found in the other station’s log, and it also imposes a penalty equal to the point value of that contact. Contacts with an incorrect exchange are simply removed. Duplicate contacts are removed without an additional penalty. In other words, a doubtful call sign deserves a repeat before you move on.

Logs and Submission

The official ARRL format is Cabrillo. Logs are due seven days after the contest ends, which is based on the end time at 1559 UTC on Sunday, and must be uploaded through the ARRL web application. The ARRL page also points out that for all ARRL and IARU HF contests, beginning 30 September 2026, only online log submission is accepted, so plan to upload your Cabrillo file rather than mail a paper log. If you need to convert a log, the page links to a Cabrillo form tool. Multioperator logs must list all operators in the operators field. For a walk-through of the format and the log checking steps, see our article on Cabrillo logs and the UBN process.

You can also assign your score to an ARRL-affiliated club by selecting the club name when you upload the log, which contributes to the Affiliated Club Competition. The ARRL awards certificates to the top QRP, low-power and high-power single operators in each ARRL or RAC section and DXCC entity, and to the top multioperator stations in each ARRL division and continent. Printable certificates are available online.

Rules You Should Not Overlook

A few general conditions apply to every ARRL contest and are easy to forget in a quiet band. All transmitters and receivers must be located within a circle 500 meters in diameter, excluding antennas, and remote receiving sites outside that circle are not allowed. Only one transmitted signal is permitted at any time. Alternating CQs on two frequencies on the same band is prohibited. Each contact needs direct initiation by both operators, either locally or by remote control. All contact elements must be exchanged over amateur radio, not by a chat room or telephone. You must identify your transmissions, and the rules treat failing to identify for more than a minute as prohibited conduct. The full list is in the ARRL rules, which you can read in the official 160 meter rules document.

The Bottom Line

The ARRL 160 meter contest is a compact, CW-only test of low-band skill: send 599 and a section if you are W/VE, send 599 if you are DX, score two or five points per contact, and multiply by sections and DXCC entities. The categories and the Limited Antennas Overlay make it welcoming to simple stations, and the long operating window gives you time for two good nights. Prepare your antenna and receive noise before the weekend, keep your call sign copy accurate, and upload a Cabrillo log within seven days.

Frequently Asked Questions

When is the ARRL 160 meter contest?

It takes place on the first full weekend in December, from 2200 UTC on Friday to 1559 UTC on Sunday. Check the ARRL contest calendar for the exact dates in your year.

What is the exchange?

W/VE stations send a signal report and their ARRL or RAC section. DX stations send a signal report. Maritime mobile stations also send their ITU region.

Can DX stations work each other for points?

No. DX stations may work only W/VE stations for contest credit, and a contact between two DX stations does not count.

How is the score calculated?

Each W/VE to W/VE contact is worth two points and each contact with a DX station is worth five points. The total is multiplied by the number of multipliers. W/VE stations count sections and DXCC entities, and DX stations count sections.

What is the Limited Antennas Overlay?

It is an optional overlay for single-operator entrants who use only single-element antennas, such as a vertical, an end-fed wire or a dipole, no more than 50 feet above ground at its highest point.

How do I submit my log?

Upload a Cabrillo file through the ARRL log submission web application within seven days after the contest ends. The ARRL notes that online submission is the only method accepted for ARRL and IARU HF contests from 30 September 2026.

The Yagi is the most familiar directional antenna in amateur radio, from the three-element beam on a tower to the small handheld one that points at a satellite. If you have ever wondered how a Yagi antenna works, the answer is surprisingly elegant: only one element is connected to the radio, and the others, which have no wires attached to them, shape the radiation by re-radiating what they receive. This guide explains the parts of a Yagi, the way the elements combine to push the signal in one direction, what controls gain and front-to-back ratio, why the bandwidth is narrow, and how multiband designs use traps. The descriptions follow the standard technical reference on the Yagi–Uda antenna.

What a Yagi Is

According to the reference article on the Yagi–Uda antenna, it is a directional antenna made of two or more parallel resonant elements in an end-fire array. The elements are most often metal rods that act as half-wave dipoles. A single driven element is connected to the transmitter or receiver through a transmission line. The other elements are passive radiators with no electrical connection, and they usually include one reflector and any number of directors. The antenna is also called a beam antenna or a parasitic array. It was invented in 1926 by Shintaro Uda of Tohoku Imperial University in Japan, with a lesser role played by his boss, Hidetsugu Yagi, which is why you will see both names. The name Yagi is the better known of the two.

The Yagi is widely used as a directional antenna on the HF, VHF and UHF bands. The same reference describes moderate to high gain of up to about 20 dBi, depending on the number of elements, and a front-to-back ratio of up to about 20 dB. It radiates linearly polarised waves and is normally mounted for horizontal or vertical polarisation. It is relatively light, inexpensive and simple to build, which explains why it is used on rooftops for television, on towers by amateurs and by broadcasting stations for long-distance shortwave links.

The Three Types of Element

The Driven Element

The driven element is usually a half-wave dipole or a folded dipole. It is the only part connected to the feed line, and the only part that is excited directly. Most often it is fed at the centre, so its two halves must be insulated from the supporting boom. Everything else in the antenna depends on the energy that the driven element radiates.

The Reflector

The reflector is placed behind the driven element, on the side opposite to the direction in which you want to transmit. It is slightly longer than the driven element. Usually only one reflector is used, because the gain improvement from additional reflectors is small, although more can be added for other reasons, such as a wider bandwidth.

The Directors

The directors sit in front of the driven element, in the direction of the beam. They are slightly shorter than the driven element. You can use any number of them, and the gain increases as you add more. Yagis with 40 directors and more have been built. The parasitic elements are typically solid rods, meaning that they are short-circuited dipoles with no break at the centre, and because a half-wave dipole has a point of zero RF voltage at its centre, they can be attached to a metal boom at that point without insulation.

Typical spacing between elements ranges from about one tenth to one quarter of a wavelength, depending on the design. The exact lengths and spacings vary from one design to the next, which is why you should not mix and match dimensions from different antennas.

Why Parasitic Elements Add Gain

A parasitic element receives energy from the driven element and re-radiates it, but with a different phase that depends on its exact length. The waves from all of the elements superpose, and the result is that they add up in the forward direction and cancel in the reverse. That is the whole trick. The reference article gives a simplified explanation in terms of reactance. An element that is longer than a half wavelength has inductive reactance, so the phase of its current lags and the delay exceeds 90 degrees. This is how the reflector behaves. An element that is shorter than a half wavelength has capacitive reactance, and the phase delay is smaller than 90 degrees. This is how a director behaves.

Now add the distance between the elements. The signal takes time to travel from the driven element to the passive one and back, so spacing also affects the phase. In an idealised case with a spacing of a quarter wavelength, the wave re-radiated by the director cancels the wave from the driven element in the backward direction, while the wave re-radiated by the reflector adds constructively there, and the opposite occurs in the forward direction. In reality, the phase delays do not reach those extremes, so the elements are given the correct lengths and spacings so that the waves from the driven element and from the parasitic elements all arrive at the front of the antenna in phase. The reference describes this as the crest of the forward wave from the reflector reaching the driven element just as the crest of the wave is emitted from that element, and then reaching the first director just as the crest is emitted from that one, and so on. Waves in the reverse direction interfere destructively, so little signal is radiated to the rear.

The result is a unidirectional beam. The main lobe lies along the axis perpendicular to the elements, off the end with the directors. To understand the terms that describe it, see our guide to the antenna radiation pattern, which explains lobes, beamwidth and front-to-back ratio.

Gain, Front-to-Back and Bandwidth

The more elements, the more gain, but there is a price. In its basic form, the Yagi has a narrow bandwidth of about 2 to 3 percent of the centre frequency. The reference notes a trade-off between gain and bandwidth, with the bandwidth narrowing as more elements are used. Bandwidth is defined here as the range of frequencies over which the gain is within 3 dB of the maximum. That is acceptable for a fixed frequency or for a single narrow band, but it limits how well a high-gain Yagi covers a wide band such as 10 metres. A designer who wants a wider bandwidth can use thicker elements or additional reflectors, and television antennas often use larger-diameter conductors for this reason.

For an introduction to how gain figures are quoted and compared, our article on dBi and dBd explains why the same antenna can have two different gain numbers.

Impedance and the Feed System

When the parasitic elements couple to the driven element, they change its feed-point impedance. Mutual coupling tends to lower the impedance of the driven element, which is why folded dipoles, which have a large radiation resistance, are often used as the driven element. The coupling reduces their impedance to the typical range of 50 to 75 ohms. A plain half-wave dipole has an impedance of about 73 ohms in free space, and with parasitic elements nearby it drops lower, so many amateur Yagis include a matching system, such as a gamma match, a hairpin match or a balun, to bring the impedance up to 50 ohms. Because the matching details differ from design to design, follow the manufacturer’s instructions for your antenna.

Design Is Mostly Computation and Trial

You might hope that there is a simple formula for the dimensions of a Yagi. There is not. The reference article explains that the relationships between element length, spacing, element diameter and performance are too complex for simple formulas. For an antenna with n elements, there are 2n minus 1 parameters to adjust, namely the element lengths and the relative spacings, and a full analysis involves mutual impedances between all the elements. In practice, designs are often empirical, starting from an existing design and modifying it, then checking the result by measurement or by computer simulation. If you want to try simulations yourself, our beginner guide to antenna modeling with EZNEC and 4nec2 shows the first steps.

This is a good reason to build or buy a proven design rather than to scale one by eye. Small changes in the length of an element can shift the resonant frequency and the pattern noticeably, particularly at higher frequencies where the elements are short. If you adapt a design to another band, check it with a model and measure the result.

Multiband Yagis and Traps

Amateur Yagis are sometimes designed to work on several bands. These designs insert a parallel LC circuit, called a trap, at electrical breaks in each element. At the higher frequency, the trap effectively truncates the element so that it is about a half wavelength long. At the lower frequency, the whole element, including the remaining inductance of the trap, is close to half-wave resonance, so a different Yagi comes into being. A second set of traps allows a triband antenna that resonates on three bands. The reference article says that, given the cost of erecting an antenna and a rotator on a tower, combining antennas for three bands in one unit is a practical solution. It also lists the disadvantages: traps reduce the bandwidth on each band, reduce the electrical efficiency, and add mechanical concerns such as wind loading and the ingress of water and insects. For a comparison of directional HF designs, see our guide to Yagi versus hex beam.

Practical Tips for Using a Yagi

• Point it correctly. The beam is narrow, so you need a rotator or a fixed heading toward the area you want to work. See our antenna rotator guide for sizing and control.
• Mind the height. The antenna’s pattern in elevation depends on its height above ground, as well as on the antenna itself.
• Use the right polarisation. A Yagi radiates linearly polarised waves, so mount it for horizontal or vertical polarisation according to the stations you want to work.
• Do not trust the SWR alone. A low SWR shows that the match is good, not that the pattern is right. Check the front-to-back ratio against stations behind the beam.
• Protect the elements and traps. Check for corrosion, loose clamps and water in the traps during your seasonal inspection.
• Add elements with care. More directors bring more gain but also narrower bandwidth and more weight on the tower and rotator.

The Bottom Line

A Yagi works because one driven element feeds power into the antenna and the parasitic elements, a slightly longer reflector behind it and slightly shorter directors in front, re-radiate that power with phase shifts that add up in front and cancel behind. The result is a unidirectional beam with moderate to high gain and a useful front-to-back ratio, at the cost of a narrow bandwidth that narrows further as elements are added. Because the dimensions interact in complex ways, use a proven design, mount it for the right polarisation and keep the beam pointed where the stations are.

Frequently Asked Questions

How does a Yagi antenna work?

Only the driven element is connected to the radio. The reflector and directors are parasitic elements that re-radiate the energy they receive with different phases, so the waves add in the forward direction and cancel behind the antenna.

Why is the reflector longer than the directors?

An element longer than a half wavelength has inductive reactance and a larger phase delay, which makes it behave as a reflector. An element shorter than a half wavelength has capacitive reactance and a smaller delay, which makes it a director.

How much gain can a Yagi have?

The reference article gives moderate to high gain of up to about 20 dBi, depending on the number of elements, with a front-to-back ratio of up to about 20 dB. The exact figures depend on the design.

Why is the bandwidth of a Yagi narrow?

The elements are cut for a specific frequency, and the phase relationships that produce the forward gain change quickly as the frequency moves away. The basic Yagi has a bandwidth of only 2 to 3 percent of the centre frequency, and more elements make it narrower.

Do the parasitic elements need to be insulated from the boom?

Not usually. A half-wave parasitic element has a point of zero RF voltage at its centre, so it can be fixed to a metal boom at that point without insulation. The driven element is different, since its two halves must be insulated from the boom.

What are traps on a multiband Yagi?

Traps are parallel LC circuits placed at breaks in the elements. They make the element act as a half wave on the higher band and allow the whole element to resonate on a lower band, so one antenna can serve several bands, at some cost in bandwidth and efficiency.

Sooner or later, every radio amateur meets a short code that looks like a licence plate for a signal: J3E, A1A, F3E or 2K70J3E. The code is an emission designator, and it describes a transmission precisely in a few characters. It appears in licence conditions in many countries, in equipment manuals, in band plans and in regulations, and it is a handy way to say exactly what kind of signal a transmitter produces. This guide shows how to read one, lists the common codes for amateur radio modes and explains why a single mode can sometimes have more than one valid designator. The descriptions follow the classification used by the International Telecommunication Union, as summarised in a public reference article.

What an Emission Designator Is

According to the reference article on types of radio emissions, the ITU uses an internationally agreed system for classifying radio frequency signals. Each type of emission is classified by its bandwidth, its method of modulation, the nature of the modulating signal and the type of information transmitted on the carrier. It is based on the characteristics of the signal and not on the transmitter used. This is an important point: a designator describes what is on the air, not how the radio makes it. The system was agreed at the 1979 World Administrative Radio Conference, and the Radio Regulations that use it came into force on 1 January 1982.

The Structure: BBBB 1 2 3 4 5

A designator has the form BBBB 123 45, where BBBB is the bandwidth, and the digits and letters that follow describe the signal. The first three of those characters are the ones that you will see most often. The fourth and fifth are optional.

1. Bandwidth (BBBB). Four characters, made of three digits and one letter. The letter takes the place of a decimal point and shows the unit: H for hertz, K for kilohertz, M for megahertz and G for gigahertz. So 500H means 500 Hz and 2M50 means 2.5 MHz. The first character must be a digit from 1 to 9 or the letter H.
2. Type of modulation (1). A letter. It refers to the main carrier and does not include any subcarriers.
3. Type of modulating signal (2). A digit.
4. Type of transmitted information (3). A letter.
5. Details of the information (4). An optional letter with practical details.
6. Multiplexing (5). An optional letter that gives the method of multiplexing.

For amateur use, the three-character core, such as J3E, tells you almost everything, and many documents leave out the bandwidth and the optional fields.

Modulation Letters

The first letter of the core describes the modulation. Those most relevant to amateur radio are as follows.

• A: double-sideband amplitude modulation, such as AM broadcasting.
• F: frequency modulation, such as FM broadcasting and most VHF voice.
• G: phase modulation.
• H: single sideband with full carrier.
• J: single sideband with suppressed carrier, used by shortwave utility and amateur stations. The principle is explained in the article on single-sideband modulation.
• N: an unmodulated carrier, a steady single-frequency signal.
• R: single sideband with reduced or variable carrier.

There are other letters, for example B for independent sideband, C for vestigial sideband, and several for pulse modulation, but you will rarely meet them on the ham bands. For a discussion of sideband choice in practice, see our guide to USB versus LSB.

The Modulating Signal Digit

The second character is a digit that tells you what kind of signal modulates the carrier.

• 0: no modulating signal.
• 1: one channel containing digital information, with no subcarrier.
• 2: one channel containing digital information, using a subcarrier.
• 3: one channel containing analogue information.
• 7: more than one channel containing digital information.
• 8: more than one channel containing analogue information.
• 9: a combination of analogue and digital channels.

The reference article adds that the types 4 and 5, which once indicated facsimile and video, were removed from use with the 1982 Radio Regulations. If you see them in an old document, it refers to the earlier system.

The Information Letter

The third character says what is being sent.

• A: aural telegraphy, intended to be decoded by ear, such as Morse code.
• B: electronic telegraphy, intended to be decoded by a machine, such as radioteletype and digital modes.
• C: facsimile, meaning still images.
• D: data transmission, telemetry or telecommand.
• E: telephony, meaning voice or music for a human listener.
• F: video, such as television.
• N: no transmitted information other than the existence of the signal.

Common Designators for Amateur Modes

Putting the pieces together gives the codes you will see most often. The table lists those given in the reference article for modes used by amateurs, together with a plain-language reading.

The reference article also lists 20K0F3E as wide FM, with a bandwidth of 20.0 kHz and a deviation of plus or minus 5 kHz, still widely used in amateur radio, weather radio, marine and aviation. It lists 11K2F3E as narrow FM with a bandwidth of 11.25 kHz, which in the United States became required for land mobile users above 50 MHz from 1 January 2013, and 6K00F3E as even narrower FM. Those are examples of how the bandwidth part gives a specific channel width to the same F3E signal.

Reading a Full Designator

Take 20K0F3E. The bandwidth part, 20K0, means 20.0 kHz. The F means frequency modulation. The 3 means one channel of analogue information. The E means telephony, so this is FM voice with a 20 kHz channel. In the same way, a CW signal with a bandwidth of 150 Hz would be written 150HA1A: 150H for 150 hertz, A for amplitude modulation of the carrier, 1 for one digital channel without a subcarrier, and A for aural telegraphy. A single sideband voice signal that occupies about 2.7 kHz can be written 2K70J3E. These two examples are built from the rules in the reference article, and the bandwidths are only illustrations, not licence figures.

The bandwidth part is not the same as the setting of the receiver filter. It describes the occupied bandwidth of the emission as defined in the regulations. If you want to understand how to choose a filter for a given mode, our guide to receive filter bandwidth covers the practical side. For the effect of a poor signal on its neighbours, see our article on key clicks and splatter.

Why One Mode Can Have Several Designators

The reference article warns that there is some overlap between signal types, so a transmission may legitimately be described by two or more designators, with a preferred conventional designator in most cases. A good example is data modes sent through an SSB transmitter. A note in the article says that the designators F1B and F1D should be used for frequency-shift keying telegraphy and data, regardless of how the signal is generated, whether by audio FSK into an SSB transmitter or by direct FSK on an FM transmitter. Occasionally, J2B and J2D are used for FSK signals produced by audio modulation of an SSB transmitter. This explains why you may see PSK31 listed as J2B in one document and as a different code in another. If you need a designator for a licence application or a form, use the one that your regulator or the equipment manual specifies.

Where You Will See Designators

• Licence conditions. Some countries list the emission classes that an amateur licence permits, using designators. If your licence lists them, you can check that a new mode fits.
• Band plans. Band plans divide a band by mode, and some of them use designators or the names of modes. Our article on the IARU band plan explains how the segments are organised.
• Equipment specifications. Manuals and type approval documents often list emission designators for a transmitter.
• Event applications. Applications for special permits and temporary licences often ask for designators with bandwidths.

Whenever a designator appears in a rule, read it as a description of the signal, not as a name of the radio or the software. A modern transceiver may generate the same designator in different ways, and the regulator is interested in what the signal does.

Common Mistakes When Reading Designators

• Confusing the digit with the number of channels in an analogue sense. The digit 3 means one channel of analogue information, not three channels. Several channels are shown by 7, 8 or 9.
• Reading the bandwidth letter as part of the mode. In 2K70J3E, the K belongs to the bandwidth. It means kilohertz and sits where the decimal point would be.
• Assuming the transmitter decides the designator. The code describes the signal, so the same designator can come from different equipment.
• Using old classes. Older documents may refer to types that were removed in 1982, such as the digits 4 and 5, or may use a different system altogether. Check the date of the document.
• Treating the optional letters as required. The fourth and fifth characters are optional, so a short code such as J3E is complete for most purposes.

Why It Matters for Operators

You do not need to memorise the whole table, but knowing the structure helps in practical ways. When you read a licence or a band plan, you can check at once whether a mode is allowed in a given segment. When you buy equipment, you can compare what the manual says the transmitter produces with what you want to use it for. When you apply for a special event permit or discuss interference with a neighbour or a regulator, you can describe your signal exactly, which is much clearer than saying that it is digital. And when you help a newcomer, the designator gives a short, universal name for the signal they are hearing. For a broader view of how modes share a band, our guide to digital modes beyond FT8 compares the modes that you are most likely to meet.

Quick Tips for Remembering the Letters

1. Start with the last letter. A means Morse code by ear, B means machine-decoded data modes, E means voice, and D means data or telemetry.
2. The digit tells you whether it is digital or analogue. 1 and 2 are digital, 3 is analogue.
3. The first letter tells you the modulation. A for AM, F for FM, J for SSB with a suppressed carrier.
4. Add the bandwidth. If a document gives the bandwidth, it comes first and uses a letter in place of the decimal point.

The Bottom Line

An emission designator is a compact, internationally agreed description of a signal: a four-character bandwidth code, a modulation letter, a digit for the type of modulating signal and a letter for the information carried. J3E is SSB voice, A1A is CW, F3E is FM voice, F1B is RTTY-style frequency-shift keying and J2B is phase-shift keying such as PSK31. Overlap between types means a mode may have more than one valid code, so always check the one that your regulator or manual uses, and you will be able to read the rules and band plans with confidence.

Frequently Asked Questions

What does J3E mean?

J is single sideband with suppressed carrier, 3 is one channel of analogue information and E is telephony. Together, J3E is the code for SSB voice.

What is the designator for CW?

A1A is the designator for CW keyed directly on and off. The A is amplitude modulation of the carrier, the 1 is one digital channel with no subcarrier and the final A is aural telegraphy. It is often but not necessarily Morse code.

What does the bandwidth part mean?

The first four characters show the bandwidth, with a letter in the place of the decimal point. H means hertz, K means kilohertz, M means megahertz and G means gigahertz, so 2K70 is 2.7 kHz and 20K0 is 20.0 kHz.

Is the emission designator the same as the mode?

Not exactly. A designator describes the characteristics of the signal on the air, not the name of the mode or the transmitter that makes it. Several modes can share one designator, and one mode can have more than one.

What is the designator for FM voice?

F3E, where F is frequency modulation, 3 is analogue information and E is telephony. A bandwidth can be added, for example 20K0F3E for wide FM and 11K2F3E for narrow FM.

Why do some documents show different codes for RTTY or PSK31?

Because there is overlap between signal types. The reference article says F1B should be used for frequency-shift keying telegraphy, but J2B is sometimes used when the signal is made by audio modulation of an SSB transmitter. Follow the code required by the document you are completing.

Long before text messages, amateur radio operators were relaying written messages across the country, and the format they used is still alive. The ARRL radiogram is a standard form for a formal message that is passed from one radio operator to another until it reaches its destination. It looks strict at first, with a numbered preamble, a precedence letter and a word count, but every part has a purpose, and once you know the pattern a radiogram is easy to fill in. This guide explains the parts of the form, how the word count works, what the handling codes mean and how a message travels through the National Traffic System. It is based on the published description of the format and the ARRL’s NTS pages, so check the current ARRL forms before you use it for real traffic.

What a Radiogram Is

According to the encyclopedia article on the ARRL radiogram, it is a piece of formal written message traffic routed by a network of amateur radio operators through traffic nets, called the National Traffic System, or NTS. It consists of a plain text message and the relevant headers that are placed into a traffic net by an operator. Each radiogram is relayed, possibly through several other operators, to someone who volunteers to deliver the message to its destination. Within the United States, amateur radio operators can send and deliver radiograms on behalf of any member of the public, which is one type of third-party traffic that FCC rules specifically permit.

The reason for the standard form is speed and reliability. A radiogram always lists its headers in the same order, so operators can read and understand them without spoken labels. This matters most in hectic, stressful situations such as a disaster, when many parties ask radio operators to move messages in and out of an affected area. The order is logical enough that many operators have memorised it and can send and receive radiograms without the form in front of them. The ARRL says on its NTS page that during disasters or other emergencies, radiograms are used to communicate information critical to saving lives or property, or to inquire about the health or welfare of a disaster victim.

The Four Parts of a Message

A radiogram has four parts: the preamble, the address, the text and the signature. The preamble contains the information needed to track the message as it passes through the system. It is created by the station of origin and, except for the check, is not changed by any station that relays or delivers the message. The address names and locates the recipient. The text contains the message itself, as authorised by the person for whom it is sent. The signature closes the message. When it is transmitted, the text is separated from the address and the signature by the word BREAK on voice or the prosign BT on CW, so the receiving operator knows where it begins and ends. The words BREAK and BT are not counted as groups.

The Preamble in Detail

The preamble has several fields, and some are optional. Their order is fixed.

1. Message number. Chosen by the originating station, it is on every message and stays with it to the point of delivery. Use digits only, with no letters, leading zeros or dashes. Many stations begin again at 1 at the start of a year or a month.
2. Precedence. Letters showing the priority of the message, on every message. See below.
3. Handling instructions (HX). Optional, and used only when a particular need exists.
4. Station of origin. The call sign of the amateur station that first put the message into the amateur system. It stays with the message, and service messages about handling are sent to this station.
5. Check. The number of word groups in the text. It is the one part of the preamble that the handling stations verify.
6. Place of origin. The city and state of the person for whom the message was created, which is not necessarily the location of the station of origin.
7. Time filed. Optional, used when the filing time matters. It is given in 24-hour format with a Z for UTC, or marked with a time zone or an L for local time. UTC is preferred, because the NTS covers many time zones.
8. Month and day. Required on every message, as a three-letter month abbreviation followed by the day in figures without a leading zero. If a time is given, the date and time must agree.

Precedence: How Urgent Is It?

The precedence tells operators which messages to handle first, which is vital when circuits are busy. The format recognises these classes, summarised from the ARRL’s definitions as quoted in the article.

The ARRL notes that these classes are not meant to prohibit handling lower-level traffic until all higher levels are passed, and that common sense dictates handling higher precedence traffic first when possible. For tests and exercises, a precedence may be preceded by the word TEST, and the text should say that it is a test message or an exercise, which helps listeners avoid undue alarm. A service message, marked SVC before the message number, is a message between stations about handling or delivery and takes the same precedence as the message it refers to.

Handling Instructions (HX Codes)

Handling instructions are optional and should be used only if a need exists. If they are used, they must stay with the message to the point of delivery. The codes begin with HX and a letter. Some examples from the published list are HXA, which means delivery by email or text message is preferred, HXC, which asks the delivering station to report the date and time of delivery, HXE, which asks the delivering station to get a reply from the addressee, and HXG, which allows cancellation if postage or other expense is involved. HXR asks for confirmation that the addressee has read the message and is reserved for emergency, priority and certified messages. More than one code may be combined, as in HXAC, provided no numbers are inserted. The ARRL publishes the full list on its NTS pages, so use the current version rather than relying on memory.

The Address and the Text

The address follows the preamble. The first line contains the full name of the addressee, written as it would most likely be found in the local telephone directory. The next lines give the street address, the city, state and ZIP code without punctuation, and a telephone number as groups of digits without hyphens. The latest version of the form also has a space for an email address. An optional op note may follow the address, introduced by the words OP NOTE, with information for the handling operators, such as the best time to call. It is not part of the message that is delivered.

The text is the part the person wants to send. An operator never originates a message for a person without that person’s permission. The text is divided into groups, five or ten to a line to make counting easy, and is usually limited to 25 words or fewer. Punctuation is not used except for a few special cases. The letter X stands for a period and counts as a group of its own, but it is never used as the last group. A slash may be used within a group, such as 304/BA. The letter R is used in place of a decimal in mixed figure groups, so 146.670 becomes 146R670. Other punctuation is spelled out, for example QUERY for a question, and counted as a group. Words such as love or regards are placed in the text and not in the signature.

For frequently sent messages, the ARRL has a brevity code called numbered radiograms. Each of 48 numbers stands for a full sentence, and the number is spelled out and preceded by the procedure word ARL. For instance, ARL FORTY SIX stands for a birthday greeting, and it counts as three words. The sentence is expanded when the message is delivered outside the system.

Counting the Check

The check is the total number of groups in the text, counted between the start and end prosigns but not including those prosigns. Operators use it to verify that the text was copied correctly: if the receiving operator counts a different number from the check, something was lost or added, and the sender can repeat the part that is in doubt. Slashes and R decimals within a group do not create new groups, while a standalone X or a spelled-out punctuation word does. Here is a short example, in which every name and number is invented for illustration.

Preamble: NR 4 R N0CALL 9 SPRINGFIELD IL DEC 3
Address: JANE SMITH / 123 MAIN STREET / SPRINGFIELD IL 62701 / 217 555 0100
Text: HAPPY BIRTHDAY X HOPE YOU HAVE A GREAT DAY
Signature: TOM

The text has nine groups, which are HAPPY, BIRTHDAY, X, HOPE, YOU, HAVE, A, GREAT and DAY, so the check is 9. Pay attention to the order of the preamble: number, precedence, station of origin, check, place of origin and then the date. That example uses no optional fields. When you send it on voice, the operator reads the groups exactly as written and uses phonetics for call signs and unclear words, as in our guide to the ham radio phonetic alphabet. On CW, the prosign BT separates the parts, and our article on CW abbreviations and prosigns explains these signs.

How the Message Travels

A radiogram travels through nets at several levels. The ARRL says on its NTS page that the system is made up of operators trained in traffic handling who take part in nets at the local, section, region and area levels every day of the year. A message that starts in one town is passed to a local or section net, then to a higher-level net that carries traffic between regions, and then back down to the level that serves the destination. Finally, a volunteer delivers it by telephone, email, text message or in person. Our guide to running a ham radio net shows how a net control station keeps this organised, and our article on ARES and RACES explains how emergency groups connect with traffic nets.

Traffic handling is also a practical skill for digital modes. Modern systems such as the one described in our article on Winlink over HF can move messages by email over radio, but the discipline of clear, accurate formal messages carries across to those systems.

Is Traffic Handling Still Relevant?

The ARRL is frank about the current situation. Its NTS page notes that the spread of low-cost and free telephone calls, text messaging and the web means the general public has many alternatives to traditional radiograms, and much of today’s NTS traffic is simply between amateurs, such as welcome messages and licence expiration notices. It also says that there are serious questions about the accuracy and reliability of the networks and that some public agencies have never heard of the NTS or have created their own backup messaging systems. For that reason, the ARRL describes a modernisation effort called NTS 2.0, with training materials in a modern format. The skill remains useful, because it teaches accuracy, discipline and the habit of verifying what you copy, and these are valuable when ordinary communications fail.

How to Get Started

1. Download the current forms and guides. The ARRL provides the radiogram form, the handling instruction list and the NTS manual on its pages.
2. Listen to a traffic net. Many sections run daily nets. Listen for a few days, and note how the net control station calls for traffic and how operators pass it.
3. Practise with exercise messages. Use the word TEST before the precedence and mark the text as an exercise, and ask the group which runs the exercise whether the messages should be delivered.
4. Check in to a net. Offer to take a message. The first few times, ask a mentor to listen to your copy.
5. Keep a log. Record the messages you originate, relay and deliver, with the times and stations involved.

The Bottom Line

An ARRL radiogram is a formal message with a fixed order: a preamble with message number, precedence, station of origin, check, place of origin and date, then the address, the text of about 25 words or fewer, and the signature. The check counts the word groups, the precedence tells operators what to handle first, and optional HX codes give delivery instructions. Whether you use it for a real health and welfare message or for practice in a net, learning the format builds the accuracy that serves every other part of amateur radio.

Frequently Asked Questions

What is an ARRL radiogram?

It is a formal written message in a standard format that is passed by amateur radio operators through traffic nets until it reaches the person it is addressed to. The system that carries it is the National Traffic System.

What is the check in a radiogram?

The check is the number of word groups in the text. The receiving operator counts the groups they copied and compares them with the check, which shows whether anything was missed or added.

How long can the text be?

The text is usually limited to 25 words or fewer. It is divided into groups, five or ten to a line, so that counting is easy.

What do the precedence letters mean?

Emergency is spelled out and means a life-and-death situation. P stands for priority, W for welfare, C for certified and R for routine. Higher precedence messages are handled first.

Can I send a radiogram for someone who is not a ham?

In the United States, amateur operators can send and deliver radiograms on behalf of members of the public, which is third-party traffic that FCC rules specifically permit. Rules differ by country, so check your own regulations.

Do I need a licence to learn traffic handling?

You need an amateur radio licence to transmit on the air. Anyone can study the format and listen to traffic nets, and many operators practise on exercise messages before they handle real traffic.

Most contests are built for people who already know what they are doing, and a newcomer who tunes across a contest weekend can feel like a guest at a party where everybody else knows the songs. The Rookie Roundup is the opposite. It is an ARRL contest designed for newly licensed operators, with an exchange that is easy to learn, a power limit that keeps everyone on a level footing and a rule that makes experienced operators work only the beginners. This guide explains who counts as a rookie, when the events take place, what you send, how scoring works and how to take part whether you are a rookie or a mentor. It is based on the ARRL’s published rules, so always check the current version before the event.

What the Rookie Roundup Is

According to the ARRL’s Rookie Roundup page, it is a contest aimed at amateurs who were licensed three years ago or less. It is a six-hour event held three times a year, in April, August and December. Rookies can contact anybody, while experienced operators, called non-rookies in the rules, may contact only rookies. The stated mission is to encourage newly licensed operators in North America to operate on the HF bands and to experience competitive amateur radio operating, and the organisers strongly encourage experienced operators to help new operators, either on the air or in person. Mentoring is a big part of the event.

That design solves the usual beginner problem. In a large open contest, a new operator with a modest station competes for attention with stations that have towers and amplifiers. In the Rookie Roundup, every station is limited to 100 watts of transmitter output, and the experienced operators who join are there to give rookies contacts, not to win. It is one of the best ways to practise contest exchanges in a friendly setting.

Who Counts as a Rookie

The rules define a rookie entry as an operator who has either made no contacts at all or has made their first amateur radio contact during the current or the preceding three calendar years, or who has not made any contacts on the contest mode (SSB, CW or RTTY) before the contest. In the second case, the operator sends the current year in the exchange. An operator may enter the rookie category only once. The ARRL page also notes that the rules were widened so that more people can take part: you can be a rookie if you were first licensed in the current or any of the three preceding years, and operators licensed earlier can still qualify if they made their first amateur radio contact within that period or if they have never made a contact on the mode of that event.

If you are not a rookie, there is no non-rookie entry category, but experienced operators are encouraged to take part and report their contact totals through the online score form. Non-rookies may call CQ, but they may only work rookie stations. The organisers also invite non-rookies to open their stations to a rookie or two and become a mentor, which is the classic elmer role. If you are thinking about getting your own licence first, see our overview of amateur radio licence classes and exams.

Dates, Modes and Bands

All events run for six hours, from 1800 to 2359 UTC on a Sunday. The rules place them on the Sunday of the third full weekend of April, August and December, and each event uses a different mode: SSB in April, RTTY in August and CW in December. The ARRL page lists the 2026 dates as 19 April for SSB, 16 August for RTTY and 20 December for CW. If you want to try CW in a gentle setting, the December event is a good chance, and it follows our guides to cut numbers and CW contest exchanges and to CW abbreviations and prosigns.

The objective is to exchange information with as many other stations as possible on the 80, 40, 20, 15 and 10 metre HF bands. Activity usually concentrates in the sub-bands that the rules list for each mode, for example around 3.545 to 3.555, 7.045 to 7.055, 14.045 to 14.055, 21.045 to 21.055 and 28.045 to 28.055 MHz for CW. All categories are limited to 100 watts of transmitter power output, and for the PEP-based modes the limit is stated as 100 watts PEP. The rules are written for North America, but stations elsewhere may take part as DX.

The Exchange

The exchange has three parts, which is easy to remember: your first name, a two-digit number called the check, and your location. The check is the two-digit year in which you were first licensed. The location is your US state, Canadian province, Mexican call area, or DX if you are in any other place. Examples from the rules include a US rookie sending a name, a two-digit year and a state, and a Japanese station sending a name, a year and DX. A rookie must have a check from the current year or one of the three preceding calendar years, and the rules give the example that in 2023 a rookie’s check was 23, 22, 21 or 20.

A short CW example shows how it flows. A rookie calls CQ RR, a station answers with its call sign, and the rookie sends the other station’s call sign, then its own call sign, name, check and state. The other station replies with the same pieces, and each side confirms it has the call sign right. Practise sending the exchange before the event, ideally with a contest simulator. Our guide to Morse Runner is a good practice tool for CW.

How to Call

The rules include special calls that make life easier for everyone. Rookies are encouraged to identify themselves by calling CQ RR on CW or RTTY and CQ Rookie Roundup on SSB. Non-rookies should call CQ R on RTTY or CW and CQ Rookie on SSB, which tells rookies that they will get a contact if they answer. Because everyone knows the calls, a rookie can spot a friendly station quickly and a non-rookie can see who is calling for them. A non-rookie station that hears another non-rookie answering should not work that station, since contacts between non-rookies are not valid in this event.

Scoring and Multipliers

Scoring is simple. A completed contact between two rookies is worth 2 points, and a contact between a rookie and a non-rookie is worth 1 point. Contacts between two non-rookies are not valid. The multipliers are US states and the District of Columbia, which make 51, the 13 Canadian provinces and territories, five Mexican call areas and one generic DX multiplier that includes US possessions and all other entities. The total number of possible multipliers is 70. The final score is the total contact points multiplied by the number of multipliers worked.

The same station may be worked once on each band, but each multiplier counts only once regardless of the band. Cross-band and cross-mode contacts are not permitted, and contacts through repeaters or digipeaters do not count. All contacts must be made from the same state, province, call area or DX entity during a single contest, so your exchange must contain the same location information for every contact. Contacts with aeronautical mobile stations do not count.

Categories and Teams

The categories are single-operator rookie and multioperator rookie. In the multioperator category, any number of rookies may operate from a single station, but only one signal may be on the air at a time with a single transmitter. Teams may be entered, with up to five different single-operator entries, which are listed separately in the results. A single-operator entry may be on only one team, and teams must be registered with the ARRL Contest Branch before the contest using the online form. Multioperator stations are not eligible for team entries. Spotting assistance is permitted for single-operator rookies, but spotting yourself or asking others to spot you is not allowed.

Mentors: How Non-Rookies Can Help

The event depends on experienced operators. The rules encourage non-rookies to help rookies in person with operating technique and instruction, including acting as the control operator to allow a licensee with limited privileges to transmit with higher privileges. Under the rules, a non-rookie who helps in person may not make any transmissions from the station or log any contacts. If you are a non-rookie working from your own station, calling CQ Rookie or CQ R and answering every rookie who calls is the best way to help. Keep exchanges slow and clear, repeat the exchange when asked and be patient with mistakes.

Preparing Your Station

You do not need a big station. A transceiver at 100 watts and a simple wire antenna are enough for a fun event. Check the antenna on each band you plan to use, set up a logging program with the exchange fields and test the keyer or voice memories. Many operators use a contest logging program that supports the event, and our guide to setting up N1MM Logger+ explains how to prepare one. A paper log and a pencil also work, since the event does not require a log to be submitted, only a score summary. Write down the exchange you will send on a card next to the radio so that you do not have to think about it under pressure.

On the day, begin on a band with good activity for the time of day, and listen before you call. If you are a rookie, you can call CQ RR and let the stations come to you or tune across the sub-band and answer others. Use both methods, and take breaks, since a six-hour event is long for a first-timer. Do not worry if you make mistakes. The exchange is short, and most operators are happy to repeat it.

Submitting Your Score

The Rookie Roundup does not require or accept logs. All score summaries must be submitted through the online Rookie Roundup score summary form within 72 hours of the end of the event, and late submissions are not accepted. Electronic certificates are emailed to the top five scoring rookies in each US call area, each Canadian province, each Mexican call area and DX, and a commemorative participation certificate can be downloaded by every rookie who submits a score. Non-rookies who submit a check log are recognised by call sign in the final results. The ARRL also asks for photographs and comments through the contest’s Soapbox pages, especially from young operators.

The Bottom Line

The Rookie Roundup is a six-hour, 100 watt, three-times-a-year contest that lets new operators try competitive operating with an exchange of name, year and location. Rookies score 2 points for every other rookie and 1 point for every experienced operator, non-rookies work only rookies, and scores are submitted within 72 hours without a log. If you are new, mark the 20 December CW event in your calendar and practise the exchange. If you are experienced, switch on the radio and make a rookie’s day.

Frequently Asked Questions

Who can enter the Rookie Roundup as a rookie?

Operators who made their first amateur radio contact, or were first licensed, in the current or preceding three calendar years, or who have not made any contest contacts on the mode of that event. You can enter as a rookie only once.

When is the Rookie Roundup?

It takes place three times a year, from 1800 to 2359 UTC on a Sunday. The 2026 dates are 19 April on SSB, 16 August on RTTY and 20 December on CW. Check the ARRL page or the WA7BNM Contest Calendar for future dates.

What do I send in the exchange?

Send your first name, the two-digit year you were first licensed, and your state, Canadian province, Mexican call area or DX. For example, name, 24 and a state, as long as the check is in the allowed range.

How many points do I get for a contact?

A contact between two rookies is worth 2 points, and a contact between a rookie and a non-rookie is worth 1 point. Contacts between non-rookies do not count. Multiply the total points by the number of multipliers.

How much power can I use?

All categories are limited to 100 watts of transmitter output. The limit applies to rookies and non-rookies alike.

Do I have to submit a log?

No. Logs are neither required nor accepted. You submit a score summary on the online form within 72 hours of the end of the event.

A confirmation on the screen is quick, but a paper card that arrives from a distant country still feels like a small victory. A direct QSL is a card sent by mail straight to the other station or to its manager, rather than through a bureau. It is the fastest paper route, and for some rare stations it is the only reliable one. This guide explains when a direct card makes sense, how to find the right address, what goes in the envelope, how return postage is handled, and why the planned end of international reply coupons changes the advice that older books give. It is written for DXers and award chasers who want a card that actually comes back.

Direct, Bureau or Electronic?

According to the QSL card reference article, cards can be sent either direct to an individual’s address or through a country’s centralised amateur radio association QSL bureau, which collects and distributes cards for that country. The bureau route saves postage because several cards for one country travel in a single envelope, but it increases delivery time because of the extra handling. Our guide to the QSL bureau system explains how incoming and outgoing cards travel, and it is the right choice when time does not matter and you are happy to wait.

Electronic confirmation is a third route. Systems such as the ARRL’s Logbook of The World match log records and can be used for awards such as DXCC. A direct card is mainly for three situations: the station does not use electronic systems, you want a physical card for your wall or for an award that accepts paper, or the operation is short and a manager will only handle direct requests. Decide which one you need before you spend money on postage.

Finding the Right Address

The most common reason for a direct request to fail is a wrong address. Never assume that the address in an old callbook is current. Use several sources and compare them.

1. The station’s own page. Many stations publish a QSL policy on their profile or website. This page is the best source because it states the preferred route, the address and the amount of return postage they want.
2. The callsign database. Callbook services such as the one described in our guide to QRZ callsign lookup show a mailing address and often a note on how to request a card. Check for a message that says bureau only, direct only or logbook only.
3. The QSL manager. For rare countries, places with no reliable postal system, and expeditions, a volunteer QSL manager may handle the mailing. The reference article notes that for expeditions this may amount to thousands of cards, and that payment for at least the postage is appreciated and is required for a direct reply, as opposed to a return through a bureau.
4. Online request systems. Some DXpeditions use an online request service, which lets you pay for the postage in advance and request a card without sending an envelope. Our article on Club Log and OQRS explains how this works.

Always confirm that the address belongs to the call sign you worked and not to a former holder or to a manager who no longer works for that station. If you worked a special event call sign, the information is usually on the event’s page, and cards are often handled by a club.

What Goes in the Envelope

A good direct request is easy for the other person to answer. Tie everything to a single envelope, and keep it simple.

• Your QSL card. It should show the call sign of the other station, the date and time in UTC, the band, the mode and the report. Our guide to QSL card design lists what to include. Many hams send two cards if they want one back, but one is enough if the station has asked for a different arrangement.
• A return envelope. This is the self-addressed envelope with postage for the reply, usually called a SASE. It must have your address in clear, printed letters.
• Return postage. See below, because the right form depends on the country.
• A short note. A polite line saying thank you, and the details of the contact if you have not included a card, is enough. Do not write long messages.
• A plain outer envelope. Do not put your call sign, radio words or a clear sign of money on the outside. Many experienced DXers use plain envelopes with no radio references, because envelopes that clearly come from hams may attract theft in some regions.

Write the address clearly, and use the country name in the language and format that the postal service expects. If the address is in a different alphabet, ask a native speaker or check the postal service’s guidance. A small mistake in the address is a common reason for a lost card.

SASE, IRC or Cash?

Return postage is where most of the confusion lies. The correct answer depends on whether the other station lives in the same country as you or abroad.

If the station is in your own country, a self-addressed stamped envelope is enough. As the international reply coupon article explains, a SASE or a return postcard will suffice for a domestic reply. If the station is abroad, your own stamps are useless to them, because a foreign post office will not accept them. This is where the international reply coupon, or IRC, was designed to help. An IRC is a coupon that can be exchanged for one or more postage stamps representing the minimum postage for an unregistered priority airmail letter to another member country of the Universal Postal Union. The reference article adds that IRCs are often used by radio amateurs sending QSL cards, and that it has traditionally been considered good practice and common courtesy to include an IRC when writing to a foreign operator and expecting a reply by mail.

The End of the IRC

This is the part that has changed. According to the same article, some postal services stopped selling IRCs a long time ago: the United States Postal Service discontinued sales on 27 January 2013, and Britain’s Royal Mail stopped on 31 December 2011. The current model, called the Abidjan model, was first due to expire at the end of 2025, but the expiry date was later extended to 31 December 2026, and the article states that the UPU announced on 15 December 2025 that it would discontinue the IRC as of 31 December 2026. Check the latest information from your postal service, since the situation varies by country, but plan as if IRCs will soon be unavailable and may not be accepted after the end of the year.

The practical consequence is that you should stop relying on IRCs. In many cases the better choice is cash. Many DXers send a US dollar bill, often called a green stamp, and it is the common currency of QSL requests. Others send a euro note, or a few of each. Always follow the instructions of the station or manager, since some ask for a certain number of dollars or euros, some accept only one currency and some prefer a postal payment or an online service. If the station says that you should send nothing because they will reply by bureau, believe them and use the bureau.

How Much to Send

There is no universal amount. The cost of postage varies between countries, and so does what a station asks for. The right amount is the one that the station or manager states on its page. If no instruction exists, a reasonable approach is to look up the current price of an airmail letter from the station’s country to yours, and to send enough to cover it. Do not guess low, since a card that arrives with insufficient postage may be ignored. A little extra helps cover the envelope and the effort, and it is a courtesy to a volunteer who pays out of their own pocket.

Safety, Etiquette and Common Mistakes

• Wrong or expired information. Check the date of the QSL information, and avoid sending a card to an address that is out of date.
• Missing details. Fill in the date, time, band, mode and report accurately. A card with missing details may be rejected.
• Requesting a card for a contact that is not in the log. Check the logs on the station’s page or on the online log search first, since it saves postage and effort.
• Sending a card too early. After a DXpedition, the logs may take weeks or months to be uploaded and processed. Wait for the announcement that the cards are ready.
• Sending valuables. Do not enclose anything else of value. Mail can be lost, and tracking is rare for a letter.
• Forgetting your own details. Print your address clearly, and add your call sign so that the card can be matched.
• Ignoring the stated policy. If a station says bureau only, a direct request creates extra work for them.

Waiting, Tracking and Following Up

Direct cards can take weeks or months. Some stations answer within days, others batch their replies once or twice a year. Keep a simple list of what you sent, with the date, the amount and the address, and mark the entry when a card arrives. Do not resend a request after only a short time, since a duplicate request creates extra work. If a long time has passed, check the station’s page for notes about delays or an update, and then consider sending a polite follow-up with a copy of your original details. Cards that were requested for an award can also be replaced by an electronic confirmation if the station uses an online system. For chasing new entities and keeping a record of what you still need, our guide to working a DXpedition offers a practical workflow.

The Bottom Line

A direct QSL is worth sending when you want a paper card quickly or when the station or manager only handles direct requests. Find the current address from the station’s own page, send a clear card with all the contact details, enclose the return postage that the station asks for, and use a plain envelope. Because the international reply coupon is being discontinued, do not rely on it, and follow the station’s instructions on cash or an online service instead. Keep a record of what you sent, be patient, and use the bureau or an electronic system when a direct card is not required.

Frequently Asked Questions

What is a direct QSL?

A direct QSL is a confirmation card that is mailed straight to the other station or its manager, rather than through the QSL bureau. It is usually faster than the bureau but costs more because you pay for postage.

What is a SASE in ham radio?

A SASE is a self-addressed stamped envelope. You enclose it so that the other station can send the card back to you. It works well for stations in your own country, but foreign stamps cannot be used abroad.

Are international reply coupons still available?

Many postal services stopped selling them some years ago. According to the encyclopedia article, the Universal Postal Union announced that the coupon will be discontinued as of 31 December 2026. Check with your local postal service, and plan to use cash or an online service instead.

How much money should I include for a reply?

Follow the amount that the station or manager asks for. If no amount is given, look up the current airmail letter price from their country to yours and include enough to cover it. It is better to send a little more than too little.

How long does a direct QSL take?

It varies widely. Some stations answer in days, while others reply in batches a few times a year, and international mail can be slow. Keep a record and be patient before you follow up.

Should I put my call sign on the outer envelope?

Many experienced DXers do not. A plain envelope with no radio words reduces the risk of theft in places where envelopes from hams may attract attention. Put your call sign on the card and the note inside instead.

Every CW operator knows that a dah is longer than a dit, but surprisingly few can say exactly how much longer, how long the gaps should be, or what “20 words per minute” means in milliseconds. Morse code timing is the foundation of both sending and reading code. A keyer that is set well is easy to copy at any speed, while a hand-sent signal with uneven gaps is hard to read even at a modest speed. This guide explains the basic timing rules, the standard words used to measure speed, the simple formula that converts words per minute into dit length, and what happens when the spacing is stretched for learning. It is based on the standard description of International Morse code, and the numbers are easy to check with a calculator.

The Five Elements of International Morse

According to the Morse code reference article, International Morse code is built from five elements, all of which are multiples of one basic unit, the length of a dit. The unit is the clock of the whole system. If you know the length of one dit, you know every other length in the transmission.

• A dit (short mark) is one unit long.
• A dah (long mark) is three units long.
• The gap between the dits and dahs within one character is one unit of silence.
• The short gap between letters is three units of silence, the length of one dah.
• The medium gap between words is seven units of silence. It was formerly five units, so you may see that figure in older texts.

This is often called the 1-3-7 rule, although the full set of numbers is 1, 3, 1, 3 and 7. If you remember only one thing, remember that the spaces matter as much as the marks. A word gap is not simply a long pause; it is a precise length that tells the listener where one word ends and the next begins.

Why the Numbers Are Odd

There is a neat property hidden in these numbers. The dit and the dah are an odd number of units long (one or three), and the gaps that always follow them are also odd numbers (one, three or seven). Because of that, any character in International Morse comes out to an even number of units when both the marks and the spaces of the whole character are counted. The reference article points out that this gives ITU Morse a two-unit staccato beat, which helps telegraphers keep their sending rate steady. You can hear this beat in well-sent code: it has a rhythm that makes it easier to copy than uneven sending at the same speed.

What Is a Word per Minute?

Characters in Morse have different lengths, because they contain different numbers of dits and dahs. The letter E is a single dit, while the letter Q is dah dah dit dah. Consequently, words also have different lengths even when they have the same number of letters. To measure speed in a consistent way, a standard word is adopted. Two standards are in common use: PARIS and CODEX.

The word PARIS is the usual standard for the words-per-minute rate. When you add up the dits, the dahs and all the gaps, including the gaps between the letters and the gap that follows the word, PARIS takes 50 units. The word CODEX takes 60 units and gives a rate that is typical of five-letter code groups, or sequences of random letters. PARIS imitates a word rate that is typical of natural language, partly because the short codes for common letters such as E and T make normal text faster than random groups. If someone states a speed without naming the standard word, the figure can be ambiguous, though in amateur radio PARIS is almost always meant.

You can check the number yourself. P is dit dah dah dit, which is 1+1+3+1+3+1+1 = 11 units including the gaps inside the letter. A is dit dah, which is 1+1+3 = 5. R is dit dah dit, which is 1+1+3+1+1 = 7. I is dit dit, which is 3, and S is dit dit dit, which is 5. Add three units of gap after each of the first four letters, which is 12, and seven units of word gap at the end, which gives 11+5+7+3+5 = 31, plus 12 and 7 equals 50. That is why PARIS makes a convenient yardstick: it adds up to exactly 50 units.

The Formula: From WPM to Milliseconds

Because PARIS equals 50 units, the speed in words per minute tells you directly how many units fit into one minute: 50 times W units per minute for W words per minute. A minute has 60,000 milliseconds, so the length of one unit in milliseconds is 60,000 divided by (50 times W), which simplifies to 1,200 divided by W. The reference article gives the same relationship: T equals 1,200 divided by W, where T is the dit duration in milliseconds and W is the speed in words per minute. At 20 WPM, the dit is 60 milliseconds, and a dah is 180 milliseconds. With the CODEX standard, the dit length at 20 WPM would be 50 milliseconds instead, which shows why the standard word must be stated if you compare numbers.

The table below uses the PARIS standard and the 1,200 divided by W formula. The dah is three times the dit, the letter gap is three times the dit and the word gap is seven times the dit.

These figures are calculated from the formula, so they are theoretical values. Real keyers and operators vary a little, and the last decimal does not matter. What matters is the ratio between the elements.

Characters per Minute and Code Groups

You will sometimes see speeds given in characters per minute or in groups per minute instead of words per minute. A common convention, as the reference article notes in its description of testing standards, is that a word is five characters long, and a speed in words per minute is close to the PARIS standard while a speed in code groups per minute is close to the CODEX standard. The reference article also states that speeds measured with the PARIS and CODEX standard words may differ by up to 20 percent. This matters when you compare historical records or practice files, because the same number can mean different speeds depending on the standard used.

Speed Records and Human Limits

Human operators have pushed far beyond everyday speeds. According to the reference article, skilled operators can often understand code in their heads at rates over 40 WPM. In July 1939, at a contest in Asheville, North Carolina, Theodore Roosevelt McElroy, W1JYN, set a still-standing record for copying Morse at 75.2 WPM. The fastest speed ever sent with a straight key was reached in 1942 by Harry Turner, W9YZE, who sent 35 WPM in a demonstration at a US Army base. At those speeds, operators are hearing phrases and sentences rather than individual words. These records also depend on the standard word and the word gap in use at the time, so they are not exactly comparable with modern figures.

Farnsworth Spacing

When the spacing rules are stretched, the timing changes. In the Farnsworth method, each character is sent at the full target speed, with the normal relative timing of dits, dahs and the gaps within each character, but the gaps between characters and between words are made longer. For example, characters can be sent at a 13 WPM rate while the extra spacing lowers the overall text rate to 5 WPM. This gives learners time to think about the sound of each character without learning it as a slow, counted pattern. The spacing is shortened as skill grows. The method is named after Donald R. Farnsworth, W6TTB. We discuss the practical side, along with the Koch method, in our article on learning Morse code and building CW speed.

The key point for timing is that two speeds exist, a character speed and an overall speed. If you are practising with software, check which one the setting controls, since many programs have separate fields for them. A common mistake is to set a low character speed in order to learn slowly, which makes every character sound wrong and teaches the wrong patterns.

Weight, Ratio and a Good Fist

Real stations are not perfect clocks. Operators have individual characteristics, and the reference article describes this as their fist: some use slightly longer or shorter dahs or gaps, perhaps only for certain characters, and experienced operators can recognise individuals by it. A good operator who sends clearly and is easy to copy is said to have a good fist, while a sloppy sender has a poor fist. In practice, most keyers let you change the weight or the dit-to-dah ratio. The default of one to three is a safe starting point, since it is the standard definition. Small changes can make the code sound lighter or heavier, but large changes reduce readability and can make a signal sound strange. For paddle setup, see our guide to iambic keying modes.

On a straight key, you create the timing with your hand. The goal is a steady rhythm and the correct proportion between dits, dahs and gaps. Beginners usually make the gaps too short, which makes characters run together, and make dahs too short, which makes them sound like dits. An electronic keyer produces perfect timing but cannot compensate for a poor choice of speed. If you use a computer interface, the timing is also affected by the software and the hardware, and our guide to CW keying interfaces explains how a dedicated keyer improves it.

Timing and Break-In

Timing also affects how the radio behaves. At high speeds, the transmit and receive switching delay, which the radio needs to prevent clipped characters, becomes a larger share of each unit. At 30 WPM, a dit is only 40 milliseconds, so a transmitter that takes a long time to switch will shorten the first dit or the first characters. This is the reason that experienced operators pay attention to the delay settings on their radios. If you want to understand how full break-in works at speed, see our guide to full break-in CW and QSK, which explains how to set the delay.

Practical Tips

1. Choose a speed you can send perfectly. A slower, clean signal is easier to copy than a fast, sloppy one. Increase the speed only when you can maintain accuracy.
2. Listen to the gaps. If a word looks wrong when you copy it, the spacing may be the problem. Check that you are not leaving the character gap too short.
3. Use a keyer or software to learn. Practise with a program that sends perfect code, and compare your own sending by recording it.
4. Check the standard. When you compare speeds, make sure the same standard word was used, since PARIS and CODEX differ.
5. Do not shorten the word gap. A short word gap is a common cause of confusion, especially in contests. Our guide to Morse Runner shows how to practise at contest speeds.

The Bottom Line

Morse code timing is simple once you see the pattern. A dit is one unit, a dah is three, the gaps are one, three and seven, and the standard word PARIS contains 50 units, so the dit length in milliseconds is 1,200 divided by the speed in words per minute. Keep the ratios accurate, remember that stretching the gaps changes the overall speed without changing the character speed, state the standard word when you compare numbers, and listen for rhythm as much as for speed. Good timing is what makes code at any speed a pleasure to copy.

Frequently Asked Questions

How long is a dah compared with a dit?

A dah is three times as long as a dit. The gap inside a character is one unit, the gap between letters is three units and the gap between words is seven units.

How do I convert WPM to dit length?

Divide 1,200 by the speed in words per minute to get the dit length in milliseconds. For example, at 20 WPM, the dit is 60 milliseconds and the dah is 180 milliseconds.

Why is PARIS used to measure speed?

PARIS is a word that takes exactly 50 units, including the gaps, and it has a length similar to ordinary text. This makes it a convenient standard for calculating words per minute.

What is the difference between PARIS and CODEX?

PARIS takes 50 units and models normal language text, while CODEX takes 60 units and models five-letter random code groups. Speeds measured with the two can differ by up to 20 percent, so always check which one is used.

What is Farnsworth spacing?

Farnsworth spacing sends each character at full speed but lengthens the gaps between characters and words. This lets learners hear each character as a whole sound while the overall text speed stays low.

Why is the word gap seven units now?

The current International Morse standard uses seven units for the gap between words. It was formerly five units, so older books and historical records may use the earlier figure.

Summer has Field Day, and January has its colder, quieter and more demanding cousin. Winter Field Day is an annual amateur radio event in which operators set up portable stations in the middle of winter, work other stations around the world and practise emergency communications in conditions that make everything harder. This guide explains when it is held, what the main rules and limits are, why some popular digital modes are not allowed, and how to prepare yourself and your equipment for the cold. The facts come from the organisers’ own pages, and you should always read the current rules before you take part.

What Winter Field Day Is

According to the Winter Field Day Association home page, Winter Field Day is an annual event that offers radio operators the chance to set up field operations in remote locations and connect with other participants worldwide. You can take part alone or bring friends, family or your whole club. The association believes that radio amateurs should practise portable emergency communications in winter environments, because freezing temperatures, snow, ice and other hazards create special operating problems. The aim is to help participants improve their preparedness for disasters and their operating skills under adverse conditions.

Operators may use the HF, VHF or UHF bands and may use voice, CW and digital transmissions. The event sets specific objectives to encourage a wide range of activities, such as using non-commercial power sources, deploying multiple antennas and making satellite contacts. In other words, the event is a practical exercise rather than a pure points race, and the organisers say it is not about how many contacts you make or the points at the end of the day. It is about whether you can successfully relay emergency information in adverse conditions.

A Short History

The history page explains that in 2006 an operator asked whether the Society for the Preservation of Amateur Radio, known as SPAR, would sponsor a winter operating event. The society’s board approved the idea, and the first Winter Field Day took place on 13 and 14 January 2007. Based on comments from participants, it soon became an annual event. In late 2015, a group of enthusiasts formed the Winter Field Day Association, which took over the responsibility for the event and has promoted it since then. The association reports that it processed more than 2,500 logs from stations around the world in 2022. The principle has not changed since the first event: preparedness is the key to a professional and timely response, and your skills should not be limited to fair-weather conditions.

Dates and Hours

Winter Field Day takes place in late January. The home page gives the dates for the next event as 23 and 24 January 2027 and calls it the fourth full weekend of January, while the resources page describes it as the last full weekend of January. Because these descriptions differ, always check the date on the official site for the year in which you plan to take part, and write it in your calendar. The resources page says the event begins at 16:00 UTC on Saturday and runs through 21:59 UTC on Sunday, which is a little over a full day of operating. Convert that to your local time, because the event is global and the UTC clock decides the start and end.

Bands and Modes

Participants can operate on the 160, 80, 40, 20, 15 and 10 metre HF bands and on all bands above 50 MHz. The WARC bands and 60 metres are not on that list, so do not plan to use them. Modes include voice, CW and digital, but with one important limit that surprises many newcomers.

FT8 and similar modes are not allowed. The organisers explain in their FAQ that the objectives are built around making sure that the event remains an exercise in emergency communications. Although FT8, FT4, JT9 and similar modes are legitimate digital modes, the organisers say that they cannot pass emergency traffic effectively. Their reasoning is that the event is about whether you can relay emergency information back and forth in adverse conditions, not about how many contacts you make. They encourage participants to use their digital skills to practise passing information with other digital methods. In a blog post of October 2026, the organisers also announced that a new mode in the latest WSJT-X release candidate, called JTTY, is capable of passing emergency traffic, so it is allowed for the 2027 event. If you want a flexible keyboard mode, our guide to JS8Call and the Fldigi setup guide explain two options that fit the spirit of the exercise, but check the current rules for each mode before you decide.

One Call Sign, One Location

The rules around logs are strict and are explained in the organisers’ FAQ. Unlike some other field events, individual operators cannot add together scores earned from different locations to give a club a combined score. The log you submit must cover only one call sign, and it must be the call sign you used during the event. All equipment and operators using the same call sign must be within the same 300 metre radius. If your club has several operators at one site, they share one call sign and one log. If your members operate from their homes, each person submits a separate log under their own call sign.

The same FAQ explains that the category you choose is discretionary and that there is no penalty for choosing the wrong one. The organisers ask you to follow the general guidelines and the spirit of the event. They give a useful example: if you operate from a communications trailer that is within walking distance of a club member’s house, where there is heat, running water and a couch, you should not call yourself an outdoor station. A trailer in a parking lot with nothing around it is a different matter. The principle is honesty about your conditions, since the exercise is only useful if you really test yourself.

The Bulletin and the Multiplier

An unusual feature of the event is the Winter Field Day bulletin. The organisers transmit it, and participants who copy it accurately and submit it with their entry can claim a multiplier. The FAQ says that if you cannot hear the bulletin, you may ask another station to send it to you, as long as you receive it entirely over amateur radio. The bulletin is sent in a digital mode, and one board member has written a guide to installing and configuring Fldigi to decode it. The bulletin schedule is published on the official site and in downloadable form. As with all the details in this article, use the current year’s schedule, since times and modes can change.

Logging and Submitting Your Entry

Use a logging program that supports the event. The resources page lists several options, among them N3FJP’s Winter Field Day contest log, a World Radio League web logger, Ham2K Portable Logger, HAMRS and N1MM Logger Plus, as well as DXLog. If you already use a contest program, see our guide to setting up N1MM Logger+ for your first contest. Pay attention to the section list and the section map that the organisers publish, because the exchange uses sections. They note recent changes, such as a new Canadian section, so always check the current list.

Logs are due by 11:59 UTC on 1 March, according to the resources page, and late entries may not be included in the results. If you discover an error after submitting, you can submit the log again and the new one will overwrite the old one, until the deadline. After the deadline, the submission page closes and all logs become final.

Preparing for the Cold

The event is about winter conditions, so most of the preparation is about people and equipment in the cold. The following list covers the issues that cause the most problems.

• Dress in layers. You will sit still for hours, which makes you colder than when you are moving. Wear insulated boots, a hat and gloves that allow you to handle small controls. Thin gloves with a warmer outer layer are popular for key and keyboard work.
• Keep batteries warm. Cold reduces the available capacity of most batteries, so keep them in an insulated box or inside your coat until they are needed. Our guide to battery and power options for portable operation explains how to size a battery, and the same sizing logic applies in winter with a generous margin.
• Protect electronics from condensation. Moving a cold radio into a warm room can cause moisture to form inside. Allow the equipment to reach room temperature slowly, and keep it in a bag when you move it.
• Use cables that stay flexible. Some cables stiffen in cold weather, and connectors can crack. Handle them carefully and check them before you start.
• Plan for ice and snow on antennas. Wet snow and ice add weight, change tuning and can bring down wires. Use sturdy supports, and check the guying of masts regularly.
• Bring a heat source and hot drinks. If you operate inside a tent, a shelter or a vehicle, follow safe heating practices and ensure ventilation. Carbon monoxide is a serious hazard in enclosed spaces.
• Tell someone where you are. If you operate in a remote location, share your plan and your expected return time.

Event Comparison

The ARRL’s own event is described on the ARRL Field Day page, and we cover it in our guide to field day planning and power. The two events share some skills, but their rules and exchange are different, so do not assume that what you learned in one will carry over to the other.

Practical Tips for a First Entry

Start small. A single operator with a simple station in a car or a garage can take part, and the event is a useful test of your portable setup. Choose a site that you can reach easily and that gives you a sense of the conditions without too much risk. Test your antenna, feed line and power source at home before you go. Practise the digital mode you plan to use and make sure the logging program works. Bring a paper log as a backup, and write down your set-up so you can improve it next year.

Above all, treat it as practice. If something fails, you have learned something useful, and that is the purpose of the event. Many participants report that the best part of the weekend is the lessons they take away, such as the realisation that their favourite coax is too stiff in the cold or that their battery needs a better box.

The Bottom Line

Winter Field Day is a late January event that tests how well you can operate portable emergency communications in the cold. It runs from 16:00 UTC on Saturday to 21:59 UTC on Sunday, uses the 160 to 10 metre HF bands and the bands above 50 MHz, excludes FT8 and similar modes, and requires one call sign and one location per log. Check the current dates and rules on the organisers’ site, prepare your people and your batteries for the cold, and use the weekend to learn what works in your station and what does not.

Frequently Asked Questions

When is Winter Field Day?

It is held in late January. The organisers list 23 and 24 January 2027 for the next event, starting at 16:00 UTC on Saturday and ending at 21:59 UTC on Sunday. Always confirm the date on the official site.

Which bands can I use?

The resources page lists the 160, 80, 40, 20, 15 and 10 metre HF bands and all bands above 50 MHz. You may use voice, CW and digital modes within the rules.

Why is FT8 not allowed?

The organisers say that the event is an exercise in emergency communications and that FT8 and similar modes cannot pass emergency traffic effectively. They encourage participants to practise other digital methods instead.

Can I add scores from several locations for my club?

No. Each log must cover one call sign, and everyone using that call sign must be within a 300 metre radius. Operators at different locations submit separate logs under their own call signs.

When must I submit my log?

The resources page says that logs are due before 11:59 UTC on 1 March. You can resubmit until then, and a new log overwrites the old one. After the deadline, the logs are final.

Do I need a lot of equipment to take part?

No. You can take part with a simple portable station, even from a car, and you can operate alone. The aim is to practise, so a small setup that you understand well is better than a large one that you have not tested.

When a line of severe thunderstorms moves across the United States, the people who give the National Weather Service its ground truth are often volunteers with a radio. This guide to SKYWARN ham radio activity explains what the program is, how amateur radio operators fit into it, what a spotter actually reports, and how to get started. It is based on the National Weather Service’s own program description, and it focuses on the United States, where SKYWARN is run. If you live elsewhere, similar programs exist, and we list some of them below.

What SKYWARN Is

SKYWARN is a volunteer program run by the National Weather Service (NWS). According to the agency’s SKYWARN program page, the NWS established it with partner organisations to obtain critical weather information, because thunderstorms, tornadoes and lightning cause hundreds of injuries and deaths and billions of dollars in damage in most years. The program has between 350,000 and 400,000 trained severe weather spotters, who give their local communities timely and accurate reports of severe weather. Although spotters provide information on all kinds of weather hazards, the focus is on severe local thunderstorms. The program began in the 1970s according to the NWS, while other sources date the first SKYWARN activity to 1965, so you will see both dates in print.

The idea is simple. Radar and satellites show forecasters where a storm is and how it is moving, but they cannot always see what is happening at ground level. A trained observer who sees a rotating wall cloud, a funnel cloud, large hail or a flooded road can confirm what the instruments suggest and help the forecaster issue a warning with confidence. The NWS notes that the information supplied by spotters, together with Doppler radar, improved satellite data and other sources, has enabled it to issue more timely and accurate warnings for tornadoes, severe thunderstorms and flash floods. The name and logo are registered trademarks of the NWS, so use them only as the agency allows.

Where Amateur Radio Comes In

SKYWARN has long been associated with ham radio. In many areas, spotters use amateur radio nets to communicate with one another during severe storms, which remains an important method because severe weather can disrupt telephone and internet services. Many local NWS offices maintain an amateur radio station that volunteers operate during severe weather. This allows licensed spotters to send their reports directly to the NWS and to receive up-to-date information about the storm, even if the normal communication channels are overloaded or damaged. It does require the cooperation of the local Weather Forecast Office and a continuously staffed station during the event. The NWS and the ARRL have a memorandum of understanding, which is listed among the program’s supplemental resources.

The ham radio side of SKYWARN usually has three parts. First, spotters in the field, who are on the road, at home or at a fixed lookout, observe the weather. Second, a net control station, often at the NWS office or at a volunteer station nearby, collects the reports and passes them on. Third, a repeater or a linked repeater system gives the spotters the range they need. If you are new to the idea of a directed net, our guide to running a ham radio net explains how a net control station keeps order. Automatic position reports through APRS can also help, and our article on APRS explains how that works.

You Do Not Need a Licence to Be a Spotter

An important point for newcomers is that you do not need a ham licence to take part in SKYWARN. The NWS encourages anyone with an interest in public service to join, and the volunteers include police and fire personnel, dispatchers, emergency medical workers, public utility workers and concerned private citizens. People affiliated with hospitals, schools, churches and nursing homes, or who have a responsibility for protecting others, are encouraged to become spotters. In practice, many spotters are not radio amateurs, and they report by telephone or through the internet. A radio licence simply adds a communication path that does not depend on the telephone network.

Training: What You Learn

Spotter training is free and typically lasts about two hours, according to the NWS. Classes are held by local NWS offices, usually in the relatively slow season before the severe weather months, and they are not typically offered all year, so schedules vary from office to office. If you cannot attend a class, the NWS also offers a free online program. You register as a general user and can then attend courses such as the spotter registration, the role of the spotter and a course on convective basics. Some offices also ask that you take a local class to learn about weather unique to your area. The NWS lists the main topics of the class as follows.

• The basics of thunderstorm development
• The fundamentals of storm structure
• How to identify potential severe weather features
• What information to report
• How to report it
• Basic severe weather safety

The NWS recommends refresher courses every two years according to reference sources, since the rules and the thresholds can change. Training is not a substitute for experience, but it prepares you to recognise what matters and to avoid dangerous mistakes. It is also the place to learn the local reporting thresholds, which vary by region and may change during an event.

What Spotters Report

Spotters typically report events such as structures struck by lightning, rotating wall clouds, funnel clouds and tornadoes, and conditions that exceed set thresholds, such as extremely strong winds, significant hail or very heavy rainfall. They also give reports during winter storms, floods, hurricanes and wildfires. Some spotters help with damage assessment after a disaster by documenting areas of damage and helping to form preliminary damage estimates. The exact thresholds depend on the local NWS office, so always follow the guidance from your own area.

A good report is short and specific. It includes what you saw, where you saw it, when you saw it and how reliable the observation is. Use plain language, avoid guessing and say if you are not sure. A typical on-air report gives your call sign or name, the location in terms of a road, a town or a landmark, the time, and the observation, for example the size of hail compared with a common object. Net control then relays it to the forecasters. Reports from spotters and storm chasers are given to the NWS so that forecasters have ground information to warn the public, including details that radar might miss.

Radio Equipment for Storm Spotting

Most SKYWARN nets run on VHF or UHF repeaters, so an ordinary 2 metre or 70 centimetre handheld or mobile radio is the basic tool. A mobile radio with an external antenna gives better range and reliability than a handheld. If you are using a handheld, consider an improved antenna, as explained in our handheld antenna upgrade guide. Your local clubs and NWS offices will tell you which repeaters and frequencies are used, and some areas also use simplex frequencies or HF links for coverage gaps. For the basics of repeater operation, ask a local club for a demonstration.

Think about power and safety as well. A battery-powered radio, a spare battery, a charger for the car and a notepad with a pencil are the minimum. Some spotters add a weather radio, a flashlight and a map. The NWS publishes a field spotter’s guide, which is listed with the program’s supplemental resources, and many offices provide printed copies at training sessions.

Safety First

The most important rule of storm spotting is that your safety comes first. Spotters report what they see, but they should not put themselves in harm’s way. Lightning, hail, flooding and tornadoes are life-threatening, and a report is not worth an accident. Keep a safe distance from the storm. Do not park under power lines, trees or bridges that could be unsafe. Never drive through flooded roads, and keep away from the path of a tornado. Many offices give additional safety guidance for spotters, including guidance on communications during an operation, and your training class is the place to learn it.

Radio equipment adds some extra hazards. Do not use outdoor antennas during a thunderstorm, and disconnect them if you have a fixed station and lightning is approaching, as discussed in our guide to station grounding and lightning protection. Mobile antennas that stand tall on a vehicle are not a safety risk by themselves, but remember that a car is not a safe place to be if you are in the path of a tornado. Learn your local shelter plan before you go.

How SKYWARN Differs From ARES and RACES

New operators often confuse the various emergency communication groups, so it helps to separate them. SKYWARN is a weather spotting program from the NWS. It uses amateur radio and other communication channels, but it is not a ham radio organisation. The Amateur Radio Emergency Service and the Radio Amateur Civil Emergency Service are volunteer communication organisations that support served agencies and emergency managers. We describe them in our article on ARES and RACES. Many hams are in more than one group. A ham who is a SKYWARN spotter and an ARES member may be asked to help with weather reports in one role and to support emergency operations in another. The key difference is who you work for: in SKYWARN, you provide weather reports to the NWS, while ARES or RACES volunteers support agencies and community response.

Similar Programs Outside the United States

Other countries have similar programs. Examples include the Canadian spotting program CANWARN, the SkyWarnUK and TORRO programs in the United Kingdom, and Skywarn Europe for several European countries, as listed in the encyclopedia entry on Skywarn. They differ in training, reporting channels and the part played by amateur radio, so check the local organisation. Radio amateurs in Europe can also take part in storm reporting through national societies and local clubs. If you live outside the United States, look for a spotter network in your own region before you assume that the American rules apply.

How to Get Started

1. Find your local NWS office. Look up the SKYWARN page for your region and check when and where the next training session takes place.
2. Attend a class. The class is free, takes about two hours and explains how to report. If you cannot attend, use the online program.
3. Join a local net. Ask local clubs about the SKYWARN nets and the repeaters they use. Listen to a few nets before you check in.
4. Prepare your equipment. Prepare a radio, a spare battery, a notepad, a flashlight and a plan for staying safe. Pack it in a bag that you can grab quickly.
5. Practise reporting. Take part in practice nets, and join the community of operators who handle reports. Practice will make you faster and clearer when it counts.

The Bottom Line

SKYWARN is the National Weather Service’s volunteer storm spotter program, and ham radio is one of the best ways to connect spotters to forecasters when the weather disrupts normal communication. You do not need a licence to join, the training is free and short, and the work is simple: observe, report accurately and stay safe. If you have a handheld radio and an interest in public service, a SKYWARN class is one of the most useful things you can do before the next storm season.

Frequently Asked Questions

What does SKYWARN do?

SKYWARN is a National Weather Service program in which trained volunteers report severe local weather, such as tornadoes, large hail and flooding, to their local NWS office. The reports help forecasters issue and verify warnings.

Do I need a ham radio licence to be a SKYWARN spotter?

No. Anyone with an interest in public service can become a spotter and can report by telephone, internet or other means. A ham licence adds a communication path that works when the telephone and internet networks are overloaded or damaged.

How long does SKYWARN training take?

The NWS says that training is free and typically lasts about two hours. The NWS also offers a free online program for those who cannot attend a local class.

What should I report during a storm?

Report events such as tornadoes, funnel clouds, rotating wall clouds, large hail, damaging winds, flooding and structure damage, following the thresholds set by your local NWS office. Keep the report short and specific, and say when and where it happened.

What radio do I need for a SKYWARN net?

Most nets run on VHF or UHF repeaters, so a 2 metre or 70 centimetre handheld or mobile radio is enough. A mobile radio with an external antenna offers better range. Ask your local club which repeaters the net uses.

Is SKYWARN the same as ARES?

No. SKYWARN is a weather spotting program of the National Weather Service, while ARES is an amateur radio emergency communications group. Many hams take part in both, but they serve different purposes.

Almost every wire antenna has the same first problem: before you can tune it, measure it or work a single station with it, you have to get the end of a line over a branch that is twenty metres above your head. A good antenna launcher turns this from an afternoon of frustration into a ten minute job. This guide explains the common ways of getting a line over a tree, which line and weight to choose, how to turn a thin shooting line into a strong support rope, and which safety rules matter. It is written for the wire antenna builder who wants a reliable, repeatable method rather than a lucky throw.

Why Getting a Line Into a Tree Is Hard

A tree is the cheapest and most flexible antenna support there is. Dipoles, inverted V antennas, slopers, end-fed wires and vertical wires all benefit from a high, clear support point, and the higher the support, the better the antenna can perform on the lower bands. The difficulty is that the best branch is usually high, thin and surrounded by smaller branches, and a heavy rope cannot be thrown that far. The solution is to start with something light that can be launched accurately, and to use it to pull up progressively stronger lines until the antenna wire or its support rope is in place.

There are four common ways of doing the first step, and each has its place: throwing a weighted line by hand, using a throw bag, shooting a weight with a slingshot or a purpose-made launcher, and using a pole to lift the line. We will look at each, but first it helps to understand the principle that all of them share.

The Two-Line Method

The method that most experienced antenna builders use has three stages. First you launch a light shooting line over the target branch with a weight. Second, you attach a stronger line, often called a pull line or messenger, to the end of the shooting line and pull it over the branch. Third, you use the pull line to pull up the real support rope or, if the antenna is light, the antenna itself. The system works because each step carries a heavier load than the last, and because the weight does the difficult job only once.

Plan the rope arrangement before you leave the ground. In most cases it is best to pass the rope over the branch and then to tie both ends to something at ground level, so that the antenna can be raised and lowered without climbing. This is called a halyard, a word borrowed from sailing. A pulley at the top is a luxury that makes hauling much easier and reduces rope wear, but it is not essential for light antennas. Our guide to push-up masts and guying covers the other common approach, and many stations use a tree at one end and a mast at the other.

Choosing a Shooting Line

The shooting line has to fly freely, survive friction in the branches and be strong enough to pull up the next line. Fishing line is the usual choice, and the fishing line article explains the main attributes: material, thickness, breaking strength, knot strength, abrasion resistance, stretch, memory and visibility. Most modern lines are made of synthetic polymers such as nylon, polyethylene or fluorocarbon, and they come as monofilament or braided multifilament. Both types have been used by antenna builders, and each has strengths.

• Monofilament is smooth and often tangle-resistant when it comes off a spinning reel, and it is easy to find. It has more stretch and more memory, which means that it can coil and kink if it is stored badly.
• Braided line is thin for its strength, has little stretch and can be easier to feel in your fingers. It can cut into skin under load and may cut through a softer line if used carelessly, so wear gloves when you pull on it.
• Bright colours help you see the line in the air and against a dark tree, which saves time when you must find the end in the grass.

Whichever you choose, check the marked breaking strength and compare it with the load you plan to pull. As a general rule, the shooting line only needs to pull up the next, heavier line, so you do not need a very strong one. A line that is too thick, on the other hand, adds weight and drag and makes the launch shorter. Use a reel, a fishing rod reel or a simple spool that lets the line pay out freely without tangling. A reel with a push-button or open-face release is popular because the line can leave the spool with almost no resistance.

Choosing a Weight

The weight must be heavy enough to carry the line over the branch and to drag it down on the other side, yet small enough to launch easily and not to cause harm if it falls. A small bag of sand or shot, a purpose-made throw weight, or a soft bag with a rounded shape are common choices. Avoid hard, sharp or metal objects when possible, since they can damage the branch, the line or your property if the shot goes wrong. A smooth, rounded shape slides through the leaves and branches more easily than a flat one. Many builders use a weight with a hole for the line so that it can slide down after it has crossed the branch.

It is wise to test the weight and line in an open space before you try it near the tree, so you can judge the range and the accuracy. Practice with a marker on the ground and aim at a branch that you can see. Once you know how the combination behaves, you will waste fewer shots, and fewer shots means less tangling and less wear on the line.

Slingshots and Dedicated Launchers

A slingshot is a small hand-powered launcher. In its classic form, according to the slingshot article, it consists of a Y-shaped frame, two strips of rubber or synthetic elastic attached to the upper ends, and a pouch that holds the projectile. One hand holds the frame while the other pulls back the pouch. Antenna builders have used this simple principle for many years to launch a weight with a line attached, and there are commercial products sold as antenna launchers that are designed for that task, with a reel mount and a safer weight.

The advantage of a slingshot launcher is height and accuracy. A good shot can reach a branch that is far beyond the reach of a hand throw, and a launcher with a sighting aid allows you to repeat a shot that nearly worked. The disadvantages are cost, the need for space around you and the greater potential for harm if you are careless. Because the same device can be misused, treat it with respect, follow the manufacturer’s instructions and check local rules on their use. Never aim at people, animals, vehicles, windows or power lines, and never launch toward a direction where you cannot see where the weight will land. Wear eye protection, and make sure that bystanders are well out of the way.

Throw Bags and Hand Throws

If the branch is lower than about the height of a house, a hand throw can be the quickest method. A throw bag is a rope stuffed loosely into a bag so that it pays out through the top when the bag is thrown. The idea comes from water rescue, where, as the throw bag article explains, it is standard equipment for kayaking and other river activities. Tree workers and antenna builders use weighted bags of similar design to throw a line over a branch. The bag trails a line behind it, and the flight is easy to judge because the weight is compact and the line stays untangled.

Throwing technique matters. Hold the end of the line firmly, since a throw that ends with the line leaving your hand wastes the shot. Use an underhand or overhand throw, lead the target and aim for a point well above the branch, because the weight will arc down and the line will pull it back as it drops. Stand clear of the area where the weight will fall and keep an eye on other people. Many people find a soft bag more comfortable than a hard weight, and it is less likely to cause damage when it lands.

Using a Pole or Extension Mast

When a launcher is not allowed or not practical, a lightweight pole can lift the line high enough to hook it over a branch. Telescopic fibreglass poles, which are also used as antenna masts, can reach several metres. A small pulley or a hook at the top of the pole holds the line, and you walk the pole beneath the branch and pass the line over. It is slow and quiet, and it does not require a launch. It is also useful for adjusting a line that has caught on a twig or for guiding a rope into position. If you already have a pole for a wire antenna, as in our article on the inverted V antenna, you can use the same pole for this job.

Comparing the Methods

Step-by-Step: A Typical Installation

1. Choose the branch. Pick a strong, healthy branch with a clear path to the ground on both sides. Avoid dead wood and branches that hang over buildings, roads or power lines. If possible, choose a branch that is far enough from the trunk to give the antenna wire room to hang.
2. Plan the antenna. Decide how long the antenna wire is and where the other end will be tied. Our guide to the sloper antenna shows how a single high support point can serve a whole antenna.
3. Prepare the line. Fit the reel, tie the weight with a secure knot and lay out the line so it can pay out freely. Test the knot with a firm pull.
4. Launch. Aim above the branch, not at it. If you miss, retrieve the weight, check the line for twists and try again. Do not keep shooting if the line is tangled.
5. Replace the weight with a pull line. When the weight reaches the ground, detach it and tie the pull line to the shooting line with a secure knot. Pull the shooting line back over the branch until the pull line is over.
6. Pull up the support rope. Attach the rope that will carry the antenna to the pull line and pull it over. Use a rope that resists sunlight and moisture, because it will hang outside for months or years.
7. Raise the antenna. Tie the antenna to the halyard with a strain-relief arrangement, so that the load does not pull on the feed point or the wire. Raise it and secure the rope at ground level.

Antenna Wire, Movement and Wear

A tree moves in the wind, and a fixed antenna wire will eventually break at the point of highest tension. Use a system that lets the wire move, for example a weight or a spring at the end, or a halyard that runs over a pulley and holds a weight at the bottom. This arrangement allows the antenna to rise and fall slightly without breaking. Check where the rope crosses the branch for abrasion, and add a short sleeve or a pulley if the rope is rubbing. A seasonal inspection should include the ropes, the knots and the wire, just as for any other antenna. Weatherproofing the coax at the feed point also matters, and our guide to weatherproof coax connectors explains how to protect it.

Safety First

Launching a line into a tree is a simple job, but safety comes first. Keep every part of your antenna and every line well away from overhead power lines, since a wet line or a wire can conduct electricity. If the best tree is near a power line, choose another tree. Do not climb a tree to place the line unless you are trained and equipped, and never climb during a storm. Check whether your property or local rules allow what you plan to do, and ask the owner of the tree before you attach anything to it. Protect the tree by avoiding wire wrapped around a branch, which can cut into the bark as the tree grows.

Also think about the people around you. Make sure no one is within the launch area. Keep children and pets away. Use eye protection. Do not use a launcher in a crowded area, and never in a direction in which you cannot see where the weight will land. If a weight gets stuck in a branch, do not pull hard on the line, because it may snap back. Cut the line and leave it, or retrieve it using a pole when it is safe to do so. For more on safety at height, see our guide to ham radio tower safety.

Common Mistakes

• Using a line that is too heavy. A heavy line reduces the range and accuracy. Use the lightest line that can do the job.
• Aiming at the branch instead of above it. The weight falls as it travels, and the line adds drag. Aim above the target.
• Using weak knots. A weak knot often fails when the line is under load. Test it before you launch.
• Forgetting to plan the return path. If you cannot lower the antenna, you cannot maintain it. Always include a halyard.

The Bottom Line

An antenna launcher, a throw bag or a simple pole are all ways of doing the same job: getting a light line over a high branch so that you can pull up stronger ones. Choose a light, bright shooting line, a smooth weight and a plan with two lines and a halyard, practise before you aim, and keep everything clear of power lines and people. With a little practice, a tree becomes a tall, free and flexible antenna support, and a wire that was once difficult to place becomes a part of your station that you can raise, lower and maintain with ease.

Frequently Asked Questions

What is an antenna launcher?

An antenna launcher is a device, usually a slingshot-style or spring-powered tool, that shoots a weight with a thin line attached over a high branch or support. The thin line is then used to pull up a stronger rope or the antenna itself.

Which line is best for launching over a tree?

Fishing line is the usual choice. Monofilament is smooth and easy to handle, while braided line is thin and strong with little stretch. Choose a bright colour so that you can see it, and use the lightest line that can pull your next, stronger line.

How do I get a heavy rope over a branch?

Use the two-line method. Launch a light shooting line first, tie a pull line to it and pull it over the branch, and then use the pull line to pull up the heavy rope. Each step carries a heavier load than the last.

Is it safe to use a slingshot for this?

It can be, if you follow the safety rules. Use a soft or rounded weight, wear eye protection, keep people and animals out of the area and never aim at power lines, windows or vehicles. Check local rules and the manufacturer’s instructions.

What if the weight gets stuck in the tree?

Do not pull hard, because the line may snap back. Try to free it gently from a different direction, use a pole if it is safe, or cut the line and leave the weight rather than risk an accident.

How high should I place a wire antenna in a tree?

As high as safely possible. Height helps the antenna on the lower bands, but it must be balanced with safety and with the strength of the branch. Choose a strong branch, keep clear of power lines and check the setup after storms.

A good hamfest guide starts with a simple promise: you do not need to be an expert to enjoy one. A hamfest is a gathering of radio amateurs that usually combines a flea market, a small trade show, talks and club meetings, and a lot of conversation in the aisles. If you have only ever met other hams on the air, a hamfest is the place where the call signs get faces. This article explains what to expect, how to prepare, how to look at used equipment without getting burned, and how to get real value out of the day even if you never open your wallet.

What a Hamfest Actually Is

According to the general description of the term, a hamfest is a convention of amateur radio enthusiasts that often combines a trade show, a flea market and various other activities of interest to hams. In the United Kingdom the same kind of event is more commonly called a rally, and you will also see words such as convention, swapmeet or expo depending on the country and the organisers. Hamfests were noted as early as 1924 in the United States, so the tradition is almost as old as the hobby itself. You can read the background in the encyclopedia entry on hamfests.

Most events take place over a weekend and can last anything from a few hours to several days. They are organised by clubs and volunteers, so the character changes a lot from place to place. A small local event may fill one school gym with a few dozen tables and a coffee stand. A large national or international event can fill several halls and outdoor fields and draw visitors from many countries. In the United States, regularly scheduled hamfests often begin with a simple fund-raising event such as a pancake or waffle breakfast, and larger events almost always include food vendors staffed by volunteers whose proceeds support a local school or charity.

The Main Parts of the Day

Although every event is different, most of them are built from the same few ingredients. Knowing them in advance lets you decide where to spend your time.

The Flea Market

The flea market is the heart of most hamfests. Individuals and small dealers lay out equipment on tables, tailgates and the ground, and attendees walk the rows looking for bargains. Haggling is the usual way to settle a price. You will find everything from the newest high-tech gear to used, refurbished and antique equipment, and surplus that was originally sold at great expense to commercial users can sometimes be found for a small fraction of its first price. Accessories that manufacturers no longer sell, such as a particular mounting bracket or a manual for an old receiver, also turn up here.

Look out for the junk box, a cardboard container full of connectors, switches, knobs, scraps from finished projects and parts from equipment that no longer exists. Junk boxes are a tradition, and they are a cheap way to stock your own bench with parts. You may also see very large and heavy old items called boat anchors, a joke about equipment that is so obsolete and so heavy that the only remaining use is to hold down a boat. Some of them are fine restoration projects. Others are exactly what the nickname suggests.

Vendors and Manufacturers

Larger hamfests include booths run by dealers and manufacturers. They sell new radios, antennas, cables, books and tools, and some present demonstrations. The very biggest events, such as the Dayton Hamvention in Ohio, the amateur radio exhibition in Friedrichshafen in Germany and the Tokyo Ham Fair run by the Japan Amateur Radio League, are the places where manufacturers most often introduce new products to the amateur radio market. At a smaller event, the vendor area may be a handful of tables, but it is still useful when you need a connector, a roll of wire or a book today rather than in a week.

Forums, Clubs and Exam Sessions

Many events include seminars on technical, operating or legal topics, meetings of clubs and special interest groups, and licence examination sessions. If you are thinking about getting a licence or upgrading, an exam session at a hamfest can be a very convenient way to do it, and the volunteer examiners are usually delighted to see new faces. Our overview of amateur radio licence classes and exams explains what to expect from the exam itself, and the hamfest is where you can ask questions in person.

Door Prizes and Social Time

Door prizes and raffles are common, and the proceeds usually support the sponsoring club. The social side is just as important as the commercial side. Regular attendees often visit their first hamfest in search of a particular piece of equipment but come back year after year because of the people. Since the internet now handles much of the buying and selling of used equipment, the social side and the talks have become a bigger reason to attend. That is also why a hamfest is a good place to meet a mentor, a topic we cover in our guide to bringing new members into a ham radio club.

Finding a Hamfest Near You

Search for events in your region a few weeks ahead. In the United States, the ARRL publishes a searchable calendar of hamfests and conventions, where you can filter by state, ARRL division or section, or by distance from a city. You can find it on the ARRL hamfest and convention calendar. In other countries, the national amateur radio society or the local clubs usually list rallies and meetings on their own websites, and club newsletters often mention smaller events that never reach the large calendars. Confirm the dates, the location, the entrance fee, the opening hours and the parking arrangements on the organiser’s own page, because details change from year to year.

It is worth noting the size of the event before you drive a long way. A large hamfest may take a full day to explore and may involve a long walk across fields. A small one can be done in an hour or two. Decide in advance whether the trip is mainly about shopping, about talks or about meeting people, and pick the event that suits that goal.

What to Bring

A little preparation makes a big difference. The list below is based on what experienced attendees usually carry, and you can adjust it to the size of the event and the weather.

• Cash in small notes. Many sellers at the flea market only take cash, and a seller will rarely hand over change for a large note on the first sale of the day. Some vendors accept cards, but do not count on it.
• A written shopping list. Include the model numbers, connector types and approximate prices of the things you want, so that you can compare quickly and resist impulse buys.
• A bag, a backpack or a small folding cart. Heavy items multiply quickly, and carrying a power supply and a box of cables across a field is tiring.
• A small tool and test kit. A multimeter, a small screwdriver set, a flashlight, a tape measure and a magnet cover most basic checks. If you plan to look at antennas or cables, a small dummy load and adapters can be handy for testing a transmitter on the spot, but only where the organisers allow transmitting.
• Weather gear. Many flea markets are outdoors. Sun protection, a rain jacket and comfortable shoes matter more than you expect.
• Your call sign on a badge. Many hams wear a name badge with their call sign, which makes conversation easier.
• A pen and a notepad or a phone. Use it to record prices and seller locations, so that you can return to a table after comparing.

How to Look at Used Equipment

The flea market can be a fine place to buy, but the rule is simple: you are buying as seen, and there is usually no warranty and no return. Treat every item as if it needs repair unless the seller shows you otherwise. Our practical checklist for buying used equipment goes into more detail, and the main points are these.

First, look at the item before you talk about the price. Check the case for cracks, burn marks and signs of water. Look at the connectors, the knobs and the display. A radio that has been stored in a damp garage often shows corrosion on the screws and the back panel. Second, ask whether it works and whether the seller has tested it. A seller who says it was working when it was put away is giving you a story, not a guarantee. Third, ask to power it up if the seller has a power source at the table, and look for obvious problems such as a dead display, a noisy volume control or a receiver that does nothing when you touch the antenna connector.

For cables and connectors, check the continuity with your meter and look for green corrosion in the braid. For antennas, check the elements, the traps and the coax connections. For power supplies, ask whether the output voltage is stable and whether the fan runs. For old equipment, look for missing knobs and covers, because those parts can be the hardest to replace. Take your time, and do not be shy about walking away. If the item is good, it will probably still be there after you have walked a few more rows.

Haggling Without Being Rude

Bargaining is part of the culture, and sellers often expect it. A sensible approach is to ask the price, look at the item thoroughly and then make a fair offer. If your offer is much lower than the seller’s price, explain your reason, for example a missing accessory or a cosmetic fault, rather than simply naming a number. Be polite and ready to walk away. Many sellers drop the price late in the day, because they would rather go home with less to carry. Some will even bundle a few items together. It is not unusual for a seller to ask more for a single part from a box than for the entire box, so it often pays to ask for the lot.

If you are the seller, prepare in the same way: clean the items, test them, mark the prices clearly and be honest about faults. Honest descriptions build a reputation in a small community, and many hams recognise familiar faces from one hamfest to the next.

Making the Most of Talks and Clubs

Do not skip the forums. A talk about antennas, contesting, satellites or digital modes can save you months of trial and error, and the speakers are usually available after the talk. Visit the club tables as well. Clubs often run demonstration stations, special event stations or information desks for newcomers. If you are building your first station, speak to local operators about antennas and noise in your area, because they know the local conditions. For a practical idea of what clubs do during large operating events, see the field day planning guide.

Safety and Etiquette

Some practical points make the day more pleasant for everyone. Keep your hands off equipment unless the seller invites you to touch it, particularly if there are small and fragile parts. Do not plug something into a power outlet without asking. Be careful with heavy items, and ask for help before you lift a large power supply or an old tube amplifier. Watch your belongings in crowded halls, and keep your wallet in a safe pocket. Respect the parking rules and the rules of the venue, which may restrict transmitting, smoking or pets. If the hamfest includes a radio operating area, follow the instructions of the organisers.

Finally, remember to be friendly. Introduce yourself and ask questions, because most hams enjoy sharing what they know. If you are a newcomer, say so, and you will often find that somebody offers advice or even an invitation to a local club meeting.

After the Hamfest

When you get home, test everything you bought before you rely on it. Clean the items, check the connectors and measure the voltage of any power supply with a meter before you connect a radio. Write down what you paid and where you found each item, so that you can recall which sellers were reliable. Put the first QSOs from your new gear in your log, and share your finds with your club. If a purchase turns out to be a lemon, treat it as the price of the lesson and move on. Many experienced hams have a shelf of such lessons.

The Bottom Line

A hamfest is a flea market, a trade show, a classroom and a reunion in one place. Find an event through the ARRL calendar or your national society, bring cash, a list and a few simple tools, inspect used items carefully, haggle politely and spend at least part of your day on the talks and the people. Even if you buy nothing, you leave with new contacts and new ideas, and that is the real prize of a hamfest.

Frequently Asked Questions

What is a hamfest?

A hamfest is a gathering of amateur radio operators that usually combines a flea market, a small trade show, talks, club meetings and sometimes licence exams. In the United Kingdom the same type of event is often called a rally.

Do I need a licence to attend a hamfest?

No. Hamfests are open to the public, and many people attend before they are licensed. Some events even host exam sessions so that visitors can sit the test on the day. Check the organiser’s page for details.

Should I bring cash to a hamfest?

Yes. Many sellers at the flea market accept only cash, and small notes make bargaining easier. Some vendors take cards, but it is wise to carry enough cash for the purchases you plan to make.

Can I test equipment before I buy it?

Often you can, but it depends on the seller and the venue. Ask politely, and bring a small multimeter. If the seller cannot demonstrate that the item works, assume it needs repair and offer a price that reflects that risk.

How do I find hamfests in my area?

In the United States, use the ARRL hamfest and convention calendar and filter by state, section or distance. In other countries, check your national amateur radio society and local club websites, and ask club members, who often know about smaller events.

Is a hamfest worth it if I do not plan to buy anything?

Yes. The talks, the club tables and the conversations are valuable on their own, and many regular visitors say that the social side is their main reason to attend.

A modern phone can do many of the jobs that once needed a shelf of books, a notebook and a clock on the wall. Used well, ham radio apps turn the phone into a logbook, a callbook, a propagation monitor, a satellite tracker and a DX alarm, all in your pocket. Used badly, they fill the screen with notifications and drain the battery without improving your operating. This guide groups the useful kinds of apps by the job they do, explains what to look for in each and shows how to build a small, reliable set of tools that supports your station instead of distracting you from it.

Think in Jobs, Not Apps

The app stores contain hundreds of titles for amateur radio, and the list changes constantly. Instead of chasing names, think about the jobs you want done. Do you want to record contacts while portable? Check whether a band is open? Be told when a certain station appears on the air? Predict satellite passes? Find a repeater while travelling? Each job has a handful of good options, and some tasks are better solved with a web page or with software on a computer. Pick one app per job, test it for a few weeks and delete what you do not use.

Keep a few ground rules. Prefer apps that work offline for field use, because mobile coverage is often poor where radio amateurs like to operate. Check what data an app collects and why, especially if it asks for location or a login. Make sure it can export your data in a standard format, so that you are never locked in. And remember that a phone is not a replacement for a radio-safe habit: do not use it while driving, and keep it away from your transmitting antenna if you notice interference.

Logging Apps

A logging app lets you record contacts on the spot, at a picnic table, a summit or a park. The best ones work without a network, store the log on the phone and export it in the standard ADIF format so that you can import it into your main logging program or upload it to a confirmation service. Look for fields for the reference of a park or a summit if you take part in those programmes, and for support for common modes. Our article on logging apps for Parks on the Air compares several approaches in detail.

Before you rely on an app in the field, run a test. Enter a few dummy contacts, export the file and import it into your main log. Check the time and date fields, which are the most common cause of trouble, and make sure the app records time in UTC. Back up the data to another place when you return, because a phone can be dropped, lost or reset. A simple notebook as a second record, as described in our guide to the paper station log, is not a bad idea.

Propagation and Space Weather Apps

Propagation apps show the current solar flux, the K index and other indicators, and some provide band-by-band forecasts. They are useful as a quick look before you decide which band to try. Treat the numbers as a guide, not a promise. The forecasts are statistical, and a real-time view of who is hearing whom is often more informative. The data usually come from public sources such as the NOAA Space Weather Prediction Center, so you can also check the original page in a browser.

To see the real state of a band, use a reception-report map. The PSK Reporter website, which our article on PSK Reporter describes, shows where digital-mode signals have been heard in the last minutes, and it is a quick test of whether your signal is getting out. A good propagation app combines the forecast with such live data so that you can compare the prediction with reality. Learn to read the K index and the flux values, as in our article on reading space weather for HF, so that the numbers mean something to you.

DX Alert Apps

DX alert apps solve a specific problem: you are waiting for a station, a country or a band-and-mode combination, and you cannot sit at the radio all day. An alert app watches spot data from the cluster networks and notifies you when a match appears. The details that matter are the sources it watches, the filters it offers, the way it notifies you and how reliably it runs in the background. A notification that arrives ten minutes after the spot appeared is of little use during a short opening, and a notification that is silenced by the phone’s own battery saver may never arrive.

LY4A DX Reminder is one example. According to the information on the LY4A site, you tell it which callsign you are waiting for, on which bands and in which mode, and it watches five sources in the background: DXScape, DXSummit, DXHeat, PSK Reporter and the Reverse Beacon Network. It keeps band and mode apart, supports CW, SSB, FT8, FT4 and RTTY, and is available for iPhone, Android, Windows and Mac. Whichever alert tool you use, test it with a callsign that is on the air now, so you know that the whole chain works. Our article on automating DX spot alerts explains the principles behind such systems.

Satellite Tracking Apps

Satellites pass overhead for only a few minutes, so a pass predictor is essential. A good app shows the time, the maximum elevation and the direction of each pass for your location, and it can warn you shortly before the satellite rises. Some apps also show the Doppler-shifted frequency to dial, which is useful for FM and linear transponders. The data come from orbital elements that must be updated regularly; an app that does not update them gradually becomes inaccurate, so check that updating is easy or automatic.

If you want to go further, a computer program can control the radio and the antenna rotator, as in our guide to Gpredict and Doppler control. For a first pass, a phone app with a compass and a simple view of the sky is enough. Keep your phone’s clock accurate, since timing errors of even a few seconds change the Doppler picture, and write down which satellites you have worked.

Callbook and Reference Apps

A callbook app looks up an operator’s name, location and sometimes a photograph from a call sign. It is useful in a contest or when you want to greet a station by name. Some apps use the database of an online service and require a login; others bundle an offline list that grows stale over time. Our article on callsign lookup and online logbooks explains how these services work. Reference apps also include band plans, Q-codes, the phonetic alphabet, grid-square calculators and exam question banks. These are small tools, but they can save a lot of time at the operating table.

Take care with personal information. A callbook lookup shows data that other people have published, and you should use it respectfully. Do not share the details of other operators beyond what is necessary, and keep your own profile current but limited to what you are comfortable with.

Repeater Directories and Field Tools

When you travel, a repeater directory can find the nearest repeaters with their frequencies, offsets and tones. Look for one that works offline or caches the data, that allows you to filter by band and mode and that lets you export a list to your radio’s programming software. Remember that repeater data go out of date quickly, so confirm the details by listening or from a local club. Other field tools include a compass and a level for setting up antennas, a GPS-based grid-square display, a unit converter and a simple torch. A phone is a very capable field assistant, but it should not be the only source of a critical item such as an emergency frequency list; keep a paper copy.

Apps by Job at a Glance

Battery, Notifications and Reliability

Phones aggressively manage background activity, and that matters for apps that need to run quietly all day. If an alert app does not wake your phone, check the battery settings and allow the app to run in the background. Check notification settings too, so that an important alarm can sound even when the phone is silenced, if the app and the system allow it. Do a test each time the operating system is updated, because a software update can change the rules.

For long field days, carry a power bank and reduce screen brightness. Turn off apps that you do not need, and keep location services off unless an app really needs them. If the phone is also your hotspot or your logging device, a failure at the wrong moment is costly, so keep a backup logging method.

Privacy and Safety

Check what an app does with your data. A logging or callbook app can reveal your location and your activity pattern, and some apps share data with third parties. Read the privacy policy, give the app only the permissions it needs and remove it if it asks for more. Be careful with apps that ask you to log in with a password; use a unique password and enable two-factor authentication where it is offered. Download apps only from official stores or from the developer’s own site, and be wary of unofficial files.

Safety also applies to how you use the phone around radio equipment. Keep the phone and its cables away from a transmitting antenna, because RF can disturb it, and follow the exposure guidelines for your station. Do not use any app while driving; if you operate mobile, use a hands-free setup and a passenger for logging.

Building a Small Toolkit

Start with four apps: one for logging, one for propagation, one for alerts and one for satellites or repeaters, depending on your interests. Use each for a month, and note what you reach for and what you ignore. Delete the rest. Keep your settings backed up and your data exported. Update apps carefully; do not install a new version just before an important contest or field day, because new bugs appear more often than you would like. If an app stops working, have a fallback, such as a web page or a paper list, so that your operating does not depend on one tool.

The Bottom Line

The best ham radio apps are the ones that do one job well and fit your way of operating. Choose logging apps that export standard files, propagation apps that use public data, alert apps that are fast and reliable in the background, and satellite and repeater apps that keep their data current. Check the privacy of every app, keep a paper or computer backup for critical information and test your tools before you need them. A small, well-chosen set of apps will support your station and leave you free to enjoy the radio.

Frequently Asked Questions

Which ham radio apps should a beginner install first?

A logging app that exports ADIF, a propagation or space weather app, a repeater directory and, if you are interested in them, a satellite pass predictor. Add a DX alert app when you start chasing specific stations. Use each for a few weeks and delete the ones you do not use.

Can a phone replace a computer for logging?

For portable operation and casual contacts, yes. For contests, large logs and award management, a computer program is usually better. Many operators log on a phone in the field and import the file into a computer log at home.

Why does my DX alert arrive late or not at all?

Common causes are background restrictions and battery savers on the phone, silenced notification channels and the delay in the spot sources themselves. Check the app’s background and notification settings, test with a station that is on the air and make sure the app watches several sources.

Are propagation forecasts in apps reliable?

They are a guide, not a guarantee. Forecasts are based on statistics and space weather data, and real conditions can differ. Compare the forecast with live reception reports and with what you actually hear on the band.

How do I keep my satellite predictions accurate?

Update the orbital elements regularly, use an app that does so automatically if possible, and keep your phone’s clock accurate. Old orbital data and a wrong clock are the two main causes of missed passes and incorrect Doppler values.

Are ham radio apps safe for my privacy?

It depends on the app. Read the privacy policy, give only the permissions that the app needs, use unique passwords with two-factor authentication where available and download only from official sources. Remember that call sign data and location data can reveal where you live and when you are away.

Every December, the 28 MHz band becomes the centre of one of the friendliest contests on the calendar. The ARRL 10 Meter Contest is a single-band weekend where operators around the world work as many stations as possible on CW, on phone or on both. It suits beginners because it uses a simple exchange and a single band, and it rewards experienced operators who find good openings. This guide explains the dates, the categories, the exchange, the scoring and a practical approach for a first entry, based on the current rules published by the ARRL.

What the Contest Is

The objective, in the contest rules, is for amateurs worldwide to exchange information with as many stations as possible on the 10 metre band. Only the 28 MHz band is used, and both CW and phone are allowed. The contest is run by the ARRL and is open to everyone, including stations outside North America. You can make contacts with any station on both modes, and each station may be contacted once per mode, so one station can count twice if you work it on CW and on phone.

The contest period is the second full weekend in December. It begins at 0000 UTC on Saturday and runs through 2359 UTC on Sunday. For 2026, that is the weekend of 12 and 13 December by the usual counting, but always confirm the dates in the ARRL contest listing and the contest calendar, since dates are maintained there. Our guide to choosing your next contest helps you fit it into your schedule.

Why 10 Metres Is Special

The 10 metre band depends strongly on the solar cycle. When solar activity is high, it can carry signals across the world with modest power and simple antennas, and a contest weekend can feel like a global party. When solar activity is lower, the band can be quiet for hours, then suddenly produce a short opening that rewards the operator who is listening. Winter in the northern hemisphere often brings good daytime conditions in years around the solar maximum, as we explain in our 10 metre band guide. Because activity during a contest draws many stations to the band, it is also a good test of whether the band is truly open, since beacons and a few CQs may not tell the whole story.

Another feature of the band is that a small station can do well. A simple vertical, a dipole or a small beam can work many stations when the band is open, and low power is not a disadvantage when everyone is competing for the same openings. That is why the contest has a Limited Antennas overlay for stations that use only single-element antennas.

Categories and Rules at a Glance

Single-operator stations can enter as Mixed-Mode, CW-only or Phone-only. Multioperator stations may enter only as Mixed-Mode. Power categories follow the ARRL’s HF categories section. The overlay for limited antennas allows a single operator to enter with a single-element antenna, such as a vertical, an end-fed wire or a dipole, no more than 50 feet above ground at its highest point; it may cover several bands, as in the case of a multiband vertical or a fan dipole. Operators who are 25 years old or younger are invited to tick the youth box on the entry form.

All stations may operate for up to 36 hours of the 48-hour contest period, and off times must be at least 30 minutes long. That means you must plan rest and time away from the radio. If you are new to categories, our article on ham radio contest categories explains the usual terms. Read the full rules for the year you enter, because the ARRL updates them from time to time; the current version is available as a PDF rules document from the contest page.

The Exchange

The exchange is short. Every station sends a signal report. W and VE stations and Mexican stations also send their state or province, using the standard abbreviations, and stations in the District of Columbia send DC. Hawaii and Alaska operate as US stations and send their state, not as DX stations. DX stations send a serial number, starting at one, and maritime mobile stations send their ITU region, which is 1, 2 or 3. The ARRL publishes a list of multiplier abbreviations on the contest pages.

A contact on CW might sound like this: the CQing station sends CQ TEST followed by its call sign, an answering DX station gives its call sign, the CQing station sends the report 599 and its state, and the DX station answers 599 and its serial number. On phone the report is usually 59. After the exchange, the CQing station thanks the other and moves on. As the answering station you do not need to repeat the other station’s call sign unless there might be confusion about which station you are answering.

Scoring and Multipliers

Scoring is simple, but you must understand the mode weights. Each phone contact is worth two QSO points and each CW contact is worth four. To calculate the final score, you multiply the total QSO points by the number of multipliers worked. The multipliers are US states and the District of Columbia, Canadian provinces and territories, Mexican states, DXCC entities and ITU regions for maritime mobile stations. Each multiplier counts once on phone and once on CW. The ARRL’s own scoring example shows 6,330 QSO points multiplied by 140 multipliers for a score of 886,200 points.

The CW weighting is a strong incentive. A CW contact is worth twice as many points as a phone contact, and a station that works a new multiplier on both modes gets credit twice. Even if you are mainly a phone operator, learning to make a few contacts on CW can raise your score considerably. If you are building your CW skills, see our guide to learning Morse code.

Station Preparation

Preparation starts well before the weekend. Check your antenna and cable on 28 MHz with an analyzer or a power meter, and fix any problems. On 10 metres, even a small improvement in height or a clean connection is audible, and a good ground system for a vertical antenna makes a difference. Set up your logging software, including the contest template, the exchange fields and the multiplier lists. Test the CW or voice keyer, test your audio level and make sure that the computer clock is accurate.

Plan the shack as well. Place a cold drink and a snack within reach and arrange a comfortable chair and good lighting. Decide your operating plan, including the periods during which you will rest, because the 36-hour limit means you must choose your off times. Many operators take their longest break in the local night, when 10 metres is closed for most paths, and then focus on the daytime hours. Our article on rest time management in 24 and 48 hour contests offers a plan.

Operating Strategy

The first decision is whether to run or to search and pounce. Running means calling CQ on a frequency and letting stations come to you, which gives the best rate when the band is open and you have a good signal. Searching means tuning across the band and calling stations that are already on the air, which is the better choice for a small station or a quiet band. Most operators combine both, as we describe in the article about running versus search and pounce.

The second decision is how to use the two modes. On CW and phone the same station can be worked twice, so move between the modes during the day. Often the CW portion of the band is quieter, and a call on CW can bring answers when the phone part is crowded. Keep an eye on multipliers. Early in the contest, any new state or country is valuable, while later you can spend time hunting the missing ones, using the spotting network to find them. A map or a list of the states you still need helps you focus. Note the time of day too: the band tends to open first toward the east in the morning and later toward the west in the afternoon.

Using Spots and Skimmers

Most operators use spotting information to find stations and multipliers. If you enter in an assisted category, you may use spots; in an unassisted category you may not. Check the category definitions before you open a cluster window. In the unassisted case, you find stations by tuning, and the beacon stations and your own listening are your guides. If you are not familiar with spotting tools, our guide to DX cluster spotting etiquette explains them, and the article on the reverse beacon network shows how automated CW spots work.

Logging and Submitting Your Entry

Use a contest logging program that handles the exchange and the duplicates for you. After the contest, export your log in the standard Cabrillo format and check it. The ARRL requires logs to be submitted within seven days after the end of the contest at 2359 UTC. According to the contest page, from 30 September 2026 the ARRL accepts only online log submission for all of its HF contests, uploaded through the ARRL’s contest log submission web application. If you need help with the format, the ARRL points to community tools for Cabrillo files, and our article on Cabrillo logs and the UBN process explains how to avoid errors that cost points.

You can also contribute your score to an ARRL-affiliated club by choosing the club when you upload your log, and there is a space for feedback and photographs on the contest’s Soapbox page. A submitted log, even from a small station, helps the organisers verify the results of others. Do not worry about a small score; a log with a few dozen contacts is still welcome.

Common Mistakes

A few errors appear every year. The first is sending the wrong exchange: DX stations must send a serial number, while W, VE and Mexican stations send a state or province. The second is forgetting that the same station can be worked on both modes and so logging it only once. The third is operating more than 36 hours or failing to take a proper 30 minute break, which puts the entry outside the rules. The fourth is missing the log deadline. The fifth is a poorly set clock, which causes mismatched times and lost contacts. Spend a few minutes before the contest to avoid all five.

The Bottom Line

The ARRL 10 Meter Contest is a simple, friendly and rewarding contest. You work as many stations as you can on the 28 MHz band during a weekend in December, send a signal report plus state, province or serial number, score two points for phone and four for CW and multiply by the multipliers worked on each mode. Prepare your station, plan your 36 hours of operating time, use both modes and submit your log online within seven days. Check the ARRL’s current rules before the weekend, and enjoy the band.

Frequently Asked Questions

When is the ARRL 10 Meter Contest?

It takes place on the second full weekend in December, from 0000 UTC Saturday to 2359 UTC Sunday. Confirm the exact dates on the ARRL contest pages, because the calendar is maintained there and can change.

What do I send in the exchange?

Send a signal report. W, VE and Mexican stations also send their state or province, and DC stations send DC. DX stations send a serial number, and maritime mobile stations send their ITU region.

How are points calculated?

Each phone contact is worth two QSO points and each CW contact four. The total is multiplied by the number of multipliers, which are states, DC, provinces, Mexican states, DXCC entities and ITU regions, counted once on phone and once on CW.

Can I work the same station twice?

Yes, once on phone and once on CW. Each station counts once per mode, so a station that is active on both modes can give you two contacts and, if it is a new multiplier, a multiplier on each mode.

How many hours can I operate?

You can operate up to 36 hours of the 48-hour period, and your off times must be at least 30 minutes long. Plan the breaks in advance so that you do not run out of operating time at the end of the weekend.

How do I submit my log?

Upload a Cabrillo file through the ARRL’s online log submission within seven days of the end of the contest. According to the contest page, from 30 September 2026 only online submission is accepted for the ARRL’s HF contests, so check the page for the current instructions.

Anyone who has operated through a full year knows that the bands do not behave the same way in January and in July. The 10 metre band may be empty for months and then open for a few hours on a September morning, and the low bands can be quiet in summer yet exciting in winter. These patterns are not random, and seasonal HF propagation is one of the most useful topics for planning your operating. This guide explains the main mechanisms behind the seasonal changes, how they affect each group of bands and how to use them when you plan DX, contests and antenna work.

Why the Seasons Matter

HF contacts over long distances depend on the ionosphere, the layers of ionised gas in the upper atmosphere that refract radio waves back to the ground. The state of the ionosphere depends on how much ultraviolet and X-ray radiation arrives from the Sun, and that depends on the angle of the Sun above the horizon. As the Earth moves around the Sun, the angle changes with the seasons, and so does the balance between production and loss of ionisation. The effect is easy to observe: the same band at the same time of day can behave differently from one month to the next.

The seasons also interact with the solar cycle. In years with high solar activity, the upper HF bands open widely and the seasonal pattern shows up as a difference between strong and very strong conditions. In years of low solar activity, the pattern is more extreme, because a band that depends on a small margin of ionisation may be open only at one time of year. For a primer on the underlying mechanism, see our guide to what decides whether you are heard, and for the solar side, the article on reading solar flux and the K index.

The Equinox Advantage

Many experienced DXers say that spring and autumn are the best seasons for the higher HF bands. There are two reasons that are commonly given. The first is geometry. Near the equinoxes, the Sun shines over both hemispheres in a similar way, so day and night conditions are more balanced between the north and the south. That helps paths that cross the equator, such as Europe to southern Africa, South America or Oceania, where both ends can be in a favourable state at the same time. The second reason is that the F2 layer in the daytime tends to be well ionised in the middle latitudes during these months.

A practical consequence is that the 15, 12 and 10 metre bands are often at their best in the weeks around the equinoxes in the years near a solar maximum, and the 20 metre band often stays open late into the evening. If you want to work new countries on the upper bands, put those months on your calendar and be on the air at the times when the paths are open. Our overview of the MUF map and ionosonde data shows how to check in real time whether the band is open.

Geomagnetic Activity Also Peaks Near Equinoxes

There is a catch. Geomagnetic activity, the disturbance of the Earth’s magnetic field that can cause blackouts and poor conditions at high latitudes, is statistically higher near the equinoxes than at the solstices. This semiannual variation is known as the Russell–McPherron effect. It was observed as early as the middle of the nineteenth century and explained in 1973 through the geometry of Earth’s magnetic field relative to the solar wind. Around the equinoxes, the geometry makes it easier for the solar wind magnetic field to connect with Earth’s field, which allows more energy into the magnetosphere.

For the operator, this means that the equinox seasons carry both opportunity and risk. The bands may be open, but a geomagnetic storm can close them suddenly, especially on paths through the polar regions. Watch the K index and other space weather data from a source such as NOAA Space Weather Prediction Center before you plan a DX session, and be ready to switch to a lower band or a different path when conditions are disturbed.

The Winter Anomaly

You might expect the F2 layer to be strongest in summer, when the Sun is high in the sky and ionisation production is greatest. In the middle latitudes, the opposite happens. As the general description of the ionosphere explains, daytime ion production in the F2 layer is indeed higher in summer, but seasonal changes in the ratio of molecular to atomic gas in the neutral atmosphere make the loss of ionisation grow faster than production. The result is that total F2 ionisation is lower in the local summer months. This effect is called the winter anomaly, and it is always present in the northern hemisphere, while in the southern hemisphere it is usually absent during periods of low solar activity.

The practical effect is that the maximum usable frequency in the daytime tends to be higher in winter than in summer at the same latitude, so the upper bands open more reliably in the cold months. That is why many operators see excellent 15 and 10 metre conditions in the northern winter in the years around the solar maximum, and weaker conditions in midsummer, even though the Sun is higher then. Treat this as a general tendency rather than a rule for every day; a quiet or disturbed Sun can override the seasonal trend.

Summer: Sporadic E and Long Days

Summer has its own attractions. Sporadic E, patches of unusually dense ionisation in the E layer, occurs more often in the middle latitudes during the daytime in summer, and it can support propagation well above the normal limits of the layer. For the operator, that means exciting openings on 10 metres and on the VHF bands, with skip distances that are generally around one thousand kilometres or more for single-hop paths. We describe the techniques in our article on sporadic E and the grey line. Openings can last from minutes to many hours, and they often come in clusters during a few weeks around midsummer.

Summer also has disadvantages for HF. Long daylight hours increase absorption in the D layer on the lower bands, so the 80 and 160 metre bands are largely closed in the daytime and noisier in the evening. Thunderstorms, which are more frequent in warm weather, create static that masks weak signals, especially on the low bands. A quiet receiving antenna helps; see the article on low-band receive antennas for ideas. Short nights also reduce the time that a low-band path is dark at both ends.

Winter: The Low-Band Season

For the low bands, winter is the season. Long nights give the 160, 80 and 40 metre bands many hours of darkness along a path, and low absorption and generally lower atmospheric noise help weak signals to be heard. As a general description of shortwave propagation puts it, long-distance transmission is most reliable at night and during the winter. This is why serious low-band DXers plan their campaigns for the months around the winter solstice, and why many of the big contests that favour low bands are held in that season.

Also remember the grey line, the band around the Earth where it is dawn or dusk, which can give strong enhanced paths on the low bands. In winter the grey line moves quickly, and you must adjust your timing every week to catch it. Be prepared for local conditions, too: in cold climates, antennas and masts can accumulate ice, and snow can change the ground conductivity under a vertical antenna.

Seasonal Behaviour by Band

This table describes general tendencies at northern middle latitudes. In the southern hemisphere the seasons are reversed in calendar terms, and near the equator and the poles the pattern is different. Use it as a starting point and learn how your own location behaves by logging band openings through the year.

Long Path and Seasonal Windows

Some paths exist only in certain seasons. The long path to the antipodes, for example, opens at specific times of year when a grey-line path lines up with the right times at both ends. Our article on long path and short path propagation explains the geometry. If a station that you need is in a hard-to-reach location, check which season gives the best chance, and then focus on that window instead of trying every week. Prediction tools can model these paths, but your own logs and the reports of other stations are the most reliable guide.

Planning Your Year

You can turn seasonal knowledge into a practical plan. Mark the equinox periods for upper-band DX and keep your antennas for 15, 12 and 10 metres in good condition by then. Prepare low-band antennas and receiving systems in autumn, so that you are ready for the winter season. Prepare for sporadic E in late spring and summer, with a monitor on the 10 metre and 6 metre bands. Check coax, connectors and masts before the stormy season, and keep a log of band openings with times and directions, because after a year it becomes your own propagation guide.

Plan contests the same way. A contest in the equinox season may reward you for a strong effort on the high bands, while a winter contest may reward the station with the best low-band antennas. Our guide to contest band-change strategy shows how to use the changing conditions during a contest. Remember that the solar cycle and daily space weather can change the picture; seasonal patterns shift the odds, but they do not guarantee an opening.

The Bottom Line

Seasonal HF propagation shapes the whole year of operating. Spring and autumn often bring the best upper-band DX, with a risk of geomagnetic disturbance near the equinoxes. Winter favours the low bands and, because of the winter anomaly, can also bring strong daytime conditions on the middle and high bands in solar maximum years. Summer brings sporadic E, longer absorption and more noise. Learn the pattern for your latitude, keep a log of what you hear, follow the space weather and plan antennas and contests around the seasons for the best results.

Frequently Asked Questions

Why are the equinoxes good for HF DX?

Day and night conditions in the northern and southern hemispheres are more balanced around the equinoxes, which helps paths that cross the equator, and the F2 layer is often well ionised in the middle latitudes. The effect is commonly reported by DXers, but geomagnetic activity also tends to be higher in these months.

What is the winter anomaly?

It is the observation that F2-layer ionisation at middle latitudes in the daytime is higher in winter than in summer, even though the Sun is lower. The cause is a seasonal change in the composition of the neutral atmosphere, which increases the loss of ionisation in summer.

Which season is best for the low bands?

Winter. Long nights, lower absorption and typically lower atmospheric noise give the 160, 80 and 40 metre bands many hours of good conditions for long-distance contacts. Summer has short nights and more static, which makes low-band DX harder.

When does sporadic E occur?

Most often in the daytime in summer in the middle latitudes, with a peak around the weeks of midsummer. It can create short-lived openings on 10 metres, 6 metres and higher bands, often with strong signals over distances of about one thousand kilometres or more.

Does the solar cycle matter more than the season?

Both matter, and they work together. The solar cycle sets the overall level of ionisation, while the season shifts the pattern within each year. Space weather can override both for a day or two, so check current data as well as the calendar.

How can I learn the seasonal pattern for my own location?

Keep a simple log of band openings with the date, the time, the band and the direction, and compare it over a full year. Use reports from other stations and prediction tools as supporting information, and update your notes after each season.

Most amateur digital voice modes were created by manufacturers or standards bodies and built into commercial radios. M17 digital voice takes a different route. It is a digital voice and data protocol developed within the amateur community, with a specification that anyone can read and implement, and it is designed for the VHF band and above. That openness has produced firmware for existing radios, new hardware and software hotspots built by volunteers. This guide explains how M17 works, what you need to use it and how it compares with the better-known DMR, D-STAR and System Fusion systems.

What M17 Is

According to the project’s description on Wikipedia, M17 was developed by Wojciech Kaczmarski, SP5WWP, with contributions from the wider amateur community. It is primarily designed for voice on the VHF bands and higher, and the project has received grants from the Amateur Radio Digital Communications organisation. The specification and the reference code are published by the M17 Project, which also runs a news feed on its home page.

The idea is to give amateurs a digital mode that they can understand fully, extend and build equipment for without paying for licences or relying on a manufacturer. The protocol is therefore documented in public, and the source code of many tools is open. This makes it attractive for experimenters, for clubs that like to build their own repeaters and for anyone who wants to know exactly what happens inside the radio.

How the Signal Works

The technical description is compact. M17 uses frequency-division multiple access, which means that each stream occupies its own frequency channel, as in analogue FM and in most amateur repeater systems. The modulation is four-level frequency-shift keying at 4,800 symbols per second. The channel bandwidth is around 9 kHz, which fits within a 12.5 kHz channel spacing. The gross data rate is 9,600 bits per second, of which 3,200 bits per second carry the actual voice or data payload, and the rest is error correction and framing.

A transmission, called a stream, is divided into 40-millisecond frames, each starting with a 16-bit synchronisation word. Six frames form a superframe, which carries the link information. The protocol allows a low-speed data channel to run alongside the voice, for example to carry position data or a short message. The link information includes the callsign of the sender and the destination, so any receiver can identify who is transmitting without a central database.

Voice Coding with Codec 2

M17 uses Codec 2, an open-licence low-bit-rate speech codec developed by David Rowe, VK5DGR, and others. The open licence is one of the reasons for its choice: nobody has to pay a royalty or sign an agreement to build a transmitter or a receiver. The protocol supports two voice rates, 3,200 bits per second for full rate and 1,600 bits per second for half rate. In the half-rate mode, the remaining capacity can carry a second data channel next to the voice.

The sound of low-bit-rate voice codecs is often described as slightly synthetic, and M17 is no exception. In practice, the audio is clear at good signal levels and degrades as the signal weakens. Developers on the project keep improving the receiving side, and recent news from the project describes experiments with a neural decoder that produces a wider-band output from the same transmitted bits. Such work shows an advantage of an open system: a new receiver can improve quality without any change to the transmitter, and every existing radio on the air benefits from the better decoder as long as it sends the standard stream.

Callsign Addressing Without a Central Registry

A distinctive design choice is the way stations are identified. M17 encodes the callsign directly in a 48-bit field that can hold up to nine alphanumeric characters. That means a radio does not need a user identity number from a central database, which is a requirement in some other digital voice systems. Your callsign is your address, and you can program it into the radio and a hotspot yourself. The system is simple to administer and respects the traditional way amateurs identify themselves on the air.

The protocol also supports a destination field, so a transmission can address a specific station, a group or a reflector. This is the way networked operation is organised, and it is similar to how amateurs use talk groups in other systems, although the details differ. The reflectors and gateways are run by volunteers, and the operators keep their own lists and rules, which you should read before you join.

Stream Mode, Packet Mode and Extras

M17 has two modes of operation. Stream mode is for continuous transmissions such as voice. Packet mode is for discrete data such as text messages, position reports, AX.25 frames and other binary data. Stream mode can deliver one 3,200 bits-per-second channel for voice or data, or two 1,600 bits-per-second channels, for example voice together with data. Packet mode supports text messaging, APRS, AX.25, and gateways to other protocols. The mode has also been demonstrated through geostationary satellite transponders, including the amateur transponder described in our guide to the QO-100 satellite.

The protocol also defines optional security features. These include authentication by digital signature, which proves that a transmission really came from the claimed station, and scrambling and encryption options. Be careful here. Amateur regulations in most countries do not allow transmissions that are encrypted to hide their meaning, so the encryption features are not for use on the amateur bands in those countries. Digital signatures, which do not hide the content, are a different matter. Always check your own licence conditions before you use any feature that goes beyond plain, identifiable communication.

Hardware for M17

You have several routes into the mode, and the market is changing quickly, so check current information from the project before you buy. Wikipedia notes that a few handheld transceivers can be flashed with open-source firmware to support M17 after a small hardware modification, and that in July 2024 a commercial handheld with native M17 support was released. Project hardware designs and open firmware such as OpenRTX are also available for people who want to experiment. A hotspot, built from a small computer and a low-power radio module, links your own radio to the network of reflectors in the same way that hotspots work for other digital voice systems; see our guide to an MMDVM hotspot for a related setup.

Software options also exist. Phone and computer clients let you listen and talk through a reflector without any radio at all, and the project publishes experimental versions that test new decoder improvements. These clients are a good way to try the mode and to hear what it sounds like before you spend money on hardware. Treat experimental software with the care that you give any early release: expect bugs, and check the sources of downloads.

Networks and Bridging

M17 networks are made up of reflectors, which act as shared rooms, and gateways that connect them to repeaters and hotspots. Traffic can also be bridged to other systems. According to Wikipedia, links exist between M17 and several other modes and networks, including DMR, P25, System Fusion, D-STAR, NXDN, AllStarLink, EchoLink and IRLP. Bridges are run by volunteers and can change, so check what is currently available. If you are interested in linking systems in general, our articles on AllStarLink and EchoLink show how other internet-linked systems are organised.

When you use a bridge, remember that the audio passes through several conversions, and each one can reduce quality. Choose a native reflector for the best result, and use bridges to talk to friends on other systems. Follow the rules of the network, and keep your transmissions short and clearly identified.

How M17 Compares with Other Digital Voice Modes

For a detailed look at the established systems, see our comparison of DMR, D-STAR and System Fusion. The main practical difference is the size of the community. DMR and the other systems have more radios and repeaters, while M17 offers openness and a fast pace of development.

Should You Try M17?

If your main goal is to talk to a lot of people in your region today, the established digital systems or plain FM repeaters will probably serve you better, because that is where the activity is. If you like to experiment, build and learn, or if you value open standards, M17 is a very rewarding project. You can start with a client program, listen to the reflectors, and then decide whether to add a hotspot or a radio. Ask your local club whether anyone is already active; the mode grows through small groups of enthusiasts who agree to try it together.

Keep expectations realistic. The network is smaller, quality depends on your receiver and equipment support is changing fast. On the other hand, you are part of a community that shapes the mode, and your reports and suggestions can influence its direction. Many amateurs find that this involvement is the best part of the project.

Getting Started: A Simple Path

First, read the project’s pages and the documentation. Second, check your licence rules for digital voice and for networked operation in your country. Third, try a client on a computer or phone and listen on a busy reflector. Fourth, if you want to transmit over the air, choose a hotspot or a radio that is currently supported, and follow the setup guide. Fifth, set your callsign carefully in the configuration, because errors in the identification field create confusion on the network. Finally, say hello, keep your calls short and join a regular net if there is one.

Etiquette on M17 Reflectors

Reflectors are shared spaces, so the usual rules of good operating apply. Listen before you transmit, because someone may already be talking. Give your callsign at the start and end of a transmission as your licence requires, keep over-length conversations to a net or a quiet room and avoid playing music or recordings. Many reflectors have module letters that work like separate rooms, so pick one that suits your topic. If you are testing, say so, and leave a pause so that others can break in. These habits make a small network pleasant and encourage newcomers to stay.

The Bottom Line

M17 digital voice is an open, amateur-built protocol that uses four-level FSK, the open Codec 2 voice codec and callsign addressing built into the protocol. It is smaller than DMR, D-STAR and System Fusion, but it is growing, it has hardware and software options, and it appeals to experimenters who value transparency. Check the current state of equipment and networks on the project’s website, follow your licence rules, avoid encryption on the amateur bands where it is not allowed and start with a software client to see whether the mode suits you.

Frequently Asked Questions

What does M17 stand for?

M17 is the name of the project and the protocol. The name itself is just a label chosen by the developers, and what matters is that the specification is open and developed in the amateur community.

Which voice codec does M17 use?

M17 uses Codec 2, a low-bit-rate speech codec with an open licence. The protocol supports a full-rate mode of 3,200 bits per second and a half-rate mode of 1,600 bits per second, where the spare capacity can carry data.

Do I need a special radio for M17?

You need a radio that supports the mode, which can be a commercial handheld with native support, a radio running suitable open firmware or a hotspot linked to a standard FM radio. You can also listen and talk through a software client without any radio. Check the project’s site for current options.

Can I use encryption on M17?

The protocol defines scrambling and encryption options, but amateur regulations in most countries prohibit encryption intended to hide the meaning of a message. Check your own rules; digital signatures that authenticate a transmission without hiding it are a different feature.

How does M17 compare with DMR?

DMR is a mature open standard with a huge number of radios and repeaters, and it identifies users by an ID from a database. M17 is newer and smaller, uses one stream per channel and puts the callsign directly into the protocol. DMR has more activity today, while M17 offers openness and rapid development.

Can I link M17 to other digital voice systems?

Volunteer-run bridges exist to several other modes and networks, but they change over time and add audio conversions that reduce quality. Check which bridges are active and follow the network rules. For the best sound, use a native M17 reflector.

Almost every radio amateur keeps some kind of log, and for decades the standard tool was a bound paper notebook. Computers have replaced it for most operators, yet a ham radio logbook on paper is far from obsolete. It does not crash, it needs no power, it works in a tent on a mountain and it forces you to listen. This guide explains what a good station log should contain, how to lay out a paper page, when paper is still the better choice and how to move your entries into a digital log so that you can confirm contacts and apply for awards.

Why Keep a Log at All

A log, like any logbook, is the record of what your station did. It proves that a contact took place, it lets you answer questions such as whether you worked a station before, and it provides the data for confirmations, awards and contest entries. A log also protects you: if someone claims that your station caused interference at a certain time, your log shows what you were doing. It is also a personal diary of your hobby, and many operators enjoy reading old pages years later and remembering a night when a rare station came through.

Rules about logs differ between countries. Some regulators require a record of transmissions under certain circumstances, such as for repeaters, emergency operation or special licences, while others do not require a station log from an individual amateur at all. Always check the current rules in your own country and under your own licence, and keep your log in a way that meets them. Where a log is optional, a good one still pays for itself.

What to Record for Every Contact

The core data is the same on paper and on a computer. If you capture these items for each contact, you can later produce a confirmation request, a contest entry or an award application without having to go back to the radio.

• Date and time in UTC: a single time standard avoids confusion across time zones. Our article on clock accuracy for digital modes explains why accurate time matters.
• Call sign of the other station: write it as heard, and correct it if you later learn the right spelling.
• Frequency or band: an exact frequency is more useful than a band alone, especially for DX and awards.
• Mode: such as CW, SSB, FT8 or RTTY, because awards are often mode-specific.
• Signal reports sent and received: using the RST or the digital mode report form.
• Name and location of the other operator: optional, but a pleasure when you meet again on the air.
• Your own station details: power, antenna and, for portable work, your location and grid square.
• Remarks: contest exchange, special event name, QSL information or anything unusual.

For contests, add the exchange that you sent and received, such as a serial number or a zone. For portable activities such as Parks on the Air or Summits on the Air, add the reference. If you are not sure what to record, record more rather than less; a note that is useless today may save a long search later.

Designing a Paper Page

A simple ruled notebook is enough, but a printed or hand-ruled page with columns is easier to read and to transcribe later. One line per contact is the best rule. Leave a margin for notes, and mark the page with the date, the station and the location at the top. A bound book is better than loose sheets because pages cannot easily be lost and the order is obvious. Use a pen rather than a pencil for the log itself, and cross out errors with a single line instead of erasing, so that the original entry remains legible.

You can add a column for power or for your own antenna if you like to compare results. Do not overcomplicate the layout, because a page that is too complex will be abandoned in the heat of a contest or a pile-up.

When Paper Is Better Than Software

Paper wins in several situations. In the field, a battery-free log is reliable, and it does not matter that a tablet’s screen is hard to read in sunshine. In a power cut or an emergency exercise, a log that needs no electricity keeps working. During a contest with a very simple exchange, a paper log or a paper dupe sheet can be fast, although a computer is almost always better for large contests. Paper is also an excellent teaching tool, because a learner who writes a call sign by hand has to listen carefully.

Paper also has weaknesses. It cannot check for duplicates automatically, look up a call sign, calculate a distance or produce an electronic file for an award. Searching a paper log for a call sign from three years ago can take a long time. If you operate often, a hybrid approach works well: keep a paper log as a backup and for portable work, and enter or import the contacts into a computer log when you return home. Our article on a callsign lookup and online logbook shows how an online service can help you fill the gaps.

Logging Digital Modes

Digital modes such as FT8 produce their own log files, and the software normally writes each contact to a file as soon as you confirm it. In that case, a paper log is less necessary, but it still has a role as a record of operating sessions and as a backup if the software fails. Some operators log only the unusual contacts on paper, such as new countries, and leave the routine ones to the program. Whatever you choose, make sure that the automatic log is backed up regularly. A lost hard drive can erase years of contacts.

If you use a computer log, learn the common file format used to exchange data between programs. Our guide to ADIF and moving your log between programs explains how to export and import, and how to avoid the usual errors with time zones and fields.

Converting a Paper Log to a Digital One

Most people who keep paper also need to move contacts into a digital log at some point, for example to upload to Logbook of The World or to claim an award. Plan the conversion before you start. Choose a logging program that lets you add contacts manually with the correct date and time rather than the current time. Type the contacts in order, check the call signs and times carefully and use a consistent format for modes and bands. After entering a page, tick it off in the book so that you know it is done.

Some programs accept manually created text or spreadsheet files and convert them into ADIF. If you have many contacts, set up a spreadsheet with a column for each field, enter your entries, check the data and then export. Check a few sample contacts in the final file against the paper log before you upload to any award or confirmation service. A date error that shifts a contact by a day is a common cause of failed matches. The Logbook of The World and other services have their own upload rules, and you should read them before you begin.

Confirmations and QSL Cards

A log is the basis for confirmations. Whether you use electronic services or paper cards, you will need accurate details to match contacts. Our overview of confirming contacts with LoTW, eQSL and paper compares the options, and the guide to the QSL bureau explains how cards travel between countries. When a card arrives, mark the entry in your log so that you know which contacts are confirmed and which are not.

Keep a note of the date and method of every confirmation request. If a station replies months later, you will want to see when you sent the request. For rare contacts, keep a copy of your log page or a photograph of it in case the other station asks for details.

Contest Logs and Submission

Contests need a precise log. If you operate on paper, record the exchange as you hear it, mark duplicates and keep a running count of multipliers. After the contest, you will have to produce an electronic file, usually in a standard format; our article on Cabrillo logs and the UBN process explains it. Check the contest rules for the deadline and for the accepted file types, and give yourself time to enter and check the log. Many contest organisers now accept only electronic logs, so a paper log is a working record that you will need to convert.

Backup and Storage

A paper log is a single copy of irreplaceable data. Photograph or scan each page when it is full, and keep the images in a second place, for example a cloud service and an external drive. Store the original book somewhere dry and away from heat and sunlight. If you keep a digital log, back it up on a regular schedule and keep at least one copy off-site. Test a restore once, because a backup that cannot be read is not a backup.

Think about how long you want to keep the records. Many operators keep their logs for life, because contacts may be needed for awards years later. Others keep them for a number of years required by local rules. Whichever you choose, label the books clearly with the call sign and the dates, and decide what will happen to them in the long term.

Common Logging Mistakes

Several errors appear again and again. The first is logging in local time and forgetting to convert, which breaks matches with the other station. The second is writing a call sign from memory instead of copying it carefully, which produces contacts that nobody can confirm. The third is skipping the frequency and recording only the band, which hides useful detail for awards. The fourth is leaving a contest or portable page without a date. Build a short habit of checking each line before you start the next one, and your log will stay useful for years.

The Bottom Line

A ham radio logbook on paper is a simple, durable tool that still fits portable operation, emergency use and learning. Record the date and time in UTC, the call sign, the band or frequency, the mode, the reports and a few remarks for each contact, and keep a clear page layout. Use a computer log for contests, awards and large numbers of contacts, and convert paper entries to a standard file when you need to confirm them. Back up everything, check your national rules and keep logging consistently; a complete log is worth more than a perfect one.

Frequently Asked Questions

Do I have to keep a log as an amateur?

It depends on the country and the licence. Some regulators require records in specific situations, while many do not require an individual amateur to keep a station log. Check the rules that apply to you, and keep a log anyway if you want to confirm contacts or apply for awards.

What is the minimum I should write for each contact?

Write the date and time in UTC, the other station’s call sign, the band or frequency, the mode and the reports. These items are required by most confirmation services and awards. Add the name, location and remarks if you have time.

Why use UTC in a log?

UTC is the same everywhere and does not change with daylight saving time, so both stations record the same time. Confirmation services match contacts by time, and a log in local time causes mismatches. Set a clock to UTC beside the radio.

Can I upload a paper log to Logbook of The World?

Not directly. You must first enter the contacts in a logging program and export an electronic file in the format that the service accepts. Check the service’s instructions, and compare a few contacts with the paper log before you upload.

Is a paper log acceptable for contests?

You can keep one while you operate, but organisers usually require an electronic log in a standard format for submission. Use the paper record as a working copy and convert it carefully, and check the deadline in the contest rules.

How should I back up a paper log?

Photograph or scan each page when it is full, store the images in at least two places and keep the original book in a dry place. For a digital log, make regular backups and keep one copy off-site.

Ask a group of experienced radio amateurs how they got started and many of them will tell you about a person: a neighbour with a tower, a club member who lent a spare radio, a friend who explained why the SWR was high. In ham slang, that person is an Elmer, a mentor who helps newcomers to find their feet. A ham radio Elmer turns a pile of confusing equipment and jargon into a working station, and it is often the difference between a new licensee who stays active and one who leaves after a few months. This guide shows newcomers how to find a good mentor and shows experienced operators how to become one.

What an Elmer Does

An Elmer is not a teacher in a classroom and does not need formal qualifications. The role is informal: answer questions, demonstrate a skill, share equipment and provide encouragement. A typical Elmer might help a new licensee choose a first radio, put up a simple antenna, make a first contact, set up a digital mode or understand why the band is noisy. Others specialise in a topic, such as CW, contesting, satellites or portable operation, and help with that topic only.

The relationship may last one afternoon or many years. Some Elmers meet a learner in person, and others help by email, chat or video call. The best ones listen first. They ask what the newcomer wants to do before they offer advice, because a person who wants to talk to the local repeater has different needs from one who wants to work DX on HF. A good Elmer gives the learner the confidence to make decisions, not a shopping list of the Elmer’s own favourite gear.

Why Mentoring Matters

Amateur radio is a hobby with a steep early learning curve. The exam teaches regulations and theory, but it does not teach how to connect an antenna, set the audio level or make a first call. A newcomer without help can spend months struggling with problems that an experienced operator solves in ten minutes. Without support, many give up. With support, they make their first contact quickly, and that early success builds momentum.

Mentoring also matters for the hobby itself. Clubs and communities depend on a flow of new members, and the skills of experienced operators are only useful if they are passed on. Our article on recruiting new members to a ham radio club describes how clubs can attract people, and mentoring is what keeps those people active.

How to Find an Elmer

If you are new, the easiest route is a local club. Clubs usually have members who enjoy helping, and many hold regular meetings, nets and informal on-air sessions where you can ask questions. Introduce yourself and say plainly what you want to do. Many clubs also run a licence class or a field day event where you can see equipment in action and meet experienced operators. If you are still preparing for your exam, our overview of how to get your amateur radio licence explains the steps and where to find a class.

If there is no local club, try other channels. Many repeaters host weekly nets that welcome newcomers, and the operator running the net can often point you to someone willing to help. Online communities and forums have active members who answer questions, and special-interest groups for CW, digital modes, satellites or portable operation often have their own mentoring schemes. Some national societies, such as the ARRL, maintain resources for newcomers and lists of local clubs; check your own national society for similar services.

How to Ask for Help

Be specific. A request such as “I do not understand antennas” is hard to answer, while “I have a dipole 6 metres high and the SWR is 3 on 20 metres” can be solved in a few minutes. Describe your equipment, what you tried and what you expected. Photographs help a lot, particularly of the antenna, the connections and the shack layout. Respect the Elmer’s time, and say thank you. A short note of what you learned and a report on how the fix worked is the best reward a mentor can receive.

Do not expect an Elmer to do the work for you. The best mentoring involves hands-on practice: the learner holds the tools, makes the connection and presses the key. If a mentor shows you how to make a coax connector, practise on a spare cable until you can do it yourself. Our guide on how to solder a PL-259 connector is one of the skills a mentor often teaches in person.

Qualities of a Good Elmer

• Patience: the questions that seem obvious to you were once new to you as well.
• Respect for the learner’s goals: advice should fit what the newcomer wants to do, not what the mentor prefers.
• Honesty about limits: saying “I do not know, let us find out” is better than guessing.
• Safety awareness: an Elmer should insist on safe practice, from ladder use to RF exposure and electrical wiring.
• Clear explanations: avoid unexplained jargon, and use examples from the learner’s own station.
• Encouragement: early successes, even small ones, keep people on the air.

The opposite qualities are easy to recognise. Be careful of mentors who criticise newcomers harshly, push expensive equipment or claim that there is only one right way to do things. A good Elmer helps a learner become independent, and does not create dependence.

Common Topics a Mentor Helps With

New operators ask for help with the same problems again and again. A first radio, a first antenna and a first contact are at the top of the list. Others include setting up a computer for digital modes, finding a repeater, understanding band plans and understanding why a signal is weak. Mentors also help with operating habits: how to call CQ, how to listen before transmitting and how to give a signal report. The article on making your first QSO on HF describes a sequence that most mentors would recommend, and it is a good starting point for a first lesson.

Mentors can also help with practical tasks that are difficult to do alone, such as raising a mast, taking measurements or reading a signal on a spectrum display. Working with another person is safer and faster. Remember that some jobs, such as work at height or near power lines, need training and proper equipment; a good Elmer will say so and will not take shortcuts.

Mentoring Formats Compared

Most people use a combination. A club mentor might help build the antenna, an online group might help with digital mode settings and a net might provide the first on-air practice.

How to Become an Elmer

You do not need to be an expert to become an Elmer. You need to know more than the person you are helping about one thing, and be willing to share it. A newcomer who passed the exam last year can help someone who passes this year, and an experienced contester can help a beginner with logging. Start small. Offer to help at a club meeting, volunteer at a licence class or invite a new member to watch you operate. Say yes when someone asks for advice, and suggest another person when you are not the right one.

Prepare a few simple projects that you can teach in an afternoon: a dipole built from wire, a cable assembled with connectors, a first contact on 2 metres or a first digital contact. Keep a box of spare parts and a small set of tools, and be ready to lend a radio for a trial. Be careful about lending valuable equipment, and agree on a date for its return. If you enjoy a particular activity, such as portable operation, you can introduce others to it; our guide to getting started with Parks on the Air shows how a day in the field can be an ideal lesson.

Running a Club Mentoring Program

A simple program works better than an elaborate one. Ask for volunteer mentors and list their interests: HF, VHF, digital, antennas, contesting, satellites and so on. When a new member joins, ask what they want to do and match them with a mentor who shares the interest. Agree on a first meeting within a week or two, because early contact is important. Check back after a month to see whether the pair are meeting and whether the newcomer has made contacts.

Keep the paperwork light. A shared list of mentors, a short welcome email and a monthly reminder are enough. Celebrate milestones, such as a first contact, a first award or a first contest. Encourage mentors to share tips and experiences, and give them the chance to learn from each other. Club newsletters and websites are a natural place to publicise the program; our article about keeping club news flowing offers ideas for communication.

Boundaries and Good Manners

Mentoring works best with clear expectations. Agree how often you will meet or talk, how you will communicate and what the newcomer wants to achieve. Respect privacy, and do not share personal details without permission. Be careful with remote access to someone else’s equipment and with lending money or gear. Treat all learners equally, regardless of age, background or experience, and never make a person feel foolish for asking a question. If a relationship is not working, it is fine to step back and suggest someone else.

If you mentor young people, follow your club’s safeguarding rules and local law. Many clubs require that two adults are present or that a parent is involved. These rules protect everyone and make it easier for families to trust the activity.

The Bottom Line

A ham radio Elmer is a simple idea with a large effect: an experienced operator helps a newcomer to reach a first contact and a first working station. If you are new, join a club, say clearly what you want to do and ask for specific help. If you are experienced, share one skill with one person and see how it grows. A little time and patience from a mentor can keep a new licensee in the hobby for decades, and it strengthens the whole amateur community.

Frequently Asked Questions

What does Elmer mean in ham radio?

In amateur radio slang, an Elmer is a mentor who helps newcomers learn the hobby. The role is informal and unpaid, and the help can be anything from choosing a radio to putting up an antenna or making a first contact. The verb to Elmer means to mentor someone in this way.

How do I find an Elmer if there is no club near me?

Try repeater nets, national society resources, online forums and special-interest groups for the activity that interests you. Many experienced operators are happy to help by email or video call, and online mentors can be especially useful for software, digital modes and operating technique.

Do I need to be an expert to be an Elmer?

No. You only need to know more than the person you are helping about the topic in question and to be willing to share it. Recent licensees can help people who are one step behind them, and honest answers such as I do not know, let us find out are valuable.

What should I ask an Elmer to help with first?

Start with something concrete that blocks you, for example choosing a first radio, solving a high SWR, setting up a digital mode or making a first contact. A specific request is easier to answer, and a quick success makes the next step easier.

Should an Elmer lend equipment to a new ham?

Lending a radio or a tool can be a great way to try a mode or a band, but agree clearly on how long the loan will last and who is responsible for damage. Check that the equipment is safe and in good condition before you hand it over.

How can a club start a mentoring program?

List volunteer mentors and their interests, ask new members what they want to do, match them and arrange a first meeting within a couple of weeks. Check in after a month and celebrate milestones. A light structure usually works better than a complex program.

Every amateur reaches the point where a problem cannot be solved by guessing. The SWR is high but the antenna looks fine, the radio resets when you transmit, or a connector seems to work only when you hold the cable. This is where ham radio test equipment pays for itself. You do not need a professional laboratory. A modest set of tools, bought in a sensible order, lets you find most faults in minutes and tells you whether your station is working as you think it is. This guide describes the instruments that matter most to a radio amateur, what each one measures and how to avoid spending money on equipment that you will rarely use.

Start With Questions, Not With Instruments

The best way to decide what to buy is to list the questions you ask most often. Is the power supply delivering the right voltage under load? How much power is my transmitter really producing? Is my antenna resonant where I want it? Is my coax healthy? Is there noise on the band and where does it come from? Each question points to a different instrument, and a small number of tools covers most of them. Buying a tool because it looks impressive is a common mistake; buying a tool because you have a measurement that you cannot make is a good investment.

Keep a notebook beside the bench. Record the readings that you take when everything works, such as the supply voltage on transmit, the SWR on each band and the power output on each mode. A reading is only useful if you can compare it with a good value, and those baseline numbers turn a mystery into a quick check later.

The Digital Multimeter

The multimeter is the first and most important instrument. A basic digital multimeter measures voltage, current and resistance, tests continuity and often checks diodes. In a radio shack it answers questions such as whether the battery is charged, whether the fuse is intact, whether the cable is broken and whether the supply holds its voltage under load. A good meter is inexpensive, but quality matters for safety. Choose a meter with proper fused current inputs and a safety rating suitable for mains measurements if you plan to look at household circuits, and use it carefully.

Learn a few simple tests. Measure the supply at the radio’s power connector while transmitting; a drop of more than a fraction of a volt suggests thin wire or a poor connection, and our guide to choosing a ham radio power supply explains why. Check continuity on a coax cable with the far end open and shorted, which reveals a break or a short without any special tools. Measure resistance across a dummy load to verify that it is near its nominal value at DC. These checks take seconds and solve a surprising number of problems.

SWR and Power Meter

An SWR and power meter, often combined in one unit, sits in the transmission line and measures forward and reflected power. It tells you how much power the transmitter delivers and how well the antenna system accepts it. The meter does not tell you everything: a low SWR is not proof that the antenna is efficient, and a high SWR measured at the radio is partly hidden by cable loss. Our article on what an SWR meter tells you and what it hides explains these limits in detail.

When you buy a power meter, check its frequency range, its power range and its accuracy. A meter designed for low power can be damaged by a large amplifier, and a meter designed for high power can be inaccurate at the few watts of a QRP rig. Many inexpensive cross-needle meters give a good picture of relative changes, while an accurate digital wattmeter is better for measuring absolute power. On single-sideband, remember that the reading depends on how the meter responds to the changing envelope; for steady measurement, use a continuous carrier or a CW key-down signal at a safe level.

The Dummy Load

A dummy load is a resistor in a metal housing that absorbs the transmitter’s power instead of radiating it. It lets you test and adjust a transmitter without interfering with other stations and without involving the antenna. If your meter shows a good SWR into a dummy load but a bad SWR into the antenna, the problem lies in the antenna or the feedline, not the radio. The article on dummy loads and testing without radiating covers the types and the limits.

Check the load’s power rating and its duty cycle. Many loads are rated for full power only for a short time, and a heat-sink or oil-filled design can handle longer tests. Use a load with a connector that matches your radio, and avoid using adapters that add mismatch. A load that is not truly 50 ohms across the band will give a misleading SWR reading, so test it with an analyzer if you can.

The Antenna Analyzer

An antenna analyzer sends a very low-power signal and measures the impedance at the connector. It shows you the resonance and the SWR across a range of frequencies in one sweep, without transmitting a loud signal. That makes it an ideal tool for pruning a dipole, checking a new vertical, testing a tuner or checking a length of coax. Modern low-cost vector network analyzers have made this level of measurement affordable to nearly everyone, and our guide to the NanoVNA antenna analyzer shows how to calibrate and use one.

The analyzer is especially useful for fault finding. If a feedline has water in it or a connector is corroded, the sweep shows a changed pattern. If you add a length of cable to the antenna and the sweep shifts, you can measure the cable’s effect directly. Always calibrate the instrument at the end of the cable you will measure through, and keep notes about the reference plane. Remember that the instrument measures at its own connector, so the result includes the effect of the cable between it and the antenna.

The Oscilloscope

An oscilloscope shows a signal as a picture of voltage against time. For a radio amateur, it is most valuable for audio and baseband work: checking the shape of a microphone signal, finding clipping in a digital-mode audio chain, looking at a keying waveform or checking a power supply for ripple. It can show a clean sine wave from a transmitter into a dummy load, or reveal the flat-topped envelope of an overdriven SSB signal. A basic digital oscilloscope with a bandwidth of a few tens of megahertz is enough for audio and low-HF work.

Do not buy a scope first. Many shacks run happily without one, and a multimeter and an analyzer solve most problems. Buy an oscilloscope when you have a project that needs it, for example if you build keyers, filters or audio interfaces, or when you chase a hum problem that you cannot see with other tools. Use the correct probe setting and the correct ground connection, because a long ground lead on a fast signal can cause false readings.

Other Useful Tools

• Frequency counter: verifies the frequency of an oscillator or a transmitter and helps calibrate a receiver.
• Signal source or generator: a stable low-level test signal for checking a receiver’s sensitivity and filters.
• Field strength or noise meter: helps locate sources of interference, especially with a small directional receiving antenna.
• Current clamp for DC: measures current without breaking the circuit and finds a hungry load quickly.
• Cable tester: a simple continuity tester for multi-pin cables, microphone cables and interface wiring.
• Soldering station and heat-shrink supplies: not a measuring instrument, but essential for repairing what the tests reveal.

Each of these has a clear job and a clear moment to buy. A frequency counter, for instance, is more useful if you build oscillators or work on microwave bands, while a simple noise-finding receiver is more important if your location has a local interference problem. Our overview of finding and killing RF noise shows how to combine such tools in a search.

Which Instrument for Which Job

Safety and Handling

Test equipment is only useful when it is used safely. Switch off power before you connect or change anything on a power circuit. Use leads and probes that are in good condition and that match the voltage range you are measuring. Never measure mains voltage with a meter that is not rated for it. When you test a transmitter, keep the antenna away from people, use a dummy load whenever possible and observe the exposure limits in our guide to RF exposure safety. Connect and disconnect connectors with the radio switched off, and handle adapters carefully, because bent pins and loose threads cause both false readings and damage.

Accuracy and Calibration

Do not expect laboratory accuracy from low-cost instruments, and do not ignore their limits. A wattmeter may be accurate to a few percent at one frequency and far off at another. An analyzer is only as good as its calibration. Compare your instruments with each other and with known references. If two meters disagree, find out why before you trust either one. A known dummy load, a stable battery or a precision resistor can serve as simple references. Record the results in your notebook, and repeat the check once a year or after any event that could have damaged the equipment, such as a drop or a power surge.

Building a Bench on a Budget

A sensible order is a multimeter, a dummy load, an SWR and power meter, an antenna analyzer, then specialised tools as the need arises. Buy new instruments from reputable sellers or check second-hand equipment carefully, using a checklist like the one in our article on buying used ham radio equipment. Add good-quality cables, adapters and connectors, because bad ones cause more measurement errors than the instruments themselves; our guide to RF connectors helps you choose them.

Organise the bench so that the tools you use most are within reach, and label cables so that you know what they are. A small shelf, a power strip with a switch and a good light are worth more than another instrument. If you share the room with other activities, a tidy portable case for the essentials makes it easy to take your measurements to the antenna, which is often where the problem actually is.

The Bottom Line

Good ham radio test equipment is not about the number of instruments; it is about answering the questions that come up in your station. Start with a multimeter, a dummy load and an SWR and power meter, then add an antenna analyzer when you build or tune antennas. Buy an oscilloscope or a counter only when a project needs it, keep notes of baseline readings and handle everything safely. With a few well-chosen tools and the habit of measuring before you change things, you will fix problems faster and understand your station far better.

Frequently Asked Questions

What is the first test instrument a new ham should buy?

A digital multimeter. It checks voltage, continuity and resistance and finds most basic faults in cables, fuses and power supplies. After that, buy a dummy load and an SWR and power meter, then an antenna analyzer if you plan to build or tune antennas.

Do I need an antenna analyzer if I have an SWR meter?

Not always, but an analyzer is more informative. An SWR meter needs transmitted power and shows SWR at one frequency at a time, while an analyzer sweeps a range at very low power and shows resonance and impedance. It saves time when you cut or tune an antenna.

Is a cheap wattmeter accurate enough?

For relative changes and general checks, a basic wattmeter is usually adequate. For accurate absolute readings, especially on SSB or at low power, a better instrument is more reliable. Check the frequency and power range, and compare the reading with another meter if you can.

Can I use a dummy load with any transmitter power?

No. Every load has a power rating and a duty-cycle limit, and many loads are only rated for full power for a short time. Check the manufacturer’s specification before you key a transmitter into one, and use a load with a heat sink for long tests.

When does an oscilloscope make sense in a ham shack?

When you work on audio, keying, power supply ripple or home-built circuits, or when you chase a problem that other tools cannot show. For general station work, a multimeter, a dummy load, a power meter and an analyzer usually cover more situations at a lower cost.

How often should I check my instruments?

Compare them with known references once a year and after any impact or surge. A stable dummy load, a fresh battery and a precision resistor are simple references. If two instruments disagree, investigate the cause before you trust the readings for important decisions.

Before many amateurs ever pressed a microphone button, they spent evenings turning the dial of a shortwave receiver. Shortwave listening, usually shortened to SWLing, is still one of the best ways to learn how the HF bands behave, and it is a hobby in its own right. You do not need a licence to listen, you do not need a transmitter and you can start with a very simple setup. This guide explains what you can hear on shortwave, how it relates to amateur radio, which equipment makes a difference and how to build a listening routine that improves your skills as an operator.

What Shortwave Listening Is

As the general description of SWLing puts it, the hobby is listening to shortwave radio broadcasts on frequencies between roughly 1.7 MHz and 30 MHz. Listeners range from casual users who want international news and music to technical enthusiasts who chase distant stations and collect confirmations, known as QSL cards, from the broadcasters. Other people listen to utility stations, such as aeronautical, maritime and time-signal transmissions, or to the amateur bands themselves.

Shortwave works because signals in this range can be refracted by the ionosphere and return to the ground hundreds or thousands of kilometres away. That is the same mechanism that makes HF contacts possible for radio amateurs. If you have read our introduction to HF propagation, you already know the basics: the best band depends on the time of day, the season and the state of the Sun. Listening is the most direct way to see that theory at work.

Why Hams Should Listen

A licensed amateur may think that listening to broadcasters is not relevant, but it is among the cheapest ways to train your ear and to understand propagation. A broadcast station on a known frequency, with a known power and a known direction, is a reliable test signal. If you can hear a station from a certain region on 15 metres at midday, you have a good idea that the 15 metre amateur band is also open toward that region. Broadcast stations also run at all times, so you can check conditions without waiting for an amateur to call CQ.

Listening also trains your patience and your ability to copy weak signals. You learn to recognise the sound of fading, of a noisy band and of interference from a local source. You also get to test your antenna and receiver without any pressure. If a signal is barely readable, you can try a different antenna, a narrower filter or a different location, and you will see the difference in a few minutes. Many amateurs say that their on-air skills improved more from a month of careful listening than from a month of random calls.

What You Can Hear

The shortwave spectrum is divided into bands that serve different users. The ranges below are broad and vary by region, and the exact allocations are set by international and national regulations, so use them only as a rough guide.

• International broadcast: news, music and cultural programmes in many languages, usually on bands labelled by wavelength such as 49, 41, 31, 25, 22, 19, 16 and 13 metres.
• Utility stations: aviation weather and position reports, maritime coast stations, press and diplomatic services and other users, often with digital or voice modes.
• Time and frequency stations: continuous carrier signals and time ticks at standard frequencies.
• Amateur radio: CW, SSB and digital contacts on the amateur bands, including the nine HF bands and the WARC bands.
• Numbers, beacons and unusual signals: a mix of experimental beacons and other transmissions that interest curious listeners.

Broadcast activity has changed in recent years. Many international broadcasters have reduced or ended their shortwave services in favour of internet distribution, while others have moved to digital formats. Schedules change often, so always check a current schedule before you plan a listening session, and treat any list of frequencies, including ours, as a starting point rather than a guarantee.

Choosing a Receiver

There are three main kinds of receiver. A portable world-band radio is the easiest entry. It has a telescopic antenna, runs on batteries and is easy to use. A communications receiver or an amateur transceiver offers better sensitivity, better selectivity and more control, especially when you want to listen to single-sideband and CW signals. A software-defined radio, either local or accessed over the internet, lets you see a whole slice of spectrum on a waterfall display. Our comparison of SDR options for ham radio describes the main choices.

Whatever type you choose, look for a receiver that covers the full range from long wave to 30 MHz, tunes in small steps and has a choice of AM, single-sideband and, ideally, synchronous detection. A narrow filter is more valuable than a long list of memories, because crowded bands need it. For an explanation of the receiver noise tools, see our article on noise blanker and noise reduction.

Antennas for Listening

Even a good receiver is only as good as its antenna. A telescopic whip can work for strong stations, but a long wire outdoors improves results at every frequency. A simple wire of 10 to 20 metres, kept clear of buildings and fed to the receiver with a proper connection, will often make a large difference. Place it as high and as far from household noise as you can. Our guide to finding and killing RF noise explains how to track down the interference that masks weak signals.

Balance simplicity with performance. A random wire with a matching transformer is a good all-round antenna for a listening station, and a magnetic loop can be a useful compact receiving antenna where space is limited. For listening, you do not need to worry about transmit power or exposure limits, so you can focus on a quiet location and good height. A small active antenna on a balcony or in an attic is often better than nothing, but be aware that a poorly shielded one can overload the receiver and create false signals.

Reading Conditions as You Listen

Shortwave listening is a live propagation report. Try this simple routine. In the morning, listen on the lower bands, such as 41 and 49 metres, where stations from your own region and neighbouring regions are usually strong. Around midday, move to the higher bands, such as 19, 16 and 13 metres, where daytime paths tend to open. In the evening, the middle and lower bands often come alive with distant signals. Note which stations you can hear and how clearly, and compare the pattern across the week.

The seasons matter too. Long-distance shortwave transmission is commonly reported to be most reliable at night and in winter, and the daytime upper bands depend strongly on solar activity. If you want a more formal view of the conditions, you can compare what you hear with the solar flux and the K index, which we explain in reading space weather for HF. After a few weeks you will begin to predict which bands will be useful, and that is a skill that carries directly into your amateur activity.

Logging and Reception Reports

Keep a log. Write down the date, time in UTC, frequency, station, language, signal strength and readability, and any interference. A notebook works, and so does a spreadsheet or a logging program. The act of logging forces you to listen carefully, and the records help you notice patterns over time. If you want a reference for the format, the system used for amateur reports, the RST scale, is explained in our article on RST signal reports.

Some broadcasters accept reception reports and reply with a QSL card or a letter that confirms your report. A good report is accurate, polite and detailed enough to prove that you really heard the programme, for example by mentioning a few items of content together with the time. Check the broadcaster’s own website for the address or the online form, and be patient: replies can take weeks or months. The tradition of collecting QSL cards is shared with amateur radio, and many people enjoy having both types of confirmation on their wall.

Utility Stations and Digital Signals

Beyond broadcast, the shortwave bands carry plenty of non-broadcast activity. Aeronautical and maritime stations use voice and digital modes, and there are also time stations and weather facsimile transmissions. Decoding these requires software and sometimes extra hardware, but a sound card interface and a free decoder are enough to start. Always treat what you hear with care. Some transmissions are encrypted, and in some countries the law restricts the use of certain information you may overhear. Listening is generally allowed, but using or passing on private information is not. Check the rules in your own country if you are unsure.

If you enjoy digital modes, you can combine your listening with the amateur side. Decoding weak signal modes on the amateur bands gives you a live map of activity, and the reports uploaded by other stations show what is being heard around the world. Our guide to PSK Reporter shows how to read that map.

Building a Listening Routine

Pick a regular time, even twenty minutes a day. Start with a short list of target stations from different parts of the world, and try to hear each one once a week. Compare the results at different times. Keep your receiver settings consistent so that you can compare notes: the same bandwidth, the same antenna and the same location. Add a new target each week. After a month, you will know which bands work from your location and which hours are best.

Join a local club or an online community if you want to share your results. Many listeners enjoy comparing their logs and learning which receivers and antennas work best in their area. If you are preparing for an amateur licence, regular listening to the amateur bands makes the exam material more concrete, and you will arrive on the air already familiar with how an exchange sounds.

The Bottom Line

Shortwave listening is an inexpensive hobby that teaches you about propagation, antennas and receivers without the need for a licence or a transmitter. Start with a simple receiver and a long wire, listen at different times of day, keep a log and compare what you hear with the space weather. Use broadcast and utility stations as free test signals, and use the habits you build to improve your amateur operating. Check current schedules and local rules, and enjoy the unpredictability of the bands.

Frequently Asked Questions

Do I need a licence for shortwave listening?

No. In most countries you do not need a licence to listen to shortwave broadcasts and amateur signals. Licences are required to transmit. Some countries have rules about what you may do with information you overhear, so check local regulations if you plan to decode utility stations.

What is the best time to listen to shortwave?

It depends on the band and the season. Lower bands tend to be better at night, and higher bands tend to work in daylight, especially when solar activity is high. Try several times a day and keep a log, because your own location and antenna will change what you hear.

Can I use my amateur transceiver for shortwave listening?

Yes. Most HF transceivers work well as receivers and offer good filters and single-sideband modes. Check whether the receiver covers the broadcast bands, because some radios restrict general coverage, and use a narrow filter when the band is crowded.

Is shortwave broadcasting still active?

Yes, but it has changed. Many broadcasters have reduced or ended their shortwave services, while others continue or have moved to digital formats. Always check a current schedule from the broadcaster, since frequencies and times are updated several times a year.

How do I get a QSL card from a broadcaster?

Send a reception report that includes the date, the time in UTC, the frequency and a short description of what you heard. Use the address or online form on the broadcaster’s own website, and be patient, since replies can take weeks or months and not every station answers.

What antenna should I use for a first listening station?

A long wire of 10 to 20 metres, installed outdoors, away from household noise and connected to your receiver, is a simple and effective choice. If you cannot put up a wire, a small active antenna or a magnetic loop can work indoors, though results will be weaker and noisier.

Morse code is the oldest digital mode in amateur radio, and one of the best ways to keep it enjoyable is to join other people who use it. The Straight Key Century Club, known as SKCC, is the largest club built around mechanical keys. It was founded in January 2006, it gives every member a number, and it organises on-air activity for beginners and veterans alike. This guide explains how the club works, how to take part, what its awards mean and how it compares with other CW clubs that you might also like to join.

What the Straight Key Century Club Is

SKCC describes itself on its own site as a group of mechanical-key Morse code operators. The main idea is simple. You make contacts on the HF bands using one of the three early types of manual key: a straight key, a bug or a cootie key. In return you swap numbers with other members, take part in club sprints, contests and special events, chase awards and use the club’s online resources and forum. Membership is free and open to licensed amateurs. The club’s page lists a very large membership, counted in tens of thousands, and it updates the number daily.

The club is not about speed. A straight key limits you to a modest rate, and a lot of the fun comes from slower, more relaxed conversations. That makes SKCC a natural home for people who are learning CW and who feel nervous about the fast pace of a contest. It is also popular with operators who simply enjoy the feel of a manual key. If you are still deciding what kind of key to buy, our guide to choosing a straight key, paddle or bug explains the differences.

How to Join and Get Your Number

You apply for membership on the SKCC website. After approval you receive a unique SKCC number. The number is the core of the club’s exchange. When two members meet on the air, each one sends the other a short exchange, and the number is usually part of it. Keep your number in your logging program so that it appears automatically. Members add a letter to the number when they reach an award level, so the suffix tells other operators how far you have progressed.

The club also publishes a handbook, a list of operating frequencies and a beginner’s section for people who are new to Morse. A volunteer network of experienced operators acts as Morse mentors for those who want help. Use them. A few friendly contacts with a patient partner are worth far more than hours alone with a practice file. If you are working on your speed, our article on learning Morse code and building CW speed offers a practical routine.

The Exchange in Practice

An SKCC contact is longer and friendlier than a standard contest exchange. You call CQ, the other station answers, and you swap signal reports, names, locations and SKCC numbers. Many operators also tell each other what key they are using, since the key type is the point of the club. A typical contact is relaxed and may last a few minutes, but it can easily turn into a ragchew. In a sprint the same exchange is shorter, but it still follows the same pattern.

Use proper abbreviations and prosigns so the exchange runs smoothly. Our guide to CW abbreviations and prosigns lists the common ones. Keep your sending clean and your spacing clear, and do not worry about mistakes. Almost every member started with a poor fist, and most are generous with newcomers. If you send a wrong character, a simple correction is fine.

Awards and Levels

The club’s awards give structure to your activity, and they are cumulative, so you advance by making contacts over time. The three main levels come from the club’s own award rules, and you should check the current rules on the club site before you start:

• Centurion: contact 100 unique SKCC members.
• Tribune: after reaching Centurion, contact 50 unique members who are Centurions, Tribunes or Senators.
• Senator: after reaching Tribune, contact 200 unique members who are Tribunes or Senators.

The club also issues many other awards, among them awards for working all states or all continents, for low-power operation, for contacts per watt, for ragchews and for using more than one type of key. The site lists them in detail with certificates and rosters. Treat the awards as a gentle guide rather than a race: a beginner might aim for Centurion over a few months, using a few regular contacts per week.

Sprints, Straight Key Month and QSO Parties

SKCC runs a regular calendar of events. The main ones listed on the club’s home page include two-hour sprints on different continents, an annual QSO party, the Weekend Sprintathon, the Slow Speed Saunter for operators who prefer a relaxed pace, and Straight Key Month in January, which is supported by a special-event station group. There are also events for beginners such as a day for novices. Dates and rules change, so always check the club’s event calendar and rules before you operate.

Sprints are a fast way to meet many members in a short time, and they are a good training ground for contesting skills. The slow-speed events are an excellent first step. If you have not yet tried a short contest on any mode, you will find a similar atmosphere in the weekly CW sprints we describe in weekly CW contests for practice.

How SKCC Compares with Other CW Clubs

SKCC is not the only CW group. Other clubs offer different benefits, and many amateurs join more than one. The CWops organisation, for example, offers free CW training through its CW Academy, sponsors weekly one-hour mini-contests, runs a CW Open once a year and issues several operating awards. Its focus is on skill-building and on contesting, and its members tend to work at higher speeds. SKCC, in contrast, focuses on mechanical keys and on relaxed on-air activity. Other groups focus on a specific key type, a specific band, QRP operation or a regional audience.

You do not have to choose. A common path is to start with SKCC for relaxed practice, take a CW Academy class or two to improve, and then add weekly mini-contests for speed. The skills transfer between clubs because the basic exchange and good operating habits are the same everywhere.

Equipment You Need

You do not need a special transmitter. Any HF transceiver with CW mode works, and a simple antenna is sufficient to make plenty of contacts. The main piece of equipment is the key. A straight key is the cheapest and the most traditional; a bug is a semi-automatic key with a mechanism that makes dots, and a cootie, or sideswiper, moves from side to side. Choose a key with a heavy base so that it does not move on the table, adjust the gap and the tension to suit your hand and use a short, well-shielded cable.

Setting the radio for a manual key is simple. Set the keying line to straight-key mode if the radio offers a choice, check that the sidetone is at a comfortable pitch and make sure the break-in setting suits you. Operators often prefer a narrow filter so that they can hear the other station clearly. When you answer a call, tune to the other station accurately; our article on how to zero-beat a CW signal shows the technique.

Operating Habits That Make You Welcome

Listen first, and ask whether the frequency is in use before you call. Use the club’s designated calling frequencies when you want to find members, and leave room for other activity. Send at the speed of the other operator, not faster. If the other operator is slow, slow down, and if you are slow, say so politely; most members will adjust. Keep your exchange short in a sprint and longer in a ragchew. Thank the other station, log accurately and record the other station’s number, because it matters for your awards.

Be generous. Answer new members, offer to help someone through a first contact and share what you have learned. The strength of CW clubs depends on a steady stream of newcomers and on the willingness of experienced operators to mentor them. That is also the quickest way to improve your own skills, because teaching reinforces your own habits.

Logging and Verification

Log each contact with the date, time, band, call sign, name, location, SKCC number and key type if you track it. Many general logging programs have fields for these items, and the club also offers its own logger and tools. Award claims are checked against the club’s records, so accurate logs matter. The club’s rules explain which contacts count, for example that each station can be counted once per band or once for an award level. Read the rules for each award before you start, because details such as the frequencies that count or the key you must use can change.

If you already keep a general log, export your data as an ADIF file when you need to submit it. The format is simple and widely supported. Keep backups, because an award application is easier to complete when your log is complete and tidy.

A Sample First Month

A realistic plan keeps the pressure low. In the first week, apply for membership, read the handbook and set up your key and your logging program. Spend a few evenings listening on the club’s activity frequencies without transmitting, so that you learn how the exchange sounds and how fast the typical station sends. In the second week, answer a few CQ calls from members who send slowly, and keep a note of the numbers you collect. In the third week, call CQ yourself for half an hour at a quiet time and see who answers. In the fourth week, try a slow-speed event or a short sprint, even if you only make a handful of contacts.

By the end of the month you will probably have fifteen to thirty contacts, a better ear and a feel for the people who are active on your bands. Keep going at a steady pace, and the first award will arrive without any special effort. If a week goes badly because of poor conditions or a busy schedule, do not worry; the club’s calendar repeats, and the rosters on the site show that many members take years to climb the levels.

The Bottom Line

The Straight Key Century Club offers a welcoming way to practise Morse code, meet other CW operators and earn awards at a relaxed pace. Join for free, take your number, make a few contacts a week and aim for Centurion first. Add other clubs such as CWops when you want classes or faster contest practice, and check each club’s current rules on its own website before you take part. Whatever you choose, the real value is on the air: regular contacts with friendly operators, and a straight key that rewards patience.

Frequently Asked Questions

Do I need a straight key to join the Straight Key Century Club?

You need a mechanical key for the club’s activity, which means a straight key, a bug or a cootie key. A paddle with an electronic keyer does not count for most of the club’s contacts, so check the key policy on the club’s site. A basic straight key is inexpensive and works well for beginners.

Is SKCC membership free?

The club states that membership is free for licensed amateur radio operators. You apply on the club site and receive a unique number. The club accepts donations, but they are optional.

How many contacts do I need for the Centurion award?

You need to contact 100 unique SKCC members under the club’s award rules. Check the current rules on the club site for how contacts are counted, what bands and modes qualify and how to submit your log.

What speed do I need for SKCC contacts?

You do not need to be fast. Many members send at a modest speed, and the club even has events designed for slow operators. Operators tend to adjust to the other station’s speed, so start where you are comfortable and improve with practice.

How is SKCC different from CWops?

SKCC focuses on mechanical keys and relaxed activity with numbered members and awards. CWops focuses on training, with CW Academy classes, and on weekly mini-contests and contest awards. Many operators join both and use each for a different purpose.

Can I take part in SKCC sprints with a low-power station?

Yes. Many members run low power or QRP and the club has specific awards for it. A simple antenna and a clear signal are usually enough to make a good number of contacts in a sprint, especially on bands that are open to your region.

For many new radio amateurs, the first handheld radio is the first piece of equipment they ever buy, and it is the one that decides whether the early weeks are fun or frustrating. A good handheld lets you hear the local repeater, join a weekly net, talk on a simplex frequency with a friend and, later, work a satellite pass or follow a hike with an emergency group. A poor choice leaves you with a radio that is hard to program, deaf next to a strong paging transmitter or tied to a battery that does not last an evening. This guide explains what a handheld transceiver does well, what it cannot do, and how to compare the features that matter before you spend money.

What a Handheld Radio Is Good At

A handheld transceiver, often called an HT, is a self-contained radio with a battery, a small display, a keypad and a short antenna. It is formally a walkie-talkie, a half-duplex device: you press the push-to-talk button to transmit and release it to listen. For amateur use, nearly all handhelds work on frequency modulation on the VHF and UHF bands, typically the 2 metre and 70 centimetre bands. That is exactly where most local repeaters, simplex conversations and public-service nets live.

Handhelds shine in three situations. The first is local contact: a repeater on a hill or a tall building can give an HT with a stock antenna a range of many kilometres. The second is portable and emergency use, where a radio that fits in a jacket pocket is more useful than a mobile rig left at home. The third is learning. Because the controls are simple and the bands are usually friendly to newcomers, a handheld is a gentle way to practise call signs, procedure and band plans before you tackle HF.

They also have clear limits. A handheld transmits with a few watts, and the antenna sits near your body at a low height, so it will not reach as far as a mobile radio with a roof antenna. It does not give you worldwide contacts, and you should not expect to work DX on a rubber antenna. If your goal is HF, a handheld is a useful companion but not a replacement for a proper station; our guide on choosing a first HF transceiver covers that path.

Check the Rules Before You Buy

You normally need an amateur licence before you transmit, and the rules differ by country. Some countries allow you to buy any radio you like and set it up yourself; others require equipment that conforms to a certain standard or a type approval. Some inexpensive radios can also transmit outside the amateur bands, and in many countries that is illegal unless the radio is used by a licensed service. Do not assume that a radio which can be programmed to a frequency is allowed to transmit on it. Learn which frequencies your licence class permits, and set the radio so that it cannot be keyed elsewhere if the firmware allows it.

Also remember that licence-free walkie-talkies, such as the common consumer products sold for family use, are a separate category with their own channels and power limits. They are not amateur radios, and an amateur handheld is not meant to be used on those channels. Keep the two worlds apart, and read your national regulator’s pages for current terms. The International Amateur Radio Union publishes the regional band plans that most national plans follow, and our overview of the IARU band plan regions explains how they differ.

Which Bands Should You Choose?

Handhelds are sold as single-band, dual-band and, less often, tri-band or wide-coverage models. A single-band 2 metre radio is simple and often cheap. A dual-band radio adds 70 centimetres, which gives you a second choice of repeaters and is better inside buildings, because UHF signals penetrate and reflect around walls and steel more easily than VHF. For most new amateurs, a dual-band radio is the sensible default. It gives you the widest choice of local activity at a modest price.

Look at what the radio can receive as well as what it can transmit. Many models include broadcast FM, airband and weather channels. These are pleasant extras, but the transmit range is what you pay for. A radio that has good wide-band reception but a weak amateur-band receiver is a poor trade for a radio amateur. Also check whether the radio supports CTCSS and DCS tones, since most repeaters need one of them to open, and whether it offers a clear way to set repeater offset and direction.

Power, Range and the Truth About Watts

Most handhelds offer a few power levels, for example a low setting of around a watt and a high setting of around five watts. Higher power does not double your range; the relationship is logarithmic, and a small change in antenna height often helps more than a large change in power. Use the lowest power that gets a clean signal into the repeater. It saves the battery, reduces the chance of overloading a nearby receiver and lowers your RF exposure. Our guide to RF exposure safety explains why keeping the antenna away from your head is good practice.

Be sceptical about advertised power in the product title. Measured output varies between samples and with battery voltage, and a fully charged battery can give noticeably more power than a half-flat one. The radio’s range is also limited by the receiver. If a radio hears poorly, a high transmit power will not save the contact, because the other station will hear you but you will not hear them.

Receiver Quality: The Hidden Differentiator

This is where inexpensive and expensive handhelds differ most, and it is the part that is least often discussed in marketing. In an urban area, a handheld is exposed to powerful transmitters: pagers, commercial radio, broadcast towers and cellular sites. A receiver with weak front-end selectivity can be overloaded by a strong signal outside the band, which produces noise, distortion or a loss of sensitivity on the channel you want. The problem is called blocking or intermodulation, as explained in our article about receiver dynamic range.

How can you judge a handheld before you buy it? Look for reviews that include measured data, such as sensitivity and blocking dynamic range, rather than only subjective reports. Ask experienced local amateurs which models work well on your own repeaters, because the interference environment differs by city. Be careful with very cheap radios: some independent tests have reported weak filtering of harmonics and spurious emissions on inexpensive models, which can cause interference to other services. A radio that meets recognised standards and has a good reputation is worth the extra cost.

Features Compared at a Glance

The table lists the features you will see on a spec sheet and what to look for in each. It is a checklist, not a ranking: decide which items matter for your use, then compare radios only on those.

Antenna and Connector

The antenna that comes with a handheld is a compromise. It is short, flexible and designed to be tolerable rather than efficient. Most handhelds use an SMA connector, but there are two common genders, and the opposite gender is used by many accessories, so check carefully before you buy a replacement antenna or an adapter. A longer whip or a roll-up antenna can improve your signal noticeably, as we describe in the guide to a handheld antenna upgrade. Keep any extra cable short, because coax loses a lot of signal at UHF.

The radio’s connector is fragile. Do not carry the radio by a heavy antenna, and avoid stress on the connector from a long whip. An adapter cable that moves the antenna away from the radio body reduces the load. For a first radio, the stock antenna is fine for learning; invest in a better antenna after you know how you use the radio.

Battery, Charging and Runtime

Handheld batteries age. After a few years a pack may deliver half of its original capacity, and that is the moment you discover that the radio is only good for an hour of net traffic. Buy a spare battery with the radio if the model has a removable one, and keep it charged. A battery case that holds standard cells is a useful emergency backup, but it usually reduces output power because of the lower voltage.

Think about charging. A radio that charges from a USB port is convenient for travel, since you can use a power bank or a car adapter. A radio that needs its own drop-in cradle and a wall adapter is less flexible. Also check how the radio reports battery state. A bar that goes from full to empty in a few minutes is a bad sign, because it hides a weak cell until it drops out.

Programming Without Pain

You can enter repeater frequencies, offsets and tones from the keypad, and you should learn to do it once, because it teaches you what each setting means. After that, programming from a computer is much faster. Open-source tools such as CHIRP support a long list of models, and our CHIRP handheld programming guide walks through a first session. Before you buy, check that your model is on the supported list and that the programming cable it needs is available at a reasonable price. A cable that uses a poor-quality chip can cause driver problems, which is a common source of frustration.

Whatever tool you use, keep a backup of your channel list. A radio that is dropped, reset or reflashed can lose its memories, and a copy on your computer lets you restore them in minutes. Organise memories in groups: local repeaters, simplex channels, emergency channels and travel. A short, well-labelled list is easier to use than a list of two hundred channels.

Digital Modes and Extra Features

Some handhelds support digital voice modes, GPS and APRS. They add cost and complexity, and they are valuable only if you will use them. Digital voice requires a network of digital repeaters or hotspots in your region and, depending on the mode, a registration or an identity. If nobody near you uses a mode, the feature is a spare button. Ask your local club which mode they prefer before you buy a radio for it. A radio with built-in GPS can send your position through APRS, which is useful on a hike or in an event, but it uses battery and requires a suitable digipeater network.

Features that are valuable for almost everyone include a clear and quick way to lock the keypad, a monitor button to hear weak signals, a dual-watch function to follow two channels and a decent scan function. Features that are less important for a beginner include a large number of modes you will not use and elaborate apps that add little to the radio.

Accessories That Are Worth Buying

The first accessory to buy is a spare battery or a power bank cable. The second is a speaker microphone, which lets you keep the radio clipped on your shoulder or belt and the antenna away from your head. The third is a programming cable. A car charger, a belt clip and a pouch are handy but optional. A rubber antenna and a roll-up antenna can be added later. Avoid buying a large kit with many accessories you will not use, because the quality is often poor and the radio is the part that you will use every day.

A Simple First-Week Plan

Charge the battery fully and read the manual once. Programme two or three local repeaters and a simplex calling channel. Listen before you transmit, to learn how the local community talks. When you are ready, make a short call, give your call sign and ask for a signal report. Use low power first. After a week, review which settings you actually changed and which features you used. That experience will tell you more about your needs than any spec sheet, and it will help you choose the next radio, if you want one, with confidence.

The Bottom Line

Your first handheld radio should be a dual-band radio from a reputable manufacturer, with a removable battery, a standard antenna connector and good programming support. Spend your money on receiver quality, battery and reliability rather than on features that you will not use. Check your national rules, set the radio up carefully, add a better antenna and a speaker microphone when you know how you work, and keep a backup of your memories. A radio chosen with those priorities will serve you for years, and it will remain useful even after you buy an HF station.

Frequently Asked Questions

What is the best first handheld radio for a beginner?

There is no single best model, but the best choice is usually a dual-band 2 metre and 70 centimetre radio from a well-known maker, with a removable battery, a standard SMA connector and support in common programming software. Ask local amateurs which radios work well on your repeaters, and prefer a model with measured test data over one with only marketing claims.

Do I need a licence to use an amateur handheld?

In nearly all countries you need an amateur licence to transmit on amateur frequencies, and rules differ by country. You can usually listen without a licence. Check your national regulator for current rules, and do not transmit on frequencies outside your licence privileges, even if the radio technically allows it.

How far can a handheld radio reach?

It depends mainly on antenna height and terrain, not only on power. On simplex, a handheld may reach a few kilometres in open country and much less in a city. Through a repeater on a high site, the range can be many kilometres. Stand in the open and raise the radio above your head to improve a weak path.

Is a cheap handheld good enough?

For learning and light use, an inexpensive radio can be enough, but cheap models often have weaker receivers and, in some independent tests, poor filtering of unwanted emissions. If you live in a busy radio environment or want to use the radio for emergency communication, a better receiver and a more reliable build justify the extra cost.

Should I upgrade the antenna right away?

Not necessarily. Start with the stock antenna to learn how the radio works, then upgrade when you know which problems you need to solve. A longer whip or a roll-up antenna can help, but check the connector gender first and keep the cable short to avoid losses.

Can a handheld be used for HF?

Standard amateur handhelds are built for VHF and UHF and cannot work on HF. For HF you need a transceiver designed for those bands and a suitable antenna. A handheld still has value as a companion radio for local contacts, portable operation and emergency communication.

A boat is a good place for an HF station, and a difficult one. The sea is an excellent ground plane, the horizon is far away and a long night watch is a perfect time for a quiet chat with a friend on the other side of an ocean. At the same time, the boat is short of space and power, the environment is hostile to metal and electronics, and every electrical device on board seems designed to produce noise. Maritime mobile operation is the name for amateur radio from a vessel, and it can be done well with careful planning. This guide covers the rules, the antenna and ground, the power system, the noise problems, the modes and nets that make sense at sea and the safety points that matter more than any contact.

Radio Amateur Operation on a Vessel

An amateur station on a boat is a normal amateur station with extra conditions. Rules differ by country, but the common principles are clear.

• The captain decides. You need the approval of the master of the vessel to install and operate a station. In the United States this is written into the rules, for example in 47 CFR 97.11, and other countries have similar provisions.
• Keep it separate. The amateur equipment must not interfere with the vessel’s navigation, communication and safety equipment, and it should be independent of it, except for permitted sharing of an antenna in some cases.
• Know whose rules apply. Inside the waters of another country, the local rules may apply, and in international waters the rules of your licensing authority and the flag state matter. Check before you sail.
• Identify properly. The suffix “/MM” after your callsign tells other stations that you are maritime mobile. Our guide to portable callsign suffixes explains how to use it.
• No business traffic. Amateur radio is for personal communication. Messages about the operation of the vessel for commercial purposes are not allowed in most countries.

The general idea of this service is described in the article on the maritime mobile service, which also covers the commercial and safety side that amateur radio does not replace.

Amateur Radio Is Not a Safety System

One point deserves emphasis. A ham station is a wonderful extra, but it is not a replacement for the equipment that keeps a crew safe. A VHF marine radio, an emergency beacon, a satellite device and the safety gear required for the type of voyage are the primary tools for a distress call. Amateur nets sometimes pass emergency traffic and have helped crews, and some operators monitor certain frequencies for exactly this reason, but a boat should never depend on a ham contact to be rescued. Treat the station as a hobby and a link with family, and keep the real safety equipment separate and in working order.

The Antenna Problem

On a sailboat, the standard solution is the insulated backstay. The rigging wire that supports the mast from behind is cut and fitted with insulators at the top and the bottom, so that a section of it becomes the radiating element of a vertical. A tuner at the base matches it to the transmitter on each band. On a motor vessel, a long whip, often 7 to 10 metres, takes the same role and mounts on the stern or on a hardtop.

The antenna is a short vertical, much shorter than a quarter wave on the lower bands, so a tuner is essential. The performance depends on the ground, as described below. The tuner is usually mounted close to the base of the antenna, and the coax from the radio runs to it. An automatic tuner with a weatherproof housing is common. The high voltage at the base of a backstay antenna is a hazard, because the RF can burn anyone who touches the wire during transmission, so cover the lower part of the wire with an insulating sleeve or keep it out of reach.

If you cannot insulate the backstay, alternatives are a long wire on the deck, a loaded whip, a wire from the masthead to the stern or a small receiving antenna and a separate transmitting antenna. Every option involves trade-offs, so decide according to the vessel, the bands and the budget. A short comparison follows.

The Ground Is Half the Antenna

A vertical antenna works against a ground, and an HF antenna on a boat with a poor ground wastes most of the power in loss. The sea would be an excellent ground, but the transmitter must be connected to it in an effective way. On a steel or aluminium vessel, the hull is a ground plane, and bonding the tuner to it with a short, wide strap helps. On a fibreglass or wooden boat, you must provide your own. Common solutions include a sheet of copper foil laid inside the hull below the waterline, connecting to a large keel or other metal parts, or a sintered bronze plate designed for radio grounding. Use wide copper strap, not round wire, because the RF current flows on the surface, and keep the connection between the tuner and the ground as short as possible.

The ground system needs to be bonded to the boat’s other metal and electrical systems with care, because stray currents and electrolysis are real risks in salt water. Seek advice from a marine electrician to ensure that the RF ground does not create a corrosion problem. The principles of a good ground, a short path, low resistance and a wide conductor, are the same as for a shore station, as our article on station grounding and lightning protection describes.

Power on a Boat

A boat has a 12 volt system, and the station should run from it directly. A good radio draws about 20 to 22 amperes on transmit at 100 watts, which is a large current for the wiring of a small boat. Use heavy cable with the voltage drop in mind, fuse it close to the battery and keep the run short. Battery capacity matters for long voyages, and our article on battery power options compares battery types, charging and solar. The radio is mostly receiving at sea, so the average load is small, but the peaks on transmit may drag a weak battery below the voltage at which the radio works well. Consider a dedicated battery or a link to the house bank through a proper fuse.

Noise on a Boat

A boat is crowded with noise sources. Alternators and engines, bilge pumps, LED lights, inverters, chargers, solar controllers, the autopilot and the electronics at the helm can all radiate. The solutions are the same as on land, applied in a tight space. Switch off one device at a time while you listen to the noise on the receiver, find the worst sources and treat them with ferrite chokes, shorter cables, shielded cables and better grounding. Our guide to finding and killing RF noise describes the method. LED navigation and masthead lights are common culprits, and a good quality replacement or a filter often solves the problem. Keep the coax away from power wiring, and add a common-mode choke at the radio and at the tuner.

Modes and Nets at Sea

Voice and digital modes both work. Single sideband is the usual choice for chat and nets, and weak-signal digital modes work well from a small antenna, since a computer can decode signals that the ear cannot. For email, position reports and weather files, many cruisers use the Winlink system through HF gateways, as our article on Winlink over HF describes. Check whether it is allowed under your licence and the rules of the country.

Several amateur nets cater to boats. Maritime mobile nets meet at fixed times and frequencies on HF, where check-in stations exchange positions, weather and conditions, and sometimes pass messages between families and boats. A well-known meeting frequency is 14.300 MHz on the 20 metre band, which is used for the Intercontinental Maritime Mobile Service Net and as a global emergency centre of activity. Frequencies and times change, so look up the current information from a national society before you rely on them.

Propagation and Operating at Sea

The sea gives a vertical antenna an advantage that land stations rarely have: a conductive surface in all directions, with nothing between the antenna and the horizon. Low-angle signals leave the boat without obstruction, which helps on the long paths that HF cruisers use. On the other hand, the antenna is short and the ground is imperfect, so expect a modest signal compared with a shore station with a beam. Choose the band by the time of day and the distance. The 20 metre band is the classic daytime band for long contacts, the 40 metre band works well for regional contacts and for night, and the 17 and 15 metre bands open in the daytime when the solar activity is good. The 80 metre band is useful for nets close to the coast at night.

A boat also moves, and the position changes the path. A voyage across an ocean may carry you through several time zones and several propagation regions in a week, so keep a table of useful bands and times for each leg. Many sailors set a regular schedule, called a sked, with a friend ashore, and agree on a main frequency and a backup. A schedule is more reliable than hoping for a chance contact, and it gives the family on shore something to rely on.

Looking After the Equipment

Salt air is hard on every connector and every switch. Use marine-grade connectors, seal every outdoor joint with self-amalgamating tape and mastic, and rinse the radio’s surroundings with fresh water when spray enters the cabin. Mount the radio and the tuner away from direct water, and keep spare fuses and a spare microphone in a sealed box. Check the antenna insulators for cracks and salt deposits at each port, and clean them with fresh water. A salt film on an insulator can conduct RF and cause the tuner to fail to find a match, which looks like a radio fault but is not. Finally, protect the equipment from lightning as far as you can by disconnecting the antenna from the tuner when the boat is unattended in a storm, and by following the guidance of a marine electrician for the grounding of the rig.

Checklist Before You Sail

1. Obtain the captain’s approval and check the rules for your route.
2. Install the antenna, insulators and tuner, and cover the high voltage parts.
3. Build the RF ground with copper strap and a short path from the tuner.
4. Wire the radio with heavy cable, a fuse and a clean power connection.
5. Test on the dock with the engine on and off, and deal with the noise sources.
6. Record the tuner settings, the SWR on each band and the best antenna length.
7. Log your first contacts and compare with a shore station on the same band, if possible.

Common Mistakes

• Neglecting the ground. A poor ground wastes power and makes tuning unstable.
• Using thin wire for power. Voltage drop reduces output and heats the cable.
• Touching the antenna while transmitting. RF burns are painful and avoidable.
• Treating the ham station as the safety radio. Keep the proper safety equipment ready.
• Ignoring noise until the voyage. Test and fix the noise sources while the boat is still at the dock.

The Bottom Line

Maritime mobile operation is a rewarding part of amateur radio, with a few special demands. Obtain the captain’s approval and follow the rules, build the best antenna and ground you can, supply clean power through heavy cable and track down the noise before you sail. Use the modes and nets that suit your route, and keep the real safety equipment separate and ready. With careful installation, a modest HF station can make a long voyage feel much less remote.

Frequently Asked Questions

What does /MM mean?

It is a callsign suffix that means maritime mobile. It tells other stations that you are operating from a vessel at sea.

Do I need the captain’s permission to operate on a boat?

Yes, in most countries. The master of the vessel must approve the installation and operation of an amateur station on board.

What antenna works best on a sailboat?

An insulated backstay with an automatic tuner is the most common solution. It needs a good ground and safe covering of the high voltage parts.

How do I make a ground on a fibreglass boat?

Use wide copper strap or foil connected to a large submerged metal surface or a sintered bronze plate, and keep the connection to the tuner short.

Can I use ham radio for emergencies at sea?

Amateur nets sometimes help in emergencies, but a boat should rely on its marine radio, beacon and other safety equipment and not on a ham contact.

Can I send email from a boat with ham radio?

Many operators use Winlink through HF gateways. Check that it is permitted under your licence and the rules where you operate.

Most antenna failures do not happen in a storm. They happen slowly, over months, as a connector lets in water, a rope loses its strength in the sunlight, a clamp loosens in the wind or a ground connection corrodes. By the time the signal weakens or the SWR rises, the damage is done, and the repair is more expensive and more dangerous than it would have been if the fault had been caught earlier. Antenna maintenance is dull, but it is one of the best returns on time in the hobby. An hour in spring and an hour in autumn, with a checklist and a record of what you find, is enough to keep a station reliable for many years. This guide gives the checklist, explains what each check is looking for and shows how to keep a simple record that makes problems obvious.

Safety Before Anything Else

The inspection involves heights, tools and, sometimes, electricity, so the safety rules come first.

• Power off. Disconnect the radio and the amplifier from the antenna before touching connectors, and disconnect the feed line at the entry point during a thunderstorm.
• Keep away from power lines. Plan the work so that no mast, wire or ladder can touch an overhead line if it falls or swings.
• Do not climb alone. Use a helper and, for a tower, proper fall protection, as described in our guide to tower safety and fall protection.
• Lower what you can. If the antenna is on a tilt-over or push-up mast, bring it down to ground level for inspection instead of climbing.
• Check the weather. Do not work in wind, rain, ice or the threat of lightning.

If a job feels beyond your skills, a club member with experience or a professional rigger is the right answer. A rusty bolt is not worth a fall.

What to Inspect

The checklist below groups the common items by part of the system. Treat it as a base and add anything specific to your own installation.

Many operators photograph each item at every inspection. Comparing the new picture with the one from last year shows slow changes that the eye misses.

Connectors and Coax

Water is the enemy. A tiny crack in a seal lets moisture into a connector, where it wicks along the braid, corrodes the conductors and raises the loss. The effect on the SWR may be small at first, but the loss and noise grow over months. Open one or two of the exposed connectors each year, check for moisture and corrosion and reseal them. Our guide to weatherproofing coax connectors shows the layers of tape, mastic and drip loops that keep the water out.

Walk along the cable and look for damage. Common faults are a jacket cracked by sunlight, a section crushed by a door or a window, and a cable pulled tight against a sharp edge. A kink may reduce the performance permanently. If the cable feels stiff or the jacket looks chalky, replace it before it fails. Run your fingers along the underside of a horizontal run, where water collects, and check the drip loop at the building entry.

Wire, Ropes and Insulators

Wire antennas move in the wind, and the movement flexes the metal. Look for broken strands near the insulators and the center, for green or white corrosion on copper wire and for stretch in the wire, which shows as sag. Our article on choosing HF antenna wire compares the materials, and the failure signs depend on the type. Replace a damaged section before it breaks, since a broken wire in a storm can land on a power line or on a neighbour’s property.

Ropes deserve special attention. Sunlight breaks down many synthetic fibres, and ropes that were fine in spring may be weak by autumn. Look for a stiff, chalky or fuzzy surface, for fibres that are broken, and for knots that have crept. Replace any rope that looks suspect, and plan to renew ropes at regular intervals in any case. Use UV-resistant rope designed for outdoor use, and tie knots that do not slip.

Masts, Guys and Hardware

Look at every clamp, bolt and turnbuckle. Where two different metals touch, a damp environment causes galvanic corrosion, which eats the less noble metal. Aluminium tube against a steel bolt is a classic example. Use stainless fasteners, apply an antioxidant compound to joints and replace anything that is badly rusted. Check that guy wires are tight and equally tensioned, that the anchors have not moved and that the thimbles and clamps are secure. Our article on push-up masts and guying explains how guy angles and tension are chosen.

Look at the mast for bends, particularly where it comes out of a clamp, and check that the sections still slide freely. Grease the sliding parts lightly if the maker allows it. Make sure that no tree branches rub against the antenna, because growth over a year can bring a branch into contact with a wire.

Wind, Ice and Mechanical Load

Every antenna is a sail. The force of the wind rises with the square of its speed, as the article on wind load explains, so a gust twice as strong pushes four times as hard. Ice makes things worse, adding weight to the wire and increasing the surface that the wind can push. An inspection is the best time to ask whether the installation still has a margin. Compare the actual antenna and mast with the ratings from the maker, and think about what has changed since you built it: a larger antenna added to the mast, a new rotor, a tree that has grown or a guy anchor that has moved.

Look for signs of fatigue. A mast clamp that has left a polished mark on the tube has been moving. A guy wire that has worn a groove in its thimble is close to failing. A cable tie that has cut into the jacket of the coax has been under strain. These small signs are easy to fix when you find them early, with a new clamp, a new thimble or a strain relief loop, and they are a good guide to where the next problem will appear. If you live in a region with heavy snow or storms, consider lowering a tilt-over mast before the worst weather and raising it again afterwards.

Rotors, Traps and Baluns

A rotor that is noisy, slow or stiff needs attention. Listen to it turn, check the cable for wear at the bend and check that the brake holds. If it has a grease port or a service plan, follow the manual, and replace worn parts before they fail on a windy night. Traps, coils and baluns are often sealed units. Look for discolouration, which indicates heat, for cracks in the housing, and for water in the drain holes. A trap that has taken in water changes frequency, and the antenna becomes mistuned. Replace a unit with a clear defect, because repair is usually not practical.

Grounding and Lightning Protection

A ground connection that has corroded does nothing, and nobody notices until the day it is needed. Check that the clamps on the ground rod are tight and free of green deposits, that the bonding wires are intact and that the lightning arrestor at the entry is firmly connected. Our article on station grounding and lightning protection describes a complete system. If your area has a dry season and a wet season, look at the connections at the end of the dry season, when the ground resistance is highest, and add a rod if needed.

Measure and Record

An inspection is stronger with measurements. When the antenna is working well, sweep it with an analyzer and store the SWR plot for each band. Then at each inspection, repeat the sweep and compare. A change in the shape or the centre frequency of the curve is an early warning of water, a loose joint or a damaged element, and it helps to locate the fault. Our guide to the NanoVNA and calibration sweeps explains how to take clean measurements. Keep a simple log in a notebook or a file with the date, the weather, the findings and the work done. In a year or two, the log will show you which parts fail first, and you can buy spares accordingly.

Spare Parts and Tools

A small kit makes a routine inspection much easier, because you can fix a small fault on the spot instead of coming back another day. Keep a few stainless bolts and nuts in the sizes that your antenna uses, a spare coax connector with a short jumper, a roll of self-amalgamating tape and a tube of antioxidant compound. Add a few metres of rope, some cable ties made for outdoor use, a pair of pliers, an adjustable spanner and a torque tool if the maker specifies a value for the clamps. A multimeter, a small analyzer and a pair of binoculars complete the set. Store everything in a single box, and renew the tape and compound each year, because they age. With such a kit, the checklist takes an hour, and the typical repair takes minutes.

Also keep the manuals and the data of the antenna, such as the element lengths, the recommended torque, the balun type and the SWR curve from the first test. When you need to replace a part, having these numbers saves time and prevents mistakes, particularly after several years when the original paperwork has been lost.

A Simple Yearly Schedule

• Spring. Check for winter damage, retighten hardware, reseal connectors, trim trees and repeat the SWR sweeps before the busy summer season.
• Before a big contest. Do a quick visual check of the antenna and the feed line, and make one sweep on the contest bands.
• Autumn. Prepare for storms and ice, check guy tension, replace ropes that show wear and clear leaves from the base.
• After any storm. Look at the antenna from the ground with binoculars, and check the SWR before you rely on it.

Common Mistakes

• Waiting for a failure. A small problem found in a routine check costs little, while the same fault after a storm costs a lot.
• Ignoring the ropes. They age quickly in sunlight and are often the weakest link in a wire antenna.
• Using mixed metals without protection. Corrosion between aluminium and steel is predictable and avoidable.
• Not keeping a baseline. Without a first SWR plot, you cannot tell what has changed.
• Climbing without a plan. Safety comes before the repair, every time.

The Bottom Line

Antenna maintenance is a short routine that keeps a station working and safe. Inspect connectors, coax, wire, ropes, guys, rotors and grounding twice a year, repair small faults early and measure the SWR so that changes are visible. Keep a log, replace ageing ropes and cables on a schedule and put safety before everything else. An hour in spring and another in autumn is a small price for an antenna that is ready whenever the band opens.

Frequently Asked Questions

How often should I inspect my antenna?

At least twice a year, in spring and autumn, with an extra check after a severe storm and before an important contest.

How do I know if water has got into my coax?

Signs include a rising SWR, increasing loss, noise, green corrosion in a connector and a wet or discoloured braid. Open the connectors and check them if you suspect it.

How long do antenna ropes last?

It depends on the material and the sunlight, but ropes in constant exposure should be checked every year and replaced every few years or at the first sign of damage.

What is galvanic corrosion?

It is the corrosion that occurs when two different metals touch in the presence of moisture. Using stainless hardware and an antioxidant compound reduces it.

Should I record SWR measurements?

Yes. A stored sweep for each band lets you compare later and find early signs of a fault before it becomes serious.

Can I do maintenance on a tower myself?

Only with proper training, equipment and a helper. If you are not sure, ask an experienced club member or a professional rigger.

Between a wire dipole in the garden and a full-size three-element Yagi on a tower lies an antenna that many stations overlook: the rotatable dipole. It is a half-wave dipole, or a shortened version of one, mounted on a mast above a rotor. You can point its strong sides toward a target and, just as usefully, point its nulls at a noise source or a strong local station. It is lighter and cheaper than a Yagi, it needs a smaller rotor and a lower mast, and on 40 metres, where a full-size beam is an enormous structure, it is often the only directional antenna that is practical. This guide explains how it works, what it can and cannot do, how it compares with other antennas and what to check before you buy or build one.

What a Rotatable Dipole Is

A rotatable dipole is a single horizontal dipole that can be turned. The antenna is fed in the center, usually with coax through a balun, and has no director and no reflector. It is therefore a one-element antenna, with the same figure-eight pattern as a fixed dipole. The difference is that you can choose the direction of the lobes. A full-size half-wave dipole on 20 metres is about 10 metres long, which is a manageable size to rotate, and a shortened one for 40 metres is often between 8 and 12 metres long, with loading coils or similar methods to reduce the length. Some designs cover two or three bands with traps, as in our overview of the trap dipole, and the same trade-offs apply.

The basic pattern of a dipole is described in the article on dipole antennas. In free space the dipole has about 2.15 dBi of gain, with the strongest radiation broadside to the wire and deep nulls off the ends. Above real ground the pattern changes with height, and ground reflection can add several decibels to the useful lobes at favourable heights.

What It Does Well

The rotatable dipole is not a beam, but it has four real advantages.

• Noise and interference control. The nulls off the ends of the dipole are deep. Turn the antenna so that a local noise source or a strong station lies in a null, and it can drop by 20 dB or more. For a station troubled by one dominant source, this is a very effective tool.
• Directional choice. The two broadside lobes point in opposite directions. Rotating the antenna lets you favour Europe and Asia on one hour and North and South America on another, without a long wire layout.
• Low weight and wind load. A light antenna places little load on the mast and rotor, which makes it feasible on a roof or a modest tower.
• Cost and simplicity. One element, one feed point and a small rotor cost far less than a multi-element beam.

These benefits explain why the rotatable dipole is popular on 40 metres, 30 metres and 20 metres for stations with modest space and for use in contests, where being able to null a neighbour station can save a contact.

What It Does Not Do

It also helps to be honest about the limits.

• It has no front-to-back ratio. The antenna radiates equally on both broadside sides, so it does not reject a station behind it, only stations off the ends.
• The gain is modest. A rotatable dipole has about the same gain as a fixed dipole at the same height, and noticeably less than a two-element Yagi, which can offer about 5 to 6 dB over a dipole.
• Shortened versions are narrow. Loading coils and short elements reduce the bandwidth, so on 40 metres the antenna may cover only part of the band at an acceptable SWR. Check the published figures against the part of the band that you use.
• Efficiency drops with shortening. A heavily loaded antenna loses a little power in the coils, and the very short designs are less effective than a full-size one.
• Height still matters. The takeoff angle depends on the height above ground, as the article on antenna height and takeoff angle explains.

Comparing It With Other Options

The table compares the rotatable dipole with three common choices, using typical values. Real figures vary with the model and the height.

If your goal is more signal on a target, a Yagi or a hex beam wins, as described in our comparison of the Yagi and the hex beam. If your goal is a rotatable antenna on a small plot and a way to deal with noise and neighbours, the rotatable dipole is attractive.

Mast, Rotor and Feed

The mechanical part decides how long the antenna will survive. A light dipole puts less stress on a rotor than a beam, but the load is still significant, and the weight is held out on a long arm. Choose a rotor rated well above the wind load and the weight, and use a mast and bearing that can take the vertical load. Our article on antenna rotators explains how to size the rotor and the control cable, and the general overview of the antenna rotator shows how the mechanism works. Add a little extra time to your plan for the first test turn, since a stiff cable or a tight clamp is easiest to find on the ground. A rotatable dipole turns through a small swept area, so it fits in a smaller space than a Yagi, but the ends sweep a circle, which you must keep clear of trees, wires and the roof.

Feed the antenna with coax through a 1:1 current balun at the center, to keep the radiation pattern clean and to avoid common-mode current on the cable. Our overview of baluns and ununs explains the choice. Allow a loop in the cable at the rotor to prevent strain as it turns, and use a rotor loop or a rotating joint, with a limit on rotation so that the cable does not wrap around the mast.

Height and Mounting

A horizontal dipole behaves very differently at different heights. At a quarter wavelength above ground, the pattern is high and rounded, which suits regional contacts and gives a weak signal toward the horizon. At a half wavelength or more, the lobes fall toward the horizon and the antenna works better for distance. On 20 metres a half wavelength is about 10 metres, which is a reachable height. On 40 metres it is about 20 metres, which is a challenge, so a rotatable 40 metre dipole at 12 or 15 metres is a compromise that many stations accept. The nulls are also deeper when the antenna is away from nearby metal, so keep it clear of the tower, guy wires and other antennas, and ideally mount it above any other horizontal element on the mast.

When you mount it on a tower, use a rotor on a plate with a thrust bearing so that the weight of the mast does not rest on the rotor itself. Keep the center of the dipole in line with the mast axis, so that the antenna is balanced, and tie the coax to the mast with a drip loop at the bottom to protect the connectors. A tidy installation lasts years, while a hurried one fails in the first storm, so allow time for each step and follow the safety rules for working at height.

Multiband Versions

Some rotatable dipoles cover two or three bands with traps or with parallel elements. The traps work like those in a wire trap dipole: each pair of traps isolates the outer parts of the elements on a higher band. The result is a single antenna with three resonances, at the price of some loss in the traps and a narrower bandwidth on each band. For a station that wants 20, 15 and 10 metres from one rotatable antenna, the arrangement is practical and compact, though a small Yagi on those bands would give more gain. For stations that want 40 metres together with 20 metres, a special design with a loaded 40 metre element and a separate 20 metre element can be used. Always check the stated performance on each band, because the manufacturer may show the SWR curve, and compare it with the part of the band that you plan to use.

Using the Nulls

The nulls are the most underrated feature. When you hear a noise or a strong station that interferes with your target, rotate the antenna slowly until the interference drops. Because the pattern is symmetrical, the nulls off both ends give you two directions to use. The depth of the null depends on the height and the surroundings, and it is usually deepest at a particular angle. If the interference comes from a nearby house, a neighbour’s equipment or a power line, try to find the direction by rotating and noting the bearing, and write it down so you can return to it quickly.

The same approach helps in contests, where a strong local station may sit on a nearby frequency. Place the null toward it, and you can often work weak signals that the strong station would otherwise cover. Check the bearing to your target stations with a great circle map first, so that the choice of direction is not guesswork.

Choosing or Building One

When you evaluate a commercial model, check the elements below.

1. Length and weight compared with your mast and rotor ratings.
2. Bandwidth figures on the band segment that you use, not only the centre frequency.
3. The balun or matching supplied, and whether it handles your power.
4. Quality of hardware, including stainless fasteners and weather seals on the coils or traps.
5. Independent reports from other stations on actual SWR and performance.

For a homemade antenna, a full-size 20 metre version made from aluminium tubing is a modest project, and you can model it before building it, using the methods in our guide to antenna modelling with EZNEC and 4nec2. Start with a simple design, measure the SWR on a test mast, and adjust the element length by small amounts.

Common Mistakes

• Expecting beam gain. The antenna is a dipole that you can turn, not a Yagi.
• Using too small a rotor. A light antenna still needs a margin for wind and ice.
• Ignoring the balun. Without a choke at the feed point, the coax distorts the pattern.
• Mounting it too low. The nulls and the takeoff angle both suffer near the ground.
• Not recording the bearings. Writing down the null directions for local noise saves much time later.

The Bottom Line

A rotatable dipole is a modest antenna with useful strengths. It gives you a choice of direction, deep nulls for noise and local interference, and a light, affordable structure that fits a smaller space than a Yagi. It does not offer front-to-back rejection or beam gain, and shortened versions have narrow bandwidth. For stations on a limited plot, especially on 40 metres, or for operators who want a tool against interference, it is a sensible choice. Size the rotor generously, use a good balun, mount it as high as you can and keep a record of the useful null bearings.

Frequently Asked Questions

How much gain does a rotatable dipole have?

About the same as a fixed dipole at the same height, around 2.15 dBi in free space. Ground reflection changes the gain in each direction.

Is a rotatable dipole better than a Yagi?

Not for gain. A Yagi gives more signal on a target and rejects the back. A rotatable dipole is lighter and cheaper and has deep nulls for noise.

Can a rotatable dipole reduce noise?

Yes, if the noise comes from one direction. Turning a null toward the source can reduce it considerably.

What rotor do I need?

One rated above the weight and wind load of the antenna, with a margin. Check the manufacturer’s figures and use a sturdy mast and bearing.

Does a shortened rotatable dipole work well?

It works, but with a narrower bandwidth and a little more loss. It is a useful compromise where a full-size element is impractical.

Which bands suit a rotatable dipole?

It is common on 40, 30 and 20 metres, and multiband trap versions exist. On higher bands, a Yagi is small enough that it usually makes more sense.

Almost every radio amateur remembers the first time they heard a distant voice from a speaker that had no wires behind it. For a child, that moment can be even stronger, because the idea that a signal travels around the world without a phone or an app still feels like magic. The challenge is how to turn that spark into a lasting interest, since a lecture about frequencies and decibels will lose most young people within five minutes. Ham radio for kids works when it begins with doing and discovering, and when the theory arrives only as an answer to a question that the child has already asked. This guide gives ideas by age, simple projects, safe habits, ways to involve a school or a club, and a path to the exam.

Why Ham Radio Suits Young People

The hobby combines many things that children enjoy. It involves building and tinkering, it has a game-like element in contacts and awards, and it teaches skills in electronics, geography, languages and science without feeling like school. It is also social in a way that most screen activities are not. A child can speak to other young people in other countries, and a shy young person often finds that a microphone or a key makes conversation easier because the topic is clear. For many families it is also a shared interest, since parents and grandparents often have equipment in a drawer.

It is worth stating one limit clearly: the child does not need to love everything. Some will love building antennas, some will love Morse code and some will love logging contacts and chasing countries. Offer a taste of each, and let the interest choose its own direction.

Activities by Age

There is no fixed rule, but the following ideas fit different stages. The table is a starting point, and an adult should always supervise.

Keep each session short for younger children. Twenty minutes of activity with a clear result, such as a message sent or a contact logged, is better than an hour of explanations.

Ideas That Work

Start With Listening

A receiver is the cheapest first step. Let the child tune across a band and listen to voices, Morse code and the strange noises of digital modes. A web-based SDR that anyone can open in a browser lets a child hear stations across the globe without any equipment, and a small receiver of their own adds a feeling of ownership. Our overview of SDR receivers for ham radio lists simple options.

Play With Morse Code

Children often learn Morse code quickly because they like secret codes. Start with a few letters as sounds, not as dots and dashes on paper, and play games in which they send names or short messages to each other with a buzzer or a light. Our guide to learning Morse code describes methods that avoid the common traps. Keep it playful, and do not compare speeds.

Build Something

A first project should work in an afternoon. A simple wire dipole made from a few metres of wire and a connector teaches how length relates to frequency. A crystal radio, an LED flasher or a small kit with a few parts gives a child the satisfaction of a finished device. Soldering requires supervision, and a safe workspace, ventilation and eye protection are essential. The tutorial on soldering a PL-259 connector is a useful exercise for an older child, once the basic soldering skill is in place.

Take Part in a Special Event

Events remove the cost of a first station. Many clubs run public demonstrations, field days and special event stations that welcome visitors, and a child who sits at the microphone with a friendly operator can make a contact within minutes. An annual scouting event is a good example, and our article on Jamboree on the Air describes how scouts and guides talk to each other by radio around the world.

Chase Something Fun

Games with a clear goal keep attention. A fox hunt, in which participants find a hidden transmitter with a directional antenna, is physical and exciting. A scavenger hunt for countries, grid squares or prefixes turns logging into a collection game. Even a simple paper map with pins for each contact gives a visual reward that grows over time.

A Simple First Weekend

If you want a concrete plan, try the following for a first weekend with a child aged ten or older. On Saturday morning, spend half an hour listening, either on a small receiver or through a web SDR, and write down every callsign and country that the child hears. In the afternoon, build a simple wire antenna in the garden or at a window, using a plan from a club or a book, and check it with a receiver to see whether signals have become louder. In the evening, learn five Morse letters and send each other short words with a flashlight. On Sunday, visit a club, a special event or an online net, so that the child hears real operators and meets other young people. Finish by writing the weekend’s results on a map or in a notebook. That small record of what they heard and made becomes the first page of a personal station log, and it gives them a reason to come back next week.

Whatever you plan, leave space for the child’s own ideas. A question such as “why did the signal get louder when we moved the wire?” is worth more than a prepared explanation, because the answer will be remembered. If you do not know the answer, say so and look it up together. Children respect an adult who admits what they do not know, and the habit of finding answers is exactly what the hobby rewards.

Keeping Teenagers Interested

Teenagers are different from younger children. They value independence, they compare the hobby with a dozen other things on their phone, and they leave quickly if it feels like a school subject. The best approach is to offer challenges and responsibility. Give a teenager a job at the club station, such as running the logging software or organising a contest entry. Introduce modes that feel modern, such as digital modes, satellite passes, remote stations and software defined radio, where the technical side overlaps with what they already enjoy. Let them find a group of peers, whether at a youth camp, an online chat or a national youth event, because a hobby that has friends in it survives much longer than one that does not.

It also helps to connect the hobby to a future path. Skills in radio, electronics, programming and antennas appear in engineering, aviation, emergency services and science, and a licence is a credible item on an application. Many professionals in these fields began as teenagers with a callsign and a wire in a tree. You do not need to push this idea, but a short mention that the hobby has a future often turns casual interest into commitment.

Safety and Good Habits

Children should learn from the start that radio is fun and also something that requires care. The most important rules are simple.

• Stay away from power lines. No antenna should ever be installed near overhead wires, and children should not help to raise masts or climb towers.
• Use low power and sensible distances. This keeps exposure low and teaches good practice. Our article on RF exposure and safety explains the principles.
• Be careful with soldering irons and tools. Use an adult’s guidance for hot tools and sharp parts.
• Protect personal information. A callsign is public, but the child should not give out an address, a school name or a daily schedule on the air.
• Treat the band like a public place. Teach the child to be polite and to ignore rude stations, and ask an adult for help if someone behaves badly.

Involving a School or a Club

A single child with a parent is a good start, but a group is more motivating. A school can start a radio club with a few kits and an experienced volunteer, and many national societies provide materials for teachers. The youth pages of the ARRL are one example of resources that include activity ideas and lesson material. International organisations also support young operators, and the IARU links the national societies, many of which run youth programmes and events.

A club can help in several practical ways. It can offer a station that the young person may use under supervision, run a short course for the exam, provide a mentor and organise an outing or a contact with another school. Our article about recruiting new members contains ideas that clubs can use to welcome young people and their families, such as a regular beginner evening and a loan of equipment. A club that treats a twelve-year-old as a real member, with a job and a say, keeps them far longer than a club that treats them as a guest.

Preparing for the Exam

When a young person wants a licence, the exam is the next step. The rules differ between countries, including the minimum age, the structure of the exam and the privileges of each class, so check with your national society or regulator. Our article on exam classes explained gives a general picture. A few principles help in any country.

1. Use question pools and practice tests in a short daily routine, so that the learning is steady and not a last-minute rush.
2. Link each topic to something practical. A question about a dipole is easier to remember after building one.
3. Study together. A friend or a parent who asks the questions makes it a game.
4. Do not rush. Passing at the first attempt is good, but failing once is part of learning and does not mean that the child is unsuited.
5. Celebrate the callsign. A first contact under the new callsign is a memorable event, so plan a special session for it.

Common Mistakes

• Starting with theory. Let curiosity come first, and explain the principle when the child asks.
• Doing everything for the child. Offer help, but let them press the key, build the antenna and write the log.
• Expecting daily interest. Interest comes in waves, and a break is normal.
• Buying expensive equipment too early. A simple receiver and a few kits are enough until the interest is confirmed.
• Forgetting other young people. A friend of the same age doubles the fun, so invite one.

The Bottom Line

Ham radio for kids is most successful when it feels like play with a purpose. Start with listening and short games, add a small building project, take part in a special event, and let the child choose the direction. Keep sessions short, supervise safely, connect with a club or a school and let the exam grow out of real interest. A child who has built an antenna and heard an answer from far away needs no further motivation, and the skills they gain last for a lifetime.

Frequently Asked Questions

How old should a child be to start ham radio?

Children can listen and take part in activities at a young age with adult help. Licence rules and minimum ages differ by country, so check your own regulator.

Can a child use ham radio without a licence?

In many countries a child can operate under the supervision of a licensed operator who takes responsibility for the station. Check your national rules.

What is the best first project?

A simple wire antenna or a small kit that works in an afternoon. A finished, working device motivates more than a long project.

Should a child learn Morse code?

It is not required for most licences today, but many children enjoy it as a code game, and it is a useful skill for weak-signal operating.

How can a school start a radio club?

Find a local club or volunteer, use a simple receiver and a few kits, and ask the national society for teaching materials. Special events and contacts with other schools keep interest high.

How much does it cost?

Listening and kits cost little. A first licence needs study material and an exam fee, which varies by country, and a transceiver can wait until the interest has been shown.

Most radio amateurs know voice, Morse and data modes. Far fewer have tried to send live video, yet amateur television is one of the oldest and most rewarding branches of the hobby. A camera, a transmitter on a microwave-friendly band and a simple receiver are enough to show a friend across the valley what your hands are doing at the bench, to share a view from a balloon or a rocket, or to run a club demonstration that people remember. The field has changed a lot in recent years. Analog television, which needed several megahertz of bandwidth and a lot of power, has been joined by digital amateur television, which uses the same modulation as satellite television, works with much less power and is built on cheap hardware. This guide explains the options and how to start.

What Amateur Television Is

Amateur television, usually shortened to ATV, means the transmission of moving pictures and sound by radio amateurs on the bands where the rules allow it. The overview of amateur television describes its history and its different forms. Video needs far more bandwidth than voice, so ATV is found on the upper bands, usually 70 centimetres and above, where there is enough space. In practice, the most common bands are 70 centimetres, 23 centimetres, 13 centimetres and 3 centimetres, together with the satellite links described below.

Because the signals are wide, ATV is a line-of-sight activity at normal power, and range depends on height and the antenna, as our article on the basics of VHF and UHF operating explains. Distances of tens of kilometres are common with modest equipment and good antennas, and many clubs run ATV repeaters that relay pictures from a hilltop.

Analog and Digital Amateur Television

There are two families of ATV, and the choice affects everything you buy.

Analog ATV

Analog ATV uses the same kind of signal as old broadcast television. On 70 centimetres, it is often amplitude modulated with a vestigial sideband, with a bandwidth of about 6 to 7 MHz. On 23 centimetres and higher bands, frequency modulation is common, with a wide bandwidth of 15 MHz or more. The pictures are simple to generate with a camera and a transmitter, the receivers are cheap and the delay is short, which suits live demonstrations and fast-moving scenes. The disadvantages are the width of the signal, which limits the number of channels, and the fact that the picture degrades slowly as the signal weakens, which means snow and noise.

Digital ATV

Digital ATV, often called DATV, encodes the video and uses a digital modulation, commonly the DVB-S or DVB-S2 standard that is used by satellite television. The signal can be much narrower, from a few hundred kilohertz to a few megahertz depending on the symbol rate and the picture quality. The picture is either clean or gone, with little in between, but it holds on weaker signals than analog and it is more efficient in bandwidth. Digital transmitters can be built from inexpensive software defined radio modules and a small computer, and receivers are often low-cost satellite television tuners or an SDR. The main disadvantage is a delay of a fraction of a second to a second, caused by encoding and decoding.

Comparing the Options

The table summarises the main differences, so you can pick the approach that fits your station.

If you have a friend nearby with analog equipment, you may start there, but most new activity is digital, and DATV repeaters and satellite use are growing.

What You Need for a First Station

A basic digital ATV station has four elements, and a basic analog station needs the same ones in simpler form.

1. A camera and a microphone. Any camera with a video output, a webcam or a camera on a small computer will do. Good lighting improves the picture more than a more expensive camera.
2. An encoder and modulator. For DATV, this is usually an SDR transmitter or a dedicated board driven by software. A number of projects use a Raspberry Pi, and the British Amateur Television Club offers designs and software through its website.
3. A power amplifier and filter. Many low-power modules produce only milliwatts. An amplifier brings the level to a few watts, and a band-pass or low pass filter ensures that harmonics do not leave your station. Our guide on low pass filters explains why this matters.
4. An antenna and feed line. A directional antenna such as a Yagi or a dish gives the best results. At 23 centimetres and above, cable loss is severe, so keep the feed line short and use a quality type.

On the receive side, you need an antenna, a low-noise preamplifier if the path is long, a tuner or SDR with demodulation software and a display. The receive chain is often the cheaper half.

Choosing a Band

The band determines the antennas, the cable loss and the other stations that you can reach. The 70 centimetre band is shared with many other services, and signals are wide, so check your national band plan and the local ATV channels. The 23 centimetre band offers more space and better antenna gain for a given size, but cable loss is higher, and the band is shared with other users, so the channel choice matters. At 13 centimetres and above, a small dish gives great gain, and line of sight becomes critical. Our 70 centimetre band guide covers the equipment and propagation on the lower of the two bands, which is a good place to begin.

For satellite use, the geostationary QO-100 transponder offers a wideband channel that carries digital amateur television between stations in a large part of the world. Our article on QO-100 describes the equipment, which includes a small dish and a converter. The wideband transponder is one of the easiest ways to send DATV over very long distances, with no need for a tower or a hilltop.

Your First Picture

Start simple and build up. The first goal is to send a picture across the room, and then across the street, before attempting a long path.

1. Connect the camera to the encoder, set the resolution to a modest value and confirm that you see a picture on the local monitor.
2. Connect a dummy load or an attenuator to the transmitter output and check the signal with a receiver at close range.
3. Choose a frequency within the band plan and a symbol rate that suits the path. A lower symbol rate gives a narrower signal and a longer range, but a lower picture quality.
4. Add the callsign to the picture as an on-screen text overlay. Identification is required, and it also helps other stations.
5. Connect the antenna, move to a clear spot and test with a friend, with both stations pointing at each other.
6. Improve the path step by step, by raising the antenna, shortening the cable and adding a preamplifier at the receiver.

Take notes of the settings for each test, because the combination of symbol rate, error correction and picture size has a large effect on both range and quality.

Receiving and Reporting

Many people start on the receive side, because it is cheap and needs no licence. A DVB-S receiver, a low-noise block or preamplifier and an antenna are enough to watch repeaters and other stations in range. The quality of the received picture depends mainly on the signal margin, which is the difference between the signal level and the minimum that the demodulator needs. Most demodulators display a margin or a modulation error ratio, and watching this value while you move the antenna is the quickest way to improve the path. If you see the picture freeze or break into blocks, you are close to the edge, and a few decibels of gain from a better antenna or a shorter cable will restore it.

When you contact another station, report more than the word “picture”. Give the signal margin in decibels if your receiver shows it, the symbol rate in use and a short description of what you see, such as blocking, freezing or a clean picture. These details help the other operator to adjust the settings, and they make your own experiments repeatable. Over a few weeks of tests, you will build up a personal table of what works for each path, and that knowledge is the real reward of the mode.

Operating Practice and Rules

Amateur television follows the same principles as every other mode. Identify with your callsign, stay within the limits of your licence and the band plan, and listen before you transmit. The wide signal means that you can easily overlap other activity, so choose channels that are in use for ATV in your region, and avoid frequencies reserved for weak-signal work. Check your national regulations on the allowed power and bandwidth, and on content, since commercial or broadcast content is not allowed. Most clubs and the national societies publish local ATV channel lists.

Be thoughtful about interference. A wide signal on 70 centimetres can disturb other users, including repeaters and satellite links, if it is poorly filtered or too strong. Use only as much power as you need, and keep the antenna pointed at the other station and not into a neighbourhood. For a general overview of the issue, the guide to RF exposure and safety is a good complement, because microwave antennas with high gain concentrate power in a narrow beam.

Projects That Use ATV

Video opens the door to projects that are difficult with voice or data. A camera in a weather balloon payload sends live views of the curvature of the earth. A camera on a model rocket or an aircraft gives a first-person view, though you must follow the rules for the vehicle. A club can send a live picture of a field day station to a display at a public event. A repeater that shows the view from a mountain gives a weather camera for the whole region. And a simple link between the shack and the workshop shows a friend how to hold the iron while soldering. Each of these builds skill in antennas, amplifiers and filters in addition to video.

Common Mistakes

• Starting with a long path. Test across the room and across the street first.
• Using too much power. A clean low-power signal often works better than a distorted high-power one.
• Forgetting the filter. Wide, amplified signals produce harmonics that can disturb others.
• Using long, thin cable at 23 centimetres. The loss can be larger than the gain of the antenna.
• Not identifying. Add a text overlay with the callsign to every picture.

The Bottom Line

Amateur television is accessible to anyone with an interest in radio and a little patience. Analog ATV is simple and immediate, while digital ATV gives better range for the bandwidth and is where most development is happening. Begin with a short test across the room, add a filter and an amplifier, choose a band in line with your band plan, and move to longer paths with a directional antenna. When you are ready for something bigger, try a repeater, a club event or a satellite link. The first live picture from your own station is a memorable moment.

Frequently Asked Questions

What is the difference between ATV and DATV?

ATV usually means analog television, with wide signals and a gradual loss of quality. DATV is the digital version, which uses narrower signals and a picture that is either clear or lost.

Which bands are used for amateur television?

Most activity is on 70 centimetres, 23 centimetres, 13 centimetres and 3 centimetres, together with wideband satellite channels. Check your own band plan and licence for the allowed segments.

Do I need a special licence?

Television is generally allowed under an ordinary amateur licence on the bands that permit it, but the details differ by country, so check your national rules before transmitting.

How much power do I need?

Digital ATV works with a few watts or less on short paths. Longer paths benefit more from a directional antenna and a low-loss cable than from extra power.

Can I send ATV through a satellite?

Yes. The wideband transponder on the QO-100 geostationary satellite carries digital amateur television and can be reached with a small dish and a suitable converter.

What do I need to receive ATV?

An antenna, a low-noise amplifier on long paths, and a receiver such as an SDR or a satellite television tuner with software to demodulate the signal and display the picture.

Almost every HF transceiver has a button labelled P.AMP or PRE, and another labelled ATT. Many operators leave the preamp on all the time because it sounds like free sensitivity, and many never touch the attenuator because it sounds like a loss. Both habits are often wrong. On the lower HF bands, an HF preamp adds nothing except noise and overload, and an attenuator frequently makes a crowded band easier to copy. On the higher bands, in a quiet location, the preamp can reveal weak signals that were hidden. The difference comes down to one concept, the noise floor, and a five minute test on your own station shows which setting to choose. This guide explains the idea and gives you rules for each band.

What Limits Your Hearing

Three noises compete at the input of your receiver. The first is thermal noise, the unavoidable background of any electronic circuit, which sets a floor of about minus 174 dBm in each hertz of bandwidth. In a 500 Hz CW filter that is about minus 147 dBm. The second is the noise added by the receiver itself, described by its noise figure, which on a typical HF transceiver pushes the floor up by 10 to 15 dB. The third is external noise, which comes from the antenna: atmospheric noise from lightning around the world, galactic noise, and man-made noise from electronics, power lines and switching supplies.

On HF, the third is the largest by far at the lower frequencies. International studies of radio noise, summarised in ITU-R Recommendation P.372, show that the noise level falls as the frequency rises. At 3.5 MHz it can be 50 dB or more above thermal noise at a quiet rural site, at 14 MHz it is about 35 dB, and at 28 MHz around 25 dB. A residential area with many electronic devices is higher still. When the external noise is far above the receiver’s own noise, the receiver’s noise figure does not matter, because it is buried.

That is the whole principle. A preamplifier improves a weak signal only when the receiver’s own noise is a significant part of the total. If the antenna already delivers noise much larger than the receiver, a preamplifier raises signal and noise together, and the ratio stays the same.

How a Preamp and Attenuator Work

A preamplifier is a low-noise amplifier at the front of the receiver. It adds gain, typically 10 to 20 dB, and lowers the effective noise figure of the chain. Its price is a reduced tolerance of strong signals, because the amplified signals reach the mixer and the later stages at a higher level, where they may produce distortion. The receiver’s dynamic range is therefore reduced, a point explained in our article on receiver dynamic range, blocking and intermodulation.

An attenuator does the opposite. It reduces the level of everything that reaches the first stage, usually by 6, 12 or 18 dB, and it removes the strongest signals before they can overload the receiver. Because it reduces the signal and the antenna noise by the same amount, it does not change the ratio of signal to noise from the antenna, but it can lower the distortion products created inside the receiver by much more than it lowers the wanted signal. On a crowded band, that makes the wanted signal clearer.

A Simple Test for Your Own Station

The rule of thumb is easy to test. Choose a quiet moment on the band you want to check and follow these steps.

1. Select a frequency with no signal and set the mode and filter bandwidth that you use for weak signals, for example 500 Hz for CW or 2.4 kHz for SSB.
2. Turn off the noise reduction and noise blanker, and set the AGC to a fixed value or switch it off if your radio allows it, so that the meter reading is stable.
3. Note the S-meter reading with the antenna connected and the preamp off.
4. Turn the preamp on and note the reading again.
5. Disconnect the antenna, replace it with a dummy load and read the meter with the preamp on and off.

If the noise with the antenna rises by about 6 dB or more when the preamp is turned on, the external noise dominates and the receiver’s own noise is minor, which means that the preamp does little for weak signals. If the reading with the antenna connected is only a little above the reading with the dummy load, the receiver’s noise is a larger part of the total, and the preamp will help. A dummy load makes a good reference, and our guide to the dummy load explains how to choose one. The test is approximate, since S-meters are not precise instruments, but the difference is usually clear.

Band-By-Band Advice

The table shows typical starting settings for a modern station in a location with moderate noise. Adjust them to your own measurements.

The pattern follows the noise: the higher the band, the more useful the preamp. Local noise changes everything, though. In a noisy suburb with plasma televisions and chargers, a preamp will not help even on 10 metres. At a quiet rural site on the same band, it can be the difference between hearing and not hearing a weak beacon.

When an Attenuator Is the Better Choice

A strong signal in the passband, or several strong signals near the receiver frequency, generate false signals and a raised noise floor inside the receiver. You can recognise this overload by a hiss or a rough sound that appears when a strong station comes on and disappears when it stops, by signals that seem to appear in several places, or by an S-meter reading that jumps when you turn the preamp on. Switching in 6 or 12 dB of attenuation often cleans this up at once. You lose a little of the weak signal, but the receiver’s distortion falls much faster, so the result is better.

The attenuator is particularly useful in a contest or a pileup on 40 and 20 metres, at night on the low bands and in a multi-radio station with another transmitter nearby. It is also useful for judging a signal, because turning it on tells you how strong the signal really is. If a station is still readable with 18 dB of attenuation, it is a strong signal, and there is no reason to listen with maximum gain.

The same idea applies to the other receiver controls. A narrow filter, described in the article on receive filter bandwidth and roofing filters, removes strong signals that are not on your frequency. A well-set AGC prevents the audio from pumping. Using all of these together gives a much cleaner receive path than relying on gain alone.

Receiving Antennas and Low Gain

There is one situation on the low bands in which a preamp is valuable. Receiving antennas such as a Beverage, a small loop or a short active antenna may have a very low output level, much lower than a full-size transmitting antenna. A Beverage is directional and rejects noise, but its signal level can be 10 to 20 dB or more below that of a dipole, so the signal and noise from the antenna may fall below the receiver’s own noise. A preamplifier then restores the level, and the improvement in signal-to-noise ratio of the antenna system is real. This is described in our article on low band receive antennas. In this case the test above shows a small rise in noise when the antenna is connected, which tells you that the preamp is needed.

Use a low-noise design with good strong-signal behaviour for such a job, and consider placing it at the antenna, so that cable loss does not reduce its benefit. Many receiving antennas include an amplifier of their own, and adding another one in the radio can overload the receiver. Check the combined gain and use the attenuator if signals sound distorted.

Reading the Radio Menu

Radios label these controls in different ways, and the labels can mislead. Some models offer two preamp stages, often called P.AMP 1 and P.AMP 2, with different gain, and an attenuator with several steps. Yaesu radios use the term IPO, which stands for intercept point optimisation, and switching it on bypasses the preamp for better strong-signal handling. Other radios offer a separate RF gain control that reduces the gain of the front end continuously. Direct sampling receivers sometimes include a digital gain setting or a dither option, which has a similar purpose. Read the manual for each setting, because the same name can mean different things on different models.

A practical approach is to make a small table of your preferred settings for each band, with the preamp, the attenuator and the RF gain, and keep it near the radio. Many transceivers can store these settings in band memories, so that the radio returns to the right choice when you change band. Update the table once or twice a year. You will notice that the best setting changes with the season and with the noise level in your neighbourhood, and that the table reminds you to check it.

Overload Symptoms and Fixes

• Rough or harsh sound when a strong signal appears. Switch on the attenuator, turn off the preamp, or reduce the RF gain.
• Signals that appear in several places. These are intermodulation products. Reduce the gain and narrow the filter.
• A noise floor that rises on a busy band. This is usually receiver overload, not propagation. Test with the attenuator.
• Clicks and pops from a nearby transmitter. Use a band-pass filter or a stub filter on the second radio.
• Preamp helps on one antenna and not on another. The antenna with the lower noise benefits, which is normal.

Common Mistakes

• Leaving the preamp on for every band. On the low bands it adds overload and no sensitivity.
• Judging by loudness. A louder signal is not a better one. Compare the signal to the noise, not the volume.
• Ignoring the attenuator. It is one of the most effective tools in a crowded band.
• Adding gain to solve a noise problem. If the noise comes from your own house, find and fix it, as our guide to finding RF noise in a modern home describes.
• Testing only once. The result changes with the band, the hour, the weather and the season.

The Bottom Line

An HF preamp helps only when the receiver’s own noise is a significant part of what you hear, which means on the higher HF bands and at quiet locations, or when a very low-level receiving antenna is used. On 160, 80 and 40 metres it usually does nothing useful, and an attenuator is often the better switch when the band is busy. Run the five minute test on each band with your own antenna, write down the result, set the radio accordingly and revisit it when the noise at your location changes. The right setting is the one that gives the best readability, not the loudest sound.

Frequently Asked Questions

Should I leave the preamp on all the time?

No. Use it on the higher bands and in quiet locations when the test shows that it helps, and leave it off on the lower bands where external noise is much higher than the receiver’s noise.

Why does the preamp make no difference on 80 metres?

Atmospheric and man-made noise on 80 metres is far above the receiver’s own noise, so a preamp raises signal and noise together and the ratio does not improve.

What does the attenuator do?

It reduces all signals entering the receiver by a fixed amount, which lowers overload and intermodulation caused by strong stations and can make weak signals easier to copy.

How do I know if my receiver is overloaded?

Signs include harsh distortion when a strong station is present, false signals that move when you change the gain, and a noise floor that rises when you turn the preamp on.

Is a preamp useful with a Beverage antenna?

Often yes, because the antenna has low output and the receiver’s own noise may then matter. Test it and use the attenuator if strong signals cause problems.

Can the noise blanker replace the attenuator?

No. The noise blanker removes short impulse noise, while the attenuator reduces overload. They solve different problems and can be used together.

Why does a 5 watt handheld reach a repeater twenty kilometres away from one hilltop but fail across a town from the bottom of a valley? Why does a station with a modest antenna on a tall mast beat a high-power station in a basement? The answer is the radio horizon. On VHF, UHF and the microwave bands, signals travel mostly in straight lines, and the curve of the earth and the terrain in the way decide how far they go. Antenna height matters more than almost anything else, and the calculation is simple enough to do in your head. This guide explains the radio horizon, gives the formula and a table of typical distances, shows what else steals range, and lists practical ways to extend it.

What the Radio Horizon Is

The earth is curved, so a transmitting antenna and a receiving antenna at ground level eventually drop out of sight of each other. The distance at which they can no longer see each other directly is the horizon. For light, it is the optical horizon. For radio, it is a little farther, because the atmosphere bends radio waves slightly downward. The radio horizon is therefore about 15 percent beyond the optical one in normal conditions.

The bending is expressed with an effective earth radius factor, usually written as k, with a typical value of about 4/3. Engineers calculate with an earth that is 4/3 as large as the real one, and the waves then travel in straight lines over it. This simple trick is the origin of the formulae that follow.

The horizon is not a hard limit. Signals continue past it, but they weaken quickly, because they are diffracted around the curve of the earth or scattered by the atmosphere. A good receiver can still hear a weak signal beyond the horizon, and special conditions such as ducting, described in our guide to tropospheric ducting, can extend the path to hundreds of kilometres.

The Formula

For a standard atmosphere, the radio horizon distance from one antenna is approximately:

• In kilometres: distance is 4.12 multiplied by the square root of the antenna height in metres.
• In miles: distance is 1.23 multiplied by the square root of the antenna height in feet.

For a link between two stations, add the horizon distances of both antennas. A station at 30 metres and a handheld at 2 metres therefore have a maximum line-of-sight path of about 4.12 times the sum of 5.48 and 1.41, which is roughly 28 kilometres. The square root has an important consequence. To double the range of one antenna, you must quadruple its height. That is why a modest increase from the roof edge to the top of a mast can change coverage noticeably, but going from a hilltop of 300 metres to 600 metres adds less than you might expect.

Range by Antenna Height

The table gives the radio horizon for a single antenna over smooth earth, using the standard 4/3 earth value. For a path between two antennas, add the two values. These are theoretical maxima, and obstacles reduce them.

The table shows why mountains and tall towers are the favourite sites for repeaters and for portable operation from a summit. It also shows how little a handheld can do at ground level: a link between two handhelds, each at 1.5 metres, has a theoretical limit of about 10 kilometres over flat ground, and it is usually far less in a town.

Three Worked Examples

Numbers make the formula easier to trust, so here are three common situations.

A handheld to a repeater. You stand in a field with the handheld at 1.5 metres. The repeater antenna is on a tower at 60 metres. The square root of 1.5 is 1.22 and the square root of 60 is 7.75, so the sum is 8.97, and multiplied by 4.12 gives about 37 kilometres. Over flat country, the link can be that long. In a town with buildings, the practical range may be a third of that, which is why a handheld that works in the field may be useless in a street.

Two mobile stations. Each has a magnetic-mount antenna at 2 metres on the roof of a car. The square root of 2 is 1.41, twice that is 2.83, and the result is about 11.7 kilometres. That is the usual range for simplex between two cars on open ground, and it matches what many operators see in practice.

A home station to a hill. You have a 12 metre mast and a friend operates from a hilltop at 250 metres. The square roots are 3.46 and 15.81, the sum is 19.27, and the horizon distance is about 79 kilometres. A modest station can therefore work a portable station on a summit that is far outside its own horizon, which explains why summit activations are so popular on VHF and UHF.

Weather and the Effective Earth

The factor of 4/3 is an average. When the air is cold near the ground and warm above it, the bending increases and the horizon moves farther away. When the air is unusually mixed, the bending decreases and the horizon shrinks a little. These changes are usually small, but they explain why a marginal link works on one morning and fails on another, and why VHF signals are often stronger in the early morning and on still, clear evenings. If you keep a log of signal strength from a distant repeater, you will see the pattern, and it is a good way to learn how local weather affects your paths. For anything that must work every day, leave a margin of several decibels above the minimum so that a poor day does not cut the link.

What Steals Range Before the Horizon

The horizon is the best case. In practice, several things reduce the distance.

Terrain and Buildings

A hill, a building or a belt of trees between the stations blocks or weakens the signal. At UHF, even a few trees or a wall cause significant loss, and a signal that is solid at VHF may be gone at 70 centimetres. Where the path is partly blocked, diffraction over the edge of an obstacle helps at lower frequencies, which is why 2 metres usually does better than 70 centimetres in difficult terrain.

The Fresnel Zone

The signal travels in an elliptical region around the straight line between the antennas, not only along the line itself. If an obstacle intrudes into the first Fresnel zone, the signal drops even though the direct line is clear. A rule of thumb is to keep about 60 percent of the first zone free of obstacles. For long links, this often means that the antenna must be higher than a simple line-of-sight sketch suggests.

Feed Line Loss

A tall mast is no help if the cable wastes half of the power. At 145 MHz and at 435 MHz, the loss of thin coax over 20 or 30 metres is large. Our guide to choosing coax for ham radio gives the numbers, and a low-loss cable can recover several decibels. A short, thick cable on a lower mast often beats a long, thin cable on a high one.

Polarization and Antenna Pattern

A vertical antenna on the transmit side and a horizontal one on the receive side lose a large part of the signal. Antenna patterns also matter, because a high-gain collinear squeezes its energy toward the horizon, which is useful for a repeater but not for a station on a hill that wants to reach a valley below.

Practical Ways to Extend Your Range

1. Raise the antenna. Height is the cheapest improvement, and mast sections, a chimney mount or a place on a hill all help. Follow the safety advice in our article on push-up masts and guying.
2. Use low-loss cable. Replace thin coax with a better type and keep the run short.
3. Use a better antenna. A Yagi or a collinear adds gain in the direction you need, and the effect is like adding transmitter power, but without the cost.
4. Match the polarization. Use vertical for FM and repeaters and horizontal for weak-signal SSB and CW.
5. Add a preamplifier at the antenna for receive-only improvement, as described in our guide to mast-mounted preamplifiers, if your receiver is limited by cable loss.
6. Choose a better location. A short walk to the top of a hill or the edge of a building can open a path that was blocked before.

Using the Horizon in Your Planning

The horizon helps in several practical situations. When you plan a portable operation, choose a summit or a clear ridge with a view toward the stations that you want to work, and estimate the range with the table. When you set up a link or a simplex net, decide who needs to be on a high point and who can stay below. When you look for a repeater, check whether its tower height and your location give a clear line, and if not, aim a directional antenna at the repeater instead of using an omnidirectional one. For event work, such as a marathon or a field day, a few high-placed stations can relay for the rest, which reduces the need for expensive equipment. Finally, when you test a new antenna, do it on a day with normal conditions and compare to an earlier reference, so that a temporary lift does not mislead you.

Basic operating practice is covered in our article on VHF and UHF simplex and repeater operating, and the horizon explains most of the situations that it describes.

When Signals Go Beyond the Horizon

Sometimes the calculation fails in your favour. A temperature inversion near the ground can create a duct and carry signals for hundreds of kilometres. Meteor trails reflect VHF signals briefly, and a sporadic E layer can give VHF contacts over thousands of kilometres. Mountain ridges can scatter weak signals in the knife-edge effect. None of these is reliable, and a link that you depend on should work under normal conditions. Use the horizon figures for design and treat everything beyond them as a bonus.

Common Mistakes

• Spending on power instead of height. A higher antenna usually beats a stronger amplifier on VHF and UHF.
• Ignoring cable loss. A long run of thin coax can waste most of the gain of a tall mast.
• Forgetting the second station. The range depends on both ends, so a low handheld limits a link with a high repeater.
• Assuming flat ground. Hills, buildings and trees block the path long before the geometric horizon.
• Treating a duct as normal. Unusual openings are fun, but they cannot support a reliable link.

The Bottom Line

The radio horizon explains most of what you see on VHF and UHF. The distance in kilometres is about 4.12 times the square root of the antenna height in metres for each end, and you add the two. Height beats power, thick cable beats thin cable, and a clear Fresnel zone beats a clear line drawn on a map. Estimate the range with the table, raise the antenna where you can, choose a good spot, and keep unusual propagation for the days when it appears.

Frequently Asked Questions

What is the radio horizon?

It is the distance at which two antennas lose line of sight because of the curve of the earth, extended slightly because the atmosphere bends radio waves downward.

How do I calculate the radio horizon?

Use 4.12 times the square root of the antenna height in metres to get kilometres, or 1.23 times the square root of the height in feet to get miles. Add the values for both stations.

Why is VHF and UHF range limited?

Signals at these frequencies are not reflected by the ionosphere in normal conditions, so they travel along line of sight and are blocked by the curve of the earth and by obstacles.

Does more power increase the radio horizon?

No. Power can help a weak signal be heard, but the horizon depends on antenna height and terrain, and beyond it the signal falls quickly.

Why does 2 metres go farther than 70 centimetres in hilly terrain?

Lower frequencies diffract better over edges and pass through trees and walls with less loss, so they often fill gaps that block higher frequencies.

Can I work beyond the horizon?

Sometimes. Ducting, sporadic E, meteor scatter and diffraction extend the path on some days, but they are not reliable for everyday links.

Most antennas are built for one band. A dipole, a Yagi or a vertical is cut to a length that suits a frequency, and it works well there and poorly elsewhere. The discone antenna breaks that rule. It is a strange-looking assembly of a flat disc above a cone, and it works over a frequency range of about ten to one, so a single antenna and a single feed line can serve the 2 metre band, the 70 centimetre band and a wide range of frequencies in between and above. This guide explains how the discone works, what gain and SWR to expect, where it is a good choice, where it is a poor one, and how to mount it and protect your receiver.

How the Discone Is Built

The antenna has two parts. The disc is a flat circle or a ring of rods on top, and the cone below it points downward, with its narrow end near the disc. The coaxial feed line runs up through the center of the cone. The center conductor connects to the disc, and the shield connects to the cone. The two parts are kept apart by a small insulator at the feed point.

The design is described in the article on the discone antenna, which also notes that it was developed in the 1940s. The principle is that the cone acts as a gradual transition from the feed line to free space, similar to a horn. Because there is no sharp resonance, the antenna presents a fairly constant impedance over a wide range of frequencies. The lowest usable frequency is set by the size of the cone. The slant length of the cone should be about a quarter of a wavelength at that lowest frequency, and the disc diameter is a little smaller than that. Above the low frequency limit, the antenna simply keeps working until the dimensions become large compared with the wavelength.

Because the elements are made from rods in many commercial models, the antenna is light and has little wind resistance, which is a benefit on a mast.

What Performance to Expect

The discone is a compromise antenna, and it is best to know the numbers before you rely on it.

• Pattern. Omnidirectional in the horizontal plane, with vertical polarization. There is no beam and no rotor.
• Gain. Roughly in the range of 0 to 3 dBi, depending on the frequency and the design. At the highest frequencies the pattern tends to tilt upward, which reduces the signal toward the horizon.
• SWR. Typically below 2 to 1 over most of the rated range, but often higher near the low end and at special frequencies. Always check the actual SWR on your own bands with an analyzer.
• Bandwidth. Ten to one is a common figure, for example from about 100 MHz to 1 GHz or more, depending on the model.
• Efficiency. Good, because there are few losses in the structure, but it cannot give the gain of a tuned antenna.

If you want to compare the number with other antennas, our explanation of dBi and dBd shows how to convert and what the figures mean in practice. A gain of 0 to 3 dBi is similar to a basic dipole, so you should not expect a big signal advantage over a simple vertical. The benefit is coverage.

Where a Discone Is a Good Choice

The antenna shines in situations in which you need many bands from one place.

Software Defined Radio and Scanners

A wideband receiver covers a huge range, and a wideband antenna matches it. For a receiver of the type described in our guide to SDR for ham radio, a discone allows you to listen to the amateur bands, air band, public safety, weather stations and broadcast signals with one cable. This is the most common use, and it is where the antenna is particularly good value.

Monitoring and Testing

A discone is useful for monitoring repeater and simplex activity across VHF and UHF, for testing handheld radios and for checking a signal at several frequencies without changing antennas. It also helps in a club shack, where several people want a general-purpose antenna for demonstrations.

Transmitting on More Than One Band

Many operators use a discone for 2 metre and 70 centimetre FM and simplex. The SWR is usually acceptable on both bands, and the antenna is much simpler than a pair of separate verticals with a diplexer. For the 2 metre bands, our overview of the J-pole, collinear and ground plane antennas gives the alternatives, and the 70 centimetre guide covers the higher band. A discone gives less gain than a collinear, but it avoids a second antenna.

Where It Is a Poor Choice

The discone is not a universal solution, and the limits are worth knowing.

• Weak-signal work. For meteor scatter, tropospheric ducting or satellite use, you want gain and, for some modes, horizontal polarization. A discone gives neither.
• Heavy interference. A wideband antenna delivers all the signals in its range to your receiver, including powerful broadcast and paging stations. Overload and intermodulation are common with simple SDRs unless you use filters.
• HF. A discone for VHF and UHF is far too small for HF. Large discones for lower frequencies exist, but they are impractical for most stations.
• Directional work. There is no beam, so you cannot reject a nearby interferer by turning the antenna.
• Horizontal polarization. Weak-signal SSB and CW on VHF is usually horizontal, and a vertical discone suffers a polarization loss against such stations, as our guide to vertical and horizontal polarization explains.

Checking the SWR Yourself

Published figures describe a typical sample, and your installation will differ. The mast, the nearby roof, the cable and the connector all change the result. After installation, sweep the antenna with an analyzer across the range that you plan to use, and note the standing wave ratio at the centre of each band that matters to you. Our guide to the NanoVNA and calibration sweeps describes how to do this with a low-cost instrument. Expect the curve to show some peaks and dips, because a discone is never perfectly flat. What you need is an acceptable value on your own bands, and a stable trace that does not change when you move the cable, which would point to common-mode current on the shield.

If the SWR is high on one band, try a few simple changes before you blame the antenna. Check the connector and the center pin for corrosion, replace a damaged jumper, move the antenna a little away from the mast or a nearby metal object, and add a ferrite choke to the cable below the antenna. Many reported problems turn out to be a bad connection, which is a much cheaper fix than a new antenna.

Building a Simple Discone

Because the geometry is forgiving, a discone is a popular construction project. A common approach uses a disc cut from aluminium or copper sheet, or a ring of eight to sixteen rods, and a cone made from the same material or from rods. The size is chosen for the lowest frequency of interest: the slant length of the cone is about a quarter of a wavelength at that frequency, and the disc diameter is about 70 percent of that length. For example, a design for 100 MHz would have a slant length of roughly 75 centimetres. The feed point is an SO-239 or N connector at the narrow end of the cone, with the center pin joined to the disc through a short, rigid connection.

Rods are easier to make than solid surfaces and weigh much less, and they work almost as well. Use stainless or plated hardware, avoid mixing metals that corrode against each other, and seal the feed point well. Test the antenna with an analyzer before you put it on a mast, and adjust the spacing between the disc and the cone by a few millimetres if the match is poor. A homemade discone will not match a professional model in all respects, but it is a pleasant weekend project that teaches a lot about wideband antennas.

Choosing a Discone

When you shop, compare a few details. The table summarises the main choices.

Cheap models sometimes have poor connectors or thin parts that corrode quickly, so inspect the feed point and the quality of the weather seal before you install it. A discone that is made for receiving only may use a thin center insulator that cannot take transmitter power.

Mounting and Feed Line

A discone should be mounted as high as practical, with a clear view in all directions, because VHF and UHF signals travel by line of sight. Keep it away from other antennas and metal structures, at least a wavelength at the lowest frequency if possible, because nearby metal distorts the pattern. Mount it on top of a mast, so that nothing is above the cone.

The feed line matters more than usual, because the loss at VHF and UHF is significant. A long run of thin cable can waste half of the signal at 70 centimetres. Use a low-loss type, and keep the run short. Our comparison of coax for ham radio gives typical loss figures. Seal the connections with self-amalgamating tape and mastic, and add a drip loop where the cable goes into the building. Finally, install a lightning arrestor or a proper ground at the entry point.

Protecting the Receiver

Because a discone is a wideband antenna, it also hears strong signals that a tuned antenna would reject. This is the main source of complaints from SDR users. Four measures help.

1. Add a broadcast FM notch filter. The very strong FM broadcast signals around 100 MHz overload many wideband receivers.
2. Use a band-pass filter for the band you are using, for example 144 to 148 MHz, when you need the best sensitivity on one band.
3. Reduce the gain. Lowering the gain in the SDR often removes ghost signals caused by overload.
4. Do not add a preamplifier automatically. Most strong-signal problems get worse with more gain, and a short, low-loss feed line is a better start.

If you transmit on a band, make sure the receiver has a protected input or a separate antenna, because a transmitter nearby can damage an unprotected SDR.

Common Mistakes

• Expecting beam-like performance. A discone has about the gain of a dipole and no more.
• Mounting it too low. Obstacles at VHF and UHF cost a lot of signal, so height pays.
• Using thin cable on a long run. Cable loss can cancel any benefit of the antenna.
• Neglecting filters. Without a notch for FM broadcast, a simple SDR often shows false signals.
• Skipping the weatherproofing. Water in a connector ruins the antenna, so use tape and mastic.

The Bottom Line

A discone antenna is a simple, rugged way to cover VHF and UHF with one feed line. It is not a high-gain antenna, but it is an excellent partner for an SDR or a scanner and a good general-purpose choice for FM on 2 metres and 70 centimetres. Mount it high and clear, use low-loss cable, protect the receiver from strong broadcast signals and choose a tuned or directional antenna when you need weak-signal performance. For monitoring, testing and general listening, few antennas offer so much coverage for so little effort.

Frequently Asked Questions

What frequency range does a discone cover?

Typically about ten to one, for example from around 100 MHz to 1 GHz or more. The exact limits depend on the size of the cone and the quality of the design.

Can I transmit with a discone antenna?

Yes, if the antenna is rated for transmitting and the SWR is acceptable on your band. Check the power rating and the connector, and measure the SWR before use.

How much gain does a discone have?

Roughly 0 to 3 dBi, similar to a simple dipole. It is chosen for bandwidth and not for gain.

Is a discone good for SDR reception?

Yes, it is one of the most popular choices. Use a notch for FM broadcast and reduce the gain if you see false signals.

Does a discone work on HF?

No. A VHF and UHF discone is far too small for HF, and an HF discone would be very large.

What polarization does a discone use?

Vertical, when mounted upright. This suits FM and repeater work but costs some signal against horizontally polarized weak-signal stations.

Anyone who has listened to a skilled CW operator in a contest has heard something that sounds almost like a conversation: the other station can interrupt, a caller drops in the moment a gap appears, and nobody waits for the end of a transmission before reacting. That behaviour has a name. Full break-in CW, also called QSK from the Q code that means “I can be heard between my signals”, switches the transceiver to receive between the individual elements of your sending, so that you listen to the band while you key. This guide explains how it works, how it differs from semi break-in, what equipment it needs, how to adjust the delay and sidetone, and how to run it with an amplifier without damaging anything.

What Break-In Means

When you press a key, the transmitter must be switched on, the antenna must be connected to it and the receiver must be protected. When you release the key, the process reverses. How quickly this happens defines the type of break-in.

With manual transmit and receive switching you press a push-to-talk button, send your message and release it, which is slow but simple. With semi break-in the radio switches to transmit at the first element and stays in transmit for a short hang time after the last one, so that it does not click between letters. With full break-in the radio returns to receive in the gaps between elements, so for a fraction of a second after each dot you are actually listening.

The practical result is that on a clear frequency you can hear the other operator, a new caller or a QRM signal appear in the gap, and you can stop sending at once. It makes CW feel more like speech.

Semi Break-In Versus Full Break-In

Both modes are useful, and neither is simply better. The table compares the main characteristics.

Semi break-in suits slow speeds and relaxed contacts. Full break-in rewards faster sending, at which the silence between your elements becomes shorter but the benefit of hearing the other side is larger.

How Fast the Switching Must Be

It helps to put numbers on the problem. At 25 words per minute a dot lasts about 48 milliseconds, and the gap between two elements of the same letter is the same length. To hear anything useful in that gap, the station must disconnect the transmitter, connect the receiver, let the receiver settle and then switch back, all in a few milliseconds. At 35 words per minute a dot is only about 34 milliseconds long, and the switching budget becomes even smaller. That is why solid-state switching and fast relays are essential, and why a relay that takes ten milliseconds to close is of no use in a QSK chain.

Fast semiconductor switches such as PIN diodes can change state in microseconds, and modern transceivers use them or similar devices inside. The receiver then has to recover quickly from the strong signal that has just been present at its input. Good designs protect the first stage and use an audio mute that opens just in time, so that the listener hears the band and not a thump. The quality of this recovery is a large part of why one radio feels pleasant in QSK and another feels harsh, and it is worth checking in a review or on the air before you buy.

Why Operators Use QSK

There are several concrete advantages to full break-in, and they are the reason that many CW contesters rarely turn it off.

• You can be interrupted. If the other station sends a question mark, a repeat request or “QRS” in the middle of your message, you hear it and stop.
• You hear the frequency. When running, you notice at once if someone else starts transmitting on your frequency, which helps you to hold it or to move.
• You gain time. Callers who are waiting can start the moment you finish, and you can answer without a silent wait for the relay to release.
• You hear your own signal quality. A good QSK setup lets you hear the receiver in the gaps, which reveals noise bursts and QRM that you would otherwise miss.

The learning effect is real. After a few weeks with QSK, many operators find that semi break-in with a long delay feels slow and clumsy.

What Your Equipment Needs

Most modern transceivers offer full break-in as a menu option, because the switching is done by solid-state devices that react in a few milliseconds. The key components are described below.

The Transceiver

Look in the CW menu for a setting named break-in, with options such as off, semi and full. Some radios also let you adjust the “delay” or “hang” for semi break-in, in milliseconds or in steps. If your radio is older, check the manual for a QSK capability, because some early designs used relays that were not suitable for fast switching.

The Keyer or Computer Interface

The keyer must send timing that is clean at the speed you use. If you key through a computer, check that the interface passes the key line without added delay, as the guide to a CW keying interface with a WinKeyer or serial port explains. Latency in the software keyer can shift the switching and cause clipped first elements.

The Amplifier

This is where problems arise. A linear amplifier with an ordinary mechanical relay cannot follow QSK at higher speeds. The relay either chatters, wears out or does not close in time, and hot switching of power into a relay can damage its contacts. Options are an amplifier with a vacuum relay, an amplifier designed for QSK with a PIN diode switch, or a separate fast antenna relay. Our article on what to know before adding an HF amplifier covers the broader choice. If your amplifier is not QSK capable, use semi break-in with a delay long enough for the relay to settle, and avoid forcing it.

Setting the Delay and Sidetone

Even with full break-in, a few settings determine how comfortable the operation feels.

1. Set the keying weight and speed first. Poor timing at the keyer cannot be repaired by break-in settings.
2. Enable full break-in. Send a string of dots and listen for the receiver audio between the dots. If the radio is still in transmit, check that the option is not on semi.
3. Adjust the sidetone. A pitch of around 600 to 700 Hz is a common comfortable choice, and it should match the receive pitch to which you tune, as the article on zero beat and sidetone pitch explains.
4. Set the semi break-in delay if used. Choose a delay long enough to cover the gaps between letters at your speed, so that the radio does not chatter.
5. Lower the receive gain recovery time if available. Some radios offer an AGC or mute recovery option that determines how fast the receiver comes back after a transmission.
6. Test with headphones. The behaviour in the gaps is easier to judge through headphones than through a loudspeaker.

Running QSK With an Amplifier

The key rule is that nothing should be switched while power is applied. In a correct QSK chain, the transceiver controls the amplifier through a sequencer, so that the antenna relay changes before any RF appears and the amplifier is bypassed or muted when the transmitter is not keyed. Many QSK amplifiers use PIN diodes at the input and output, with timing set by the manufacturer, so that the amplifier follows the transceiver within a couple of milliseconds. Follow the manual, use the connection that it describes, and do not add a third-party relay in the keying line without checking the timing.

If you add a band-pass filter or a low pass filter in the transmit path, such as those in our guide to low pass filters, check that they are rated for the power and that they are not placed after a mechanical relay in such a way that the relay breaks power. Hot switching is the most common cause of relay failure in a QSK station.

Dealing With Relay Noise

An amplifier that does QSK with relays can be loud, and a rapid click at 30 words per minute becomes tiring. Several measures help. Choose a vacuum relay, which is faster and quieter than many standard types. Mount the relay on foam or rubber feet, so that the click does not carry through the desk. Place the amplifier on a shelf or on the floor, and put a short cover over the relay if the manufacturer allows it. Some operators move the monitoring to the headphones and keep the radio speaker off, which hides the sound of the shack and puts the receiver in the gaps. These changes do not alter the switching, but they remove the annoying part.

When Not to Use Full Break-In

QSK is a tool, and some conditions favour semi break-in. At very slow speed, the long gaps mean that the receiver is loud between elements, and the switching noise is distracting. When using a transmitter and amplifier that cannot follow it, forcing QSK shortens relay life. On a weak-signal contact with a very strong local station nearby, the receiver recovery after each element can produce clicks or desensitisation. Finally, if you use a radio with a long receiver recovery after transmission, the gain in hearing between elements may be small. In each case choose semi break-in with a modest delay and you lose little.

A Practice Routine

To get used to QSK, spend a week with it on every contact, even on the weekly practice contests. Start at a modest speed, so that you have time to notice the sound between elements. Ask a friend to break in on you during a test contact, by sending a single dit in a gap, and practise stopping at once. Then try it in a pileup or a sprint, where the benefit is largest. Within a short time the gaps become part of how you hear the band, and you will notice a missing break-in on any radio that does not offer it.

Common Mistakes

• Using QSK with an ordinary amplifier relay. The relay may be destroyed, and it will not follow high speeds.
• Setting a very short semi break-in delay. The radio chatters between letters.
• Ignoring the sidetone pitch. A mismatch between sidetone and receive pitch makes zero beating harder.
• Blaming the radio for keyer problems. Check the software latency in the interface first.
• Leaving the speaker on in a quiet room. Relay and switching noise is much less annoying in headphones.

The Bottom Line

Full break-in CW lets you listen to the band between your own elements, so you can be interrupted, hear a caller at once and keep a frequency with confidence. Most modern radios offer it as a menu option, and the main hardware limit is the amplifier, which needs a fast or vacuum relay or PIN diode switching. Set the keyer timing first, choose a comfortable sidetone, test with headphones and use semi break-in whenever your amplifier or conditions are not suited to QSK. A few evenings of practice are enough to make it feel natural.

Frequently Asked Questions

What does QSK mean?

QSK is a Q code that asks whether the other station can be heard between signals. In amateur practice it names full break-in, in which the receiver is active in the gaps between elements.

Is full break-in better than semi break-in?

For fast contacts and contests it usually is, because you hear the frequency in each gap. For slow, relaxed contacts or with equipment that cannot follow it, semi break-in is a sound choice.

Can I use QSK with any linear amplifier?

No. The amplifier needs a fast relay, a vacuum relay or PIN diode switching. Check the manual before enabling full break-in with an amplifier.

Why does my radio click when I use QSK?

Internal or external relays switch in each gap. Quieter relays, a foam mount or headphones reduce the sound, and some radios use solid-state switching without a click.

What sidetone pitch should I use?

Many operators choose between 600 and 700 Hz because it is comfortable for long sessions, but the right value is the one that you can copy easily and that matches your receive tuning.

Does QSK work with a computer keyer?

Yes, if the interface passes the key line with little delay. Check the software settings if the first element is clipped.

A DX cluster tells you what is on the air right now, and that is exactly why it is not enough on its own. By the time a rare station appears as a spot, you have no time to prepare, no time to check the antenna and no time to decide which band and mode deserve your attention. DX news bulletins work in the opposite direction. They tell you about operations days or weeks before they start, and they tell you how the team plans to operate, which is often more useful than the callsign itself. This guide explains the main kinds of source, what each is good at, how to read an announcement, and how to turn a stream of news into a short list of contacts that you actually try to make.

Why Bulletins Still Matter in the Age of Spots

Spots are a snapshot. A bulletin is a plan. If you know that a team will be on a remote island next month, that they carry two stations, and that they intend to focus on 40 and 30 metres at night, you can decide in advance what to prepare. You might raise a receiving antenna, clear a weekend, update your log with the entity that you need, or simply check the propagation path on a calendar of solar conditions. Without the bulletin you are reacting. With it you are choosing.

Bulletins also help you avoid the common mistakes. Operators often chase a callsign that is not new for them because they did not know which entity it counts for, or they miss the first days of an operation because they assumed that it began later. News gives the dates in UTC, the name of the entity and the way to confirm a contact afterwards. Our article on how to work a DXpedition describes the second half of this process, which is what to do when the station is on the air.

The Main Kinds of DX News Source

There are several families of source, and a sensible station follows one or two of each. None is perfect, but together they give a good picture of what is coming.

• Weekly bulletins by email. Several long-running newsletters collect announcements, QSL information and operating plans into one message every week. The Daily DX is a well-known example, and the OPDX Bulletin and the 425 DX News are others. Each has its own style, its own editors and its own network of contributors.
• Calendars of announced operations. The NG3K Announced DX Operations page lists operations by date, with the callsign, the location and links to the team website. It is the quickest way to see what is planned for the next few weeks.
• Team websites and social posts. The best source for an individual operation is the team itself. Its page usually has the schedule, the equipment, the QSL manager, the online request form and the live log.
• Logging and spotting services. Club-level and personal alert tools notify you when a wanted station is spotted, which complements the planning that a bulletin gives you.
• Club and national society news. Local reports on a national DX group or society page often include announcements that are of special interest in your region.

Most operators find that one weekly bulletin, one calendar and the website of each team that they care about is enough. More than that and the volume becomes tiring, and you start to skip the news altogether.

How a Typical Announcement Is Structured

Announcements follow a loose pattern. Learn it once and you can read any of them in a few seconds. The first line gives the callsign and the place, usually followed by the entity name in capitals, because the entity is what matters for DXCC. The next lines give the dates and the operators, then the bands, modes and the number of stations, and finally the QSL route and the link to the page of the team.

The dates deserve attention. They are almost always in UTC and they are almost always approximate for the end of the operation. Weather, transport and licence problems move arrival and departure by a day or two. A good habit is to put the start date in your calendar and to treat the end date as the earliest possible finish, so that you do not leave the chase until the last evening.

Also read what is not said. A listing that names no operators, no website and no QSL manager is often an early rumour and not a confirmed plan. A listing that includes a licensing note, a boat or aircraft booking and a team page is much more likely to happen.

Comparing Types of Source

The table below summarises what each kind of source is best for, so you can decide where to spend your attention.

The sources complement each other. The bulletin and the calendar tell you what to expect, the team website tells you how the operation develops, and spots and alerts tell you the moment to sit down at the radio.

Turning News Into a Plan

Information is only useful if it changes what you do. A short routine makes this easy.

1. Compare with your own list. Check each announced entity against your log. Our guide to how DXCC works explains the entity list and how to track what you need. Ignore what you already have confirmed on the bands that you use.
2. Rank by difficulty. A rare entity with two stations is a priority. A common entity with a large team is something you will work almost by accident.
3. Check the path. Look at the distance and direction from your location, and think about which hours should be open. A simple great circle map helps to see whether the path crosses the pole or the auroral zone.
4. Mark the calendar. Note the first possible day and the expected focus of the team, such as low bands or digital modes.
5. Prepare the alert. Add the callsign to your cluster filter or your alert tool, as described in our article about automating DX spot alerts.

With five minutes of work per announcement, you end up with a short list of targets for the month and not a long list of vague intentions.

Different Goals, Different Reading

A new DXCC chaser wants entities. A contester wants activity in a specific contest, with multipliers. A low band enthusiast wants to know who plans to be on 160 and 80 metres. A satellite operator wants rare grids. Read the same bulletin with your own goal in mind and you will find that most items are irrelevant and a few are essential. That is how you keep the volume manageable.

Reading Between the Lines

The wording of an announcement contains hints that experienced chasers learn to notice. Phrases such as “if the permit arrives” or “weather permitting” mean that the plan is conditional. A statement that the team will be active “on all bands” is not the same as one that lists the bands and the number of stations, because the second shows real equipment. A team with a record of earlier operations, a donated-funds statement and a clear schedule is more reliable than a first-time announcement with a short text.

Look also at the QSL information. A team that describes its logging system, the upload frequency and the online request process has thought about the end of the operation as well as the beginning. That makes it more likely that your contact will be confirmed with little effort.

When news conflicts, trust the team itself over any third-party report. A bulletin edits and forwards information, which means a delay and sometimes an error, while the team page is the primary source. If two bulletins disagree about the dates, check the team page and wait for an update before you change your plans.

Avoiding Rumours and Spam

Not every announcement is real. Some are optimistic plans that never get a licence, and a few are deliberate hoaxes. Four simple checks reduce the risk.

• Look for a primary source. A team page, a society announcement or a licensing authority note is better than a repost.
• Check the callsign format. The prefix must belong to the claimed entity, as our guide to callsign prefixes explains.
• Wait for confirmation of spots. If a callsign appears only in one spot and nobody can hear it, do not call endlessly.
• Be careful with QSL requests. Use the route that the team publishes on its own page, and do not send money to an address that you saw only in a comment.

Treat the quiet period before an operation as normal. Many teams publish little until they arrive on site, and that does not mean that the plan has been cancelled.

During the Operation

When the operation starts, switch from planning to action. Watch the team page for notes about schedule changes, because teams often switch bands according to propagation and post a short update. Use the live log search if the team provides one, to check whether you are already in the log on a given band before you call again. Do not ask for personal reports on the team page or social media; the operators are busy and the log will be uploaded after the end of the operation. Finally, remember that thanks and brief positive reports are welcome and that long chat or complaints about the operating style are not.

Keeping the Routine Light

The danger with any news habit is that it grows until it becomes a chore. Set a fixed time once a week, for example on the evening that your bulletin arrives, and spend ten minutes on it. Read the announcements, copy the interesting dates into your calendar and add the new callsigns to your alert list. Then close the message. Between those sessions, look at the news only when an operation that you care about is under way. This keeps the hobby enjoyable, and it ensures that your radio time is spent on contacts and not on reading. If you chase several awards, keep one simple text file with the entity, the dates and the notes, and delete each line when the operation ends.

Common Mistakes

• Following too many sources. You skim, miss the key item and stop reading.
• Treating end dates as fixed. Operations often end earlier or later than announced.
• Ignoring the time zone. The dates and times are UTC, which can shift the local day.
• Waiting for the spot. A planned approach lets you be ready on the first day, when pileups are smallest.
• Forgetting confirmation. Check how the team handles QSLs before the operation ends, as our guide to Club Log and OQRS shows.

The Bottom Line

DX news bulletins turn the cluster from a surprise machine into a planning tool. Pick one weekly bulletin, one calendar of announced operations and the team pages of the entities you need, compare them with your own list, and put the start dates in your diary. Read each announcement for the entity, the dates in UTC, the bands and the confirmation route, and check the team page whenever sources disagree. A few minutes a week is enough to make sure that the next rare station is a planned contact and not a missed one.

Frequently Asked Questions

What is a DX news bulletin?

It is a regular message, usually weekly, that collects announcements about DX operations, QSL information and other news for radio amateurs who chase distant stations.

Are DX news bulletins free?

Some are free and some are offered by subscription or with limited free access. Check each publisher’s own page for current terms before you decide which to follow.

How far ahead are operations announced?

Large expeditions are often announced months in advance, while smaller operations may appear only a few days before. The calendar pages are updated as new plans arrive.

Should I use bulletins or the DX cluster?

Use both. Bulletins and calendars give notice of what will happen, and the cluster shows what is happening now. Together they cover planning and action.

What time zone do bulletins use?

Almost all use UTC for dates and times. Convert them to your local time when you put them in a calendar.

How do I know an announcement is genuine?

Look for a team website, named operators, licensing information and a QSL route. When in doubt, wait for confirmation on the team’s own page.

When the band is noisy, the signal fades in and out or the path is disturbed by flutter, many digital modes simply stop decoding. A small group of keyboard-to-keyboard modes was designed to keep going in exactly these conditions, and the best known of them is Olivia MFSK. It trades speed for resilience: the text comes slowly, but it arrives, often when a signal is barely visible on the waterfall. This guide explains how Olivia and its relative Contestia work, what the numbers in a mode name mean, how to choose settings for a given band, how to set up fldigi and how to operate so that you get decodes without wasting bandwidth. It is for operators who already use a mode such as PSK31 or FT8 and want a tool for the difficult days.

What Olivia and Contestia Are

Olivia is a digital mode based on multiple frequency shift keying with strong forward error correction. It sends text by switching among a set of tones, and it spreads each character over many symbols, so that a burst of noise or a short fade destroys only a small part of the information, and the decoder can rebuild the rest. The mode was designed by Pawel Jalocha and is described in the article on Olivia MFSK, where its tolerance of negative signal-to-noise ratios is discussed. Depending on the settings, a decoder can copy signals that are well below the noise level in a normal speech bandwidth.

Contestia is a close relative. It uses a similar structure, but with a smaller set of characters and shorter blocks, which makes it somewhat faster for a given robustness. The Contestia page summarises how it relates to Olivia. A third mode in the same family of robust choices is MT63, which uses many carriers at once and a long interleaver, and is covered in the MT63 article. All of them are keyboard modes: you type, the computer transmits and the other station reads the text on the screen.

Reading the Mode Name

Olivia and Contestia modes are written as two numbers separated by a slash, such as 8/250 or 16/500. The first number is the count of tones, and the second is the bandwidth in hertz. More tones in the same bandwidth mean slower symbols, which makes the mode more robust against timing disturbances such as multipath. A wider bandwidth for the same number of tones means faster symbols and a higher speed, but it also admits more noise. As a rule, a narrow setting with many tones is the choice for the weakest and most disturbed paths, and a wide setting with fewer tones is for stronger signals and faster exchanges.

Common Settings

The table compares the settings you are likely to meet, with some familiar modes for context. Bandwidths are approximate, and the practical result depends on conditions.

Our comparison in digital modes beyond FT8 gives more context on where each of these fits, and the guide to JS8Call describes the more automated approach to weak-signal keyboard messaging.

Setting Up fldigi for Olivia

Most operators use fldigi, because it supports Olivia, Contestia, MT63 and many other modes in one program. If you have not yet configured it, the guide to fldigi setup with sound card, rig control and macros covers the basics. The interface between the computer and the radio must also be sound, with isolation to avoid hum and noise, as described in the article on sound card interfaces and ground loops.

1. Select Olivia from the modes menu, and choose the tone and bandwidth setting, for example 16/500.
2. Set the audio centre frequency, which is usually about 1500 Hz, so that the whole signal sits in the middle of the receiver passband. With a 500 Hz mode, the tones span roughly 1250 to 1750 Hz.
3. Check the receiver filter. If it is narrower than the mode, part of the signal is cut off, so widen it or use the full SSB filter.
4. Look at the Olivia section of the configuration for the synchronisation settings, which control how tolerant the decoder is of frequency error and how long it integrates before it decides.
5. Turn on automatic tracking only if you need it, and use the ALC and audio level rules described below.
6. Enable the mode identification option if you want the other station’s program to switch to your mode automatically.

Keep the Level Low

A robust mode is also a power-hungry one, because it transmits continuously at constant amplitude. That is no reason to run high power. Keep the audio level low enough that the ALC shows no action, and reduce the output power if the transmitter runs hot. The mode works at low power precisely because the decoder is sensitive, and extra power brings splatter without extra copy.

Tuning and Finding Activity

The decoder needs to find your signal to within a small frequency error, and it needs a few seconds to synchronise. Tune a signal so that its tones appear centred in the waterfall, and wait for the first characters. If the text does not appear, check the settings, because a mismatch in tones or bandwidth gives no decode at all. Olivia signals look like a block of closely spaced tones with a distinctive sound, a warbling noise that rises and falls.

Activity is concentrated in the digital segments of the HF bands and around a few well-known frequencies, which change over time and between regions. Look at the band plan for your region, and check a recent source for the current gathering points. Scheduled nets and weekend operating events often use these modes, and a short call on the waterfall frequency usually draws an answer. If you want to know how well you are heard, ask the other station for a report and note the signal-to-noise figure that the program displays.

How to Operate

• Listen first. A mode with a wide signal and long transmissions needs a clear space. Check that the frequency is free for at least a minute.
• Send short messages. A speed of a few words per minute means a long message takes a long time. Keep transmissions compact and keep the exchange simple.
• Use macros. Prepare standard messages with your call sign, name, location and signal report, so that you do not type them slowly while the other side waits.
• Be patient. The decoder has a delay, and the text appears in blocks. Do not interrupt.
• Use the narrowest mode that works. A narrower signal leaves more room for others. Move to a wider setting only if the path demands it.
• Identify clearly. Give your call sign at the beginning and the end and follow the rules of your country.

When to Choose Olivia

Choose Olivia or Contestia when the path is difficult. They are a good choice on low bands with static noise, on paths with flutter such as those that cross the polar region, on crowded bands with weak signals and in emergency or expedition work where an exchange must get through. They are a poor choice when you want speed or when the band is busy and a wide signal will cause problems. For a quick contest exchange, RTTY or a faster mode is better. For automatic scheduled messaging, JS8Call has more tools. For most daytime chat on a clear band, PSK31 or a voice mode is simpler. Treat Olivia as a specialised tool: you need it only occasionally, but when you do, nothing else will do the job as well.

Why the Mode Is So Robust

Three ideas explain the performance. First, the signal is spread over many tones and a long time, so that a fade or a burst of static hits only part of the message. Second, the error correction adds redundancy, so that the receiver can reconstruct missing symbols from the ones that arrive. Third, the receiver correlates the incoming tones against all the possible patterns and chooses the best match, which works even when each individual tone is hard to see. The price of this approach is time: the receiver waits until a whole block has arrived before it decides, so the text appears in bursts, and the speed is low. Once you understand the trade, the settings make sense. A longer block and more tones improve the odds and slow the text, and a shorter block does the opposite.

Using Olivia for Messaging and Emergencies

The robustness makes these modes attractive for emergency and expedition messaging, where a short message must get through on a poor path with simple equipment. A message sent in Olivia can be received on a modest antenna in the presence of noise that would stop a speech contact. Groups that practise emergency communications often keep a robust keyboard mode in their toolbox, together with a link to email over radio, a topic covered in our article on Winlink gateways and modes. Agree the setting, the frequency and the schedule in advance, practise at least once a month and keep the text brief and structured so that the slow speed is not a problem.

A First Test Session

You can learn the mode without a partner. Start fldigi, choose Olivia 16/500 and listen on the digital segment of a band that is open, watching the waterfall for blocks of tones. When you see one, click on it, wait for the first text and note how long the decoder takes to lock. Try the same signal in a different setting and see what happens. When you are ready, find a friend, agree on a setting and exchange a short message. Two or three sessions like this teach the mode better than reading, and they give you confidence to call a station when conditions are poor.

Common Mistakes

• Mismatched settings. If the tones or bandwidth differ between the two stations, there is no decode. Agree the setting before you start.
• Overdriving the audio. A wide signal with distortion splatters across the band.
• Too narrow a receiver filter. The decoder never sees the whole signal.
• Using a wide mode when a narrow one will do. You waste bandwidth and cause interference.
• Not allowing time. The mode synchronises slowly, and you need to wait for the first block.
• Expecting speed. The mode is slow by design, and that is the price of its robustness.

The Bottom Line

Olivia MFSK and Contestia are the tools for the days when other modes fail. They use many tones and strong error correction to decode text far below the noise, at the cost of speed and bandwidth. Choose a setting such as 8/250 for the weakest paths or 16/500 as a general default, centre the signal on the waterfall, keep the audio level low and use short messages and macros. Agree the setting with the other station, listen before you transmit and use the narrowest mode that works. You will not use these modes every day, but when a path is disturbed, they let you keep the conversation going.

Frequently Asked Questions

What is Olivia MFSK?

A keyboard digital mode that uses multiple tones and strong error correction to send text reliably on weak, noisy or fading signals. It is slow but very robust.

What does 16/500 mean in Olivia?

The first number is the count of tones and the second is the bandwidth in hertz. So 16/500 uses 16 tones in a bandwidth of 500 hertz.

What is the difference between Olivia and Contestia?

Contestia is related to Olivia but uses shorter blocks and a smaller set of characters, which makes it somewhat faster for the same robustness.

Which software supports Olivia?

The program fldigi supports Olivia, Contestia and MT63, and other programs also offer them. Both stations need the same tones and bandwidth setting.

Is Olivia better than PSK31?

It depends. Olivia works much better on weak and disturbed signals, but it is slower and wider. PSK31 is more efficient on clear paths.

How much power do I need?

Very little. Low power with a clean signal works well, and extra power can cause splatter. Keep the ALC idle and the audio level low.

Few projects in amateur radio combine electronics, weather, geography and a good chase across country quite like a high altitude balloon flight. A latex balloon lifts a small payload through the weather to the edge of space, a radio beacon tells the world where it is, and a team on the ground follows the signal to recover the payload after it comes down. The same technology, in the form of foil pico balloons, can circle the globe for weeks. This guide explains how a flight works, which payload and radio you need, how to set up the tracker and APRS so that the signal is useful and polite, what the regulations require, how to plan a recovery and what to expect from a pico balloon.

How a Balloon Flight Works

A typical flight uses a large latex weather balloon filled with helium or hydrogen. As it rises, the pressure falls and the balloon expands until it bursts, usually at an altitude of around 25 to 35 kilometres. A parachute then slows the payload for the descent. The whole flight lasts a few hours. The ascent rate is a few metres per second, and the horizontal drift depends on the winds, which can carry the balloon a hundred kilometres or more from the launch site. The overview of high-altitude balloons and the page on weather balloons give the physics and history.

The conditions are harsh. The temperature in the upper troposphere falls to about minus 50 degrees Celsius or lower, the air is thin and the payload spins and swings. The batteries must keep working in the cold, the electronics must survive vibration and the antenna must remain connected. A flight is also an excellent test of radio range: at 30 kilometres the radio horizon extends some 600 to 700 kilometres in every direction, so a low-power signal can be heard by many stations at once.

Two Kinds of Balloon

The latex flight is the better first project, because the payload comes back and can be reused. Pico balloons are a more specialised hobby: the payload is tiny, the radio is a weak-signal beacon and the reward is a long flight that you follow online. The page on pico balloons describes the idea.

The Payload

A basic payload for a latex flight has five parts: a GPS receiver, a radio tracker, a battery, a parachute and an insulated box. Many people add a camera, a temperature and pressure sensor and a spare tracker in case the first one fails. Keep the total mass low, because mass affects regulations, the balloon size and the risk of injury or damage if the payload falls.

• GPS receiver. It must be set to a flight mode that allows operation at high altitude. Many consumer receivers limit altitude by default, and in that case they stop reporting at about 18 kilometres. A receiver with a high-altitude or airborne mode keeps working. Test the setting on the ground before you launch.
• Tracker. A small transmitter that sends the position at regular intervals. For amateur flights, an APRS tracker on a VHF channel is the common choice, since many receiving stations and gateways already exist.
• Battery. Primary lithium cells handle the cold better than alkaline ones and are lighter. Fit enough capacity for the whole flight, with extra for the time on the ground. Our article on battery options for portable operation compares chemistries.
• Antenna. A simple quarter-wave wire or a small dipole hanging below the payload is typical. Keep it away from the battery and the foam walls, and mount it so that it points down, where the receiving stations are.
• Insulation and recovery aids. A foam box protects the electronics from the cold. Add a label with contact details, and consider a small buzzer or light to help find the payload in a field.

Cameras and Extra Sensors

Most teams add a small camera, because the pictures from the edge of space are the reward that makes the project popular with schools and clubs. A compact action camera or a single-board computer with a camera module will do. Check that the memory card is large enough for the whole flight and that the battery lasts in the cold, and point the lens through a hole in the box so that frost does not form on a window. A temperature and pressure sensor adds useful data and helps you to see when the balloon bursts. Extra sensors should never delay the tracker or add weight that pushes the payload over a legal limit. If a feature is not essential for tracking and recovery, leave it for the second flight.

Setting Up APRS for a Balloon

Balloons use the same system as vehicles and fixed stations, described in our guide to APRS position reporting, igates and digipeaters, but they need special care because of their altitude. A balloon at 30 kilometres can be heard by dozens of digipeaters and gateways at once, and each of them may repeat the packet. If you use a long digipeater path, the result is a flood of duplicate packets on a busy channel. The common advice is to use a short path or none at all, and to send a beacon at a modest interval, such as every minute or two, rather than every few seconds.

1. Use the correct frequency for your region, which is 144.390 MHz in North America and 144.800 MHz in Europe.
2. Set the position beacon interval to about one to two minutes, and avoid more frequent reports.
3. Use a short or empty digipeater path, such as a single hop at most.
4. Send the altitude in the packet, and add telemetry for temperature, battery voltage and pressure if the tracker supports it.
5. Choose a call sign with a suitable suffix, and include a short comment with the project name.
6. Keep the output power low. A few hundred milliwatts is enough from altitude.

On the ground, your own receiver can decode the packets with a sound card and software such as the program described in our guide to Direwolf and packet radio TNCs. Public tracking sites collect the packets received by volunteer gateways and show the balloon on a map, which makes it easy for the team and for followers to watch the flight.

Regulations and Safety

A balloon is an aircraft in the eyes of the law, even if it is a small one, so you need to know the rules before you launch. Most countries regulate unmanned free balloons by weight and size, and some require notification of the aviation authority, a flight plan or a permit. In the United States, the relevant rules are in the aviation regulations on unmanned free balloons, found in Part 101, Subpart D, and other countries have equivalent regulations. Read them, check the current text and, if in doubt, ask the authority. Stay well under the weight limits for light payloads, avoid airports and busy air routes, and choose a launch site that is open and clear of power lines.

The radio side requires an amateur licence for the transmitting station, with a control operator who is responsible for the emissions. Keep the power low and follow the band plan. Handle the gas safely: helium is inert, but hydrogen is flammable, so use it only if you know the safety rules and have the correct equipment. Never launch in poor weather, in thunderstorms or with strong surface winds.

Predicting and Chasing the Flight

Before launch, use a flight prediction tool to estimate the path from the weather forecast. The tool needs the balloon mass, the gas amount, the ascent rate and the burst altitude, and it returns a predicted landing point. The prediction is only an estimate, but it helps you to choose the launch site and to position the chase team. On the day, update the forecast shortly before launch, because the winds change.

The chase team follows the balloon in a car, using the live tracking page on a phone and a radio receiver as a backup. Make sure that the driver is not also the navigator. When the payload descends, the signal may fade at low altitude, since the radio horizon is short. A directional antenna and the techniques in the guide to radio direction finding and fox hunting help to find the final position. Ask permission before you enter private land, and do not climb trees or approach power lines. If the payload is out of reach, leave it and ask the owner or the authorities for help.

After the Landing

Collect the payload, check the data and share the results with the people who tracked the flight. Note the burst altitude, the flight time and the distance travelled. Thank the stations who sent reports, because the project depends on a community of listeners. The data you gather will help you to improve the next flight.

A Word on Pico Balloons

A pico balloon is a small foil balloon carrying a tracker that weighs only a few grams, powered by a tiny solar cell. It floats at a level of about 10 kilometres or higher, drifts with the wind and may circle the Earth many times. The trackers usually transmit short weak-signal messages that are collected by receivers around the world, using methods like the one described in our guide to the WSPR beacon system. Flights depend on weather, balloon quality and luck, and the designs are an exercise in saving every gram. If you enjoy a project that is both electronic and meteorological, a pico flight rewards patience.

Working With a School or Club

Balloon flights are ideal group projects. A club can divide the work into payload, tracking, launch and recovery, and each member learns a different skill. Schools often join in, with students designing the experiments and following the flight online. If you involve young people, make sure that an adult holds the licence and the responsibility for the transmitter, keep a written safety plan and brief everyone before launch. Publishing the flight path and the pictures afterwards builds interest in the hobby and brings new members to the club.

Common Mistakes

• A GPS without flight mode. The tracker stops reporting high up, and you lose the balloon.
• A long digipeater path. It floods the channel with copies of the same packet.
• Too much power and too frequent beacons. A few hundred milliwatts and a beacon each minute are enough.
• Ignoring the rules. Check weight limits and notification requirements before every launch.
• Using a poor battery in the cold. Test the battery in a freezer before the flight.
• No recovery plan. Send a team, a map and a way to ask landowners for permission.

The Bottom Line

A high altitude balloon flight turns a small amount of radio equipment into a memorable adventure. Build a light payload with a GPS in flight mode, an APRS tracker with a short path and a sensible beacon interval, a lithium battery and an insulated box. Check the regulations for your country, predict the path, launch from a clear site and chase the signal with a team and a backup receiver. Share the data with everyone who listened. Start with a simple latex flight, learn from the results and decide whether you want to try a longer project such as a pico balloon. The project teaches more about propagation, antennas and logistics than almost any other hobby activity.

Frequently Asked Questions

How high does a high altitude balloon go?

A typical latex weather balloon rises to about 25 to 35 kilometres before it bursts. A parachute brings the payload back down, and the flight lasts a few hours.

What radio do I use to track a balloon?

Most amateur flights use an APRS tracker on a VHF frequency, because there are many receiving stations and tracking sites. Other options include LoRa and weak-signal beacons.

Why does the GPS stop working at altitude?

Many GPS receivers limit altitude in their default mode, often around 18 kilometres. Use a receiver that supports an airborne or high-altitude mode and test it before launch.

Do I need permission to launch a balloon?

Often yes. Rules depend on the country and the payload weight, and some require notification of the aviation authority. Check the current regulations before you launch.

How do I find the payload after landing?

Use the live tracking page, a backup receiver in the chase car and a directional antenna for the last stretch. Ask landowners for permission before you enter private property.

What is a pico balloon?

A small foil balloon carrying a tiny solar-powered tracker. It floats at altitude for days or weeks and sends weak-signal reports that many stations can receive.

A holiday does not have to mean a break from the hobby. With a small radio, a few metres of wire and a battery that is allowed on a plane, you can make contacts from a hotel room, a rented house or a campsite in another country. The trick is not buying the lightest rig on the market. It is putting together a kit that packs small, goes up in minutes, respects the people around you and follows the rules of travel and of the country you visit. This guide to travel ham radio covers the rig, the antenna, the power supply, the packing and security questions, the licensing side and a few operating tips so that your first trip is a success.

Choosing the Radio

For travel, weight and power consumption matter more than anything else. A QRP transceiver, with an output of five watts or so, is small, light and runs on a small battery. Several current models are designed for portable use, and some cover HF and 6 metres, with built-in keyers and digital mode support. Our introduction to QRP operating explains why five watts reach farther than most newcomers expect, and the QRP overview gives the background. If you already own a 100 watt radio, think about whether you really need it on the trip. A full-size radio and its power supply can weigh several kilograms, and the antenna that you can hang in a hotel room will not make good use of the extra power anyway.

Choose a mode that suits your trip. CW needs the smallest rig and the narrowest signal and works well on low power with simple antennas. FT8 and other digital modes need a laptop or a small computer and an interface cable, but they let you make many contacts from a quiet room with a weak signal. Single sideband is the easiest for conversation but needs more signal. Many travellers pick two modes, such as CW and FT8, and plan accordingly.

The Antenna

The antenna is the heart of the travel station, and it determines how many contacts you will make. The best choice depends on where you will stay.

• End-fed wire. A length of wire with a matching unit is the usual choice. It packs into a pocket and goes up with a bit of string. Our guide to the end-fed half-wave antenna shows how to build one that works on several bands.
• A telescopic fibreglass pole. A pole of 5 to 10 metres supports one end of a wire or holds a vertical. It fits into a suitcase and can be mounted on a balcony rail or in a garden.
• A random wire and a tuner. A long wire from a window to a tree, with a small tuner, tolerates a lot of variation.
• A small loop. A magnetic loop is quiet and compact, though it needs careful tuning and is less efficient at low power.

In a hotel, the window is often the only possibility. A wire can be dropped from a window down to a stake or a tree, or run horizontally along a balcony, but you must respect the hotel’s rules and the safety of other guests. Never let a wire hang where it can trip someone, never throw a line across a road and never attach anything to a building without permission. If you have any doubt, ask the management, or choose a lodging that has a garden or a balcony.

Power for Travel

A QRP transceiver draws about one to two amperes on transmit, and much less on receive, so a small battery can run it for hours. The battery is also the item that causes most trouble on a plane. Lithium batteries are regulated by aviation authorities. The usual rule is that spare lithium batteries must be carried in the cabin, not in checked luggage, and that batteries up to 100 watt-hours can be carried without special approval while larger batteries need permission from the airline. The aviation authority’s guide to lithium batteries explains the details, and your airline may have additional rules, so check before you pack.

The watt-hour figure is voltage times capacity. A 12.8 volt LiFePO4 pack of 7 amp-hours holds about 90 watt-hours, which is under the 100 watt-hour threshold, and it will run a QRP rig for several hours of operating. Our overview of battery options for portable operation compares the main chemistries. Label the battery, put it in a bag that protects the terminals from short circuits and carry the manufacturer’s specification sheet if there is one.

What to Pack

Licence, Rules and Call Sign

Before you travel abroad, find out whether your licence is valid in the country you will visit and which call sign format you must use. In many European countries, a CEPT recommendation allows visitors with a licence from a participating country to operate for a limited time without extra paperwork, as our article on operating abroad under CEPT TR 61-01 explains. Other countries have bilateral agreements or require a permit. The rules cover the bands you may use, the power and the prefix you must add to your call sign.

Identify the station as portable or as the visitor in the way that the country requires, and remember the rules for the suffix described in the guide to portable call sign suffixes. Keep a copy of the licence with the radio. Some countries do not welcome amateur radio equipment at customs, and a few treat any transmitter with suspicion, so read the official guidance before you leave and consider whether it is wise to bring a radio at all.

Security and Customs

A radio in a bag can attract attention at airport security, as it looks like a box of electronics and wires. Pack it so that it is easy to remove and show. Keep the antenna wire coiled and tidy, and be ready to explain, politely and briefly, what it is. Carrying the licence and a short note helps. Do not hide the equipment, and do not pack it in checked luggage, where it can be lost, damaged or stolen. If you are asked to switch a device on, do so; a radio that is receiving normally is not a problem.

Operating From a Room

Once you arrive, take a few minutes to plan. Choose a window or a balcony that gives the antenna as much height and clearance as you can safely have. Check the noise on the bands before you set up the wire, because hotel electronics, chargers and lighting can produce strong noise in a small room. Try different positions of the radio and the antenna, and use headphones so that you do not disturb neighbours. Keep the power low, the signals clean and the sessions short in the early morning or evening. A calm approach avoids complaints, which are the main way a hobby at a hotel ends early.

Plan some activity before you go. Look up the local radio club or a regional award, or join a portable activity such as parks on the air if you are going to a place with a registered park. The parks on the air programme gives hunters a reason to listen for your call. Most operators are glad to talk to a visitor, and a call from a distant place often draws a small pileup.

Two Sample Kits

It helps to decide in advance how much you want to carry. A minimal kit for a short city break is a pocket-sized QRP rig, a small battery, a 10 metre wire with a matching unit, a few metres of cord, a paddle and a pair of earbuds. It weighs about a kilogram, fits in a small pouch and is enough for CW or FT8 on one or two bands. A comfortable kit for a week at a holiday house adds a telescopic pole, a second wire for another band, a larger battery that still meets the cabin limit, a small laptop with a digital mode interface, a headset and a folding mat to put everything on. It weighs perhaps three kilograms and gives you a proper evening of operating. Choose the kit that suits the trip, not the one that makes the packing list look impressive, and test the whole kit in your garden before you leave, so you know how long it takes to set up and what you have forgotten.

A Simple Trip Timeline

1. Four weeks before: check the licence rules for the country and any permit that is needed.
2. Two weeks before: choose the kit, charge and label the battery and test the antenna outdoors.
3. One week before: print the licence and the rules, and pack the cabin bag.
4. On arrival: check the noise, choose the antenna position and plan a first contact on a quiet band.
5. Before you leave: take down the antenna, collect all the wire and leave the room as you found it.

Respect and Safety Abroad

Be a good guest. Keep your transmissions at a modest power, avoid operating during hours when a hotel is quiet and never run a wire across a public path. Pay attention to local rules on radio exposure and keep the antenna away from your own head if you run more than a few watts indoors. In some places, an unusual antenna can attract questions from neighbours or from officials, so be ready to explain what you are doing in simple terms and with a smile. Most people are curious and friendly once they understand that it is a hobby and not a threat.

Common Mistakes

• Packing a battery in checked luggage. Spare lithium batteries belong in the cabin.
• Bringing too much. A kit that is too heavy stays in the cupboard. Keep it small.
• Skipping the licence check. Operating without authorisation in another country can create real problems.
• Putting up a wire without permission. Respect the owner of the building and other guests.
• Forgetting the noise. Test the band before you rely on a location.
• Relying on a single mode. Pack equipment for CW and for one digital mode, in case conditions or noise favour one over the other.

The Bottom Line

A good travel station is small, light and simple. Choose a QRP transceiver, an end-fed wire with a pole or a string, and a lithium battery that meets airline rules. Check your licence and call sign requirements for the country, carry the equipment in the cabin with the papers, and be polite about security and about where you put the antenna. On arrival, test the noise, use headphones and plan a few contacts around local clubs or portable activities. Done well, a few watts and a few metres of wire turn any holiday into a chance to meet operators around the world, and the whole kit fits into a small bag.

Frequently Asked Questions

Can I take a ham radio on a plane?

Yes, in most cases, in carry-on luggage. Keep batteries in the cabin, protect the terminals and be ready to show the radio at security. Check your airline’s rules before you travel.

What is the best radio for travel?

A compact QRP transceiver that runs on a small battery. Choose by weight, bands, modes and power draw, and avoid anything that needs a large power supply.

How big a battery can I carry?

Spare lithium batteries up to 100 watt-hours are normally allowed in the cabin without approval, while larger ones need the airline’s permission. Always check the current rules.

Can I operate from a hotel room?

Often yes, with a low-power station and a wire from a window or balcony, if the hotel allows it and you keep the antenna safe. Ask the management when in doubt.

Do I need a licence for the country I visit?

You need authorisation. Some countries accept foreign licences under agreements such as CEPT, and others require a permit. Check the rules before you travel and carry a copy of your licence.

Which antenna works best in a hotel?

An end-fed wire or a random wire with a small tuner is the easiest to pack and use. A compact loop is quieter on receive but less efficient.

Sooner or later it happens to every active operator: you are in the middle of a net, a rare DX contact or a friendly chat and a signal appears on the frequency with no purpose except to spoil it. It may be a stream of whistles, a repeated word, music or a carrier. Deliberate disruption is rare compared with ordinary interference, but it is memorable and it wears down the enjoyment of the hobby. This guide explains intentional interference in ham radio: how it differs from the accidental kind, the main types you will meet, why the best response is usually silence on the air, how to document and report a problem, and what technical steps keep you operating while the matter is dealt with.

Intentional and Accidental Interference

Interference comes in many forms, and most of it is not intentional. In the amateur shorthand, QRM means man-made interference from other stations, QRN means static and natural noise and QRL asks whether the frequency is in use. Most QRM is accidental. Two stations call at the same time, a station does not realise the frequency is busy, a net operator starts on a clear channel and a distant signal arrives later. Equipment faults add more: a switching power supply, a faulty street light or a solar inverter can wipe out a band, as our guide to finding and killing RF noise at home explains.

Intentional interference is different, because someone chooses to disturb communications. Rules in most countries forbid it. In the United States, for example, the amateur service rules state that no amateur operator may willfully or maliciously interfere with or cause interference to any radio communication or signal, and you can read the wording in Section 97.101. Other countries have similar provisions. The general topic of deliberate disruption is described in the article on radio jamming.

Types of Deliberate Interference

It helps to recognise what you are dealing with, because the right response depends on the source. The categories overlap, and you cannot always be certain who is responsible.

Intruders From Other Services

Not every unwanted signal comes from a person who wants to annoy you. Some bands are shared with other services or are used illegally by stations outside the amateur service. Broadcasters sometimes operate near the edges of an amateur band, and radar systems can produce pulses that sound like a regular tapping. Over-the-horizon radar has been heard on several HF bands in the past. Amateur societies run monitoring programs to log such signals and to inform regulators. The IARU monitoring pages describe how this works in Europe and show where to send reports.

Why Not to Reply on the Air

The natural reaction is to tell the person to stop. It is also the worst reaction. A person who interferes deliberately is looking for a response. Every angry message gives him what he wants, it tells him that the attack works and it prolongs the problem. A discussion on the air also adds to the interference, it breaks the rules about courtesy and it hands him material for a recording that can be used against you or the net. Experienced operators therefore follow a simple rule: do not acknowledge, do not argue and do not mention the interferer by call sign on the air.

Instead, carry on as if nothing had happened. If the interference is too strong to continue, move the net or the contact to a prearranged alternative frequency, and tell the other stations briefly and calmly. Do not announce your reasons in detail. Keep transmissions short and businesslike, use the same phrases you would use in normal operation and avoid speculation about who the person is.

Documenting the Problem

Evidence is what makes a report useful. A regulator cannot act on a statement that somebody was annoying. It needs dates, times, frequencies and recordings. Make documentation a habit as soon as a problem repeats.

1. Write down the date and the start and end time in UTC, the frequency, the mode and the band conditions.
2. Record the audio or save an IQ recording if your SDR can do it, including some time before and after the interference.
3. Note the direction if you have a directional antenna, and the signal strength at your location.
4. Ask other stations to log the same event, because bearings from several places can help locate the source.
5. Keep a short description of the effect on your operation: which net or contact was disrupted and for how long.
6. Do not edit the recordings. Save the original files and make a copy to share.

Stations that can listen on several bands or that use a panadapter see patterns that a single receiver misses. If the interference only occurs when a certain band is open, or at a certain time of day, the pattern itself is evidence. If your reports of the problem show that the signal hops between frequencies, that is also worth noting.

Reporting It

Choose the right channel. Interference to the amateur service is reported to the national regulator, which has the power to investigate and enforce, and in many countries the national amateur society has volunteers who help gather evidence and liaise with the regulator. In the United States, the ARRL runs a volunteer monitor program, and in Europe each member society has its own contacts. Send a clear, factual report with the evidence listed above, state what you observed and avoid accusations that you cannot prove. A polite report with good evidence is far more effective than a long complaint.

If the interference is to a net or a club repeater, tell the club officers and keep them informed. Many clubs have a plan for harassment, which can include a change of frequency, a change of access method or the use of a temporary tone. Do not take action against a suspected person, do not visit his home and do not publish his name. Leave enforcement to the authorities.

Staying on the Air

While the matter is being dealt with, use technical and operating methods to keep communicating. You cannot remove a strong signal on the same frequency, but you can often reduce its effect.

• Narrow filters and notches. A narrow CW filter or a notch can remove a steady carrier or a whistle. The article on noise blankers and noise reduction explains what DSP features can and cannot do.
• Antenna directivity. A beam or a receiving antenna with a null can point away from the source. Our guide to low-band receive antennas shows how nulls are used.
• Frequency changes. Move the contact a few kilohertz. A jammer on a fixed frequency may not follow, though this is not guaranteed.
• Split operation. In a DX pileup, listen on a different frequency from the transmitter, as described in the guide to working a pileup.
• Digital modes. Weak-signal modes with error correction can work through interference that destroys speech.
• Schedules. Arrange a contact by another means and use a different band or time.

Good Etiquette That Prevents Problems

A surprising amount of what looks like deliberate interference is simply impatience. Before you transmit on a frequency, listen for at least a minute and ask whether it is in use. On CW, send QRL, and on phone, say “is this frequency in use” and wait. Nobody owns a frequency, and a net or a QSO has no formal priority, but courtesy asks you to move if someone is already using it. When you follow good practice, and when your own signal is clean, you remove one common source of disputes. Cluster etiquette matters too, and the article on DX cluster spotting etiquette shows how to avoid creating problems for others.

Planning a Net to Withstand Interference

Regular nets are the usual targets, because their time and frequency are predictable. A net that has thought about the problem in advance copes far better. Agree a backup frequency, preferably on a different band or on VHF, and announce the plan at the start of the net, not in the middle of an attack. Make sure that the net control station has a clear procedure: continue, pause, move, or close. Use a repeater with a tone or a closed access method if the net is local. Rotate the net control duty so that one person does not carry the whole load, and keep a short written record of any disruption so that the club can show the regulator a pattern. Plans like these are short and cost nothing, but they turn a stressful surprise into a routine move.

What Not to Record or Share

Recordings are useful evidence, but treat them with care. Share them with the regulator, the monitoring group or the club officers, and do not post them publicly with the name of a suspect. Public posts can start arguments, may identify the wrong person and can make the situation worse. Keep a private archive with the date and the details, and hand it over when asked.

Looking After Yourself

Dealing with deliberate interference can be upsetting, particularly for newer operators who do not know how common it is across the hobby. Remember that the person causing it is a very small minority, that the vast majority of operators are friendly and that the problem is not your fault. If you feel frustrated, take a break from the band, talk to your club and return when you are ready. Mentors in the club can help newcomers to see that a calm response is a sign of experience, not of weakness. Sharing experience also helps the group to decide on a common policy, which makes every member more confident.

Common Mistakes

• Arguing on the air. It rewards the interferer and spoils the band for everyone.
• Retaliating with your own interference. It makes you part of the problem and may break the rules.
• Reporting without evidence. A report needs time, frequency and a recording to be useful.
• Naming suspects. Guesses about identity can be wrong and can lead to trouble for you.
• Assuming every problem is deliberate. Check your own station and the local noise first.
• Giving up the band. Move, adapt and return. The interferer usually loses interest when there is no reaction.

The Bottom Line

Deliberate interference is rare but it is real, and the best response is calm and technical. Do not reply on the air, do not retaliate and do not name suspects. Record the time, frequency and audio, ask other stations to confirm, and send a factual report to the regulator or the monitoring group of your national society. While the issue is handled, use filters, antenna nulls, a change of frequency or a digital mode to keep operating. Practise good etiquette yourself, so that your own habits never cause problems for others. A band is a shared resource, and the operators who keep their composure are the ones who keep it usable for everyone.

Frequently Asked Questions

What is intentional interference?

It is the deliberate disruption of other stations’ communications, such as jamming a net with carriers, music or repeated words. Rules in most countries forbid it.

Should I respond to a jammer on the air?

No. A response encourages the person and adds to the problem. Carry on, move frequency if necessary and document the event for a report.

How do I report ham radio interference?

Send a factual report with dates, times in UTC, frequencies and recordings to the national regulator and to your national amateur society, which may have a monitoring program that can help.

Is QRM always intentional?

No. Most QRM is accidental, caused by stations that do not realise a frequency is in use, or by equipment such as power supplies and inverters. Check your own station first.

Can I confront the person causing the interference?

You should not. Confrontation can escalate the situation and may be unsafe. Leave identification and enforcement to the authorities.

How can I keep operating during interference?

Use a narrow filter or a notch, a directional or null antenna, a different frequency or a digital mode, and arrange backup frequencies for nets in advance.

Most contests are not lost on the air. They are lost in the days before, when a cable turns out to be broken, the logger does not talk to the radio or the antenna that worked in the summer fails at the first gust. The cure is a plain, written contest station checklist that you work through at fixed times before the start, so that the first hour of the contest is spent making contacts and not diagnosing faults. This guide gives a practical timeline for the last two weeks, with the tests that matter for software, rig control, keying and audio, antennas, power and backups, and a short routine for the final hour. It suits the first contest and the fiftieth, and you can adapt it to a single-operator station or a multi-operator team.

Why a Written Checklist Works

Under pressure you forget things you know perfectly well. A checklist replaces memory with a routine, and it makes problems appear when you still have time to solve them. It also gives you a record of what was tested and when, which is useful when a fault appears. The best checklist is the one you write for your own station and improve after every contest, adding the item that caught you out last time. Keep it on paper or in a note on your phone, and tick off items as you go. If you are new to the sport, the overview of radiosport gives the background to how contests are scored and why preparation matters so much.

Start by choosing the contest and reading its rules. The contest calendar lists the dates, times in UTC and links to the rules. Check the exchange, the categories, the bands, the power limits and the log deadline. Many mistakes come from small details, such as a different exchange for stations in different regions or a rule about the maximum operating hours.

A Timeline for the Last Two Weeks

Software and Logging

The logger is the center of the station, so test it first. Enter your call sign, name, zone and grid exactly as the contest requires, and select the right contest in the logger. Make a dozen test contacts and check that the logger fills in the exchange fields correctly, rejects duplicates and counts multipliers. If you use a program such as the one described in our guide to setting up N1MM Logger+ for your first contest, pay attention to the entry window, the band map and the telnet connection to the cluster.

• Connect to the DX cluster or the skimmer feed, and confirm that spots arrive and filters work.
• Check that the computer clock is accurate, using the methods in the guide to computer clock accuracy, because the log must record the correct UTC time.
• Turn off automatic operating system updates and any program that might start a scan or a backup during the contest.
• Make a backup of the logger configuration and the country file, and save it on a separate drive.
• Export a test log in the format that the contest requires, so you know that it works before the deadline. The article on Cabrillo logs and the checking process explains the format.

Rig Control, Keying and Audio

Test each link between the computer and the radio, on every band and mode that you will use. Change the band on the radio and check that the logger follows, and change the band in the logger and check that the radio follows. Switch between modes and make sure the frequency display agrees. Test the CW keying with the keyer and the computer, at several speeds, and listen to the sidetone and the transmitted signal with a monitor receiver. For sideband, record the voice messages and test them on the air at low power to a friend or with a monitor receiver, as described in the guide to the voice keyer for SSB contests.

Audio and Headset

Wear the headset for a full test session and adjust the volume, the balance and the microphone gain, because discomfort grows with every hour of the contest. Check that the footswitch or the keyboard transmit control works, and that the computer sound system does not switch devices after a restart. Write down the audio settings you use so that you can restore them.

Antennas, Feed Lines and Power

Walk the antenna system. Look at every connector for water and corrosion, check the guy lines and the supports and inspect the rotator cable. Measure the SWR on each band and compare with the figures from the previous year. A rise in SWR is a warning that something has changed. If you have an antenna switch, test every position and every band, and label them clearly.

For power, test the supply under load by transmitting at full power for several minutes on the band that draws the most current, and check the voltage at the radio. A thin cable or a loose terminal shows up as a drop in voltage at the transceiver. If you plan to use a battery backup or a generator, test it too. A small uninterruptible power supply on the computer prevents a power cut from losing the log. Keep fuses and spare cables within reach.

Spares and Comfort

• Spare parts. Keep spare jumpers, adapters, a spare microphone, a spare paddle or key, fuses, batteries and a roll of tape.
• A paper backup. Keep a sheet with the exchange, your call sign and the contest rules. If the computer fails, you can continue on paper.
• Food and drink. Prepare meals that are easy to eat and drink water regularly.
• Lighting and temperature. A comfortable room supports long operating periods. Check the seat, the desk height and the lighting.
• A rest plan. Decide when you will sleep and for how long. The article on rest time management in 24 and 48 hour contests helps you plan it.

Noise and Neighbours

Check the noise level on every band in the evening, with everything in the house switched on as it will be during the contest, because lighting, chargers and switching supplies change the noise. If a source appears, find it now. During the contest you can also warn your household about your plans and pick times when noisy equipment can be switched off.

The Last Hour

An hour before the start, sit down at the station and run through a short list. Check the clock, the logger settings and the call sign. Check the cluster connection and the band map. Select the antenna for the first band, set the power, test the keyer and the voice keyer, and clear any old test contacts from the log. Fill the water bottle, find the notes with your frequency plan and silence the phone. When the contest begins, make the first call slowly and listen, because the first minutes are the best test of whether the whole chain is working. A calm start leaves more time for contacts and gives you more energy for the second half.

A Dry Run Is Worth Two Hours

The best single test is a dry run: a short session of one to two hours that follows the real contest procedure from start to finish. Pick a weekend evening when a regular weekly contest or a sprint is running, and operate it as if it were the big one. Use the same logger profile, the same headset, the same band changes and the same keyer messages. Make contacts on at least two bands and two modes. Export the log at the end and check it. A dry run reveals the things that a bench test does not: the cable that is just too short when you turn the chair, the macro that sends the wrong exchange, the microphone that picks up the fan and the habit of leaving the speaker volume too loud. Many operators find that the first twenty minutes of a dry run produce a list of five small fixes.

Multi-Operator and Remote Stations

If several people share the station, the checklist needs a few more lines. Agree who is responsible for each task, such as the logger, the antennas, the power and the food. Test the changeover between operators, including the logger login, the headset and the keyer macros, and make sure each operator can find the notes. For a remote station, test the connection from the operating location at the time of day that you will use it, because latency and dropouts change during the day, and keep a plan for what to do if the link fails. In both cases, write down who has the authority to stop the operation if there is a safety problem. A clear plan matters more when more people are involved.

After the Contest

The checklist does not end when the contest does. Save the log immediately, make a copy on a second drive and export the file in the required format before you go to sleep. Write a short note while the memory is fresh: what failed, what nearly failed, which band changes paid off, and what you would change next time. Add the lessons to the checklist as new lines. Over a few contests, the list becomes a precise description of your own station, and the preparation takes less time each season while the results improve.

Common Mistakes

• Updating software the week of the contest. A new version may change settings or break a driver. Freeze the setup ten days before.
• Testing only on one band. A fault often shows up on one band only, such as a bad antenna switch position.
• Leaving test contacts in the log. Clear them before the start, or export only the real contest period.
• Not testing the log export. Discovering a format problem on deadline day is stressful.
• Underestimating fatigue. Plan sleep and food, not only equipment.
• Not writing down what worked. After the contest, update the checklist with what you learned.

The Bottom Line

A contest station checklist moves the work of problem solving from the contest weekend to the days before it. Read the rules, freeze the software ten days before, test the logger, rig control, keying and audio a week before, walk the antennas, measure the SWR and check the power system, then run a practice session and export a test log. The day before, check the clock, spares, food and rest plan, and in the last hour go through a short list. Afterward, add every surprise to the list. Operators who follow a routine like this start the contest with a station they trust, and they spend the hours on the air making contacts.

Frequently Asked Questions

When should I start preparing for a contest?

About two weeks before. Read the rules, choose your category, and freeze software changes ten days before the start so there is time to fix any problems.

What should I test first?

The logger and the connection between the logger and the radio, since most contest day problems come from software settings and rig control. Then test keying, audio, antennas and power.

Should I update my software before a contest?

Do it early, at least a week or ten days before, and test afterwards. Do not update in the last days, and turn off automatic updates for the contest weekend.

How do I check my antennas before a contest?

Inspect connectors, supports and cables, and measure the SWR on every band. Compare the values with earlier measurements, and investigate any change before the contest.

What should I do in the last hour?

Check the clock, the logger settings, the cluster connection and the antenna switch, clear test contacts, prepare food and water, and make a calm first call.

Why export a test log?

Because the log format has strict requirements, and you want to find any problem in the export before the deadline, when there is no time to repair it.

A half-wave dipole is the reference for most wire antennas, and it is hard to beat for simplicity. If you have a little more space, however, you can gain several decibels without a rotator, a tower or any metal other than wire. The extended double zepp, often shortened to EDZ, is a center-fed wire about one and a quarter wavelengths long that concentrates its signal broadside to the wire. This guide explains what the antenna is, how long to cut it for each band, what pattern and gain to expect, how to feed it, how it behaves on other bands and how to build and test one that actually works.

What the Extended Double Zepp Is

The name comes from the early Zeppelin antenna, a wire trailed from an airship and fed at the end. The double zepp is two half-wave elements in line, fed at the center, and the extended version lengthens each side so that the whole antenna is about 1.28 wavelengths long. Each leg is roughly 0.64 wavelength. The article on Zepp antennas describes the history and the family of related designs.

The reason for the extra length is the radiation pattern. A half-wave dipole has a broad figure-eight pattern. When the antenna is lengthened, the currents on the two halves reinforce each other more in the broadside direction, and the pattern becomes narrower, which concentrates the power. The gain over a half-wave dipole is about 3 dB, which is a halving of the power needed for the same signal in the preferred directions. That is an improvement that most operators notice, and it comes at no more cost than additional wire.

The price is directivity. The beam is narrower than that of a dipole, so the antenna favours directions at right angles to the wire and gives less signal along the wire. If you want to reach a particular region, orient the wire so that the broadside direction points there. The two directions are opposite each other, so the antenna serves a region and its opposite side of the world.

How Long to Cut It

The length depends on the band, on the wire and on the height above ground. A good starting point is a total length in feet of about 1,250 divided by the frequency in MHz, or about 380 divided by the frequency for metres. Because the real figure varies, cut the wire a little long, measure and trim. The table shows total lengths for common bands, calculated for the middle of the band with this rule.