G1inf - Amateur Radio Station

Grinding to a halt

2011-10-05T18:01:00.003+01:00

Regular visitors may have noticed that posts to this blog have thinned-out over the last year. The situation will not get better; my life has changed, and I can no longer support more than one blog. Choosing which to keep was very difficult; but I felt that this one is composed of material which would be better presented in ebooks. It was always my intention to do just that; compile a 'best-of',

Delivery of Unobtanium

2011-07-10T15:33:00.002+01:00

Crystals for 10140kHz have become very difficult to obtain of late. A lot of hams have become interested in QRSS, and this sub-band of 10m is a prime focus for the specialisation. I had to order from a supplier in the US, and yesterday they arrived, complete with a complementary ballpoint pen!I will be taking time in constructing the next manned experimental propagation transmitter (MEPT), and

30-metre Propagation Transmitter

2011-06-07T19:53:00.006+01:00

Another new direction in radio for me; weak-signal work. Well, I've been involved with low-power radio (QRP) since my return to the amateur scene in 2005, but this is a new departure. I'm currently operating a manned experimental propagation transmitter (MEPT) in the 30m band. There are lots of people doing this now, and the body of knowledge we are corporately and severally building is

Simple passive filter for simple receivers

2010-05-04T19:16:00.006+01:00

I've built one of these before, but it was impractically heavy. This one is much smaller; I can cheerfully let it dangle from the headphone socket of a radio without fear of it tearing the cable or damaging the socket. Because it is added inline with the headphones, it can be used on any radio, but it will only match the impedance of a pair of iPod or Walkman-style 32-ohm headphones. It's a

What is a goniometer?

2009-11-12T18:37:00.004Z

Goniometer - The name means 'angle measurer'. In radio context, it is a set of coils arranged to determine the bearing (direction) of a transmitter. The scan at right is from the 1938 Admiralty Handbook of Wireless Telegraphy, a two-volume set which has spent more than half of its existence in my collection.The name Goniometer was chosen for the blog because although its relevance to modern

003 Fitting Part 1

2009-11-10T20:58:00.005Z

Hacksawing, filing, finishingMetal, and other materials from which we make the hardware of our projects, will need to be cut to shape to form the basic components of cabinets, panels, PCBs and other parts. Even when ready-made cases and enclosures are purchased, some cutting operations will be necessary to make the item fit our purpose.HacksawsHacksaws are the basic cutting tool for hard

USB-Powered Direct-Conversion Receiver

2009-11-05T21:08:00.006Z

I've built and blogged one of these before, but now I've developed the idea a little. The original suffered with a poor antenna and although it worked, it was more than a little deaf. The new USBrx has eighteen components, including the connectors, antenna and panel.Loop antenna wire (32feet, 9.75m) - any insulated wire will do.Loop antenna connectors male (2 required)Loop antenna connectors

002 Hand Tools

2009-10-29T17:24:00.016Z

Some tools are absolutely necessary for building radio equipment. The following short list should be shopped for, before attempting any practical work. These are the bare minimum required to assemble the projects detailed in this book, and may be all you ever need...Soldering ironPliersCuttersScrewdriversKnifeSpannersTrim-toolMultimeterWe'll discuss each tool in turn, and suggest what to buy to

24MHz HF Theremin

2009-10-26T11:06:00.002Z

I've been wanting to blog this for a few months, but life got in the way of preparing enough material for release. I've updated the static site at g1inf4u with enough information for an experimenter to try their luck with one. The full link is here, and do please comment if you'd like more information.The theremin is a 'mature' project; it's been around for a couple of years. The original still

001 Health and Safety

2009-10-25T06:49:00.002Z

When I was sixteen, I began my apprenticeship as an avionics / instrument technician. The first thing we did was to attend a lecture on industrial safety, complete with scary movies of industrial accidents and a long list of 'thou shalt not' behaviour modes. This was before we'd even seen the workshop which would be our daytime 'home' for the next forty weeks.It would be wrong of me to treat my

Basic Skills - Introduction

2009-10-25T06:41:00.002Z

In support of the projects, I will be releasing some skill-related posts. These articles give the reader an introduction to each skill, and will also give links out to any resources the author finds during his research. The content is based on the author's own experience and learning, but there's a lot more to know.The set begins as it should, with words of caution. Electronics assembly and

Simple AF Amplifier

2009-10-22T19:49:00.012+01:00

The Simple Audio Frequency (AF) Amplifier. An easy and useful introduction to home-build electronics, this project will take a low-level audio-frequency signal and boost it to 200 times its original strength. It has a level control to adjust the output for comfort, and will drive a pair of iPod / MP3 player headphones, or a small loudspeaker. It uses a 9V battery (PP3 / MN1604), and requires no

Cheap and Easy 4mm Connectors

2009-10-18T18:32:00.009+01:00

An interim post; I felt it was worth sharing. I have used red bullet crimp connectors for some years as a cheap alternative to 4mm 'banana' plugs, which are used for test and measurement connections. Only the red ones work; the yellow and blue crimps are too big. Earlier today, I found it was easy to use the female crimps to make workmanlike sockets for use in test equipment.All you need is a red

Back to Basics

2009-10-15T20:06:00.005+01:00

I've decided to start over. New ground rules for myself, and heaps of benefits for readers.(1) I will post updates here regularly, every Thursday. If anything can't wait, it'll get posted, but the Thursday post is the routine.(2) The amateur construction ebook will have its projects posted as news items here, with links to PDFs as they are completed. The project PDFs are free for anyone to

New Way of Business at G1INF

2009-10-13T21:05:00.002+01:00

I have on my bureau, alongside my netbook, a small lump of FR4 which has seen more prototype radios than the skip behind one of my old salt mines. It's about to get another ride on the resin-cored express, and this time it's a very simple little project.I've rationalised the way I'm going to present projects. I'll start small, and build up to meatier jobs. The progress will be rendered here in

Diversion into sales

2009-10-02T17:21:00.000+01:00

I'm letting the new radio percolate for a few days, while I sort out some sale stock for my eBay account. I've built up a significant amount of surplus over the years, and I'm disposing of some of it to make room, and funds, for the kits project. I'll be releasing the stuff onto the lists over the weekend, and I'll update here with links and information on the items available.Another thread of

Early Development Prototype - CW84

2009-09-26T21:20:00.000+01:00

I'm calling it the CW84 because it's a refinement of an 80-metre cw transceiver I made about four years ago, which I called the CW80. Not only is it four years younger, but the true wavelength of a 3.550MHz signal is 84 metres. It's a direct-conversion receiver, very straightforward in design, with an equally simple transmitter tacked onto it. A 700Hz offset is added to the transmitted signal by

Witlessness and woe

2009-09-24T21:53:00.000+01:00

If I've learned anything this evening, it's how to waste three hours work on one simple detail. The new radio was laid out three nights ago, and it looked elegant, compact and concise in its prototype stripboard form. The resonators, 1K pots and 100p COG capacitors arrived today, so it all looked good for a first build. Thursday evenings are free of Sea Cadet obligations, and nothing was planned

2009-09-22T20:14:00.000+01:00

It's wonderful to watch your ideas take shape, and weird to watch the shape change as the ideas mature into workable products. The latest radio is no exception. I went through a panic stage four days ago, and the direct-conversion receiver / cw rig turned into a Pixie II, and back again. Do a search for the Pixie II, it's a fascinating exercise in minimalism. The PA transistor doubles as the

Getting Ready for Business at g1inf4u

2009-09-16T17:02:00.000+01:00

The pace is hotting-up. I now have most of the Internet elements of g1inf4u in place, and now the real work starts. I have an outline design for an 80m cw transceiver, to be made available in modules. Each module kit comprises a bag of devices, a piece of copper-clad board and instructions. I may change my mind and put the whole thing on one lump of FR4, or even make two versions (modular and

Morse Code Advocacy

2009-09-14T17:31:00.000+01:00

This Saturday gone was hard work, but great fun. I delivered a talk and teach-in to forty-eight 10 - 12 year-old Junior Sea Cadets, along with their twelve adult and senior Cadet team leaders at an Adventure Camp. I presented a potted history, a practical demonstration of current amateur radio usage and then let them loose with keys and oscillators. The kids loved it. They were given a copy of

A New Station - M6BMO

2009-09-08T20:02:00.000+01:00

My youngest son, Billy, recently qualified as a Foundation licensee. He studied with the Worthing and District Amateur Radio Club, to which we are both very grateful for their help and support. Now Bill is an M6, he needs a radio, and there lies a problem. I can't afford a 'black box' rig for him, and as a Foundation ham he can't use my homebrews. He can, however, use a radio made from a

Somewhere new to rest my case

2009-07-10T16:26:00.000+01:00

New website!Yahoo! Geocities is due to close its ports later this year, so I'm migrating the best bits of http://uk.geocities.com/egnaro937@btinternet.com/index.html to a Google Site - http://sites.google.com/site/g1inf4u/home . I've already added a page about the Poundshop DC receiver, along with basic info on the 24MHz theremin and the closed-circuit RF trainer projects.The new site will take

Closed-Circuit Radio

2009-07-06T20:56:00.000+01:00

I've wanted to do this for some years, and I've finally taken the plunge. All the non-radiating radio network trainers I've come across have used some form of multi-port telephone system, where the students and tutor are connected together and may talk amongst themselves. They have PTT switches, headsets and boxes full of electronics, but they lack the one thing real radio networks have - a radio

Forty-Metre SSB Superhet Transceiver

2009-06-19T13:47:00.000+01:00

Yet another HF superhet rigI like doing unusual radios, so when I decided to produce yet another HF superhet, I felt compelled to give it a twist.The current project uses two SA602 mixer/oscillators, and a DPDT relay to swap the signal path around to take the rig from receive to transmit. I used the fortuitous layout of the SA602's inputs and outputs, along with the equally serendipitous pinout