Some “home experiments” done by the Curmudgeon during an unanticipated regional power failure led to the conclusion that the external urban radio noise level at 14 MHz near his house typically measured about 12 microvolts at a receiver input, while during the blackout the ambient noise level was reduced to about 0.2 microvolts under identical equipment conditions.  While these were not “laboratory grade” measurements, they clearly indicated that high ambient noise level problems do exist, especially in metropolitan environments.  See http://rfblog.lbagroup.com/free-at-least-extremely-cheap-noise-part-1/.

To be thorough about these results, we must examine several other possible explanations for the high noise level.  Some radiofrequency noise does occur from natural processes, and perhaps one or more of these processes might be contributing to the large urban high noise levels.  Cosmic noise sources can contribute to the overall background, but they become important above 15 MHz, and this measurement occurred below that frequency.  Natural terrestrial noise sources are very important at VLF but become far less significant above 10 MHz.

Suffice it to say, the observed S-meter value during the power blackout, when both cosmic and world-wide terrestrial natural noise sources were in operation, was very close to the thermal noise background of the receiver itself; at most these natural sources contributed one or two additional dB of noise.  This is far below the typical daily urban noise level, which is some 35 dB higher than the thermal background.  Thus it is unlikely that the majority of today’s long-term HF noise problems are due to naturally-occurring sources.

In response to Part 1 in this series, reader James Medlock commented that much of today’s noise problem lies in the VHF and UHF portion of the spectrum, and not just at HF.  He is correct, of course, but there is a reason why the VHF/UHF problems are not highlighted to the same degree as the HF problem: the VHF/UHF noise problem is far less easily observed.

Spectrum Displays for UHF Wideband Modulation

In the HF spectrum, voice communications are overwhelmingly transmitted using envelope modulation modes (i.e., double-sideband, inserted carrier and single-sideband, suppressed carrier amplitude modulation).   Of course, there are also a number of character-based transmission modes in use at HF, but the transmission conditions using these modes are not typically directly observed by the operators.  Most observations of transmission problems are made aurally.

And envelope modulated modes are notably susceptible to random radiofrequency noise; when present it is always audible in the received signal.

In contrast, most VHF/UHF voice communications are transmitted using either frequency modulation or multi-level digital modulation.   [A notable exception is the Aeronautical Mobile Service, which has always used envelope modulation transmission modes.]  Both of these VHF/UHF modes have some degree of noise immunity inherent in their operation.  Thus ambient noise may well affect the reception of RF signals, but the listener may well not be aware of the interference unless the received FM signal is truly marginal or the digital signal “falls off a cliff.”  Additional comments and/or measurements of VHF/UHF ambient noise levels from readers who have access to VHF/UHF receivers with AM detectors (or who are using spectrum analyzers) to gauge the noise levels at these frequencies, would be welcomed. [Of course, much engineering/scientific work on these problems has also been performed and the results have been published.]

Thus it appears that the majority, perhaps even the vast majority, of the ambient metropolitan RF noise is of man-made origin.  What sorts of man-made systems produce the noise?  The Curmudgeon will list several major classes, with the expectation that readers will add to the list.  The first one, and perhaps the most obvious, is the modern electrical power distribution network.  By definition this wire conductor-based network carries large 60 Hz currents, in the case of utility electrical transmission networks on the scale of hundreds to thousands of Amperes, equivalent to as much as Megawatts of electrical power.  Moving charges produce EM fields, but the primary 60 Hz field is not the real problem here (in reality, the harmonics of 60 Hz also ride the lines, but above the fourth harmonic the effects become small.).

But it’s the voltages involved that are more the source of radiofrequency noise.  These voltages range from a minimum of 4 kV on some old local distribution networks, up to 500 kV and even higher for major transmission lines.  If the power transmission/distribution networks had been machined out of a single slab of copper or aluminum, the world would be subject to far fewer noise problems.  Instead they are constructed from various lengths of wire conductors that are spliced or clamped or bonded together, sometimes using jumpers where wire segments meet.

Bad Powerline Connectors – Major RF Noise Sources

If a junction isn’t perfect, a small spark gap can easily result.  Given some substantial voltage on the conductor, an arc can be struck across that gap.  And then that arcing gap recreates radio history: “King Spark” again takes to the air, aided by the long runs of the electrical conductors which form natural, multi-wavelength antennas.

Dirty, cracked, broken insulators, especially old glass and ceramic units, to which the conductors are tied or are suspended, also can harbor spark gaps.  And corona discharge, the leakage of electrons directly into the atmosphere, can also produce both audible and electrical noise.

The modern utility practice is to place electrical distribution networks in underground conduits, and the thickness of earth above them does help considerably to suppress radiation of RF noise.  But the original, old, weathered aerial distribution networks, found in the older parts of cities, are the major offenders, and while there are programs underway to “underground” these circuits, in reality it may be another half-century before the work is finished.

Radiation of EM noise from power networks, which can be detected as high as 500 MHz, is technically a violation of the FCC Part 15 Rules, and the FCC could in principle visit fines on the utilities if it wished.  This is very unlikely, except perhaps in the most egregious of cases.  Nevertheless, to varying degrees the individual electrical utilities do show some willingness to “clean up” noise problems as they are identified by customers.  Some utilities are very cooperative and have on staff dedicated troubleshooters with professional training and equipment, who will attack reported problems.  At the opposite end of the scale, other utilities will resolutely deny that problems even exist.

Next on the list are the large, power-consuming pieces of electrical machinery.  These are classified by the FCC as “unintentional radiators:” they produce and transmit some radio-frequency energy, although they were not designed to do this and the transmitted energy doesn’t aid in the work of the machine.  This class includes large motors, electrified transport systems, welding stations, RF-fired ovens, electric fences, etc.  They too are covered by Part 15 of the FCC Rules, although enforcement is very rare.

RF Welders Can Operate at 100 KW or More!

Next add in the radio-frequency industry itself: broadcasters, public and private radio common carriers, radars, consumers’ local area data networks, etc.  The space around large metropolitan areas is rich with these intentional radiators, which contribute to a very large EM energy density in the area.  Given these densities, mixing occurs at many spots and additional new mix product frequencies are generated and transmitted.  The result is a “dirtying up” of the spectrum leading to rising noise floors.  We’ll have more to say about these problems later.

Automobile ignition systems play their unique parts in raising the overall noise level, although the situation in this area has improved considerably over the last fifty years.

The final contributor to the noise pollution is a new entrant into the classification, one which probably wouldn’t even have been listed as late as twenty years ago.  These are the ubiquitous digital devices which today characterizes our culture.  As is well understood, almost all digital devices operate by generating rectangular pulses and/or square wave signals to represent the digital data being processed.  In order to operate at the high speeds characteristic of modern computing devices, these pulses must necessarily have very fast rise and decay times.  Thus as Monsieur Fourier has elegantly shown us, very rapid processes in the time domain produce signals in the frequency domain that are very rich in harmonics!

Noise Spectrum from Several WalWart Digital Power Suppies (Clifton Labs)

Since 1963, LBA has been providing RF equipment and engineering consulting services for
radio and television broadcast and wireless communications.

The May 17 event is the “Spring Lunch and Learn” meeting of the Minnesota State Wireless Association in Eden Prairie, on the western edge of Minneapolis. Association members are invited to hear from Horne and Liz Hill, who is director of state and local affairs for American Tower Corporation (ATC).

Wireless Trends and Technology (T squared) will be the general topic of discussion. Horne was invited to speak after he helped an upper Midwest client and association member win approval for a cell tower. Hill is an executive with ATC, which is one of the largest providers of tower space to the wireless industry.

Horne is a regular participant in wireless industry panel discussions. A registered professional engineer with a doctorate in electrical engineering, he has spoken in the last year at 4G wireless conferences in Chicago and Miami.

The Minnesota State Wireless Association is a nonprofit professional organization offering a unified message in local issues. It strives to provide general awareness of the wireless industry and educates customers and public officials about the wireless industry in Minnesota.

Expected to attend the May event are tower professionals, engineers, executive administrators, and industry attorneys.

LBA Group provides FCC compliance, RF safety, and other engineering services to the wireless industry.

This workshop is another in a series sponsored by the FCC to explore ways to remove broadband access impediments. LBA Group CEO Lawrence Behr has been a panelist or the presenter in two prior conferences. At the FCC Chairman’s invitation, Mr. Behr was part of an expert panel, reported in this blog: http://antennablog.lbagroup.com/how-to-kick-up-broadband-deployment-use-am-radio.  In conjunction with the Wireless Communications Association International (WCAI), LBA presented a subsequent webinar http://antennablog.lbagroup.com/a-webinar-truth-am-and-wireless-are-compatible.  That was followed by an FCC invitation to present the case for AM collocation to an industry group at the FCC Headquarters, reported here: http://antennablog.lbagroup.com/fcc-invites-behr-to-give-testimony-about-colocation. LBA has also advocated for AM colocation in other testimony and rulemaking proceedings. LBA Group has become recognized as the foremost expert and advocate for AM collocation in the country today.

LBA Chief Technical Officer Chris Horne, PE, PhD will present a discussion on colocation of wireless facilities on AM broadcast towers. He will be joined by attorney John Trent, who represents rural AM stations, and Bob Vinikoor, an owner of AM stations presently hosting wireless antennas.

Other presenters will include Crowne Castle, SBA Towers, Sprint, the FCC staff, and other industry siting experts.

The forum will provide an overview of how collocations can promote the availability of mobile broadband, public safety, and other wireless services in a manner consistent with community priorities.  Panelists will discuss the technical, structural, and business considerations underlying collocations on a variety of structure types, including wireless towers, AM radio/broadcast towers, public safety communications towers, utility infrastructure, rooftops, and water tanks.  The workshop will explore examples of cooperative solutions that have facilitated wireless deployment while recognizing community interests.  We will also discuss the significance of the FCC’s Nationwide Programmatic Agreement for the Collocation of Wireless Antennas.

The Wireless Telecommunications Bureau contact is Don Johnson at (202) 418-7444 or by e-mail:  donald.johnson@fcc.gov.  Please e-mail James Swartz at james.swartz@fcc.gov to pre-register for attendance or to view the webcast at www.fcc.gov/live.

LBA has developed several industry-leading proprietary approaches to AM collocation. Read more at http://www.lbagroup.com/associates/am-wireless-colocation.php. For colocation assistance, contact Mike Britner at 252-757-0279 or mike.britner@lbagroup.com.

Such pollution is, of course, known as radio frequency (RF) noise, which is defined (for our purpose) as “unwanted signals.”  Such signals are not intentionally generated for communications purposes, hence when their frequencies occur within a communications channel they tend to compete with and to fully or partially obliterate the meaning of the message carried in that channel.  (The field of Information Theory deals, in considerable part, with the problems of conveying messages in the presence of noise.)

Measured Circuit RF Noise (Source: EEWeb)

Noise is a fundamental process, which arises from the fact that physical objects possess energy. This energy results in their constituent parts (atoms and free electrons) being set into constant motion by the distribution of energy within the object.  Thus a resistor sitting on a table will produce a tiny noise voltage just by virtue that it has absorbed enough thermal energy to bring itself to room temperature.  Thermal noise generally is of very low level and it does not usually radiate into surrounding space.  But it does play a role in the design of receivers.

Noise processes of larger magnitude that do radiate RF noise into space can also be naturally-occurring phenomena, but not all radiated noise occurs naturally. There are two broad classes of radiated noise sources: natural and man-made.  Natural sources are further sub-divided into cosmic and terrestrial.

Cosmic Noise Spectrum (Source: ScienceFantasy)

Cosmic noise sources include nuclear processes within stars, processes occurring on planets and asteroids, and the background radiation remaining from the Big Bang at the creation of the universe.  Cosmic noise is important in setting the ambient noise level for signals above about 15 MHz, but with increasing frequency it diminishes in magnitude from that point.   One of the few major disruptions that cosmic noise produces occurs when the sun aligns directly with the bore of a ground based receiving dish, which is in use with a geostationary radio satellite link, and solar radiofrequency radiation overwhelms the satellite signal.  These disruptions occur only for a few minutes twice a year.  Other intense (non-noise) reception problems occur periodically from large-scale solar eruptions.

Natural terrestrial noise sources include, in major part, the continuous series of lightning strikes associated with worldwide thunderstorms primarily in the tropics and, to a smaller extent,  processes involving charged particles trapped in the upper atmosphere by the earth’s magnetic field.  The radio frequency noise produced by natural terrestrial sources tends to peak at the lowest frequencies and to diminish in strength with increasing frequency.  Thus the background noise level from tropical storms may be sufficiently high at the low end of the HF band of frequencies (3 MHz) to prevent reception of weak communications signals, but of little consequence at the high end (30 MHz) where cosmic noise sources become more important.

And then there is man-made noise.  This noise arises from the fact that humans have harnessed electricity (the flow of free electrons in conductors, driven by the “pressure” produced by differences of electrical potential [voltage] along the conductors) to do useful work.  Moving electrons produce surrounding electromagnetic fields that can, and often do, propagate through free space.  Noise fields can also be created from electrical discharges, when breakdown of dielectric materials leads to arc discharges.  With good engineering design these manufactured fields can be prevented from radiating and thus producing noise.  However, “good engineering design” is too often the polar opposite of “good quarterly ‘bottom line profits’,“ and this is almost always an unequal contest.

Regulatory enforcement is intended to redress the balance in this contest, but as we have previously seen the magnitude of the problems and the application of counter-pressure on the regulators from sources of vested (financial) interests have been effective in blunting regulatory enforcement.  Thus the world is now awash in man-made noise.  Let’s see how large the increase in RF noise has become during the time while all of us have been devoting our attentions to other matters.

Since blog postings on Amateur Radio Service topics seem to draw the largest sets of reader responses, we’ll structure this discussion in ARS terms.  In this case the ARS is the “canary in the coal mine,” but the effects on all users of the RF spectrum are similar.

The following “unplanned experiment” will illustrate the problem of man-made noise pollution in a graphic manner.  The Curmudgeon lives in a reasonably large metropolitan area.  Several months ago, in the middle of an afternoon, the commercial power suddenly failed at his house.  Outages are uncommon but not unknown there, and the Curmudgeon is ready for them.  Most of the on- board communications gear is powered directly from a battery plant, with the batteries under constant trickle charge (not unlike almost every fixed microwave installation and telephone central office).  The electronics are not even aware when/if commercial power fails.  And a gasoline-powered generator in the back yard will provide 240 VAC power to the house during extended outages.

As soon as it was evident that the outage was not due to a household or neighborhood fault and that power would not be quickly restored by power company circuit switching, it became clear that no more useful work could be done that afternoon.  Thus it was a good occasion to turn to the Amateur (and other) radios for some monitoring to see what might be happening.

The Curmudgeon’s station equipment (radios and antennas) is modern and meets currently accepted performance levels.  And, of course, many signals were available for monitoring that afternoon, as the hams in 99.99% of the US were not suffering power blackouts.

But one thing had radically changed.  Normally on 20 meters (14 MHz) the background ambient noise level indicated by the radios would vary, under changing daily conditions, between S-5 and S-9 (signal strength units).  A change of one “signal strength unit” represents, ideally, a doubling or halving of signal source field strength voltage.   But that afternoon the background noise level was …….virtually undetectable!  The radio signal strength readout indicated an ambient noise level during the power outage ranging between undetectable and S-1.

What the S-meter Means IARU Region 1 Technical Recommendation R.1 defines S9 for the HF bands to be a receiver input power of -73 dBm. This is a level of 50 microvolts at the receiver’s antenna input assuming the input impedance of the receiver is 50 ohms. For VHF bands the recommendation defines S9 to be a receiver input power of -93 dBm. This is the equivalent of 5 microvolts in 50 ohms. The recommendation defines a difference of one S-unit corresponds to a difference of 6 decibels (dB), equivalent to a voltage ratio of two, or power ratio of four. Signals stronger than S9 are given with an additional dB rating, thus “S9 + 20dB”, or, verbally, “20 decibels over S9″.

At least 99% of the routine background ambient noise power had been silenced when commercial power stopped flowing.  The radio noise that was heard that day consisted largely of the thermal noise produced by receiver and antenna.  And signals from other Amateurs across the country stood out in bold relief from the minuscule noise background.  Signals that would ordinarily have been buried under the prevailing noise level now could be easily received.  It was as though access to the rest of the world had been “opened up.”  And a similar situation existed on AM broadcast band and all the other Amateur HF bands that were also checked.

In the days shortly after power had been restored, some planned testing indicated that the amount of everyday background noise contributed from inside the Curmudgeon’s own house was negligible.  Likewise, removal of the antenna transmission line from the receiver reduced the indicated ambient noise level back to that of the thermal receiver noise.  Thus no noise was being conducted into the receiver through the power or other wiring.  All of the noise was being radiated through space from external source(s) to the receiving antenna.

Thus the “unplanned” field testing made possible by the power outage and the later confirmatory planned tests showed conclusively that a large radiated noise field exists in a metropolitan environment.  More importantly, virtually all of the ambient noise is being created through the use of electricity, both in its distribution through the electrical grid and in the operation of electrical devices.

This is not exactly “breaking news” to most of us, but we do tend to forget how prevalent and how large the noise floor problem really is.  Until, of course, these rare “experiments” come along.

Moreover, a few fortunate Amateurs live in remote, sunny locations and do not have commercial electrical service.  In some cases their nearest commercial electrical service may be several miles away, and thus these folks live in homes and operate Amateur stations powered by their own solar photovoltaic plants.  In speaking with some of these folks over the years, they have said that their ambient noise levels are very low every day (unless electrical storms are in their area) and do not become troublesome.  This is the matching, mirror image picture of the “accidental experiment” that was reported above.

If the rapid strip mining of the remaining spectrum for short-term profit and convenience is analogous in human biology to a heart attack, then the slow and insidious invasion of man-made noise into the spectrum would be analogous to a growing cancer.  Noise systematically chokes off the ability to operate reliable wireless communications circuits, and the cumulative effects of its attack mimic those of metastasizing cancer cells.

Remember that we’ve introduced this problem of man-made noise in terms of the Amateur Radio Service.  But the discussion applies equally as well to military, maritime, broadcast, and utility users of the radio spectrum.  All are plagued with these background noise problems.

In the next part we will look at the effects the increasing RF noise pollution and what might be done about it.

What do you think?

Let’s save the universe for RF!

The Old RF Curmudgeon

Since 1963, LBA has been providing RF equipment and engineering consulting services for radio and television broadcast and wireless communications.

The Federal Communications Commission (FCC) today acted (WT Docket No. 12-69) to examine the wireless system interference concerns should the Lower 700 MHz band utilize a single band class for devices operating across the Lower 700 MHz A, B, and C Blocks.

In its NPRM, the FCC seeks comment on technical and operational factors as they may impact customers of Lower 700 MHz B and C Block licensees.  The FCC has focused on two interference concerns that may result from use of a single band class: (1) reverse intermodulation interference from adjacent DTV Channel 51 operations; and (2) blocking interference from next door high-powered operations in the Lower 700 MHz E Block.  The FCC requests commenters  to submit measurements and quantitative analyses defining the magnitude and extent of adjacent Channel 51 and Lower 700 MHz E Block interference risks, the availability of effective measures to mitigate interference, relative performance of single band class devises, and costs to the wireless industry in implementing interoperability.

The FCC also wishes to explore possible next steps to take to promote interoperability in the Lower 700 MHz band should it find harmful interference is minimal, or can be readily mitigated.  The FCC NPRM sets out various options to help achieve the ultimate goal of interoperability.

LBA has 50 years of experience in RF interference management. For assistance, contact Mike Britner at 252-757-0279 or mike.britner@lbagroup.com.

Here’s your chance to be a part of the discussion! WCAI International is sponsoring a free webinar on the DAS on Thursday, March 29, at 4 p.m. Register HERE.

Addressing the issue will be David Saab, vice president for development at Selective Site Consultants. The Overland Park, Kan., consulting company is a leading provider of services to telecommunications, development, and construction industries. LBA Group Inc. chief technical officer Chris Horne will introduce the speaker and moderate the follow-up discussion.

DAS systems solve in-building wireless coverage problems

“Site development” is the industry term for the disciplines needed to build wireless infrastructure. Today’s wireless world began with a handful of towers and rooftops and exploded with the success of the cell phone. Voice begat data, data begat broadband, and the more people who used it, the more site development activities unfolded.

But the wireless boom revealed the limitations of tower or “macro” sites. The physics of radio waves and propagation through certain building materials—along with the sheer concentration of users—are overwhelming wireless networks. This has led to the development of in-building and other Distributed Antenna Systems.

DAS is deployed inside a structure as well as in limited geographical areas, such as shopping districts and parking lots. But DAS cannot be as straightforwardly deployed as the traditional tower or rooftop systems. Walls get in the way and so do other RF emissions. Limitations on space, safety, and interoperability mean carriers must work together to create networks that provide effective mobile end-user experiences.

The problem is a small in scope but big in implications, and you can learn more about it in the webinar.

LBA provides top-down review and evaluation of DAS and small cell requirements. We specialize in relating enterprise wireless coverage needs to available technologies to aid management decision making and implementation budgeting and control. Contact Mike Britner at 252-757-0279 or mike.britner@lbagroup.com.

Why is the United States (and, to a somewhat lesser extent, the rest of the First World) consuming, burning up, pillaging the finite amount of radiofrequency spectrum at a rapid, accelerating, and unsupportable rate?

Why are we (in this North American society) in effect “strip mining” this gift, this natural resource, primarily just for short term financial gain and/or transient pleasure?  What will we do after the entire available spectrum is consumed and the demand for still more spectrum continues unabated, after all the “administrative fixes” and other sleight-of-hand spectrum management tricks have been applied and still there is not enough?  When, as a result of ever increasing spectrum loading, ambient noise levels continue to rise and coverage areas continue to shrink?

What will we do when we find ourselves as a society and an economy trying to shovel six new pounds of puppy poop into our sole remaining one pound bag?

From much pondering and thinking about the problem a tentative “first cut” at a general explanation did finally emerge, and it is presented here for discussion, along with a proposed approach for a solution.

The Curmudgeon has used the following list of observations, all from his personal experience, as part of the work toward a first tentative answer.

1.  A young saleslady at an electronics store operated by a well-known nationwide chain cannot answer the question “can this TV set (which I am considering buying) receive over-the-air television broadcasting?,” a medium of which she has no knowledge.

2.  A middle-level IT manager, needing to transfer one of his wire line digital networks onto a public wireless platform, cannot understand that wireless networks do not have the inherent transmission reliability of an Ethernet system, and that different wireless carriers have different service area coverage maps.

3.  Cellular telephone base station technicians have never heard of the equivalent private land mobile radio networks, and in any case have no interest in learning anything new beyond the details of their own field of employment.

4.  Employees in an IT department in a large corporation sit at their desks making cell phone calls (on company-funded commercial mobile carrier accounts) while their desk telephones are at easy arms’ reach.

5.  Many, probably a majority, of Amateur radio operators have no idea at all what kinds of radio services co-share the spectrum, even one kilohertz outside the edges of their own ham bands.

6.  Computer owners reflexively install “wireless routers” in their homes and apartments and accept potential security problems and range-reduction from RF congestion, rather than to do a one-time installation of Ethernet cable.

7.  AM radio broadcasters complain about “excessive ambient radio noise” and reduction of their coverage contours in the urban areas that they serve, leading to increasing inability of their audience to receive usable service from the broadcasters.

In the Curmudgeon’s judgment all of these situations largely, but certainly not uniquely, point toward a common source, one basic origin:

The citizens of the United State, in overwhelming numbers, do not understand at a conscious level that the radiofrequency spectrum exists as a physical medium, that it is a finite resource which they themselves own, and that it is in some respects a “fragile” structure requiring attention. 

Little Public Spectrum Education Is Offered in The US.

The average, even the well-educated, citizen of the United State is clueless about this.  Few know of the existence of electromagnetic fields, and even fewer are conversant with how the fields lay out and are used for practical needs.  No individual outside of the wireless industries could begin to place even a rough economic value on this unique natural resource, and in today’s economy it is the “cost” of something which determines how it is treated.  “Free goods,” which are not subject to “full-cost accounting” and thus whose prices do not include their real environmental costs, are almost always squandered, and today the use of the radiofrequency spectrum is, for consumers, a free good.  (Cellular telephone carriers and broadcasters, of course, have a radically different view of this!)

Is it therefore surprising that consumers are smitten by the idea of doing all their communications (in the general sense of the term) and their entertainment “wirelessly,” and that many manufacturers of consumer goods look at no-cost use of the radiofrequency spectrum as a quick, cheap, and easy way to increase their sales?

What practical need does the public have for understanding the existence, limitations, and liabilities of the spectrum?  Why shouldn’t they just continue to “flow their individual lives onto the spectrum” and never think twice about what they are doing?  For them, generally, there has always been “sufficient spectrum” into which to expand their needs and, to be accurate about this problem, most areas of the country and most radio services didn’t begin to experience serious spectrum shortages until perhaps the beginning of the 1990s.  It’s a fairly new problem, but one that is growing in seriousness and urgency.

The place to have once learned something about the spectrum is in the elementary and secondary schools, but elementary school teachers generally are not well-conversant and comfortable with science (and math) and in secondary schools only a tiny percentage of U.S. students (i.e., the “nerds”) study physics.

Even in the small number of surviving high school physics classes, the curriculum unit on the EM spectrum flashes rapidly by, with just a mention that “radio lies between this frequency point and that point, while above it……..”  Even five minutes in a physics class spent discussing the basic structure of radio applications (transmission, wave propagation, and reception) and mentioning some of the services which occupy the spectrum would be a “great leap forward” in public understanding.

In engineering schools the EM spectrum often gets short-shrift.  ME, CE, BioE., and Comp.E students will get very little exposure to it, and even within the EE field “electromagnetics” isn’t a high priority subject area when compared to DSP, digital circuit design, solid-state devices, etc.  Consequently many engineers themselves aren’t able to discuss the topic knowledgeably with their non-engineering friends.

If the electromagnetic spectrum could at least be recognized by the general population as a publicly-owned natural resource that needs to be kept sustainable, there would be some basis for hope.  Proposals, for instance, to massively log and clear-cut Yellowstone National Park would almost certainly be met with strong opposition from a public that is knowledgeable about the damages that would result from this action.  They would raise considerations about long-term resource sustainability versus short term profit.  The same kind and degree of response should result from proposals to strip-mine the radiofrequency spectrum.

But there is precedent for public action on radiofrequency conservation from other independent efforts already occurring in a different part of the electromagnetic spectrum.  Terrestrial astronomers have had some success in dealing with “light pollution,” created by the existence of indiscriminate outdoor illumination within large cities during the hours of darkness.  The increased city light fluxes, when scattered by atmospheric particles (thus producing, i.e., “noise” in our working vocabulary), diminish the astronomers’ ability to receive very small numbers of photons from distant stars and galaxies.  So the astronomers have begun working with local governments to institute more efficient (and controlled) nighttime lighting and thus to lower their local background noise levels.  And they have had reasonable successes with their efforts.

If one technical field has shown the path, why cannot we, the (relatively low frequency) occupants of the same spectrum, follow their lead?

A tentative list of the goals for a program of going to the public with a campaign for education and spectrum cleansing would include:

1.  Bringing to general public awareness the existence, function, ownership, uses, and need for sustainability of the radiofrequency spectrum.

2.  Making the public aware of the economic value of the spectrum as a limited natural resource.

3.  In view of the natural scarcity of spectrum, leading a new public discussion of a prioritization of uses for the spectrum.

4.  Sponsoring a campaign for reclamation, abatement, and clean-up of human-caused radio noise pollution, including non-radio electrical noise generators.  This would include pressing for both “efficiency” in individual applications (i.e., the “most bang per input watt” and the least perturbation of the general radio noise level for each proposed RF application).  This is in line with other conservation campaigns, both for increased energy efficiency and for reduction of pollution from various kinds of sources.

The IEEE Has resources to Lead Spectrum Education

Finally, there is the question as to who should be the “point man” to conduct the campaign.

The Curmudgeon has an initial recommendation.  It should be the IEEE, the largest professional organization which deals with “matters electrique.”  They have both the stature and the experience to conduct this campaign, which might well begin with increasing their own members’ understanding of the spectrum.  The IEEE has already published some articles dealing with radiofrequency spectrum matters in their general interest engineering magazine Spectrum and thus has an existing understanding of the problems.

The very notion that the citizens of the United State could actually understand this matter of great natural and economic importance and could participate in gaining effective control of the existing problems is astounding!  But the Curmudgeon has faith that it could be done.  Wouldn’t this be a fine time to get it started?

What do you think?

“Let’s save the universe for RF!”

The Old RF Curmudgeon
(A conservative conservationist)

Since 1963, LBA has been providing RF equipment and engineering consulting services for radio and television broadcast and wireless communications.

Chris Horne, the chief technical officer of LBA Group Inc., will host and moderate the webinar’s Q&A period following a presentation by Joe Blanchard, chief operating officer of Spokane, Wash.-based ReliOn. The company is a global leader in development of modular, fault-tolerant, proton exchange membrane fuel cell technology.

ReliOn fuel cell for remote site power

An estimated 1,300 fuel cell systems are situated at cellular and telecommunication sites in North America as backup units during periods of interrupted power service. The hydrogen fuel cells have several advantages over the more traditional diesel power units, including being quieter, longer-lasting, and more easily and less frequently fueled.

Integrating the units into a wireless provider’s energy management plan can have significant bottom line consequences. Utility rates can be reduced and credits earned for a company that has reduced its peak power demand. The webinar will offer examples of how to optimize energy usage.

Blanchard joined ReliOn in 2005, coming there after 18 years in management at Texas-based Fujitsu Network Communications, an innovator in connection-oriented Ethernet and optical transport technologies. In all, Blanchard has been working for more than a quarter century in design, development and support of products spanning DLC/DSLAMs and FTTx systems, telecom cabinets and power systems, optical transport, DWDM systems, Class 5 switching and PBX systems.

Horne is a professional registered engineer with a doctorate in electrical engineering. He is a board member of WCAI, the trade organization for the wireless broadband industry with a mission of advancing opportunities for the industry. The organization’s several hundred members include such heavyweights as AT&T, Sprint and Clearwire.

The hour-long WCAI webinar begins at 4 p.m. eastern standard time.  Member sign-up details here.

Since 1963, LBA has been providing RF equipment and engineering consulting services for radio and television broadcast and wireless communications.

Members of the three-person panel were Thomas Knippen, who is vice president and general manager at Benton Ridge Telephone Company and W.A.T.C.H. TV; Greg Williams, senior VP for corporate and business development at BelAir Networks; and Jeff Kohler, co-founder of JAB Wireless, Inc. and responsible for merger, acquisition and corporate development activities.

A technical examination of licensed and unlicensed spectrum was carried out before an audience of about 40 wireless operators, venture capitalists and technologists. The panelists weighed in on two corollary questions: how can wireless congestion be mitigated, and is the better answer in parsing available spectrum or creating new technology?

Their conclusion: a combination of technology and spectrum management is necessary.

“There was a consensus that unlicensed spectrum is here to stay,” Horne says. “Both WiFi hotspots and small and large companies who deploy unlicensed networks will be a part of planning to improve the wireless experience.”

One panelist observed that for a company to utilize “WiFi” does not always mean deploying it. Rather, a company might use unlicensed frequency bands for distributing and backhauling traffic for experimental work or partner with carriers to offload cell traffic.

The industry fully recognizes that wireless network congestion is a genuine problem to be addressed by development of new equipment and technology. To get by at the moment, AT&T is using carrier WiFi to offload traffic in the unlicensed spectrum. Heterogeneous Networks—HetNets—have a crucial role in enhancing capacity. Some fixed wireless operators are partnering with mobile wireless carriers to offer complementary off-loading and backhauling of internet traffic.

All internet service providers are reeling from the data explosion. Consequently, unlicensed ISPs and licensed ones are eying one another to meet their disparate needs. The time may be ripe for partnerships.

Management of the radio spectrum was viewed by panelists as two forces at play: regulation of spectrum versus the “market.” It was noted that cloud services like Apple iCloud and Google music require even more bandwidth and high throughput. That led to the suggestion that a combination of regulated “white spaces” and unlicensed offload might be the best way to mitigate the capacity issue

Panelists also weighed in on the use and practicality of TV white spaces in rural areas where unlicensed space is not congested. Rural areas have better propagation conditions, one panelist noted, but the technology right now does not have any special performance incentives. Panelists talked of the various tradeoffs involved and concluded TV white spaces are an option but not a preeminent one.

Some current WiFi developments were touched on by the panel. It was noted that chip maker Broadcom announced plans for “gigabit WiFi” device, two and three times faster for the 5 GHz band. Unconfirmed reports surfaced about mobile equipment and services supplier Ericsson purchasing BelAir Networks, which provides strand-mounted picocell devices for the unlicensed bands for carrier offload. The Japanese operator KDDI claimed that its new free WiFi network with Android smartphones reaches 10,000 locations and will scale to 100,000 locations by March.

A specialist in wireless system engineering, Horne is a veteran of such discussions as this one. He was a panelist last fall at a 4G World conference in Chicago where splitting and rebranding spectrum was dissected for conference attendees.  Horne is leading another conference presentation in April at a Minnesota State Wireless Association event entitled “The Future of Wireless.”

Panelists (from left) were Chris Horne, Tom Knippen, Greg Williams, and Jeff Kohler

As wireless cell towers and antennas flourish, towns, cites and municipalities are challenged to adopt ordinances that let citizens receive the best telecommunications services available. Regulatory legislation hasn’t helped. The Telecommunications Act of 1996 was over 500 pages long; during debate, most legislators considered it to only be about deregulation. But buried inside the Act, in Section 704, lay a crafty clause about the siting of cell-phone towers that trips up planning and zoning groups.

For this and other reasons, zoning boards are challenged to approve high-quality wireless services. It doesn’t help when they don’t understand microwave propagation.

An appreciation of microwave propagation comes into play when carriers and network operators are faced with securing wireless transmission media (often a microwave link “backhaul”) that relay the wireless traffic to the landline network or between towers. As more educational institutions offer additional classrooms in distance education and remote video conferencing, their needs also increase for wireless systems and backhaul.

Collocation Tower with Cellular and Backhaul Antennas

As a case in point, a town in Illinois accepted an application from SBA Towers to replace an aging tower on a college campus with a taller monopole structure to allow better backhaul of college networks and to support more wireless tenants. The existing short tower was structurally limited but was situated in adequate campus space to meet setback and other pertinent city requirements. The application was presented to the town by wireless zoning attorney Richard Connor Riley, supported by expert testimony from LBA’s Chris Horne. Chris’ work included a microwave path study of the existing and proposed college backhaul link.

This is where it gets interesting.

The study was performed for a proposed new digital transmission system serving four video conference classrooms and also transporting all internet traffic between the college and a remote teaching facility. The included digital microwave link would be a backup to an existing fiber network between the two campuses.

Controversy arose centered on a proposed antenna dish that was needed to support the data requirements of four video conference classrooms. It would replace an existing microwave dish that served only one classroom and was an outmoded analog link with limited performance and capacity compared to the proposed digital replacement.

When LBA evaluated the microwave installation, it confirmed that greater height was needed for the new dish to support the required performance of the system. It had not been obvious to zoning authorities that such an increase was necessary; the devil was in an “invisible” gremlin!

A close evaluation of the microwave path between the campus and a far terminal revealed that a tall hotel building under construction several miles away was rising exactly in the path of the beam. At its final height, the building would penetrate the microwave Fresnel zone and block the microwave signal. Based upon LBA’s engineering evaluation, the town zoning board was persuaded to approve the SBA tower application, and clear the way for the higher microwave dish. The university learning network was saved!

So – just what is this mysterious microwave path Fresnel zone?

In order for radio waves emitted from a transmitting antenna to reach a receiver without attenuation of power, a certain amount of 3-dimensional space is required. The radio wave energy cannot reach the receiver via one straight line in space. Think of a hole the size of a needle in a concrete wall. If you shout across a pond to the wall, do you think all the sound penetrates only the hole?

The Fresnel zone or First Fresnel zone (0.6) is a three-dimensional elliptical space surrounding the line of sight path from the transmitter to the receiver. If a reflective object is placed anywhere on the edge of the ellipse, it will cause a reflected signal that, due to propagation delay, is delayed 180 degrees (“carrier phase shift”) with the line of sight signal at the receiving antenna. Digital radio equipment is typically robust in the presence of propagation fades and other noise. However, if there is an obstruction between the antennas (ground, buildings, natural objects, etc.), the radio waves will be reflected, resulting in multipath interference and unacceptable bit error rates–think old TV “snowy pictures.

Depiction of a Fresnel Zone in urban environment

A 0.6 Fresnel zone clearance is normally desired for microwave paths. While “line of sight” (LOS) is important, it obviously is not always adequate. Even though the path may have clear LOS, when obstructions penetrate the Fresnel zone, unwanted signal attenuation results.

This is precisely what happened in this case; a building encroached upon the 0.6 Fresnel zone of the proposed college microwave link. Such obstacles can wreak havoc on wireless backhaul including transmission errors and signal reception issues.

The take away here is that next time you plan a microwave backhaul link, be sure to consider the Fresnel zone, LOS obstructions, and other antenna placement factors. Consider every detail of the traversed terrain, including vegetation, existing, and planned construction. A detailed path study will provide valuable input results for an efficient tower placement scheme that meets both coverage and transmission quality metrics. A not unimportant byproduct is that it also provides the basis for a credible defense of a tower proposal in an increasingly contentious zoning environment.

LBA can help with all of the above. LBA also offers RF Engineering services including expert testimony and system design. We offer extensive zoning technical support here. Other capabilities include microwave system design, path study, and RF engineering services here.

“As one of the awardees from around the country, you have distinguished yourself as one of the leading entrepreneurs in the United States,” said Kenton Clarke last week in announcing LBA Group’s listing among 2,500 successful businesses in the U.S.  Clarke is CEO of DiversityBusiness, the nation’s largest organization of minority-owned companies doing business with Fortune 1000 firms, government agencies and universities.

Besides the national recognition, LBA Group earned a spot in two significant state rankings by the same organization: Number 51 among top 100 minority businesses in North Carolina and an identical ranking among top 100 privately held companies in the state.

The three awards continue LBA’s run as a recognized small business success story in an economy that tests the mettle of every company.

“LBA is particularly honored to be recognized for 2011,” says Lawrence Behr, company founder and CEO. “It is gratifying because it comes at a time of international economic stress. We are succeeding because of the commitment and excellence of our diversified team.”

Behr entered the industry in 1963 after becoming fascinated as a teenager by AM broadcast engineering. First hiring out his skills, the young Behr soon formed his own company.

Today, LBA Group, Inc is comprised of two units: LBA Technology, Inc. which markets such products as AM antenna systems, antenna test equipment,  EMF shielding, and RF safety monitors to wireless, commercial and military users; and consulting firm Lawrence Behr Associates, Inc., offering  professional services including cell tower zoning and RF safety compliance, RF safety training, EMF shield design and testing, RF interference resolution and distributed antenna system (DAS) services.

LBA Group is very much a global company. It has been deeply involved in telecommunications projects on every continent—from Europe to the Middle East and Africa and across the entire length of South America. A contract completed in January was for India’s radio broadcast system.

LBA Group and other award-winners will be recognized at the organization’s 12^th annual National Business Awards Conference, held this year on April 25 at a resort in Mashantucket, Conn.

We have now finished reviewing the dismal (partial) list of historic FCC spectrum management engineering mistakes, and in this final part of the series we’ll look at some suggestions for how the FCC could, ideally, conduct this highly-important function.  The Commission would never adopt any of these proposals, of course, but “even engineers can dream!”

As detailed earlier in this series, too many times the FCC regulators have dipped their pinkies into technology and have tried to force ‘regulated” spectrum management solutions which buck the well-known laws of physics.  Their regulatory development process (at a general level) seems to operate as follows:

 1. Especially under prodding from Congress and/or from specific entrepreneurs or regulated industries, promote development of a new spectrum-using technology by proposing an allocation of a slice of spectrum to accommodate the new systems.

2. After the public discussion and the submission of Comments has ended, ignore recommendations from well-qualified engineers and technical experts, both within the Commission and external to it, which are in full or partial opposition to the proposal as written.

3. Adopt the proposal by using administrative fiats that declare that the opposition’s technical findings are “of no merit” or, alternatively, by issuing their own “administrative fixes” to circumvent any identified problems.

4. After operations of the new technology are implemented, begin receiving complaints from established spectrum licensees/users that their existing operations are becoming affected by the new activities.

5. Transfer the burden of proof that damages have indeed occurred entirely to the complaining parties, while retaining the option for the Commission administratively to dismiss the complaints because of “non-proof” of the claims (at least to the Commission’s satisfaction!) or because of the demonstrated narrow “technical compliance” by the newly established systems with “existing Rules.”  This then leaves the federal judicial system as the only remaining remedy for redress of damages, again at the injured licensees’ own expense.

6. Finally, if matters cannot be resolved in any other easy way, propose an ad-hoc “administrative settlement” together with modified Rules which solve few of the FCC-created problems, leaves no party satisfied, but provides an easy way for the FCC to exit gracefully.

FCC Spectrum Management Universe

The FCC’s historical record in spectrum management is one of repeated poor-to-disastrous engineering decisions, punctuated with occasional successes (for example, the Personal Communications Service [PCS]).  Too much at the FCC has gone too badly wrong for too long a period of time for this level of poor agency performance to be dismissed or to be labeled as “unimportant.”  Their cumulative record is equivalent to leaving Apollo 11 motionless on the launch pad, rather than on its way to a first lunar landing.  At the bottom of it all, this record is one of failure!

The Curmudgeon is an informed citizen who is angry about the quality of regulation that has been historically provided by the FCC.  Not angry because the FCC is a governmental regulatory organization.  Angry, rather, because it has been government done poorly!  Angry because the FCC has always been an organization with grossly insufficient direction from both its own scientists and engineers and those in the outside professional community.  Angry because the people at its top who cannot possibly understand the spectrum management engineering arguments and their ramifications still make the final decisions.

It is generally not the case that the FCC is administered by uneducated bureaucratic dummies who are the “survivors” in the civil service.  (The Commissioners themselves are political appointees, so not much relief can be expected there.)  Their top staff people may well have advanced degrees from well-recognized universities in law, economics, public service, or business.  But they may also carry college academic transcripts that indicate they earned grades of C- or lower in their “introductory survey of physics for non-science majors” or “business calculus” courses, the last technical requirement courses they might ever take.  It would be fascinating to know!

Would you still believe that a solid background in a technical discipline isn’t really a necessity for a successful top manager in that same discipline?  Then you ought to consider the prospects for a hospital surgery department managed by a Wall Street options trader.  Or an airline’s Pilot Training and Certification Department administered by an (non-aviator) economist.  Or a nuclear power plant Reactor Operations department led by a divorce lawyer.  And, for that matter, a clinical psychological counseling group managed by an RF engineer!

There are few easy decisions to be made in the area of RF spectrum management, which, by its very nature, is a highly technical area.  Is it not perhaps reasonable and rational for the regulatory decision makers in spectrum management to be highly qualified in its physics and engineering disciplines?  Is it not reasonable for the regulators to accept, and even to actively seek, engineering advice from non-governmental technical experts?  Certainly lawyers can write the subsequent Rules, and economists can do the industry financial assessments.  But highly experienced engineers need to make the spectrum management decisions!  And by the way, in this new and enlightened era politicians and lobbyists would be nowhere to be seen around the FCC!

What a beautiful, satisfying dream-in-progress experience this was…..which dream was abruptly terminated in mid-course by the clamor of trash cans clanging in the alley behind The Portals in Washington, D. C.!  “And so another typical day at the FCC begins……..”

What do you think?

“Let’s save the universe for RF!”

The Old RF Curmudgeon

Since 1963, LBA has been providing RF equipment and engineering consulting services for radio and television broadcast and wireless communications.

The 4GWE conferences attract wireless carriers and industry stockholders who are keen to stay on top of swiftly changing technologies and applications. Anyone in the wireless industry knows the sweep of change involved these days, and one such phenomenon is the lowering of barriers between licensed and unlicensed wireless spectrum providers.

At the conference, Horne—a registered professional engineer with a doctorate in electrical engineering—will be one of five panelists in a discussion of “Breaking Down the Licensed-Unlicensed Wall.”

Because the demand for more spectrum is blurring and fusing the worlds of licensed and unlicensed internet service providers, the panel will explore the possibility of more efficiently utilizing spectrum by blending it between the two ISP categories. This fuzzing of distinctions between licensed and unlicensed providers crosses the threshold into another brave new world of spectrum usage.

Another example of the movement toward parsing spectrum is the Federal Communications Commission’s approval of sharing UHF and VHF television channels. The decision came after experimental trials of TV spectrum-sharing were conducted in several areas, including Wilmington, N.C.  KTS Wireless is a pioneer in this whitespace radio technology.

Horne is a veteran of such discussions as these. He was a panelist last fall at a 4G World conference in Chicago where splitting and rebranding spectrum was dissected for conference attendees.

For the Miami discussion, on the panel with Horne are Thomas Knippen, vice president of W.A.T.C.H. TV; Phillip Merrill, owner of Arizona ISP company, BeamSpeed;  Dr. Mohammad Shakouri, vice president of broadband solutions provider Alvarion; and Greg Williams, senior vice president of BelAir Networks.

Conference attendees can take part in the panel discussions, network with wireless world peers, and view new products and services of an expected 200 exhibitors on the convention center floor. To register for the conference, or for more information, the 4GWE contact person is wireless spectrum, overloaded wireless spectrum, 4G Wireless Evolution conference,4G Wireless Evolution conference,4G Wireless Evolution conference, 4GFrank Coppola at 203-852-6800 extension 131 or he can be e-mailed at fcoppola@tmcnet.com.

Here at LBA Group Inc., our team did a magnificent job of tuning out the static and vectoring in on solutions to customers’ needs. Consequently, we are able to look back on the year with considerable satisfaction and to look forward to 2012 with genuine eagerness. We believe we are well-positioned to ably serve old and new customers and to grow our position in the market.

So… Happy Holidays from all of us at LBA Group Inc. May your New Year be replete with personal and professional success.

In this post we will finish the list of FCC historic spectrum management mistakes that began with Part 1 of this series.

12.  Land Mobile “Re-farming:” (1990s-present). By itself not a major league blunder, but more of a “wolf in sheep’s clothing” gambit.  The basic idea is to halve, and then later halve again, the occupied (RF channel) bandwidth used by individual private land mobile networks, in order to squeeze ever more of them into a very limited amount of spectrum.  This kind of action is consistent with the basic FCC practice of just ignoring the laws of physics whenever it suits their administrative needs.  There is nothing fundamentally wrong with the concept, except that the compliant licensees will inherit new systems with operating characteristics different from those to which they designed and built their original systems on the (then) wider channels.

Private land mobile operations overwhelming use analog FM emissions, and as the bandwidth of an FM channel is progressively narrowed, the inherent signal/noise advantages of FM emissions, compared to envelope-modulated methods, proportionately diminish.  By the time the occupied channel is narrowed to the bandwidth of an equivalent AM signal, there are no remaining FM signal/noise advantages over AM.  Hence with new “AM performance-equivalent networks,” system operators will find themselves with smaller than expected operating radii and an increase in operational noise problems.  (Different problems apply to digital land mobile radio systems, which are not considered here.)

Mobile Radio is Still the Backbone of Public Safety

13.  “Broadband” Public Safety nationwide interoperability network (2000s-present).  This one is more than just an engineering blunder; it’s a total system failure!  September 11, 2001, showed the glaring deficiencies in our Public Safety first responders’ radio networks, especially in the area of interoperability of responders from different agencies under emergency conditions.  Commendably the FCC began quickly to develop a plan for a replacement “nationwide broadband interconnect network” for the current fragmented system, including clearing spectrum at 700 MHz to house it.  But now September 11, 2011 has passed and as a nation we have produced………. nothing!  We’ve diddled around with “novel economic concepts” for funding the system, to no avail.  But we haven’t really begun in earnest to design and to build the new system.  On the “FCC time table” it would be another 2½ centuries before the US would first land men on the moon!  It might just be more productive for a different agency to take on this priority project.  “Hey, NASA…………!!!”

14.  Digital broadcast radio – “In Band On Channel” (2000s).  This really isn’t inherently a bad engineering idea, rather more of a botched implementation.  Eventually broadcast radio (AM and FM) will need to transition from the analog world to the digital realm, to join just about every other medium of contemporary information transfer.  Unfortunately with a huge installed base of radio receivers, comprising a much larger number of receivers than the equivalent installed television receiver base, the “single national transition day” concept that was used with some success for television probably isn’t feasible for radio.  And there is insufficient unused broadcast radio spectrum to assign to our current broadcasters temporary “second, digital channels,” as was done with television.  Some sort of simultaneous “dual mode on a single channel” radio transmission scheme is necessary to permit a long time-scale transition before the analog modes sunset.

For the simultaneously compatible digital system the FCC chose the Ubiquity IBOC concept, which the manufacturer promoted as “In-Band On Channel.”  Unfortunately the engineering reality is somewhat different; it’s “IBAC, In-Band Adjacent Channels.”  In both AM and FM band digital modes, digital modulation sidebands on the analog carrier can extend into both first adjacent channels.  Spectrum analyzers will demonstrate that presence, and on-air interference complaints corroborate the problems.  If, instead of the FCC’s administratively “bending” physics to meet its regulatory needs, it had instead planned for the necessary cleared adjacent channel spectrum and made adjustments to currently assigned stations, the concept might have worked from the beginning.  Or if it had ordered multiplexing of the programming from all the stations in a particular “city of license” onto a single new digital-only carrier (as is done in satellite radio broadcasting) while continuing with the existing separate analog carriers, the transition to new receivers could have been facilitated.  Now ????

FCC Mapping of Broadband Availability – 2010

15.  “The Broadband Superhighway” (2000-present).  In the words of the late great Ed Sullivan, “this one is really, really big!”  Trusting the “big carriers” to develop a physical and operational structure for an affordable nationwide, universal broadband digital network, a capability required today as essential infrastructure in the global economy, the FCC again dropped the ball.  The carriers failed to develop a universal network.  Today there is no single nationwide broadband highway that extends into most citizens’ homes or businesses, or even a plan for one, but rather a patchwork of different high cost (relative to other countries), modest performance transmission methods and services.

Now that we are in the fourth quarter of the game with the clock running down, the FCC is ready to play “catch up football” and to begin throwing Hail Mary! passes.   But there is still no workable plan.  And indeed the FCC (as well as other cognizant federal agencies) still shows almost no interest in the single solution that would meet the requirements: universal basic fiber-to-the-premises networks with sufficient natural operating bandwidth to meet every conceivable future need.  Instead they are expediently promoting everything but that solution.  Most perniciously, the FCC is casting its hungry eyes upon the RF spectrum on which to do a “quick and dirty” RF implementation, contemplating devouring huge chunks of spectrum for new “broadband” transmission services that could better done on land lines (i.e., there is no justification for supplying RF broadband service to an urban building).

If the FCC were in charge of developing a universal, nationwide materials-transportation network for example, they would today be enthusiastically promoting all of the following (and more):  mule trains, river canoe traffic, one-shot space cargo missiles, under-sea dolphin delivery systems, etc.  They would be involved in everything except clearing land and laying rails or asphalt on it.

GPS Interference Problem Illustrated – GPS Working Group (PDF)

16.  LightSquared (present day).  “Just when you thought it was safe to go back into the water…..!”  This is the matter that precipitated the original visualization of the Sweet Sixteen list.  In the year 2000, to its credit the federal government’s executive branch opened the (until then) mostly military-oriented Global Positioning Satellite system to the general public and thereby launched an entirely new industry:  high accuracy Navigation and Timing.  With cheap and useful terrestrial hardware and a reliable and well-maintained fleet of satellites, and especially with secure satellite operating frequencies that could be successfully received over most of the surface of the planet, GPS offers levels of technology, convenience, and service never before available.  But even that achievement may not be sufficient to preserve GPS as we have grown to know it.

In its mania to develop some kind of “universal broadband” service, the FCC now stands ready to sacrifice GPS.  In a block of L-band frequencies immediately adjacent to the block in which the civilian GPS service now operates (military GPS has additional satellite frequencies for its needs), the FCC has given LightSquared a waiver of Mobile Satellite Service (MSS) rules to permit “supplemental” terrestrial broadband data services to otherwise inaccessible locations.  In fact, LightSquared proposes a system of over 40,000 transmitters, virtually identical in function to those already deployed by AT&T, Verizon and others for wireless service. The LightSquared licenses to construct and operate the system are conditioned on resolving interference problems with GPS.

On the face of it, the MSS and GPS systems should be “compatible.”  They both would operate from comparable orbital space locations with comparable transmitted power levels. But the huge number of terrestrial MSS “repeaters” each operating at powers up to 1600 watts, change the game! Blockage of the received GPS signals through receiver overload from strong adjacent channel MSS terrestrial repeater transmissions becomes a huge risk!  Even a Boy Scout working on a merit badge in “radio” should be able to see through this one!

In just a decade GPS has come to be the underpinning for a number of essential, critical services.  It has been widely successful.  Why jeopardize it?  “What must the FCC have been thinking?” The civilian GPS manufacturers and the military both strongly oppose the plan.  Yet the FCC continues with it.  [The utterly bizarre and high intricate politics behind this proposed system, which details are to byzantine to explore here, do explain much of the apparent illogicality. (hint: “think $$$”)].

Next time, in the final installment of this series, we’ll postulate how an engineering-competent FCC might approach spectrum management.

What do you think?

“Let’s save the universe for RF!”

The Old RF Curmudgeon

Since 1963, LBA has been providing RF equipment and engineering consulting services for radio and television broadcast and wireless communications.