Low Power Signals: Special Interest Noise

NAB/NPR attempt to dupe congress on interference

May 2000

On January 26th 2000, the Federal Communications Commission voted to create a new low power FM service. The new rules allow small non-profit groups, libraries, churches and community organizations to apply for licenses to operate simple, inexpensive local radio stations. Such groups used to be able to get local radio licenses in the early days of FM. In the early 1960s, there were thousands of non-commercial community radio stations. Since a policy change in 1978 urged by NPR, community radio licenses have been nearly impossible to get.

The FCC was dismissive of the need for local radio licenses in the ensuing 22 years, but were convinced to take action by a broad coalition of ethnic language groups, media activists, city councils and public safety groups. They were further spurred to action by the looming threat of the pirate radio movement. A series of surprising courtroom victories created legal doubt about the fairness and legitimacy of our nations broadcasting rules. Though some of the microbroadcasters cases were ultimately lost in the courts (currently on appeal), a great deal of momentum was created and many otherwise upstanding citizens were taking to the airwaves without a license as a form of protest against corporate domination of media. The pirate radio operators put the sometimes progressive FCC chairman William Kennard in an awkward position. As the chief guardian of an orderly spectrum, he could not allow an open rebellion against the FCCs allocation system. Kennard admitted, however, that pirates had some legitimate concerns about overly concentrated ownership of media and the lack of opportunity for communities to use the airwaves. The new FCC Chairman decided that he would make it a priority of his administration that legitimate opportunities be created for new voices on the radio dial.

In conjunction with his campaign to crack down on pirates, Kennard announced that he was ready to make some real changes to the FCC policies regarding who could get a radio license. The FCC opened a rulemaking proceeding in January of 1998 to examine their allocation rules, and sought public comment about what sort of shape the new radio service should take. They got more public comment then they bargained for! A new record was set for public participation in the Low Power FM Radio proceeding. There were over 3500 comments on docket 99-25, overwhelmingly favorable for the new service. This was just a fraction of the tens of thousands of informal inquiries that the FCC received yearly about starting a local radio station. The formal comments were often dozens and sometimes hundreds of pages long, with elaborate engineering schemes, various allocation methods and documentation of enormous support for the concept. William Kennard was excited at the prospect of such invigorated citizen participation at the FCC, and pledged that he would make every effort to build such a service if the FCCs engineers found it to be technically feasible.

Four formal engineering studies were prepared for the LPFM proceeding to address the single biggest issue: interference to incumbent broadcasters. The only opponents of the new service were the people who already owned or worked for radio stations. The incumbent broadcasters argued that any new stations, no matter how small their power, would dramatically increase interference and cause their stations to lose the service area that they had become accustomed to having. LPFM proponents claimed that the amount of interference that could be caused by the new stations was so small that it would make virtually no difference to the overall radio environment.

Overpowered By Funk

To understand the technical issues involved, it is important to clearly understand the difference between Frequency and Power. Frequency is what we use to differentiate between stations on the FM band. Each station has its own frequency, which is what makes it different from all the other stations in town. Frequency is measured in millions of cycles per second, otherwise known as megahertz. One station might have a frequency of 91.3 MHz, another might have a frequency of 92.5 MHz. The frequencies are allocated in channels, that are .2MHz wide, and by convention they are only on odd decimals running from 88.1, 88.3, 88.5......107.9 MHz. In Europe both odd and even decimals are used: channels can be 88.1, 88.2, 88.3 etcetera. If you have ever heard a radio station describe itself as being "91 FM," they are probably actually broadcasting on 90.9 or 91.1 FM. Two stations are described as Co-channel if they share the same frequency. If you operate a station on 91.3FM the stations that are first adjacent to you are 91.1 ( first adjacent channel below) and 91.5 (first adjacent channel above). The second adjacents for 91.3 FM are 90.9 and 91.7 MHz, etcetera , etcetera...

Power is a measure of the strength of the radio waves. Power is measured in watts. A stations power measures its ability to penetrate walls, the number of times that it can bounce off of obstructions and still be able to induce a listenable signal in the receiver. Typical radio stations operate with powers of 6000 to 50,000 watts: some older stations broadcast with as many as 300,000 watts. It should be remembered that radio is actually pretty much the same phenomenon as light, and that the waves travel, bounce and dissipate in mostly the same way as light does. FM signals can often travel to the horizon with just a few watts of power. They are quickly overwhelmed , however, if there is another signal of the same frequency and higher power close to the receiver. If the FCC wanted to prevent any interference at all between radio stations, it could only license one radio station in the whole world. As a practical matter, the FCC engineers and policy makers balance the need for new stations versus interference that will be created. New stations are allowed if they do not cut into the protected coverage of old stations. They do this by making sure that transmitters are far enough apart that they do not cut into each others main service territory.

Interestingly, most interference is not "caused" by transmitters. The channel allocation scheme that is still in effect today was designed before the invention of the transistor. When all stations were tube driven and the technology was more primitive, stations had a tendency to wander off frequency as they heated up. A wide berth was left for them so that they would not interfere with their neighboring stations. Today radio stations do not wander at all- microprocessors keep them within a tiny fraction of their allotted frequency. Even a hundred dollar pirate radio kit can perform up to the very strict current FCC standards for staying exactly on channel.

The real interference problem is in receivers. Car radios and component receivers generally have no problem handling interference from radio stations on adjacent channels. They have good systems of filters so that the listener only hears the station they are trying to get. These filters only cost a few pennies, but the manufacturers of some walkman, boomboxes and clock radios leave them out to keep their costs down.

Pigs in a Blanket?

The only substantive form of interference that can be cause by an LPFM station is what is known as "blanketing" interference. This is the interference that is caused in a small radius right around the broadcast antenna. What happens is that the receiver is so overwhelmed by the power of the close signal that it has a hard time filtering out the more distant signals of other radio stations. It is sort of like listening to a clock radio in the middle of a Led Zeppelin concert- you and maybe 3 people around you may be able to hear the clock radio better than the PA system, but to everyone else, the "interfering" noise from the clock radio is unnoticeable. The blanketing effects are thought of as affecting the co-channel, first, second and third adjacent channels. There are also limited effects on other channels when radio stations of very high power are involved. These effects created by the new low power FM service could be heard for perhaps as much as 400 feet around the transmitter site. It is also important to realize that LPFMs, like full power radio stations, are required by law to address any interference complaints caused by their stations. They can do this by purchasing cheap filters for affected radios, shielding and grounding, moving the affected radio, or even buying the affected person a better radio. Interference caused by blanketing is more related to the quality of the receiver than anything else. Stereo receivers and car radios tend to perform almost flawlessly, but cheaper boom boxes, clock radios and walkmans have more spotty performance.

What the four engineering studies tested was the receivers vulnerability to interference if you allowed low power signals to occupy second and third adjacent stations. The studies all had basically similar results, but the interpretation of the findings was diametrically opposite. The differences in interpretation rested on the issue of how to set standards for what level of interference should be considered to be unacceptable. The standard of audio quality that the NAB used in its tests was so rigorous that over half of the radios tested failed to meet it, even when there was no interfering signal at all! The FCC chose to conduct its own tests, and based upon their findings and their evaluation of all the other studies decided that while current interference regulations were appropriate for full power stations, low power stations could be exempted from the current third adjacent protection standard. The FCC found that 19 out of the 21 radios they tested adequately withstood interference even if second adjacent channel restrictions were lifted. In spite of this positive finding, and the widespread public support for lifting the second adjacent channel restriction, they chose to leave the second adjacent restriction in place. They also chose not to allow thousand watt LPFM stations that they had initially planned. Only the LP10 watt and LP100 watt stations were created under the new service.

The Unmentionable Truth: Broadcasters already have their own LPFM service

The FCC had two other major sources of experience upon which it based its decision. The unmentionable secret is that low power FM radio, from a technical standpoint, already exists. Across the country there are thousands of translator stations which are technically identical to the proposed LPFMs. Translator stations are stations that are given to full power radio licensees in order to fill in their coverage. Sometimes there is a big hill in the path between the radio tower and a neighborhood that the broadcaster wants to cover. A low power translator is allowed to locate in the area that is shaded by the hill from the full power transmitters rays. In recent years, translators have been allowed to be fed via satellite to areas that are not part of the original radio coverage. In fact it has become a fairly common practice to establish a full power radio station somewhere in the plains where the radio band is almost empty because no one can hear it but a bunch of prairie dogs, then scour the entire US for low power translator licenses. Particularly some fundamentalist religious outfits have acquired chains of hundreds of low power radio stations across the country in this manner. In the spirit of the original rules, these low power translator stations are not allowed to create their own programming (they are supposedly just used for fill-in). In practice, however, they are used to bring programming into cities in which it does not yet have any channel. Low power translators are well known to cause miniscule interference, and broadcasters generally like them because they create opportunities for extension of a stations coverage area. The actual transmitters that translators and Low Power FMs will use are the same. The NAB and NPR position is that when their stations employ translators, the interference caused is acceptable. When low power radio stations that are independently operated use the very same equipment, there will be enormous new interference problems that will degrade the quality of the FM band.

What did you say about Grandfathers shorts on the radio station?

Even more compelling is the case of "grandfathered short space stations." These are stations that were built a long time ago, when higher power levels used to be authorized by the FCC. There are about 400 of these stations in the country today which exceed the current protection rules for second and third adjacent stations. These stations have been licensed for many years and the study of their interference characteristics sheds light on the overcautiousness of the current FCC rules. Despite their often dramatic overstepping of todays interference protection requirements, there is no record of significant interference complaint. In 1996, the NAB said that "And though NAB would support improvements/modifications of facilities that might result in some increased short-spacing to second and third adjacent channel stations, it is our expectation that such increases would be minimalŠ" However, they emphatically stated that they felt that such changes based on available evidence regarding second and third adjacent interference should have "no implications for the FM medium as a whole." To the NAB, the laws of physics appear to be written in two sets of books- one book for their members, and a very different book for everyone else. Of course, the stations that they were advocating for were stations that NAB members owned, so interference caused by them was considered to be acceptable to the NAB. The real world experience of translators and "grandfathered short space stations" are direct evidence that the true concern of the NAB is not interference: the attack on low power FM can be seen as nothing more than the anti-competitive maneuvers of an oligopolisic industry.

NAB: An Aether Tiger?

If the NAB were actually only concerned about interference, they would have declared victory with the scaled down LPFM report and order that was issued in January of 2000. Most major cities in the US would not be adding more than 1 or 2 new stations as a result of LPFM. However even this was too much for the NAB to bear, since it would have meant that a coalition of media reform groups and non-profits had beat them at a game that they generally considered themselves to own. The NAB as an organization has been slowly declining in its influence over the past few years since its crowning achievement, the Telecommunications Act of 1996. The Telecommunications Act allowed for deregulation on an unprecedented scale in the communications industry, and led to an unprecedented concentration of corporate ownership of media. Not so long ago, it was considered scandalous that 50 companies controlled a large share of the media. Today, just six corporations control a vast share of all media, including TV, radio newspapers, magazines, cable, movies, music and internet.

Ironically, the NAB sowed the seeds of its current malaise. Large companies like Fox, Disney and General Electric bought up hundreds of channels in all forms of media. These behemoths no longer need the NAB to advocate for them because they have their own lobbyists in Washington. Fox lobbyists can advocate for the specific interests of Fox, as opposed to the interests of broadcasters in general. In fact, a rift started to develop inside NAB between the numerous small business owners and the corporate types. The big players are pushing the NAB to promote policies that would allow further consolidation. The fight against LPFM has been used as an opportunity to show that the NAB still has some lobbying muscle and to unite incumbent broadcasters. It has also helped to obscure for small-time owners where the real threats to their businesses lie: the new corporate dominated satellite and internet radio services. Satellite radio, due to start being received by the public in a few months, is dominated by the same big corporations that own chains of hundreds of radio stations.

The NAB announced a two pronged attack. They would sue the FCC in the courts, and they would try to get legislation passed that would strip the FCC of the authority to make a pro-LPFM decision. At first LPFM advocates were not very concerned about the so-called "Broadcast Preservation Act of 1999." The legislation was so broad and ill-conceived that it would have been the first time in the 66 year history of the FCC that congress has presumed to limit the FCCs authority with regard to how it can make technical decisions regarding broadcast interference. Members of Congress do not in general take it upon themselves to micro-regulate technical standards on issues they do not really understand. It is properly the role of the engineers at the FCC to make such decisions. The legislation was unpassable in its original form, but it did plant the seed in many representatives minds that Congressional oversight was appropriate on this issue.

All Things Consolidated

NAB made its best move by recruiting NPR into the fray. Though NPR reporters and affiliates stations are divided on the issue, the top management of NPR has gone all out against LPFM. NPR claims to support the concept of LPFM, but they have supported the NABs interpretation of the engineering studies. In fact, it was NPRs arguments in 1978 that ended the early wave of community radio in this country. NPR called for the end of the class D 10 watt community radio license, in an attempt to clear away local radio stations to build its national network. Today, we have seen the results. In the entire country, there are only about 200 community radio stations left (out of about 12,000 total stations). By contrast, almost the entire the US population has access to a signal that carries NPR programming, and many towns have several stations that carry NPR but no community station that carries local news. NPR may be public, but they operate on a scale that makes them as cut-throat a competitor as any commercial station. Their main stated objection to LPFM is that they fear that it may limit their ability to set up more translators to further spread the availability of their programming. Many affiliates have stated more frankly that they are concerned about competing with LPFMs for pledge drive money, and are concerned that their audiences for non-commercial radio will be fragmented by competition from new stations. NPRs president, Kevin Klose, testified before Congress that NPR supported the Broadcasting Preservation Act Of 1999.

An Elephant in Donkeys Clothing

As the bill gathered co-sponsors, the NABs real strategy kicked in. They got John Dingell, democratic Congressman of Michigan, to claim to "save LPFM" by in effect eviscerating it. He proposed a "compromise" in which the FCC would not be able to go forward with any changes to interference standards until they showed a new "field tested*quot; study to Congress. This would mean that about 80% of the new stations would not be able to go on the air. There is no funding available for the study at the present time. It also includes a clause to insure that anyone who ever operated an unlicensed station would be ineligible to apply under the new rules.

Calls for more testing are actually just a stalling tactic. The technical record is entirely clear- as the long experience of the FCC in regulating translators and short space stations makes evident. The NAB is trying to stall LPFM enough to let the normal course of money and power smother this aberration of public-minded policy at the FCC. The NAB is betting heavily on a Republican victory in the presidential race this fall. The Chairman of the FCC is chosen by the President. If George Bush wins in November, it can be assumed that the current chairman will step down and the new chairman will be handpicked by the broadcasting lobby. In this election cycle (1999-2000), the NAB has given 75% of its contributions to Republicans and 25% to Democrats.

At this point, the FCC is going ahead with its plans to license low power stations. Any stations not licensed between now and January are likely not to be licensed at all, regardless of any evidence gathered by further studies.

Dissimulating Simulations

Much of the scientific basis cited by those who voted for this bill in the House of Representatives is a compact disc that was recently circulated to Members of Congress by the NAB. This disc had the appearance of scientific study, but it was in fact more of an "artists rendering." It purported to be what two radio stations would sound like competing to be heard on a receiver, but what was presented was actually the sound of two audio tracks laid on top of each other with a mixer. The broadcasters also maligned the professionalism of the FCC engineering staff. The FCC Chiefs of the Office of Engineering and Technology and the Mass Media Bureau, Dale Hatfield and Roy Stewart, responded with uncharacteristic candor. "One particularly misleading disinformation effort involves a compact disc being distributed by NAB that purports to demonstrate the type of interference to existing radio stations that NAB claims will occur from new low power FM radio stations. This CD demonstration is misleading and is simply wrong."

The NAB eventually pulled the original track off of its website, claiming that it had clearly stated that it was a simulation. They replaced it with tracks of actual recorded interference, ostensibly from a pair of short space third adjacent station in Washington DC. But once again, the NAB used a false example- much of the interference heard on these tracks actually has nothing to do with third adjacent interference. This test looked much more impressive to congressional staffers, but broadcast engineers on an engineers list-serve got a good laugh. The transmitter test locations that NAB used for their testing were very close to several other radio stations. Traces of those other stations can be heard on the recorded tracks, clearly contributing to the recorded interference. Nowhere on their website does NAB say that the interference is definitely caused by a third-adjacent signal. They merely claim that this "interference (was) suffered... in the presence of a third-adjacent channel interfering signal." It can fairly be suspected that some of NABs lawyers must have taken a sharp look at the wording of this "new evidence" before it was released.

"An Ocean of Interference"

In fact, all of the studies so far have dramatically over-represented the interference that could be caused by Low Power FM. Even the tests that a coalition of Low Power advocates sponsored failed to test for the most important question. All of the tests were done in laboratories, with a single "undesirable" signal versus a single "desired" signal. In the real world, there are many other powerful signals in the mix, which combine in many ways to create a wide variety of interfering effects. Interference is not limited to co-channel, first, second and third adjacent signals: interference can come from mixing of signals in any adjacency inside the blanketing contour of a powerful radio station. Field tests that looked at the baseline interference environment of FM radio would doubtless find that many hundreds of LPFM stations could be added with barely any effect on the overall interference environment of FM radio. A testing regime that could scientifically prove such an obvious conclusion would cost millions of dollars. The NAB got its public relations writers working overtime to come up with the image of "islands of radio coverage amidst an ocean of interference." The part that they neglect to mention is that the broadcasters themselves that are creating the ocean of interference. Low power broadcasters could never create even a fraction of a percent of the interference that is caused by the radio stations that are already on the dial.

Science: Politics by Other Means?

The LPFM radio stations will in fact create between 64 and 200 times more new radio service than interference, according to a study by Dr. Theodor Rapport, a distinguished engineering consultant and developer of major contributions to our nations wireless system. That small amount of interference which might be created is outside of the zone in which stations are protected by FCC rules. In other words, it is only incidental, marginal coverage, far from the incumbent transmitter, and already of such low quality that any interference is moot. All radio services create some inadvertent interference. An engineer can not say that there will be no interference, but the magnitude of potential interference created by LPFM is so small and meaningless that it is almost inconceivable to the lay observer. The standard that NPR and the NAB want to hold these new stations to is a standard that NAB/NPR stations systematically and legally fail.

Unfortunately, Low Power FM advocates were overconfident that the facts spoke for themselves. They also presumed that the expertise of the FCCs engineers would be respected by Congress. Many members of congress made their decision based upon the first deceptive CD. It seemed to them that the safest thing to do was to require more testing, since there were a bunch of engineers arguing for both sides of the issue. The House voted 274 to 110 in favor of the Dingell amendment, within a few weeks of its introduction.

Now LPFM faces a fight in the senate. Senator Judd Gregg of New Hampshire sponsored the Senate version of the bill, S.B. 2068. This bill is identical to the original Broadcasting Preservation Act, calling for a complete ban on LPFM. It is likely that if it comes to the floor of the Senate, it will be modified to match the text of the Dingell amendment. A wildcard in the debate is the new bill proposed by Senator John McCain. This bill would allow for LPFM to rollout as planned by the FCC, but would give incumbent broadcasters an unprecedented opportunity to sue LPFM operators. Regulatory authority over interference would be removed from its traditional home at the FCC and handed over to the court system, advised by the National Academy of Sciences. It would in effect create two independent systems for regulating interference. Most observers consider the lawsuit element of the McCain plan to be unworkable, but the introduction of McCains bill may take some of the steam out of the push to pass Senator Greggs proposed legislation. The NAB wrote an angry letter to McCain, because even though his bill would ultimately create a very favorable situation for them, it derails their attempt to stop LPFM licenses from being given out before the election.

Despite the protestations of the broadcasters, it is apparent that this fight has nothing to do with harmful interference. This author is forced to conclude that the roots of the battle over LPFM are not technical- they are in fact philosophical. In the wake of the Telecommunications Act of 1996, consolidation of media ownership has reached an all time high. In this oligopolistic regulatory environment, economies of scale and automation dominate the logic of radio production. Minority ownership has dropped dramatically as well in the ensuing years. Broadcast professionals of thirty years standing are regularly kicked off the air by slick marketing experts while mom-and pop radio stations are being bought up at a furious pace by the corporate giants. Many radio stations do not even have their own programmers any more. Most of the work of creating our radio culture is done today not by practitioners of the radio art, but by statisticians and computers. The root of the visceral reaction of incumbent broadcasters can be seen as no more or less than this this: a coalition of church groups, schools, activists, radio pirates and ordinary citizens had the audacity to think that even though they might not have the slickest voices or the fanciest degrees or the biggest money, they thought that they could make better radio with their hearts and souls and local talent than the experts could make with all their technology. That philosophical battle will rage on no matter how many Senators votes money can buy.