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.