Radio Free Capitol Hill
Jesse Walker | June 22, 2007, 10:55am
Good news for fans of
neighborhood radio: Reps. Mike Doyle (D-Penn.) and Lee Terry (R-Neb.) introduced a bill yesterday to loosen the government's restrictions

on starting independent, low-power stations in urban areas. Sens. Maria Cantwell (D-Wash.) and John McCain (R-Ariz.) sponsored the Senate's version of the legislation. (Yes,
McCain. Initially a vocal opponent of low-power radio, he did an about-face several years ago; these days he's pretty good on the issue.)
Here's what the bill does:
* It repeals the
Radio Broadcasting Preservation Act of 2000. This misnamed law, pushed by the National Association of Broadcasters, hobbled the FCC's plan to license new low-power stations by effectively limiting the available slots to the countryside. (Fun fact: In the House, every Republican except Ron Paul and Ed Royce backed the bill.)
* Within carefully defined limits, it allows stations to transmit closer to each other on the FM band, thus making room for more broadcasters.
* It asks the FCC, when issuing licenses, to give low-power projects that offer their own programming the same consideration given to "translator" stations that retransmit signals originating elsewhere.
The law is called the
Local Community Radio Act of 2007. The folks at the Prometheus Radio Project offer some tips on helping it pass
here.
Update: McCain isn't the only presidential candidate backing the bill. I just got an email from Ron Paul's legislative director letting me know his boss is signing onto it as well.
J. P. Carlo | June 24, 2007, 5:12am | #
Regarding Robert's comment:
(I'm not an "expert" on radio by any means, though not far from it...)
Yes, it is true that FM stations can be squeezed quite tightly together - in various parts of the VHF spectrum, the spacing between channels is typically either 12.5 kHz or 15 kHz. (That would correspond to 0.0125 or 0.015 on your FM dial). Stations can operate on adjacent channels without interfering with each other, although they can't get much closer than that (below 10 kHz spacing, the stations will begin to interfere with one another).
However, these are narrow-band FM transmissions. FM radio in the 88-108 MHz band is wide-band FM, to give significantly greater fidelity (audio bandwidth), as well as being transmitted in stereo (two simultaneous signals). This requires that the FM signal occupy a significantly larger chunk of frequency space (about a factor of ten).
(To give a basic explanation... an FM signal takes up a finite amount of frequency space(called the bandwidth) around a central frequency. You start with an informationless carrier, a continuous sinusoidal wave at a fixed central frequency. The signal is added by modulating the carrier so that it includes components of slightly higher and lower frequencies. The signal is encrypted as the degree of deviation of the signal from the central frequency. The signal is decrypted by converting the frequency deviations back into an audio signal. The issue is how much frequency deviation corresponds to a given change in the audio signal - the larger the deviation, the greater the fidelity of the audio signal, but the more frquency space the signal occupies. In order to have a successful system, the transmitting station and the receiver need to "agree" on this ratio, known as the modulation index.)
There are two standard formats for FM transmission - narrow and wide band (I'll spare you the specific characteristics). (It's also possible to transmit narrow-band FM with what is known as half deviation, and a corresponding reduction in signal quality, enabling even closer channel spacing - 7.5 kHz or 6.25 kHz. FRS/GMRS, for example, operates with half deviation narrow-band FM.)
So you can't compare narrow-band FM transmissions (such as NOAA weather radio, and most police/fire/etc. communications) to wide-band stereo FM (broadcasters on 88-108 MHz).
It goes without saying that you could squeeze many more stations onto the FM spectrum (at least a factor of 10-20 more by changing the modulation index), but you'd have to give up sound quality.