Why are FM radio stations organized the way they are?
March 13, 2004 7:42 AM   Subscribe

Why are (FM) radio stations organized the way they are? I don't listen to the radio much, but after spending some time at home recently, I remember an observation I made as a kid: classical/jazz and college stations are sub-92, pop/hip-hop/etc. are 92-102, and oldies/classic/hard rock are 102+. I've definitely seen exceptions, especially in larger cities, but this split does seem pretty accurate overall. Is there a reason for it?
posted by Sinner to Media & Arts (9 answers total)
The FCC reserves FM frequencies below a certain mark (I think it's 91.9 MHz) for non-commercial stations. Those tend to be public or educational stations, which tend to play classical and jazz. Above that, anything goes, and I don't know of any split at 102 MHz.
posted by Vidiot at 7:57 AM on March 13, 2004

Are the higher requencies more powerful and hence more valuable? If so, it would make sense that the most popular (commercially popular) music stations would be at the top.
posted by o2b at 8:11 AM on March 13, 2004

This FM chronology page is helpful, although the divisions mentioned no longer really applies, except, as Vidiot says, in the lower noncommercial range:

June 27, 1945. FCC allocates 88-108 MHz for FM broadcasting, with 88-92 MHz to be reserved for noncommercial broadcasting, and allocates 106-108 MHz for facsimile broadcasting. Within the 92-106 MHz spectrum, FM stations are to be allocated as follows: 92.1-93.9 community; 94.1-103.9 metro; 104.1-105.9 rural.

Also, while we're here:
How the Radio Spectrum Works.
History of 10-watt stations.
posted by Mo Nickels at 8:16 AM on March 13, 2004

As Vidiot pointed out, the only guideline you can use is the FCC's regulations that reserve the lower portion of the FM band for non-commercial educational broadcasting. The means from 87-92 mHz you'll find college stations, religious stations, NPR stations, etc. They tend to play more classical, jazz, etc. Everything above that is more or less free to flip to any format that the owners think is viable. The FCC does NOT dictate the format of a radio station, current legislation notwithstanding. It's simply an anomaly that you've observed certain formats falling into certain frequency ranges. That wouldn't hold up across the whole country if you were to survey a large enough sample.

ON PREVIEW: on o2b's question about power, higher frequencies does NOT mean HIGHER power. While they are somewhat related on the AM band, it's not really true on the FM band. An engineer or physicist could explain it better, but there really isn't any connection.
posted by marcusb at 8:18 AM on March 13, 2004

99 and 100 are memorable. It makes sense that the stations aiming at the larger audiences would have the money to buy the best frequencies.

Part of this is due to Clear Channel and other large conglomerates. Instead of a start-up station buying a cheap frequencie and eventually growing large there, they start out large due to solid backing.
posted by smackfu at 8:52 AM on March 13, 2004

I believe the spectrum was allocated this way because the lower the frequency comes on the spectrum, the less power it takes to generate the broadcast. Since FM signals correspond with the number of cycles that station generates on the broadcast spectrum, the lower you go on the radio dial, fewer frequency modulations are required to generate that signal. Picture a sine wave with 92 cycles vs. a sine wave with 106 cycles. Since it takes less power to generate fewer cycles, the FCC reserved the lower frequencies in the FM band for non-profit use; in theory, non-profits will have less money to pay their power bills.

Or, they really liked jazz and contemporary Christian music and wanted to make sure both would always have a home. When it comes to the FCC, you never can tell...
posted by herc at 9:05 AM on March 13, 2004

I think I read once that Clear Channel likew to buy up similar frequencies for similar types of music. When you travel to another town, makes it easier to find the music you like by the company that wants you to listen.
posted by croutonsupafreak at 11:41 AM on March 13, 2004

Response by poster: Great answers, all. Thanks. Although I still feel like the break at around 102 for classic rock, etc. has some validity, I'm skeptical about it myself. Perhaps it's just a local thing. Thanks again!
posted by Sinner at 3:44 PM on March 13, 2004

99 and 100 may be memorable, but they also have the desirable quality of being in the middle of the dial -- thus there's a strong "walk by" factor. (q.v. Birth of the Mall for the built-environment equivalent.)

A little perusal of the AMFMTVOnline database -- set band to FM, and choose various Formats (or pull up an entire Market nowhere near you to compare) -- should show there's no greater plan at work here.
posted by dhartung at 10:24 PM on March 13, 2004

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