Before last June's transition to digital for full power TV stations, if a market had an analog TV channel 6 in the area, people in that market could listen to TV channel 6 by tuning their radio to 87.7 FM. The reason for this is because the old analog TV format had two major carriers on its channel, one for picture, and one for the sound, broadcasting in the wide FM modualtion scheme. In the case of TV channel 6, the picture was at 83.25 MHz, and the sound at 87.75 MHz, right at the left end of a typical FM radio, which people could tune in to listen to a TV station, mostly for news shows or maybe a sports play-by-play on that specific TV channel.
In Milwaukee, there was a channel 6 on WITI-TV, which is currently a FOX affiliate, and people were listening to the TV station on the radio. But when the DTV transition completed and channel 6 began broadcasting solely in the digital format on a UHF frequency, the radio simulcast went away. Even if the station were broadcasting digitally on its old analog frequency, FM radios would not be able to tune in to the audio since digital TV uses a different and more advanced modulation than FM. Now in Milwaukee, those who have enjoyed listening to the channel 6 audio on their FM radios can do so by getting an HD radio, and tuning in to 106.1 FM HD-3, since HD radio stations can multicast the same way digital TV stations can. Again, since WITI switched to a UHF frequency for its digital TV broadcast, the old channel 6 frequency pretty much opened up.
Meanwhile in Chicago, 95.5 FM, owned by a major corporate radio company, which had been a long running contemporary jazz, or "smooth jazz" format that had been fairly successful for over 20 years, changed its format to Latin pop, taking the smooth jazz format off Chicago radio. But a station manager Pat Kelly, and a small company Venture Technologies Group, had a plan to get the format back on the air, using the FCC allowance that a low power TV station could continue to broadcast in the analog format - create a low power TV station that plays smooth jazz, and broadcast it on the open channel 6 frequency. So a small locally owned company WLFM, LLC, was born. They got a license from the FCC to broadcast on the channel 6 frequency at 3,000 watts, which would qualify it as a low power TV station, from Chicago, and get the music heard on the radio at 87.7 FM. Very strong FM radio stations broadcast at 50,000 watts, but 3,000 watts would still provide a fairly large listening area. So on May 22nd, 2009, days before the DTV transition took place, WLFM-LP began broadcasting, and smooth jazz was back on Chicago radio.
The trick here to make the TV station legal was to have some kind of a picture broadcasting on the 83.25 MHz analog picture carrier, so WLFM-LP puts a continuous slide show of Chicago landmarks along with a station ID logo and a weather ticker on the picture while the music plays on the audio carrier that is heard on 87.7 FM. I actually can tune in to the channel 6 over the air on my analog TV tuner and see that picture, although it is grainy because I am pretty much in the fringe area of the Chicago TV market, but it is there, and the audio on the TV sounds good, so it works on TV channel 6, and on 87.7 FM on my radio.
I discovered this sort of by accident because I had just purchased an FM transmitter adapter for my car to listen to audio on my BlackBerry on my car radio, since that radio was not Bluetooth enabled. I had figured with TV channel 6 from Milwaukee moving to UHF and all digital that 87.7 FM would always be clean for my adapter, but I was curious to see if there was a low power TV station within 200 miles of me that I would be concerned about while on the road. So a TV station search on the FCC's Web site came up with WLFM-LP channel 6 out of Chicago. I tune in to 87.7 FM on the radio, sure enough, I hear smooth jazz, and had to set my adapter to 87.9 FM which for the most part has little noise.
So now WLFM-LP channel 6/87.7 FM, for nearly a year now, has brought the smooth jazz format back, and using local billboard advertisting and social media to get the word out, thanks to the FCC rules allowing low power TV stations to continue to be analog, and hopefully the company will have a solid audience. Two questions arise, though - how long with the low power analog allowance last, and will other companies in other markets follow suit to bring a niche format to the far left of the FM dial?