Maybe two years ago Bonneville started a trend – they took an existing AM News/Talk programming format from KTAR and “moved” it to FM. There were always a few FM News/Talk stations – this trend is moving an existing AM programming format to FM. According to my count, there are now 140 FM News/Talk stations. Why is this happening? A lot about radio has changed since the 1960s and radio is adapting.
– the end of the monopoly of 50 kw clear channel AM stations. Back in the early 1980s, the FCC let it be known that nighttime AM stations that covered much of the country at night (WBZ, WBT, KDKA, WOWO, WJR, etc…) would be scaled back to allow local stations to stay on at night – by 1986, the FCC no longer issued new daytime only AM licenses. We now have the worst of both worlds – the clear channel stations are now regional stations with directional antennas and the local AM stations are too weak to be of much use (many are less than 50w at night)
– the marriage of AM stations with FM Translators – this is now fully under way with FCC support. AM stations can now have the AM signal carried on the FM band without having an FM station license. This allows the AM stations to have fairly decent local coverage at night. I see this as just a transition to eventually transfer the AM licenses to the FM band.
– most radios force you to choose AM or FM and don’t go seamlessly between AM and FM stations. People tend to leave the radio set either on AM or FM, especially in their car. If people can hear their AM station on FM, they are more likely to keep the radio on FM and listen to other FM stations owned by the same radio company in the same city.
– young people are listening to music on iPods now, not radio (despite what Nielson says…) as FM radio loses music listeners, it opens the door for talk radio. Since children tend to be the opposite of their parents (it’s a rule!), there are probably more than few 20 something Glenn Beck fans, especially if he invades their FM radio and they actually listen to his show, not what other people say he says
– if HD radio ever catches on, the HD2 or HD3 channels are being used often as a way to offer the existing AM stations on the FM frequency
– production values of AM programming are improving – because AM programming is now streaming on the internet and on HD channels, it’s no longer good enough to have a mono phone quality analog signal with 60 Hz hum…. the smarter syndicated talk shows incorporate high fidelity stereo music and pay attention to FM type sound quality since the 8 kHz analog AM limitations no long are the barrier. After you listen to AM digital on the internet, you don’t want to go back to over the air.
– directional AM antenna farms are very expensive to run and maintain – many AM stations have as many as 6 antennas to make their signal go in a specific direction. Back in the heyday of AM radio when you might have a 60% share in a market, that wasn’t a big deal. When you have a 0.6% share, the engineering, security, insurance, maintenance and electricity costs are much harder to justify.
An FM antenna doesn’t need much infrastructure, except people tend to like them to be up high to get the signal as far as possible. For AM, a tall antenna is a requirement, not an option – the radio tower is tuned to a specific frequency and the antenna itself is typically around 300 feet long to match the resonance of the transmitter frequency. The typical FM wavelength is something like 18 inches, so it is trivial to change frequencies on an FM antenna by just tweaking a trimming capacitor, not building an entire new antenna system.
The AM band itself isn’t that useful of spectrum any more – it has the issues of signals bouncing off the ionosphere at night, and picks up noise from electrical storms and assorted electrical discharges.
There is group of people who get much enjoyment over DXing – which means trying to listen to radio stations very far away and letting them know you heard them (you send them a QSL card stating the date, time, and signal quality of what you heard – and if they are real old-timers, they might reply with a thank you card :))… but the Internet is undermining that hobby. Other than as a fallback if/when the internet goes down some day, it’s much easier and simpler to use internet radio guides to listen to far away stations than to stand on the roof of your barn holding a directional antenna in a thunderstorm to try to pick up that station in Australia :)