May 01, 2015 09:57AM
Hear's a thought that will come out of left field, but I've contemplated what the FM broadcast band will look like in the future. Now, eventually there will be a total conversion to a digital format. It's going to happen, but just how it might happen is the question and here's the possible answer. The biggest gripe about IBOC, HD Radio, (Whatever the hell ya want to call it.), is that it hogs bandwidth way, way, more than 200KHz. How do you solve that? Eliminate the analog FM's with all of those transmitters and each community have a centrally located transmitter. What would come out of that TX? Digital stations, but when you select a station on a 88 - 108MHz tuner, you won't be selecting a FREQ, but an IP address of what you want to listen to. And the entire 20MHz of that FM band? What can you do with a FREQ spread that wide? Quite a bit. The band won't go away since it has characteristics that wi-fi and 800MHz cellular just lack propagation-wise. THE RX / TX infrastructure is there. If you use the entire 20MHz bandwidth of the FM band and use digital frequency multiplexing, what could you pump into that? Quite a bit, and my guess would be more than the 100 analog stations that could currently fill with the analog FM band now. In essence, this would make for much better use of the spectrum in a FREQ range that can carry 100km, or more, from the TX source. This is not new since we are already sort of doing this with digital HD TV with the 8VSB format. There, you have a 6MHz bandwidth (I think that it's still that.) and you cam multiplex up to six TV channels and other data. They are even contemplating using TV stations to multiplex internet downloading. (And with my Pat #6,342,862, I am watching that.) That's with audio and video real time streaming in a limited bandwidth. Now, imagine how many audio channels you can stuff in while multiplexing with a 20MHz bandwidth? At this point, I suspect you folks get the picture. Oh, a bigger example of this is wi-fi at 2.4GHz. Now, apply that to the 88MHz - 108MHz spectrum.
Now comes the big $64K question, who can take advantage of this new way of spectrum wide broadcasting? Those that can afford it. And if you have a central transmitting facility in you community, who can be on it and who will be excluded? Yes, I'm sure that the technology will reach the pirate level to spectrum-wide TX from their location, but you would have to tell your potential listeners your IP address of your station, and loose lips, sink ships. Now, if a central spectrum-wide TX were to allow every local station to have access to the site, like LPFM'ers, college stations, and the few locally owned stations, then they would all have the benefit of range and audio quality. That would be great, but it would be a pipe dream. This is something that we might want to consider now if we want future access to the airwaves, no matter what method they chose. Now, what are they going to do with the existing AM MW spectrum is anyone's guess.That could be up for grabs! (Yeah, another pipe dream.)
Subject Author Views Posted

Analog FM's days limited? Eventually.

ThaDood 624 May 01, 2015 09:57AM

Re: Analog FM's days limited? Eventually.

Lee 426 May 04, 2015 11:14AM

Re: Analog FM's days limited? Eventually.

ff 493 May 05, 2015 10:25AM

Re: Analog FM's days limited? Eventually.

ThaDood 406 May 06, 2015 09:09AM

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