Why don't voice radio communications use FM?

"Larry Dighera" wrote in message
.. .

AM frequencies are currently 25 kHz wide. FM would require more
bandwidth. Regardless, where would you place these newly allocated
frequencies?


On Sat, 2 Sep 2006 09:10:19 -0700, "RST Engineering"
wrote in
:

That's just not true. For a given voice signal, I can squeeze the same
amount of fidelity into an FM channel that I can into an AM channel.

That's the first time I've heard that.

The current actual transmitted bandwidth of a VHF AM signal is about 4 kHz..

Does that mean the highest audio frequency transmitted it 2kHz?

Standard deviation on a VHF FM signal is 3.5 kHz.. Bessel and Armstrong to
the rescue once more {;-)

BTW, the current European channel spacing is 8.3 kHz.. Now THAT's going to
be a challenge for us AMers to meet.


And, I suspect, it would be completely impossible for FM to fit within
8.3 kHz channel spacing with the same fidelity?