On Fri, 6 Feb 2015, Ralph Mowery wrote:


"FranK Turner-Smith G3VKI" wrote in message
news
FM has always been a legal mode for 80m in the UK, it's just that nobody
normally uses it intentionally.
Provided you're using no more bandwidth than normal AM I can't see a
problem.

I am sure every country has slightly differant rules. As I don't operate FM
below the 10 meter band I am not up on the current regulations in the US
where most of the stations I was hearing are at. At onetime in the US we
could use something like around 2 to 3 khz deviation on 80 meters I think .
That used to be called somethink like sliver band. Maybe still can.
However some of those on 3.85 MHz were way wider than that. I think that
below 30 MHz it is only on some portions of 10 meters that deviations as
wide as 5 KHz can be used in the US.

There was definitely a period when FM was promoted for the HF bands, not
just 10Metres as later happened. Hallicrafters had an CW/FM HF
transmitter at one point, obviously it was a whole lot simpler to add FM
to a transmitter than AM. I thought SOnar also had some HF FM
transmitters in the same period, but looking around, I've yet to find what
I thought I'd read about that years ago.

Even later, the ARRL Handbook had a 220MHz transmitter into the seventies
that was primarily a CW transmitter (or exciter for a separate plate
modulated amplifier, but it also had narrow deviation FM, just in case
someone wanted to do phone up there. But the expectation was to use slope
detection, this wasn't part of the "move commercial 2way FM radios to the
ham bands for channelized operation", that came later.

Michael