[Boatanchors] Fasten your seatbelts

[Glen Zook]

Since FM/PM is allowed on every frequency on which phone operation is allowed except for the 60 meter band (so long as the modulation index is kept at 1 or below on frequencies below 29.0 MHz) I have been "toying" with trying some really narrow FM on HF (like +/- 500 Hz or less).  My 75A-3 receiver has the optional discriminator and the bandwidth can be taken down to as narrow as 500 Hz which would allow deviation of around +/- 200 Hz.

There are those who say that such narrow deviation would not work.  However, the same thing was said when deviation went from +/- 15 kHz to +/- 5 kHz and now with the "new" commercial requirements of +/- 2.5 kHz.  The seriously reduced bandwidth should increase the effective "range" significantly.

Since the old Motorola and General Electric (among others) used crystals in the 3 MHz range getting a signal on 75 or 40 meters would be easy.  Then any "boat anchor" transmitter running Class "C" could be used for an amplifier (just run the FM/PM signal into the transmitter like you would use an external VFO).  

Glen, K9STH

Website:  http://k9sth.com


--- On Thu, 9/24/09, Rod Hogg <revcom at wbsnet.org> wrote:

I remember "wideband" could be about as wide as you yelled, hi.  I cut my teeth in two-way with the conversions in the 60's. Doing the "narrow band" mods to GE Prog-lines, (even had some Pre-Prog stuff), Motorola Twin-V and T-Power was fun, had a few 80D's to do too.  After several hundred it became a real bore, besides keeping them all running!
 
Gave up on the GE receivers, GE had so many changes it wasn't funny.  Some even came back to original circuit.  The squelch was horrendous to work with.  Was very glad to get rid of all them when MastR Pro came out and the Motracs.
 
They are using +/- 1.25Khz a little around here now too!   What's next?