On Thu, 24 Mar 2005 21:35:45 -0800, Frank Gilliland
wrote:

For CW the same thing however you would need some expensive filters to get
more use out of a 10 KHz wide channel using a mode that needs anywhere from
300 to 500 Hz at most. The transmitting station needs a way to move it's
signal around on the channel etc. so more that one can use the extra
bandwidth. Using different tones for each station would work, but then you
still need the narrowband filters at each end to selectively filter the tone
for the one station you want to hear.


I was thinking about that, which is what prompted this idea. All it
would take to transmit is to attach an audio oscillator in SSB.
Receiving might be a bit more difficult, but using a fixed-frequency
audio filter and the clarifier knob you can pick up just about any CW
signal in the channel bandwidth. For a filter, you can run both sides
of a stereo equalizer in series, and it can even tune different audio
freqs. After that, all you would need is a tone detector with a light
bulb. So the most expensive piece of equipment is already made and is
pretty common, while the other two pieces could be built from a kit by
just about anyone with a soldering iron.


Congratulations! You've just re-invented AFSK.

Dave
"Sandbagger"
http://home.ptd.net/~n3cvj