[Lowfer] TAG in PSKAM10 Mode

[Ed Phillips]

John Andrews wrote:
> 
> Ed,
> 
> The only trouble with the transverter approach is with frequency stability.
> If you do it right, it should certainly work in this application.
> 
> Remember that this application only requires translating a very small audio
> bandwidth up to RF. For those who prefer to roll their own, and not tie up
> the ham rig, there are the usual two approaches: filter or phasing. Lyle,
> Dex and possibly others have done filter rigs by using tuned circuit filters
> with the sound card output set to a fairly high audio frequency like 5 kHz.
> I built a phasing exciter, and stick with my usual 800 Hz. The audio phase
> shift can be done fairly simply as you aren't concerned with a 2-3 kHz wide
> bandpass.
> 
> Either way, it would be fun to see more of the guys set up to put sound card
> generated audio on the air.
> 
> John Andrews

	Understand the frequency stability problem (small difference between
relatively large and somewhat unstable numbers) but figure drift should
be plenty low enough for PSK31 and PSKAM10 work where slow drift isn't
going to hurt too much.  As for exciters, I do have a 3/4 built "filter
exciter" which I started 25 years ago and never finished.  Used CMOS
switch (4066?) for balanced modulator and very sharp Collins 200 kHz
filter.  I never got beyond looking at the signal out of the filter as
galloping laziness took over. 

	I also built some wide-range phase shifting circuits but never went
beyond that.  I helped another guy put together an SSB rig back in the
early 50's, it was homebrew using the Millen canned phase shift units. 
For now I thought I'd play with the Jackson Harbor thing more or less as
a stunt for local experiments.  Intend to use the same output stage as
my regular lowfer transmitter and just paste the amplified output of the
converter into it.  May or may not work out OK.  I have some of the 2
MHz  OCXO's which Fair Radio Sales had a few years back.  Two of them
give around a cycle or so beat per hour.  Not as good as a really good
XO but still could be used to generate the frequency reference if
required.  If I use one with the converter and the 160 meter output of
my 756PRO I should be able to get out a signal which would be more
stable than what I plan..........  

	How well do the sound cards work at such high audio frequency outputs? 
Thinking about their HI-F I use they should be just fine, but???

Ed