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Re: Constant frequency Doppler tuning



    Does anybody have the pinouts for a cable connecting a 9-pin serial plug to
    the 6-pin DIN plug for the Yaesu FT-736R CAT interface?

It's not just a cable.  The problem is that what comes out of a Wintel box
is RS-232 (+/- 7-15V) and the CAT interval is TTL (approx. 0.7-3.0 V).  So
you'll need some kind of adapter.  I think a recent ARRL Handbook should
have a homebrew description in their station accessories chapter.  I did 
my own, because i couldn't figure out where to get the PC board images in
a reasonable amount of time.

If you want to homebrew it, you'll need a level shifter between the computer

and the FT-736R, and if my memory services me well, you can use a Maxim
MAX232 to do that job (single +5V supply).  You may also want to implement
PTT for packetoperation or other purposes (like a software auto-patch and/
or answering machine, for example).  Depending on your taste in components,
you'll want an NPN transitor and some resistors, or a suitable optoisolator,
to drive PTT, which you'll want for packet work and perhaps other purposes
if you're 'station program' can use that.  I used a spare modem control line
on the same serial line as the CAT interface, but a pin on the parallel port 
will work at least as well.

I remember that the drawing in the FT-736 manual for one (or more) of the
connectors was a little confusing.  Make sure you know whether it is being
drawn from the "solder side" or the "pin side" in the case of the DIN-5
and for the miniphone, which is audio-on and which is audio-out.

    I want to implement the "One True Rule," ie.
    constant-frequency-at-the-satellite doppler tuning.  I'm going to try
    InstantTune first, since I've already got it, and I'm already an
    InstantTrack user. ITUNE sounds great for regular analog contacts.  

I had a great time homebrewing my own 'station program' using GTK under
LINUX.  I've implemented several rules, and use that PTT line to aid in
tuning.  One of these days, i'm going to hack an auto-tuner for the analog
birds.  It's fun to only have to worry about azimuth (fixed elevation by
design for me) and have the computer worry about doppler.  Alas, lots of
folks move around from time to time during QSOs on FO-20/FO-29, so you
do end up doing a bit of manual tuning.

But i must say, it sure is nice in the other station is using the 'constant
frequency at the satellite' rule.  I think i should be able to do well with
someone operating totally manually, but it's those who half-track things
that make me work, and round-tables are particularly challenging on the
LEOs.

73's and good luck.  Feel free to write if you have further question, albeit
i just started a new job and may be even slower than usual to response.

		         -- KD6PAG  (Networking Old-Timer, Satellite QRPer)
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