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AO40rcv Doppler Compensation????



Help! (:-)

I'm trying to get AO-40rcv's doppler compensation system working with my
FT736R, so that I can leave it happily chugging away grabbing AO-40
telemetry.  Sadly I'm not getting anywhere very fast, and wonder if
anyone out there has managed to get this combination to work, and if so,
how?

>From the 'Rig Frequency Control Page' (in AO40rcv) If I select 'COM1,'
'Manual Rate Control,' and 'Use RTS/DTR' and then monitor the RTS and
DTR lines whilst manually selecting positive and negative doppler
correction I get:

RTS - Goes from -10V (approx) to -5V (approx) when negative doppler
correction applied.
DTR - Goes from -10V (approx) to -5V (approx) when positive doppler
correction applied.

(I would have thought that either line should go to +10V when active?)

My initial thought was to use the RTS/DTR lines and connect to the
FT736R's mic click (up/down) connections.  However, looking at the RS232
to TTL level converter that Moe includes in the AO-40rcv's help notes
for Mic Click working, it would appear to pull the up or down
connections to ground, which won't work with the FT736R which need's
either pin 1 or pin 3 of the mic connection connection to pin 2 to go
either up or down in frequency. (Any interface suggestions?)

So, is it possible to use Pin 3 on the COM port (TXData) into the CAT
connection on the back of the FT736R? (Assuming you have a level
converter again).  However, I have no idea what the ASCII 'UP' and 'DN'
commands are for an FT736R - the User Guide is pretty useless in this
respect.  I've tried connecting the computer to the CAT port using Moe's
suggested interface, with no success.

Can anyone offer any suggestions to this poor confused sole? (:-)

73's

Ken, G0RVH

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