[amsat-bb] Re: AO-7 help

Andrew Glasbrenner glasbrenner at mindspring.com
Sat Sep 26 08:52:59 PDT 2009

Glen Zook wrote:
> I haven't used AO-7 for some time (need to revise my antennas to do so again).  But, back in the "goode olde dayes" (when the satellite first went into orbit) we didn't have any problems with Doppler.  The accepted method was to leave the transmit frequency alone and keep one hand on the receiver to compensate for the frequency shift and send CW with the other hand (or hold the microphone for SSB).  No one even thought of compensating for Doppler any other way.
> Of course at the time everyone used a separate receiver and transmitter (no transceivers) so you could keep the receiver active while transmitting.  There were hundreds of QSOs made on each orbit and everyone had a "ball".
> Glen, K9STH
> AMSAT 239 / LM 463
> Website:  http://k9sth.com
The half-duplex part is what makes it hard. I ran from 1992 until about 
2006 without computer tuning, although I followed the current AMSAT 
protocol of tuning the higher of the two frequencies. You don't drift 
into others as much that way. I've tried this all ways, and if you are 
going to run half-duplex, life is much easier with CAT tuning.

73, Drew KO4MA

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