[amsat-bb] Re: AO-7 help

Joe nss at mwt.net
Sat Sep 26 08:59:41 PDT 2009


Finally someone on this board, that also remembers what the big knob on 
the face of the radio is used for.

Maybe it's a age thing of when you got into the hobby? Like when I got 
into this hobby when Novices were only allowed crystal control.  It 
wasn't all that different from using the birds.

You listened to your transmit freq. to see if it was clear. and threw 
out a CQ.

THEN YOU TUNED THE VFO   and I mean a LOT  like up and down the whole 
band looking to hear your call.  almost everyone was not by choice 
operated split back then.  You could only afford so many crystals.  I 
remember many times CQing on my 1 crystal for 40 meters 7.109  and find 
someone calling me at 7.127  or whatever freq. they happened to own.  
You had to listen to not only your own transmit freq. in case a general 
or someone with a VFO called you on freq., or if nothing heard started 
tuning around looking for someone off freq.

It was not un common to call CQ  then tune for a minute or so looking. 
and everyone knew this so if you were answering a CQ but way off freq.  
you made a long call  like maybe up to a minute even to give the guy a 
chance to find you calling him.

It just drives me insane to hear people complaining about a little 
doppler,  turn the big knob  DUH!


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
>--- On Sat, 9/26/09, Andrew Glasbrenner <glasbrenner at mindspring.com> wrote:
>Those splits are only right when Doppler is zero. Other wise, you have around +/-7 khz shift to deal with. It's really tough to work AO-7  half-duplex with no Doppler tuning. REALLY tough. If you have a PC nearby, I'd recommend trying to use SatPC32 to control the Doppler shift during the pass. CAT cables are pretty cheap on Ebay, and really easy to set up with the 897.
>Also, since you are using gain antennas AND are half duplex, you should make sure you keep the power output low, like 5 watts or so, since you can't hear if you our overdriving the uplink and making the satellite FM for everyone.
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