[amsat-bb] Re: SSB Operation on the Satellites

Tom Schaefer, NY4I ny4i at arrl.net
Thu Jun 9 04:08:34 PDT 2011

A rookie observation….

That article was written in 1994—well prior to the state of the art in full doppler correction. I use MacDoppler for adjusting the VFOs and it happily adjusts both of them. The ONLY time I run into a problem where the received station is moving is when it is clear someone is NOT using full doppler correction.

I would humbly submit that this being 2011 and both SatPC32 and MacDoppler handle full doppler correction, the exception should be the One Tune Rule and the norm should be full doppler correction. I know that when I work someone that is also using full doppler correction, it is a joy as the radio just happily stays tuned and we move during the whole pass. 

Is the state of the art still such that we are all using radios that do not support full doppler correction?

I will put my flame suit on now…



Tom Schaefer, NY4I
ny4i at arrl.net
Monitoring EchoLink node KJ4FEC-L 489389
DSTAR Capable  APRS: NY4I-15

On Jun 9, 2011, at 6:23 AM, John Heath wrote:

> Hi Satelliters,
> Might cause some flames with this  but here goes:
> With a good few years of operating on the SSB sats, AO's-10,13,40, RS10, 
> FO-20,FO-29 and 98 countries confirmed I can agree totally with the "one true 
> rule" in theory. When stations at each end of the QSO use the method it works 
> flawlessly, I have done it with QSO partners using Fod track and with Instantrak 
> computer Doppler correction, but there is the problem.
> Many of the stations that you want to work will be using manual tuning methods, 
> so as you maintain your frequencies at the satellite, according to the rule, 
> your QSO partner will have to search for you. Then when its your turn to 
> transmit he will have to search for you. 
> The practical solution that I and I believe most of the ops. I have worked seem 
> to use is to have short overs and to adjust frequencies the TX to try and keep 
> the QSO in a fixed spot on the receiver.
> Following the other "often recommended" method of adjusting the higher frequency 
> irrespective of its function, up link or down link, cause QSO's to drift across 
> the pass band causing problems for other users.
> The other point worth making for newcomers to the SSB birds is to start on the 
> easy passes/satellites first to get the knack of manual tuning. For example, try 
> VO-52 with its 2m downlink, and to pick low elevation passes where the rate of 
> change of frequency due to Doppler shift is less. Don't expect to get it right 
> with near overhead passes of FO-29 until you have delevop  your skills.
> We were all beginners once so don't be afraid to have a  go and make a few 
> mistakes.
> I am pleased to say that in my experience the SSB satellites have a great user 
> community who maintain high operating standard and welcome new ops.
> Have fun on the birds
> 73 John G7HIA
> Lamenting the loss of our lovely HEO birds, Happy Days !!
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