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Re: Tuning with AO40rcv... (was Re: AO40RCV & FT-847)




  Fernando,

  In my opinion, "open loop" (tracking program prediction
based)  doppler will not work well for AO-40 telemetry
(at least not in this climate.), although it's 
certainly better than nothing!  

  The predictions are accurate enough, but do not take into
account the thermal drift of the converters.  (Both my
drake, and my 3733 drift substantially when the wind
blows, or at night, as the temperature is dropping.


  -al
  WB1BQE



Fernando Mederos wrote:
> 
> René,
>     I completely agree.
>     My question should have been: assuming small steps which would not fuzz
> AO40rcv decoder, is the traditional doppler compensation scheme (orbit
> prediction) accurate enough for decoding telemetry SSB signals with that
> software?
>     Maybe this subject was already discussed, I was looking for a solution
> to automate telemetry capture without having a dedicated radio...
> 
> > I think the main difference between controlling the frequency by CAT and
> the
> > way AO40Rcv it does by mic click is that AO40Rcv takes the criteria for
> > frequency control from the actual received signal and keeps it always at a
> > certain AF frequency, e.g 1500 Hz. While CAT control through a prediction
> > program supplies a theoretical frequency value which can have some offset
> > to the AO40Rcv method. So the AO40Rcv method is more reliable and does not
> > depend on keplerian elements or other influences but only on the actual
> > received signal.
> 
>     73 de Nando, CX6DD
> 
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