[time-nuts] Voyager space probe question

[Hal Murray]

jimlux at earthlink.net said:
> I don't know about Voyager, but on the SDST and later, the auxosc is a  TCXO
> with fair to middling performance. A good part of the "art" of  communicating
> with an "old" spacecraft is knowing/predicting/guessing  where the "best lock
> frequency" is, because DSN sweeps very slowly  through that frequency hoping
> the spacexraft receiver acquires it in a  <10Hz BW filter.  If you don't see
> the transmitter frequency (in  turnaround mode) jump when acquisition occurs,
> you widen up the sweep,  or slow it down, or turn up the exciter power.  When
> round trip time is  measured in hours, this is a slow process<grin> 

Neat.  Thanks.

How often do you contact old spacecraft?  How much does the TCXO drift due to 
aging since the last time you talked to it?  How much does the temperature 
change?  What else changes that influences the TCXO frequency?

If you are transmitting on the right frequency, how long does it take the 
receiver to lock up?


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