Re: Q0-100 Web-SDR 198Hz frequency error



From: Gary M1EGI
Date: Tue, 22 Jun 2021 10:33:22 PDT

Hi Andy,

Could some of this be explained by the satellite itself?

Oscillators used, thermal changes onboard due to activity on the main payload?

Just a thought.

Plus the bird itself is not in a true fixed point (WRT the ground stations).

If it's part of a cluster in particular it will move around, I think in a 24 hour cycle.

What does the unexpected offset show 12 hours later, if some 200Hz the other way, maybe that's the cause?

This was explained to me some years ago, by one of the site guys we worked with, when involved with a new DBS uplink install that we were providing the TX PA's for.   But I don't remember the sort of figures he illustrated things with, but the frequencies used were in the 12 GHz area.

(That, as a result of a question I asked, relating to why the antenna positioners kept whirring every few minutes, if the satellite was in a "geostationary" orbit.   That resulted in a good 45 minutes very interesting diversion from amplifier problems, and a visit to one other much older uplink facility on the same site, to see a chart recorder output.)


Dave G8KBV


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