[amsat-bb] VO-52 Frequency Drift

John Papay john at papays.com
Mon Mar 26 08:04:18 PDT 2012

VO-52 has been a very loud and easy to work satellite
since the recovery and change to the Dutch Transponder.
The CW beacon is very loud and you can usually find an
image of it elsewhere in the transponder passband.

If you are running full doppler control, you have probably
noticed that your settings (uplink calibration) have to be
changed from pass to pass.  The beacon frequency is not constant
either so I suspect that the frequency source is not very
stable.  Stability is usually a function of temperature so
it would appear that the temperature inside the satellite is
changing due to internal electronics and/or effects from the
sun.  This would be something that the control team would be
aware of.  Any feedback from them would be appreciated.

I do not recall that the India Transponder had a similar problem
but maybe someone else could comment on that.  If it did drift, it
was only one or two hundred Hz.  Initially the difference between the
India and Dutch Transponder was about 2KHz.  Now it seems to vary plus
or minus 500 Hz or so.  Maybe some others can comment on this.

John K8YSE

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