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AO40: Update 2000-01-14

Dear All, 

here some updates to Karl's report from January 07. 

* V/U/L1 Receiver * 
The V-band, U-band and L1 receivers are working OK on the HiGAIN
antennas, but none of them is receiving signals with the OMNI antennas.
Either the OMNI antennas are damaged or the cabling or the antenna

* V-TX * 
The V band transmitter was tried several times on HiGain antennas,
because we know they are working OK with the receivers. No beacon signals
were heard, but telemetry might indicate that the TX is working. Further
tests will be conducted, including trying the V-TX again with the OMNI

* U-TX * 
No tests have been yet conducted on the U-band TX, but it is planned to
also test the U-TX again on HiGain and Omni antennas once the spin is 
reduced and the heat pipes start working again.

* Attitude Control System * 
The attitude control system is fully functional. Unfortunatly due to the
high spin of about 17 RPM the sun changed faster than we could change
the attitude. Because the sunangle is now about 60 degrees, the sun
sensor electronic stopped working, that's why the indicated Spin in the
telemetry is now almost 0 RPM. Without sun and attitude information no
magnetorquing can be performed, thus no further attitude or spin change 
was done. However, Karl Meinzer DJ4ZC is developing a new de-spinner
software algorithm, which does not use the Sun sensor information. It
will be tested in the next week and will than be used to reduce the spin
and move to better spacecraft attitude. 

Once sun angle and antenna pointing is improving. the V-TX and U-TX
status will be determined by better controlled and suitable experiments.
ATOS and the wheels will also be tested as soon as possible.. 

73s Peter

Peter Gülzow, DB2OS
Vice-President AMSAT-DL

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