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Mars Global Surveyor/Odyssey UHF tests



Here's an opportunity for you to _really_ test your 70cm satellite
receive setup.

A test of the Mars Global Surveyor and Mars Odyssey is currently
underway, and there is a possibility that amateur EME class stations
could detect one or both of the spacecraft.  The object of the test is
to measure the signals using the 46 meter dish at Stanford University.

Both spacecraft will be transmitting a pure carrier at 437.1 MHz.
MGS will have its CW beacon on continuously.  Therefore, MGS is the
best bet for detection by amateurs.  The power is approximately 30
dBm EIRP at its peak from Mars and will vary as MGS orbits the planet
with occultations every orbit.  A document listing occultation times for
MGS (and Odyssey) is available at:


http://members.verizon.net/~km1p/MGS_UHF_Test_2003.pdf


The largest signal will be seen just before ingress and just
after egress when the UHF antenna on MGS illuminates in the Earth
direction.  Antenna pointing information can be generated using JPL's
HORIZONS system at:

http://ssd.jpl.nasa.gov/horizons.html


The CW beacon for MGS is turned on at 2003-07-01 07:55:00 UTC
spacecraft event time (SCET) and goes off at 2003-07-03 16:20:00 UTC
SCET.  Although MGS transmits at 437.1 MHz with right hand circular
polarization (RHCP) there will be a varying  Doppler shift to the
signal of tens of kilohertz.  It is unlikely that amateurs will have
enough sensitivity to see the signal unless Doppler compensation is
applied to the received signal.

JPL will be testing again in late August during Opposition.  Information
will be forwarded as it becomes available.  For up to the minute information
subscribe to the mars-net list  by sending an e-mail to
majordomo@alum.wpi.edu with the words "subscribe mars-net" in the
body of the e-mail.

-Joe KM1P
 ...
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