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OSCAR-11 Report







                OSCAR-11 REPORT    14 August 1999

Owing to a 'stuck' elevator motor in my antenna system, reception of
OSCAR-11 during the period 16 July to 14 August 1999 has been poor.
However the satellite appears to be transmitting consistent signals
on the 145.826 MHz. beacon, and sufficent telemetry has been captured
to verify that the bird is in good health.  Owing to the difficulty
in getting a replacement elevator and the need for some mast
maintenance it may be some time before normal reception is restored.
If anyone can help with supplying telemetry during the next few
months this would be appreciated.  Please e-mail me at
g3cwv@amsat.org if you can help, but don't send any telemetry at this
stage.

The battery voltage during daylight passes has remained fairly
constant, the average value observed was 13.6, with a range of 13.0
to 14.1 volts.

The internal temperatures have risen slightly during this period.
They are now 1.0C and minus 0.4C for battery and telemetry
electronics respectively. On Wednesday August 11 during the 14:13
pass, slightly lower temperatures of minus 0.2C and minus 1.4C were
recorded.  This glitch may have been caused by the effects of the
general solar eclipse which occurred on that day. I would be
interested to hear from anyone who captured any telemetry on August
11th.

A single WOD survey of channels 1, 2, 3, 61 (magnetometers) dated 15
July 1999 has been transmitted.  This shows the increased spin period
of about 450 seconds, which occurred when the WOD was started, and
has now been corrected by the attidude control system.

The operating schedule is unchanged.

        ASCII status (210 seconds)
        ASCII bulletin  (60 seconds)
        BINARY SEU (30 seconds)
        ASCII TLM (90 seconds)
        ASCII WOD (120 seconds)
        ASCII bulletin (60 seconds)
        BINARY ENG (30 seconds)

The ASCII bulletin is currently a static message, detailing modes and
frequencies of all the amateur radio satellites.

There  are  additional  status  blocks  after  each bulletin is
transmitted, and between ASCII TLM and WOD.

The mode-S beacon is ON, transmitting an unmodulated carrier, but
telemetry indicates that it has partially failed, and delivering half
power.  This beacon is a useful test source for those testing mode-S
converters, prior to the launch of P3-D. However the signals are very
weak, and there is a lot of Doppler. Users should also note that the
polarisation of OSCAR-11 is LHC. Even if you can't hear OSCAR-11,
your equipment may still be OK for P3-D. Any reports of reception on
2401 MHz.  would be most welcome.  Please e-mail g3cwv@amsat.org.

The 435.025 MHz. beacon is normally OFF.  However it can sometimes be
heard when the satellite is being commanded by ground control, ie.
within range of Guildford, UK.  When the 435 beacon is transmitting,
the 145 beacon is normally OFF.  The data transmitted is mainly
binary.

Listeners to OSCAR-11 may be interested in visiting my web site.  The
web site contains details of hardware required and some software for
capturing data, and decoding ASCII telemetry and WOD.  There is an
archive of raw data (mainly WOD) for analysis, which is continually
being expanded, as new data is captured.  Also included are some
audio files, examples of each type of data transmitted by OSCAR-11,
each one plays for about ten seconds.  There are also examples of
mode-S reception.  All the audio files are zipped, so that they can
be played off-line.  These should help listeners identify the various
types of data, and give an indication of the signal quality required
for successful decoding.

The URL is -

      http://www.users.zetnet.co.uk/clivew/

If you place this bulletin on a terrestrial packet network, please
use the bulletin identifier $BID:U2RPT40.CWV, to prevent duplication.

73 Clive G3CWV   g3cwv@amsat.org



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