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OSCAR-11 Report

                OSCAR-11 REPORT    17 May 2000

During the period 15th April to 16 May 2000 fairly good signals have
been received from the 145 MHz. beacon.

The battery voltage during daylight passes has continued to
decrease. The average value observed was 13.6, with a range of 13.1
to 14.0 volts.

The internal temperatures have again decreased, by about two degrees
C.  They are now 0.6C and -0.6C for battery and telemetry electronics
respectively.  Further reductions in temperature are expected until

The Z axis magnetorquer counter reached its maximum value of 1024
towards the end of April. This has stopped further magnetorquer firings,
and the attitude is now being controlled solely by the passive
gravity gradient boom. The magnetometer readings indicate that the
attitude remains nominal.  The spin period has steadily increased during
the month from -231 to -324 seconds.  Ground control operations are
needed to reset the counters.

A single WOD survey of channels 10, 20, 30, 40 (+Y, -X, +X solar
array currents, array voltage), dated January 06 has been
transmitted. Note the year of this WOD survey is incorrectly
displayed as 99. This survey clearly shows the solar eclipses, and a
spin period of 340 seconds.

Users should note that the date in the hardware generated ASCII
telemetry is now advanced by THREE days, and the other dates (which
are generated by software) are advanced by ONE day. Ground control
may be able to correct the software generated dates, but not the
hardware generated date.

The mode-S beacon has been heard by Alan G2HIO, who reports good
signals.  He uses a 5ft dish, with 1.5t loop, and Drake converter.
Many thanks for the report Alan.

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

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 -


If you place this bulletin on a terrestrial packet network, please
use the bulletin identifier $BID:U2RPT49.CWV, to prevent duplication.

73 Clive G3CWV   g3cwv@amsat.org

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