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OSCAR-11 Report







                OSCAR-11 REPORT    13 September 1999

During the period 14 August to 12 September 1999 consistent signals
have been received from the 145.826 MHz. beacon, inspite of my
antenna problems, although the amount of data I can collect
is limited.  Jeff KA2WQM has very kindly offered to provide telemetry
and WOD data while I have this problem, and during antenna repairs.
Thanks Jeff.

Due to reduced eclipse times the battery voltage during daylight
passes has increased. The average value observed was 13.9, with a
range of 13.6 to 14.2 volts.

The internal temperatures have risen by about two degrees during
this period. They are now 3.4C and 1.8C for battery and telemetry
electronics respectively.

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

Reports of the mode-S beacon have been received from Tony G3GHI, Ted
WA2HKS, Kevin G8DRT and Alan G2HIO.  All are using Drake converters,
with various antenna systems.  Kevin managed to hear the beacon on a
simple dipole antenna during an overhead pass, at a mobile location.
He had done some of the recommended Drake modifications, including
increasing the length of the filter lines, but had retained the
original crystal which gave an IF of 123.5 MHz, into his Yaesu
FRG 9600 receiver. Many thanks for all those reports.

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:U2RPT41.CWV, to prevent duplication.

73 Clive G3CWV   g3cwv@amsat.org



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