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OSCAR-11 report





                OSCAR-11 REPORT    18 October 2000

During the period 16 September to 17 October 2000 excellent signals
have been received from the 145 MHz. beacon.  The satellite is
currently experiencing favourable solar conditions and this should
continue until the end of the year.

Ground control operations on 05-October reset the magnetorquer
counters, and the spin period has now started to slowly return to it's
nominal value, after drifting to -227 seconds.

The battery voltage observed during daylight passes has continued to
increase. The average value observed was 14.0, with a range of
13.9 to 14.1 volts.

The internal temperatures have increased by a further 2.7C during
the month. They are now 5.8C and 4.2C for battery and telemetry
electronics respectively.  This rise in temperature is expected to
continue as the solar eclipse times become shorter.

The single WOD survey of channels 10, 20, 30, 40 (+Y, -X, +X solar
array currents, array voltage), dated 06-January has now been
replaced by a new survey of channels 1, 2, 3, 61 (X, Z, Y
magnetometers & status) dated 06-October-2000.

The mode-S beacon has been heard by Victor OE1VKW. Signals were heard
at three degree of elevation, and at higher elevations were up to 10
dB above the noise.  Victor uses a 1.2m dish with RHCP helix.
Receiver is an ICOM IC-970D with UX-98 module for 2.4 - 2.45 GHz. and
a DX2320/1 broad band pre-amp.  Victor is concerned about the
temperature stability of mast-head down converters, and is
experimenting with all the equipment located inside his shack.

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:U2RPT54.CWV, to prevent duplication.

73 Clive G3CWV   g3cwv@amsat.org


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