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OSCAR-11 Report





                OSCAR-11 REPORT    18 December 2000

Once again it's been an uneventful month for OSCAR-11. Good 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.

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

The internal temperatures have now started to decrease slightly as
the eclipse periods start to lengthen. They are now 6.2C and 4.4C
for battery and telemetry electronics respectively.

The single WOD survey of channels 1, 2, 3, 61 (X, Z, Y magnetometers
& status) dated 06-October-2000, has been transmitted.

The spin period has varied between 218 and 299 seconds. Seven
positive magnetorquer correction pulses and zero negative pulses have
been counted, while there have been 281 Z-axis correction pulses.


The mode-S beacon has been heard by Chris nn0v, Hans DL6KG, and
Giuseppi IK2GXE.  Chris reveived strong signans on his nine foot
dish, FM RX, and TV type LNB.  Hans uses a G0MRF converter, with a
pre-amp and backfire antenna. Guseppi reported signals 6dB above
noise. He uses a 30 element antenna into a home brew DB6NT pre-amp
and converter. Many thanks for 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:U2RPT56.CWV, to prevent duplication.

73 Clive G3CWV   g3cwv@amsat.org


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