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OSCAR-11 Report







                OSCAR-11 REPORT    16 March 1999

OSCAR-11 celebrated its 15th Birthday on 01-March. The satellite was
designed, built, tested, and successfully launched by a Delta rocket
within a time scale of six months, and with a budget of only
450,000 ukp. To minimise cost, selected commercial grade components
were used instead of the more expensive space qualified types.

On the evening of March 1st 1984, G3RWL ran a launch net on
eighty metres, which reported the successful deployment of the
satellite.  Shortly after launch, strong signals were heard on
145.825 MHz. as it passed over the UK.  Unfortunately next day all
contact with the satellite was lost, and it was a further ten weeks
before contact was restored, and commissioning could start.  Since
that time the satellite has given good service, enabling many
scientific experiments to be done, and has provided a news bulletin
service for Radio Amateurs.  A few failures have occurred during the last
fifteen years, but then that's a very long time, and the environment of
space is very hostile!  Congratulations to the UOSAT team on a
fine achievement.

During the period 17 February to 16 March 1999 good signals have
been received from the 145.826 MHz. beacon. The battery voltage has
remained fairly fairly constant, averaging 13.8 volts, during
afternoon passes, when the satellite has been illuminated for some
time.

The internal temperatures have remained fairly constant at
are now 5.4C and 3.8C for battery and telemetry electronics
respectively.

A single WOD survey dated 06-January-99 of solar array currents and
array voltage ie.channels 10, 20, 30, 40 (+Y, -X, +X, V), has been
transmitted.  The sound of this WOD contains a characteristic
musical tone which occurs when the constant data captured during
solar eclipses is transmitted.

The mode-S beacon has been heard by Viktor OE1VKW who reports -

"Heard on Friday March 5 (orbit 80327) and Monday March 8 (orbit # 80371)
at elevations greater than 30 degrees (range less than about 1500 km).
Maximum signal S 2 to S 3 (range around 700 km).

Equipment: 40 element Yagi, horizontal polarisation, SSB UEK 2000 SAT
Converter, IC-275."   Many thanks for that report Viktor.

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.  It is considerably weaker
than DOVE, which should be used for initial testing. 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:U2RPT34.CWV, to prevent duplication.

73 Clive G3CWV   g3cwv@amsat.org



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