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OSCAR-11 Report



                  OSCAR-11 REPORT

                  16 December 2004

During the period 24 November to 16 December 2004 the 145.826 MHz. beacon
has been heard transmitting continuous ASCII telemetry from 04 December to
14 December. During this period good signals have been received, inspite of
the problems, which were reported last month. On several occassions the
signals have been stronger than usual.

The beacon operates under control of the watchdog timer. Observations have
indicated that the cycle is approximately 10.3 days ON followed by 10.4
days OFF. Assuming that this cycle continues, the beacon should switch ON
around 25/26 December.

Variations in the 14 volt line current have continued, mainly between 755
and 880 mA. However during one pass of 12-December, a value of 300 mA was
recorded.

The internal temperatures have remained fairly constant, with a little
random variation. They are now 19.6C, 17C and 22.8C for battery, telemetry
electronics and command decoder, respectively. Solar eclipse predictions
indicate that the satellite is now in continuous sunlight, which will
continue until the end of April next year.

The battery voltage has varied between 11.2 and 13.8 volts.  The average
voltage has increased to 13.2 volts. The voltage of 11.2 was observed
during a pass on 10 December. On that pass external and internal
temperatures were noticeably lower than normal, and the beacon signals
were of poor quality.

The period of rotation about the Z axis had been determined from the solar
array currents.  Values of between 264 and 510 seconds have been observed.

Users of OSCAR-11 should note that the date in the telemetry is now
advanced by FOUR days.  The time is advanced by 20.4 minutes, and this
error is increasing by about one minute per year.

OSCAR-11 now operates in a default mode, controlled by the watch-dog timer.
The satellite transmits continuous ASCII telemetry for approximately 10.3
days on 145.826 MHz., followed by 10.4 days of silence. This regular
sequence might be interrupted by ground control, at any time.

At the present time the mode-S beacon 2401.5 MHz. and the UHF
beacon 453.025 MHz. are both OFF.

Listeners to OSCAR-11 may be interested in visiting my web site.

The web site contains details about using a soundcard for data
capture, and also details about using hardware demodulators. There is
software for capturing data, and decoding ASCII telemetry.
There is an archive of raw data for analysis, which is continually
being expanded, as new data is captured.  Originally this was for
WOD, but it is now being expanded to include ASCII telemetry. At the
present time the telemetry covers 1996 to August 2004.  I will add
other years as time permits.  In parallel there is a news archive
which provides an overview of the state of the satellite, at the
times when the telemetry was captured.

If anyone out there can provide any data, particularly for the 1984
to 1993 years, this would be most appreciated.  Please e-mail me
with details.  However please DO NOT SEND ANY FILES, before futher
discussion.

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:U2RPT104.CWV, to prevent duplication.

73 Clive G3CWV   g3cwv@amsat.org
----
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