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OSCAR-11 Report



                  OSCAR-11 REPORT

                  15 February 2005

During the period 25 January to 15 February 2005 excellent signals have
been received from the 145.826 MHz. beacon, transmitting continuous ASCII
telemetry from 04 February to 14 February.

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 24 February.

At the present time the satellite is in full sunlight, and therefore
temperature changes are caused by changes in attitude, and spin rate. The
hot external surfaces will cause some nearby internal parts to warm up
faster than others. Random variations of internal temperatures of around
two degrees C have occurred. The current internal temperatures are 19C,
201C and 245C for the 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.

The battery voltage has varied between 11.9 and 12.8 volts.  The average
voltage was 12.4 volts, a reduction of 0.7 volts since the last report,
when a trend towards lower voltages was noted.

The period of rotation about the Z axis had been determined from the solar
array currents.  Values of between 295 and 400 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 20.5 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 December 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:U2RPT106.CWV, to prevent duplication.

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