[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

OSCAR-11 Report

                OSCAR-11 REPORT    17 March 2000

OSCAR-11 has clocked up another year in orbit, and celebrated its
16th Birthday on March 1st. Despite a few minor problems which have
arisen during its long existence in the very harsh environment of
space, the satellite still remains in good working order.
Congratulations to the UoSAT team!

During the period 15 February to 16 March 2000 good signals have
been received from the 145 MHz. beacon, although on one occassion
signals were rather weak, and had to be decoded manually.

There has been another increment in the dates displayed by the
satellite.  The date in the hardware generated telemetry is now three
days advanced, and the software generated dates are now one day
advanced.  This glitch occurred between 26 to 29 February.  Possibly
it's a Millennium leap year problem in the hardware chip used to
generate the date.  Ground control may be able to correct the
software generated dates, but not the hardware generated date.

The battery voltage during daylight passes is unchanged. The average
value observed was 13.8, with a range of 13.4 to 14.1 volts.

The internal temperatures have decreased by one degrees C.  They are
now 3.8C and 2.2C for battery and telemetry electronics respectively.

A single WOD survey of channels 10, 20, 30, 40 (+Y, -X, +X solar array
currents, array voltage), dated January 06 has been transmitted. Note
the year of this WOD survey is incorrectly displayed as 99. This
survey clearly shows the solar eclipses, and a spin period of 340

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

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 -


If you place this bulletin on a terrestrial packet network, please
use the bulletin identifier $BID:U2RPT47.CWV, to prevent duplication.

73 Clive G3CWV   g3cwv@amsat.org

Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org