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OSCAR-11 report





                OSCAR-11 REPORT    17 January 2001

I have recently noticed a Y2K problem in some of the OSCAR-11
packages on my web site.  Programs effected are ORBILL.BAS,
ORBMAG.BAS and SATILL.BAS. The problem is easily fixed and details
can be found in the OSCAR-11 page at www.users.zetnet.co.uk/clivew/.
I will be updating these packages in the near future.

During the period 16 December 2000 to 16 January 2001 good signals
have been received from the 145 MHz. beacon.

Users of OSCAR-11 should note that the year displayed in the ASCII
status blocks is incorrectly shown as 0 ie. 2000.  There is currently
a similar error of one year in the date of the latest WOD survey
which is shown as 06/01/0. Ground control should be able to correct
these errors. Users should also note that there is a three day error
in the hardware generated telemetry date.  Unfortunately this cannot
be corrected.

The battery voltage observed during daylight passes is unchanged. The
average value observed was 14.0, with a range of 13.7 to 14.1 volts.

The internal temperatures have continued to decrease by one degree C
as the eclipse periods lengthen. They are now 5.02C and 3.2C for
battery and telemetry electronics respectively.

The solar eclipse forecast for 2001 follows a similar pattern to
that of the last three years, ie fairly constant at the start of the
year, a dip in the Summer, and a peak in the Autumn.  This year there
appears to be an small increase in the variation between maximum and
minimum amounts of sunlight, which is likely to result in a greater
variation of temperature compared with last year.  This year's
forecast was based on the 2000 day 356 Keplerian element set, using
SATILL.BAS, and is only as good as that data.

The WOD survey of channels 1, 2, 3, 61 (X, Z, Y magnetometers &
status) dated 06-October-2000, has now been replaced by Channels 10,
20, 30, 40 (+Y, -X, +X, solar array currents, array voltage), dated
06 January. The array voltage shows the effect of solar eclipses, the
decrease of battery voltage during dark periods, constant voltage
during charge, and overvoltage when the battery is fully charged.
Both WODs are available for download from my web site (details
below).

The spin period has varied between 256 and 311 seconds. Two positive
magnetorquer correction pulses and zero negative pulses have been
counted, while there have been 324 Z-axis correction pulses.

More reports than usual have been received recently about the mode-S
beacon, presumably due to the OSCAR-40 activity on this band. The
beacon has been heard by Jerry K5OE, Christ PE5YES, and Jack W9JIU.
Jerry reported signals 9 dB weaker than OSCAR-40.  He uses a 16 turn
helix, Conifer pre-amp, and Drake 2800 converter. Christ reported
good signals with a 2.5 turn helix into an SSB UEK-2000. Finally Jack
reported S3 signals at TCA. 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 (number 115) 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, as an alternative to OSCAR-40. 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 OSCAR-40 when commissioning is
complete. 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:U2RPT57.CWV, to prevent duplication.

73 Clive G3CWV   g3cwv@amsat.org


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