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

OSCAR-11 Report





                OSCAR-11 REPORT    16 February 2001

During the period 16 January to 14 February 2001 good signals
have been received from the 145 MHz. beacon.

The battery voltage observed during daylight passes is slightly
lower. The average value observed was 13.9 with a range of 13.7 to
14.1 volts.

The internal temperatures have slightly decreased. They are now 4.6C
and 2.8C for battery and telemetry electronics respectively.

The WOD survey of channels 10, 20, 30, 40 (+Y, -X, +X, solar array
currents, array voltage), dated 06 January, has been transmitted. The
array voltage shows the effect of the solar eclipses. The array
voltage also shows the decrease of battery voltage during dark
periods, the constant voltage during charge, and the overvoltage when
the battery is fully charged. The WOD is available for download from
my web site (details below).

The spin period has varied between 280 and 315 seconds. At the start
of the reporting period the Z-axis magnetorquer counter reached 1024.
This has stopped attitude control pulse firings, and ground control
action is needed to reset the counters.

Reports of mode-S reception have been received from Andy VK3TDO and
Jorge LU4EBC.  Both stations report hearing weak signals using SSB
converters with 60 Cm dishes.  Many thanks for those reports.

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 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:U2RPT58.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



AMSAT Top AMSAT Home