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

OSCAR-11 Report




                OSCAR-11 REPORT    16 February 2002


During the period 14 January to 15 February 2002 good signals
have been received from the 145 MHz. beacon.

The internal temperatures have varied up and down within a band of
about one degree C. during this period.  However there does seem to
be a trend towards lower temperatures.  These temperatures are now
4.4C and 2.6C for battery and telemetry electronics respectively.

The battery voltage observed during daylight passes is unchanged.
The average value observed was 13.8 with a range of 13.7 to 13.9
volts.

The rate at which the SEU counter increments has increased slightly,
from 771 to 785 counts per day. Decoding the SEU binary telemetry
shows four permanent memory failures at locations 3EC0, 37B1, 21C0
and F96. Locations FF5A FF58 also fail less frequently. These
permanent memory failures tend to mask out the display of the less
frequent failures, owing to the limited storage for this data in the
satellite.

The WOD survey of channels 10, 20, 30, 40 ( +Y, -X, +X array
currents, & array voltage ) dated 06 January 2002 has been
transmitted.  An initial sample of this data may now be downloaded
from my web site, details below. Users should note that the year in
the date of u the new survey is incorrectly given in the status
frames as 2001.

The spin period has drifted between 193 and 237 seconds, although no
particular trend is apparent. The attitude is controlled solely by
the gravity boom gradient, as the Z-axis magnetorquer counter has
reached saturation (1024). Ground control action is awaited to
reset the magnetorquer pulse counters.

The mode-S beacon on 2401.5 MHz. has been heard by Ryan KF9T, and Mark
KC4ENN at the University of Illinois. They report strong signals on
their 15 dB loop antenna and Down East converter. Many thanks for
that report.

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, nominally transmitting an unmodulated
carrier on 2401.5 MHz. There is however a VERY low level of AFSK
modulation which has been detected on strong signals. Telemetry
indicates that the beacon has partially failed, and is 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 2401.5 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:U2RPT70.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