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

OSCAR-11 Report





                OSCAR-11 REPORT    19 October 1999

I am indebted to Jeff KB2WQM of Ocean View New Jersey, who
provided most of the telemetry for this report, during my recent
holiday and during subsequent antenna maintenance and repairs.  I am
now able to receive OSCAR-11 normally. Many thanks Jeff.

During the period 12 September to 18 October 1999 reliable signals
have been received from the 145.826 MHz. beacon.

The Z-azis attitude correction counter has now reached its limit of
1024, which has stopped further firings of the magnetorquers.  Ground
control action to reset the counters is expected in the near future.

The battery voltage during daylight passes has shown less variation
than usual. The average value observed was 14.0, with a range of 13.6
to 14.1 volts. The higher value being observed many times.

Sometime between September 20 & 24 the steady state main 14 volt line
current decreased from 595 to 560 mA. The reason for this change is
not obvious from the telemetry. In March 1998 there was a similar
drop in current from 625 to 595 mA, also without any obvious cause.
Although any reduction in power drain is welcome, the cause remains a
mystery.

The internal temperatures have risen by about three degrees during
this period. They are now 6.6C and 5.0C for battery and telemetry
electronics respectively.

The single WOD survey of channels 1, 2, 3, 61 (magnetometers) dated
15 July 1999 has again been been transmitted.  This shows an
increased spin period of about 450 seconds, which was current when
the WOD was started, but has now been corrected by the attitude
control system.

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
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:U2RPT42.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