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[jamsat-news:1168] * SpaceNews 25-Oct-99 *
SB NEWS @ AMSAT $SPC1025
* SpaceNews 25-Oct-99 *
MONDAY OCTOBER 25, 1999
* OSCAR-11 NEWS *
During the period 12 September to 18 October 1999 reliable signals
have been received from OSCAR-11's 145.826 MHz VHF-FM 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 and 24m 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
The internal temperatures have risen by about three degrees during
this period. They are now 6.6C and 5.0C for battery and telemetry
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 remains 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 transmitted after each bulletin 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
polarization of OSCAR-11 is LHC. Even if you can't hear OSCAR-11,
your equipment may still be suitable for P3-D communications. Any
reports of reception on 2401 MHz would be most welcome, and should
be directed to Clive Wallis via e-mail at: firstname.lastname@example.org.
OSCAR-11's 435.025 MHz UHF-FM 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 MHz beacon is
transmitting, the 145 MHz beacon is normally OFF. The data transmitted
is mainly binary.
Listeners to OSCAR-11 may be interested in visiting Clive's OSCAR-11
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 -
[Info via Clive Wallis, G3CWV]
* OSCAR-10 NEWS *
AMSAT-OSCAR-10 is currently experiences eclipses at perigee of approximately
30 minutes in duration. During these eclipses, there should be complete loss
of signal. Slow tumbling of the satellite along with poor illumination of
the solar panels and poor antenna positioning are producing some significant
of downlink signals. The perigee eclipses are expected to continue for at
least the next several months. They will slowly move towards a later period
in the orbit and a corresponding longer duration into the early part of 2000.
For example, by 2000/03/01, the eclipses will have moved to MA 45-72 and will
be 75 minutes long. AO-10 won't be "eclipse free" again until March 25, 2000.
[Info via Stacey E. Mills, W4SM]
* FEEDBACK/INPUT WELCOMED *
Comments and input for SpaceNews should be directed to the editor
(John, KD2BD) via any of the paths listed below:
WWW : http://www.njin.net/~magliaco/
PACKET : KD2BD @ N2SMV.NJ.USA.NA
INTERNET : email@example.com, firstname.lastname@example.org
SATELLITE : AMSAT-OSCAR-16, KITSAT-OSCAR-25
<<=- SpaceNews: The first amateur newsletter read in space! -=>>
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