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[jamsat-news:818] * SpaceNews 20-Apr-98 *

* SpaceNews 20-Apr-98 *

BID: $SPC0420


			  MONDAY APRIL 20, 1998

SpaceNews originates at KD2BD in Wall Township, New Jersey, USA.  It
is published every week and is made available for non-commercial use.

The FO-29 satellite was switched into Mode JA on 1998-Apr-20 at 0700 UTC
because the command staion detectd 2 bit errors in the on-board-computer.
Resetting and reloading software into OBC will take a while, and the
satellite  will remain in Mode JA until that time.

[Info via Kazu Sakamoto, JJ1WTK]

In response to many requests for information regarding methods of decoding
OSCAR-11 signals, Clive Wallis has added a package of information to his
OSCAR-11 Web site regarding this topic.  The web site also contains 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.

The web site also contains some audio files, including a recording of the
Mode-S beacon which plays for 20 seconds.  The other audio files  are
examples of each type of data transmitted by OSCAR-11, and each one plays
for about ten seconds.  All the audio files are zipped so that they can
be played off-line.  They should help listeners identify the various
types of data, and give an indication of the signal quality  required
for successful decoding.

The URL of Clive's OSCAR-11 Web page is:


When the previous OSCAR-11 report was written, ground control operations
were taking place to investigate a "shut down" that had occurred a few
days previously.  These operations were successful and normal service
has been restored.  During the period 1998-Mar-21 to 1998-Apr-15,
excellent signals have once again been received from the 145.826 MHz

Reception reports of the Mode-S beacon have been received from Mike,
WL7BQQM, Ed K9EK, and Jim KK3K.  These reports were all received after
the "shut down" occurred, indicating that beacon is still OK.  Many
thanks for those reports.

Since the "shut down", the telemetry indicates that there is a reduction
in the 14 volt line current of about 50 mA and a reduction in the +5 volt
current of about 25 mA.  The reason for these changes is not obvious as
the status telemetry does not show that any units have been switched off.
The only obvious change in status telemetry is that the four bits associated
with the CCD camera integration period and gain have changed from ones to
zeros.  The camera power is OFF (unchanged).

For several years, Clive has been monitoring the efficiency of the power
conversion process on OSCAR-11 (the ratio of power output to power input).

Power input = Sum of solar array currents * Array voltage

Power output = Battery volts * (Charge current + 14volt line current)

The efficiency calculated in this way has usually been around 80 to 85%.
However since the "shut down" it has fallen to around 65 to 70%.  Clive
welcomes explanations or suggestions regarding this anomaly.

A new WOD survey of channels 1, 2, 3, 61 (magnetometers) dated 1998-Mar-19
has been started.  Anyone using this survey should note the unusual starting
time of 16:00:05 UTC.

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)

There are also 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 only half power.
This beacon is a useful test source for those testing Mode-S converters
in preparation for the launch of P3-D.  It is considerably weaker than
DOVE, which should be used for initial testing.  Any reports of S-Band
beacon reception should be directed to Clive Wallis at: 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 MHz beacon is transmitting,
the 145 MHz beacon is normally off.  The data transmitted is mainly

[Info via Clive Wallis, G3CWV]

Dr. Dave Larsen, N6CO, of the MIREX team has announced a special MIR School
Day communications test on 1998-Apr-27 between 1000 UTC and 2300 UTC.  The
purpose of the test is to let as many schools as possible communicate
their position and brief message via MIR.  To date, there are about 30
schools signed up, with only seven being outside of the USA.

As was demonstrated during the 1998-Mar-11 test, as many as 50 schools in
a single footprint can probably participate and still have an excellent
chance of being seen.  If you can set up your TNC, and modest 2m FM
transceiver to an omni antenna at a school, then you are welcome to
participate.  For details, see the previous announcements on the subject,
or browse http://web.usna.navy.mil/~bruninga/mirex.html.

[Info via Bob, WB4APR]

The ARRL Letter, dated 1998-Apr-04 stated that the second civilian
frequency for the Global Positioning System (GPS) could wind up within
Amateur Radio's secondary allocation at 1.2 GHz.  A decision on whether
the new, second frequency will be 1205 or 1250 MHz is expected to be made
in August.  An allocation at 1250 MHz could mean the end of Amateur Radio
in the band between 1240 and 1260 MHz.  The Amateur 23-cm band runs from
1240 to 1300 MHz.

In February 1997, the Departments of Transportation (DOT) and Defense (DOD)
announced an agreement assuring civilian GPS users of a second frequency,
referred to as L5, and considered essential for critical civilian GPS uses.
According to a DOD news release, the White House Commission on Aviation
Safety and Security, chaired by Vice President Al Gore, "called for the
establishment of a second civil frequency as part of a broader program
to maintain US leadership in aviation and satellite technology."

Further information on this subject is available at:


[Info via John Santillo]

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/
INTERNET  : kd2bd@amsat.org, magliaco@email.njin.net

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