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[jamsat-news:520] * SpaceNews 21-Apr-97 *

* SpaceNews 21-Apr-97 *

BID: $SPC0421


			  MONDAY APRIL 21, 1997

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

The launch of the GOES-K weather satellite for NASA and the National Oceanic
and Atmospheric Administration (NOAA) aboard a Lockheed Martin Atlas 1 rocket
(AC-79) is scheduled for April 24.  Liftoff is targeted to occur at the
opening of a launch window which extends from 1:50 - 3:09 a.m. EDT (0550 to
0709 UTC), a duration of one hour and 19 minutes.  Launch will occur from
Pad B at Complex 36 on Cape Canaveral Air Station.

GOES-K is the third spacecraft to be launched in the new advanced series of
geostationary weather satellites for NOAA.  The spacecraft is a three-axis
internally stabilized weather satellite which has the dual capability of
providing pictures while performing atmospheric sounding at the same time.
Once in orbit the spacecraft is to be designated GOES-10.

AC-79 marks the final launch of an Atlas 1 rocket, a derivative of the
original Atlas Centaur developed by NASA which had its first successful
launch in 1963.  Future launches of GOES weather satellites in the current
series will be on Atlas II vehicles.

NASA Television will carry live the GOES-K/AC-79 Prelaunch Press Conference
on Tuesday, April 22 starting at 1 p.m. (1700 UTC).  NASA Television is
available on the GE-2 satellite, Transponder 9C, located at 85 degrees West.

[NASA Press Release via Larry Van Horn]

Several users of the AMSAT-OSCAR-10 Mode B communications transponder have
reported some frequency instability ("FMing") of downlink signals and the
beacon during use.  This is probably due to a lack of illumination on the
spacecraft's solar panels.  Users are asked to refrain from using AO-10
during such periods.

It has been a quiet month on OSCAR-11.  During the period 19-Mar to 16-Apr,
good steady signals have been received from OSCAR-11's 145.826 MHz beacon.

Recent telemetry shows that the increasing solar eclipses have continued
to reduce the internal temperatures by a further four degrees, now about
12 degrees C below the full sunlight condition.  The battery voltage
continues to be rather low, in the range 13.3 to 13.8 volts.

The single WOD survey of channels 40, 50, 52, 63, (Array voltage, battery
charge, battery voltage, BCR status) dated  22-Feb has been transmitted
during this period.  A short file of this WOD is available from the Clive
Wallis's OSCAR-11 WWW site, and will be updated when the WOD is changed
and the maximum amount of data has been received.

Two AMSAT bulletins by Richard G3RWL have been uploaded.  Topics have
included RS-16 / Zeya information and a Phase-3D progress report.
Bulletins always include current Keplerian elements for OSCAR-11, and
often for satellites featured in the bulletin.

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)

OSCAR-11 can be heard on 145.825 MHz.  Modulation is 1200 baud AFSK,
with tones of 1200/2400 Hz.  There have been many designs for suitable
decoders, including the high performance correlation demodulator (used
by ground control), designed by James Miller G3RUH.  However, the simplest
way is to use an old telephone modem that uses Bell 202 or V23 tones.
It is essential to invert the modem's output signal before feeding it
into the computer.

It is also possible to use a BAYCOM type modem which does not require
any output inversion.  Just connect its output to RXD instead of CTS.

Another way is to use a HAMCOM interface instead of a modem.  A small
program called EM1200M2.COM (which is part of EMBAYCOM) emulates a
modem on port 2.  Port 1 is used for the terminal display program.
Unfortunately, this method uses two COM ports, and can be a little
tricky to wire up.

For ASCII, the serial port should be set to 1200,E,7,1.  If the port is
set up to eight bits, then some filtering of the data will be requiredi
before it can be displayed.

Further information and software is contained in file CTERM.ZIP, which
can be downloaded from the following URL:


[Info via Clive Wallis, G3CWV g3cwv@amsat.org]

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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