SB NEWS @ AMSAT $SPC1229
* SpaceNews 29-Dec-97 *


BID: $SPC1229


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			       SpaceNews
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			MONDAY DECEMBER 29, 1997


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


* MIR NEWS *
============
MIREX president Dr. Dave Larsen, N6CO, reports that the previously announced
Mir crossband frequency experiment has been abandoned for now because of
problems with the amateur radio antenna on Mir.  The crossband test was to
have started on 01-Dec-97 and lasted three months.  It was to have involved
a 70-cm uplink to Mir along with a 2-meter downlink.  US astronaut Dave Wolf,
KC5VPF, has been on 145.985 MHz FM simplex from Mir, but only sporadically.

A space walk at the end of December will check, and if necessary, repair the
2-meter/70-cm dual-band antenna on Mir.  There is concern that the antenna
may have been damaged during a recent space walk that took place in November.
The Kenwood TM-733 transceiver aboard Mir has been connected to the
spacecraft's SAFEX repeater antenna for the time being.

The new packet radio TNC on-board is currently suffering from a problem that
is the result of improper parameters being entered into the TNC.  The TNC is
not properly interpreting the DCD (data carrier detect) logic, and thinks
the uplink frequency is busy most of the time, even when it is clear.  The
internal timers in the modem will periodically respond to packet data,
and dump the contents of the TNC's transmit buffer in a long transmission.

Groundstations are asked to refrain from using the Mir PMS until the crew
has time to correct the problem.  This request also applies to those who,
despite repeated requests, continue to digipeat beacons and holiday greetings
via the Mir TNC.

The MIREX teams is hopeful that the problem with the TNC can be cleared up
before the end of the year.

In the meantime, here is a list of the commands interpreted by the new TNC
on Mir:

	LL n          LIST LAST n MESSAGES
	LM(ine)       LIST UNREAD MESSAGES ADDRESSED TO YOU
	LO [+|-]      LISTING ORDER
	LT            LIST TRAFFIC
	LTn           DISPLAY LOCATION TEXT n=1-4
	K(ill) n      DELETE MESSAGE NUMBER n
	KM(ine)       DELETE ALL READ MESSAGES ADDRESSED TO YOU
	R(ead) n      DISPLAY MESSAGE NUMBER n
	RH n          DISPLAY MESSAGE n WITH HEADERS
	RM(ine)       READ ALL MESSAGES ADDRESSED TO YOU
	S(end) call   SEND MESSAGE TO callsign
	S[B|P|T] call SEND BULLETIN, PRIVATE, or TRAFFIC

[Info via the AMSAT News Service, WF1F, and CT1EAT]


* HINTS FOR THE NEW YEAR *
==========================
Richard, G3RWL, reminds satellite users that when the new year starts, so
do the day numbers in the Keplerian elements used by satellite tracking and
orbital prediction software, and some old tracking software refuses to cross
between the years.  A tactic to use in this instance (until 1998 keplers
arrive) is to deceive the software by giving it a 1997 date; i.e. 02-Jan-98
is 33-Dec-97, etc.

Another problem comes in some software when the epoch in the keplers contains 
spaces, i.e. "1998__4.xxxxx".  The tactic here is to edit the kepler file 
before feeding it into the program so that the spaces are replaced by zeros.
Extra zero's do *not* affect the checksum of 2-line elements.

Some amateurs still use "old" tracking software that requires a sidereal
time constant for the current year.  The siderial time constant for 1997 
was 0.27693880 and the value for 1998 is 0.27627570.


* SpaceNews ANNIVERSARY NEWS *
==============================
In celebration of the 10th anniversary of SpaceNews, a special anniversary
graphic has been uploaded to the AMSAT-OSCAR-16 and KITSAT-OSCAR-25 digital
communication satellites.  Watch for it!


* THANKS! *
===========
Thanks to all who sent messages of appreciation to SpaceNews, especially:

		KA2DRV	AA6AE	KH6ABA	VK8KTC	TG9IKE

and students at Huntington Park High School, Los Angeles, California who
receive SpaceNews via the AMSAT-OSCAR-16 digital communication satellite.

All the best wishes to everyone for a healthy and happy New Year!


* 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 @ KS4HR.NJ.USA.NA
INTERNET  : kd2bd@amsat.org, magliaco@email.njin.net
SATELLITE : AMSAT-OSCAR-16, LUSAT-OSCAR-19, KITSAT-OSCAR-25


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/EX