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>Path: infoac!unido!mcsun!uunet!jarthur!usc!zaphod.mps.ohio-state.edu!magnus.acs.ohio-state.edu!tut.cis.ohio-state.edu!n8emr!gws
>From: gws@n8emr.uucp (Gary Sanders)
>Newsgroups: rec.radio.amateur.misc
>Subject: AMSAT NEWS SERVICE BULLETIN 075.01
>Message-ID: <1991Mar18.014833.1339@n8emr.uucp>
>Date: 18 Mar 91 01:48:33 GMT
>Sender: gws@n8emr.uucp (Gary Sanders)
>Organization: HAM BBS, 614-895-2553 (1200/2400/v.32/pep)
>Lines: 177


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| 		Relayed from AMSAT BBS  NETWORK              |
| N8EMR's Ham BBS, 614-895-2553 1200/2400/9600/V.32/PEP/MNP5 |
==============================================================


HR AMSAT NEWS SERVICE BULLETIN 075.01 FROM AMSAT HQ
SILVER SPRING, MD MARCH 16, 1991   
TO ALL RADIO AMATEURS BT
 
AMSAT Ground Command Team Brings AO-16 And LO-19 BBS Back On-Line
 
After spending two weeks studying memory dumps, NK6K and G0/K8KA have
determined the cause of the on-board computer crash which occurred on 
AO-16 March 2.  NK6K traced the crash back to an inefficient way  
in which a "homebrew" PACSAT user program requested information about 
new files stored on the BBS.  Because of the slow way the search for new
files was being performed and the fact that at the time crash there 
were over 560 files stored, the file server took a lot longer to search
than normal.  After sixty seconds, a critical software timer timed out,
and as NK6K puts it, "the dominoes started falling."

Now that this problem has been identified, G0/K8KA has made a change in
the PACSAT file server software so that this problem won't re-occur.  
Also, new implementation notes will be published so that all writers of 
PACSAT ground station user software will be aware of the change in the 
PACSAT Protocol. 

As of 03:00 on March 15, 1991, the BBS on AO-16 is back in operation.
Likewise, the BBS on LUSAT-OSCAR-19 (LO-19) is on-line, according to
LU7XAC.  It is believed that the LO-19 on-board computer crash was due
to the same problem, manifest in a slightly different way.  NK6K points 
out that PACSAT BBS software is much more robust with each new version, 
and the time between crashes is longer.    

/EX
SB ALL @ AMSAT      $ANS-075.02
EXPERIMENTERS DAY SCHEDULE

HR AMSAT NEWS SERVICE BULLETIN 075.02 FROM AMSAT HQ
SILVER SPRING, MD MARCH 16, 1991
TO ALL RADIO AMATEURS BT

PACSAT Experimenter's Day Operations Schedule Set


The schedule for future PACSAT Experimenter's Day operations is:

  DATE           START TIME               END TIME

20 March       0500 UTC - 20 March      0430 UTC - 21 March
27 March       0320 UTC - 27 March      0255 UTC - 28 March
03 April       0505 UTC - 03 April      0615 UTC - 04 April

While operation of the S-Band and raised cosine PSK transmitters is scheduled 
to be conducted weekly, users are cautioned that these operations may be 
shortened or canceled to allow uploading of improved spacecraft software.  
Watch for bulletins in the BBS and the telemetry text frame of AO-16 for 
changes to the schedule.

Starting with the 20 March 91 session, all AO-16 bulletin transmssions
will be stopped and the telemetry rate set to 20 seconds or faster so
that higher than normal rate data may be taken.  The file server will
remain open.

[ANS thanks Bruce Rahn, WB9ANQ for the information for this bulletin]

/EX
SB ALL @ AMSAT      $ANS-075.03
OPERATIONS NET SCHEDULE

HR AMSAT NEWS SERVICE BULLETIN 075.03 FROM AMSAT HQ
SILVER SPRING, MD MARCH 16, 1991
TO ALL RADIO AMATEURS BT

AMSAT-NA Operations Net Schedule

AMSAT Operations Nets are planned for the following times.  Mode B nets are
conducted on an AO-13 downlink frequency of 145.950.  Mode J/L nets are
conducted on an AO-13 downlink frequency of 435.970.
 
 Date      UTC   Mode  Phs     NCS     Alternates   U.S. day 

23 Mar 91  1400   B    216    KA5SMA     WB9ANQ     Saturday

 - reorientation to 180/0 and mode schedule change 27 March 91 -

30 Mar 91  2345  J/L   103    WJ9F  WB9ANQ  KA5SMA  Saturday
07 Apr 91  0315  J/L    99    WD0E  WA5ZIB  KA5SMA  Saturday
17 Apr 91  0330  J/L    97   WB6LLO  N5BF    WJ9F   Tuesday

The Operations Net features guest speakers approximately every other week 
to provide up-to-the-minute information on topics of interest to various
sorts of satellite users.  Watch ANS for information on guest speakers
and topics.
 
/EX
SB ALL @ AMSAT      $ANS-075.04
AO-13 TRANSPONDER SCHEDULE
 
HR AMSAT NEWS SERVICE BULLETIN 075.04 FROM AMSAT HQ
SILVER SPRING, MD MARCH 16, 1991
TO ALL RADIO AMATEURS BT
 
AO-13 Winter Schedule, AO-10 No Longer Available
 
AO-13 TRANSPONDER SCHEDULE 

  Mode-B : MA 000 to MA 165 |
  Mode-JL: MA 165 to MA 190 |
  Mode-LS: MA 190 to MA 195 |
  Mode-S : MA 195 to MA 200 | <= Mode B is Off - no swishing!
  Mode-BS: MA 200 to MA 205 | <= QRP on BS please.
  Mode-B : MA 205 to MA 256 |
  Omnis  : MA 240 to MA 060 |

This schedule is expected to continue through 27 March 91

The command team requests that you make a specific effort to use QRP on Mode B
between MA 200 to 205.  This is specifically to help those people who are 
experimenting with Mode S.

SPACECRAFT ATTITUDE PREDICTIONS FOR AO-13:
 
     DATE         BLON      BLAT       
  1991 Mar 17    209.0     -1.2
  1991 Mar 24    209.1     -1.1    Move towards 180/0 begins March 25.

Around 27 March 91, AO-13 is scheduled for a reorientation to target 
BLON = 180 and BLAT = 0.  The transponder schedule for 27 March 91 through
19 June 91 is expected to be:

  Mode-B : MA 000 to MA 095 |
  Mode-JL: MA 095 to MA 125 |
  Mode-LS: MA 125 to MA 130 |
  Mode-S : MA 130 to MA 140 |
  Mode-BS: < discontinued > | <-- Note 1
  Mode-B : MA 140 to MA 256 | <-- Note 2
  Omnis  : MA 240 to MA 030 |


Note 1 - The transponder schedule for 27 March 91 to 19 June 91 will see
the end of Mode-BS because Mode-S operation while the Mode-B transponder
was active was impractical due to interference from Mode-B users.

Note 2 - Originally the attitude change back to 210/0 was planned for
early May because solar eclipses affecting AO-13 begin on 22 May 91
and in the past it has been the AO-13 command team policy NOT to 
magnetorque during eclipses.  However, in August this year we have NO 
choice but to magnetorque during the eclipses so it was thought that we 
could gain some experience in magnetorquing during eclipses in June with 
a bonus of an extra month of operation with the more favourable attitude 
of 180/0 in the process.

The downside of this proposal is that ALL transponders will have to 
be switched OFF from MA 200 through perigee to MA 035 from 22 May 91
to 24 Jun 91 even though magnetorquing will not start until 17 Jun 91.
Having the transponders OFF from MA 200 to MA 035 from 22 May 91
until 17 Jun 91 will give us an opportunity to guage the state
of the battery prior to the start of the eclipse.

Currently, OSCAR-10 is obviously not receiving sufficient solar panel 
illumination to support even the beacon much less the transponder.  
PLEASE DO NOT attempt to use OSCAR-10 until further notice.  This period 
of dormancy is expected to last for several months.  As soon as OSCAR-10 
can support Mode-B transponder operations it will once again be released 
for general use.  Early reports of OSCAR-10's beacon returning to full 
strength can be sent to VK5AGR @ PACSAT-1, @ UOSAT-3, @ 8J1JBS, or @ 
VK5WI.  73, Graham VK5AGR

/EX
-- 
Gary W. Sanders (gws@n8emr or ...!osu-cis!n8emr!gws), 72277,1325
N8EMR @ W8CQK (ip addr) 44.70.0.1 [Ohio AMPR address coordinator]
HAM BBS (1200/2400/9600/V.32/PEP/MNP=L5) 614-895-2553
Voice: 614-895-2552 (eves/weekends)
-- 
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