
SB SAT @ AMSAT   $ANS-035.01
ANS APOLOGY

HR AMSAT NEWS SERVICE BULLETIN 035.01 FROM AMSAT HQ
SILVER SPRING, MD FEBUARY 4, 1995
TO ALL RADIO AMATEURS BT
BID: $ANS-035.01

APOLOGY

ANS Bulletin 035.04 released January 28 mentioned, in a negative
manner, a specific design feature of the "R. J. Myers" S Band
dish.  This, or any other reference to the adequacy or inadequacy
of any commercial product should not have appeared in ANS, and
AMSAT-NA Management takes full responsibility for this slip-up.
ANS bulletins are the official voice of the Radio Amateur
Satellite Corporation (AMSAT) and thus should confine themselves
to factual material, not personal opinions.  ANS should be
contrasted with AMSAT-BB which is a vehicle for free exchange of
ideas and information between individuals and, unless otherwise
specifically stated, nothing that appears on BB represents the
official position of AMSAT-NA.

As the to Bob Myers Communications S Band dish, AMSAT-NA takes no
position on it, one way or the other, however, Bill Tynan (W3XO)
AMSAT-NA President was quoted as saying, "I can say personally,
that in the many notes I have seen posted on AMSAT-BB, I have
never seen another comment that the Bob Myers Communications dish
does not perform well.  This opinion has also been reflected in a
number of personal conversations I have had with various
satellite operators who use this dish."

ANS apologizes to Bob Myers Communications for any harm this
bulletin might have done to the organization.

/EX
SB SAT @ AMSAT   $ANS-035.02
UO-22 EXPERIENCES A SEU

HR AMSAT NEWS SERVICE BULLETIN 035.02 FROM AMSAT HQ
SILVER SPRING, MD FEBUARY 4, 1995
TO ALL RADIO AMATEURS BT
BID: $ANS-035.02

UO-22 Suffers A Single Event Upset (SEU)

Between 22:00 and 24:00 UTC on 29-JAN-95 during an orbit where UoSAT-OSCAR-22
passed through the South Atlantic Anomaly (SAA), the spacecraft suffered a
crash of its OBC-186.  What was first thought to be a straightforward software
crash proved to be much more serious.  Examination of Very Large Scale Integrated
(VLSI) telemetry during morning passes on 30-JAN-95 revealed that the current
drain of the OBC-186 was running about 3 times the normal value.  Following a
number of short real-time tests and observations, ground controllers took the
decision to power down the OBC-186, RAMDISK and associated hardware for several
hours before attempting further diagnostic activities.

The OBC-186 was left in the powered down state for a period of roughly 18
hours before ground controllers resumed recovery attempts.  In the meantime,
VLSI telemetry was left on the downlink and a number of experiments were
switched off under telecommand as a power saving measure.

During the first morning pass over Europe on 31-JAN-95 ground controllers began
a systematic power up procedure of the OBC 186 and all associated hardware.
Observations were very promising as current drain for the OBC-186 had returned
to normal and the bootloader was observed on the downlink indicating nominal
operation of the flight computer hardware.

On the following pass over Europe, UoSAT engineers and ground controllers
uploaded a series of diagnostic software into the spacecraft to test both the
Error Detecting And Correction (EDAC) memory and the RAMDISK.  All tests 
returned positive results with no errors reported in either system.  The 
diagnostic software for the RAMDISK was left running for the next orbit 
which would pass through the SAA after going LOS at the UoSAT command 
and control center.

On the final morning pass the test software was observed to still be
operating as expected reporting no errors and the decision was taken to
begin the software reload process.

This process was completed during the evening passes on 31-JAN-5 over Europe.

While the recovery of UO-22 is good news indeed, it is an unfortunate
necessity that the RAMDISK had to be powered down as part of the recovery
process.  Unlike a straightforward software crash this anomaly resulted in the
loss of all files contained aboard the UO-22 file server.

Controllers have decided to limit uploading of files to the spacecraft for
the next 24 hour period as the final stages of the recovery process unfold.
After the spacecraft is deemed to be stable the store-and-forward system
will once again be opened for use by users world-wide. We appreciate
everyone's cooperation while we work the remaining operational issues.

[The AMSAT News Service (ANS) would like to thank Doug Loughmiller (G0SYX),
 UoSAT Spacecraft Operations Manager, for this bulletin item.]

/EX
SB SAT @ AMSAT   $ANS-035.03
AMSAT OPS NET SCHEDULE

HR AMSAT NEWS SERVICE BULLETIN 035.03 FROM AMSAT HQ
SILVER SPRING, MD FEBUARY 4, 1995
TO ALL RADIO AMATEURS BT
BID: $ANS-035.03

AMSAT Operations Net Schedule

To take full advantage of the upcoming "good" phase on AO-13, the
following AMSAT Operations Net Schedule will be in place.  The primary
downlink frequency for all Ops. Nets will be 145.950 MHz.  In case a
QSO is in progress on that frequency at net time, 145.955 MHz will be
used as an alternate.  Net control for all of these nets will be
Keith (W5IU); however, anyone is welcome to serve as an alternate.
Reports on all phases of OSCAR operations are welcome.  Guest speakers
on special topics will be scheduled as availability permits.

Day    Date       Time       Coverage
________________________________________________________

Sat  11-FEB-95     18:00      NA, SA, WEu, Af
Sat  18-FEB-95     22:00      NA, SA

Note:  All times are in UTC; therefore, Sun. dates are actually Sat.
evening in USA.  Times do not conflict with ZRO Tests.

Thanks - Keith, W5IU, AMSAT VP of Operations

/EX
SB SAT @ AMSAT   $ANS-035.04
WEEKLY OSCAR STATUS REPORTS

HR AMSAT NEWS SERVICE BULLETIN 035.04 FROM AMSAT HQ
SILVER SPRING, MD FEBUARY 4, 1995
TO ALL RADIO AMATEURS BT
BID: $ANS-035.04

Weekly OSCAR Status Reports: 04-FEB-95

AO-13: Current Transponder Operating Schedule:
The Mode Schedule from 19-DEC-94 until 20-FEB-95 will be:
Mode-B  : MA   0 to MA 100 |Omnis : MA 230 to MA  25
Mode-BS : MA 100 to MA 130 |
Mode-S  : MA 130 to MA 132 |<- S beacon only
Mode-S  : MA 132 to MA 155 |<- S transponder; B trsp. is OFF
Mode-S  : MA 155 to MA 160 |<- S beacon only
Mode-BS : MA 160 to MA 180 | Blon/Blat 180/0
Mode-B  : MA 180 to MA 256 | Move to attitude 230/0, Feb 20
[G3RUH/DB2OS/VK5AGR]

AO-27: W9ODI reported that AO-27 was on last weekend, Jan 28-29.
[W8GUS & W9ODI]

IO-26: Ground controllers IV2VOO and IK2OYD have loaded and succesfully ran the
the latest version of IHTX code.  This code allows for a scheduled OFF of the
main trasmitter to preserve battery power and increase TX power during the
mostly used parts of the orbit.  WOD dumps are underway to analiyze the new
power trends and the BBS code upload will begin next week if all is OK.  [I2KBD]

The AMSAT NEWS Service (ANS) NEEDS YOUR HELP! The ANS looking for volun-
teers to contribute weekly OSCAR status reports.  If you have a favorite
OSCAR which you work on a regular basis and would like to contribute to
this weekly bulletin, please send your observations to WD0HHU at his
CompuServe address of 70524,2272, on INTERNET at wd0hhu@amsat.org, or to
his local packet BBS in the Denver, CO area, WD0HHU @ N0QCU.  Also, if
you find that the current set of orbital elements are not generating the
correct AOS/LOS times at your QTH, PLEASE INCLUDE THAT INFORMATION AS WELL.
The information you provide will be of value to all OSCAR enthusiasts.

/EX

