kd2bd@ka2qhd.UUCP ( Wall Township NJ) (01/07/89)
Bulletin ID: SPC90109
---------
SpaceNews
---------
MONDAY JANUARY 9, 1989
SpaceNews originates at KD2BD in Wall Township, NJ, and is available on
packet radio bulletin board stations across the North America and around
the world on the MTTBS telephone BBS at (201) 494-3649, the Unix UUCP
USENET News Network, and also on WangNet.
* MINI-TUTORIAL: DECODING OSCAR-9 TELEMETRY *
---------------------------------------------
Decoding and analyzing OSCAR-9 telemetry is a easy for anyone having an
HF receiver available to them. UoSAT-1 (OSCAR-9) currently transmits on
21.002 and 14.002 MHz using 10 WPM CW and 100 mW of transmitter power.
OSCAR-9 also transmits on VHF, but uses 1200 baud ASCII for downlinking
digital information to Amateur Radio ground stations around the world.
I occasionally post news bulletins I receive from OSCAR-9 on VHF.
Look for these bulletins on systems that also carry SpaceNews.
OSCAR-9's telemetry contains 60 analog "channels" that are transmitted by
it's on-board computer to ground stations. On HF, however, only the first
10 channels are downlinked by the HF beacon(s).
The format for OSCAR-9's HF telemetry is: NNDDD, where NN is a two digit
channel number, and DDD is a three digit telemetry value that is used as
as the argument of a calibration equation. Calibration equations are used
to convert the "raw" telemetry data values into real units like milliamperes,
volts degrees Celsius and nanoTeslas.
An OSCAR-9 CW telemetry "frame" might look something like:
AMSAT 00380 01370 02661 03481 04598 05046 06027 07056 08040 09033
Notice that the channel numbers range from 00 to 09. The numbers following
these numbers are the raw telemetry values that are substituted into
the calibration equations for decoding the actual telemetry data.
Each calibration equation was calculated to give the best "straight-line"
fit to the actual measured performance of the telemetry sensor before launch.
Equations for OSCAR-9's first ten analog telemetry channels are as follows:
00 : SECONDARY SPACECRAFT COMPUTER CURRENT : I = 1.2N (mA)
01 : SOLAR ARRAY CURRENT (+X FACET) : I = 200 + 1.12N (mA)
02 : BATTERY HALF VOLTAGE : V = N/100 * 1.01 (volts)
03 : RADIATION DETECTOR A OUTPUT : Count = 40N * (1.04)
04 : RADIATION DETECTOR B OUTPUT : Count = 40N * (1.04)
05 : MAGNETOMETER EXPERIMENT HX-COARSE : Bx = (129N - 64824) (nT)
06 : MAGNETOMETER EXPERIMENT HY-COARSE : By = (129N - 64433) (nT)
07 : MAGNETOMETER EXPERIMENT HZ-COARSE : Bz = (129N - 64072) (nT)
08 : BATTERY PACK-A TEMPERATURE : Temp = (474 - N)/5 * (1.01) (C)
09 : SPACECRAFT FACET TEMPERATURE : TEMP = (474 - N)/5 * (1.01) (C)
Listen for OSCAR-9 from around 7:00 to 9:00 (AM & PM) local time each day.
If you hear the spacecraft and decode the telemetry, send me a note, and
I'll include your data in an upcoming SpaceNews issue.
If you have a narrow-band FM receiver capable of receiving 145.825 MHz,
you can try listening for OSCAR-9 on VHF also. On Thursday's you'll be able
to hear OSCAR-9's "Digitalker" speak selected telemetry data in plain
english (yes, you CAN hear non-human voices from space!).
Good luck!
* OSCAR-9 NEWS *
----------------
UoSAT-OSCAR 9 Weekly Operating Schedule :
TUE : Diary reload occurs. VHF-FM beacon is OFF the air.
WED : CCD Video transmission - 1200 baud synchronous data.
THU : Digitalker sends telemetry in English until 14:00 UTC.
After 18:00, the Diary will transmit a sequence of TELEMETRY, BULLETIN
and WOD using 1200 baud ASCII until next Tuesday, when a reload occurs.
The 145.825 MHz NBFM General Data Beacon is ON the air according to
the above schedule. In addition, the 14.002 and 21.002 MHz beacons
are currently active sending Morse telemetry and A0 using 100 mW
of power. The 2.4 GHz FM beacon is OFF the air.
* FEEDBACK WELCOMED *
---------------------
Feedback regarding SpaceNews can be directed to me (John) via the following
paths:
UUCP : ucbvax!rutgers!petsd!tsdiag!ka2qhd!kd2bd
PACKET : KD2BD @ NN2Z
* JOIN THE RANKS! *
-------------------
Amateur Satellite operations can be very educational, rewarding and fun, but
in order to communicate through any one of our "OSCAR"s, you must first have
an Amateur Radio license. For information on the requirements for earning an
Amateur Radio license in the U.S., write:
THE AMERICAN RADIO RELAY LEAGUE
225 MAIN STREET
NEWINGTON, CONNECTICUT 06111
* SOURCES *
-----------
Some of the news contained in this SpaceNews issue was obtained via
OSCAR-9, OSCAR-11 and the KA2QHD and NN2Z PBBSs.
* BID$ *
--------
SpaceNews is available for UNLIMITED distribution.
Please use Bulletin ID: SPC90109 when posting this bulletin on packet radio
BBSs that support bulletin IDs. Thank you.
Note: The BID$ have changed to an eight character format for
compatibility with new W0RLI PBBS software.
* MESSAGES de KD2BD *
---------------------
>> KY2N : Bob, the new, shorter BID$ are now in use.
>> VE3LVQ : Alan, thanks for your interest in SpaceNews. I hope these
"mini-tutorials" are of interest to you!
>> N1CUI : Ward, I get in touch with you regarding distribution to
Ridgefield, CT.
>> ALL : Thanks for reading SpaceNews.
>> SpaceNews is a production of KD2BD Software. All rights reversed. <<
<eof>
--
UUCP : ucbvax!rutgers!petsd!tsdiag!ka2qhd!kd2bd
PACKET : KD2BD @ NN2Z (John)
..."There is no expedient to which a man will not resort to
avoid the real labor of thinking." ....Sir Joshua Reynolds.