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SO-35 parrot repeats UO-11 telemetry!



Hi folks,

Earlier today something interesting happened during the SO-35 parrot 
pass over South Africa (14:46 UTC).  As Sunsat descended towards 
Antarctica, a 1200 bit/s data stream was heard during the playback 
periods.  We suspected another bird and found that UO-11 downlinks 
its telemetry at the SO-35 parrot up/downlink.  Although it hadn't 
risen for our ground station yet, it was in range of Sunsat's RX.

The DSP56002EVM demodulator for UO-11 (adapted by Doug Braun, NA1DB, 
from a 1200 bit/s modem by Pawel Jalocha, SP9VRC) and UO-11 filtering 
and capture software (by Clive Wallis, G3CWV) was used to decode the 
following from one 10 second period (we happened to record the parrot 
pass):

__7gb__ @5__ ___ U___
 Au_o_Mode is sel_cted@
__S<__I_d:_-0218 
 Z Mag_i__ngs:  10 
 + SP_N firingC: `3___@
 - SPI_ _irin_: 0 
 __U coun_      @"_f__@
_AAA_WASH poi_terat B_E1_
 _OD_{__enced @@6 10____0 at_0 :0 _ 
 w_th Aan_ei__#1 ,_2 3 ,61 ,@
_ ___ Ckmmand:109 to 0 ,_0 
 Attitude control initiat_d, mo__@3 _

Having never before decoded UO-11 telemetry, we discovered that it 
was supposed to look more like this:

 Time: 6 :19 :31 UTC
 Auto Mode is selected
 Spin Period: - 358
 Z Mag firings:  154
 + SPIN firings: 2
 - SPIN firings: 66
 SEU count       26018
 RAM WASH pointer at DC8D
 WOD commenced 11 /11 /95 at 0 :0 :5
 with channels 1 ,2 ,3 ,61 ,
 Last Command: 109 to 0 , 0
 Attitude control initiated, mode 3

Clearly not perfect copy, but enough to get someone new interested in 
the old bird.  ;-)

73 de ZR1CBC, Johann

+------------------------------------------------+
  JG Lochner  ESL, Universiteit van Stellenbosch
  e-pos:      lochner@ing.sun.ac.za
  webtuiste:  http://esl.ee.sun.ac.za/~lochner
+------------------------------------------------+
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