brainwagon "There is much pleasure in useless knowledge." — Bertrand Russell

22Jan/080

UO-11 also wakes up from its nap…

Another old time satellite might be waking up from its sleep as it comes out of a period of eclipses. Joanne Maenpaa mentioned that UO-11's telemetry beacon had been heard on 145.825, so I decided to try to give it a listen on its pass to the east. Despite the fact that it was fairly low, I heard the 1200 baud AFSK telemetry quite clearly. I don't have the ability to decode it (couldn't find any Mac programs that would), but I recorded a couple of minutes of it using Audacity on my mac anyway. Because someone might be able to decode it from this data, here's the compressed .wav file:

UO-11 Telemetry, 2008-01-23 around 04:27 UTC

Here's a screen dump of Audacity, showing the 1200 and 2400 Hz carriers that make up the AFSK signal.


Spectrum of UO-11 Telemetry

Addendum: Douglas Quagliana, KA2UPW did what I hoped someone would: ran my recording successfully through his own UO-11 decoder. From the email he sent me:


Hi Mark,
 Thanks for posting the recording!

 I downloaded your recording and ran it through
my DSP soundcard UO-11 demodulator. Most of the
data in your recording looks like this, although
other sections are quite noisy.

UOSAT-2           0711024074656
000000010001020002030003040004050005060006070007080008090009
100001110000120003130002140005150004160007170006180009190008
20000221000322000023000124000625000726000427000528000A29000B
30000331000232000133000034000735000636000537000438000B39000A
40000441000542000643000744000045000146000247000348000C49000D
50000551000452000753000654000155000056000357000258000D59000C
60800E615FC1620004633305644402651E0C662AC467000168000E69000F

All of the columns of zeros are telemetry channels that have
failed. This agrees with what Clive has previously reported.


Earlier Clive reported:
>The current status of the satellite, is that all the analogue
>telemetry channels, 0 to 59 are zero, ie they have failed.
>The status channels 60 to 67 are still working. The real
>time clock is showing a large accumulated error [...]

Last month the clock was about 74 days slow, but it is now
about 81 days off.

In the past UO-11 also used to send stored ASCII bulletins
as well, but I think that capability of the satellite ended
when the spacecraft computer turned off. Anyone know
for sure?

Thanks alot Douglas for the decode.

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