Mostly just the regulars, got W0DXC, which is one of those annoying club addresses with no email contact on QRZ. Sigh, oh well. W0DXZ (thanks Ben, for correcting me). Heard from WA8SME Mark, KG7EZ Chris, W6GMT Brock, WA6DIR Larry and probably a couple of others.

AO-51, Morning of Jan 31, 2008

Tuning for the Doppler shift on VO-52 is a bit challenging, particularly when you have an antenna in one hand. You all are probably bored with this stuff, but here’s my evening passes recording. It was pretty nice: you can hear WD4FU, the Gainesville, FL station for the University of Florida radio club. It’s the first time I remember hearing a Florida station, and my Maidenhead gridsquare calculator lists its distance at about 3800km. Nice. I am still having difficulty knowing exactly how to adjust the tuning to get natural sounding SSB, but a few more passes, and I bet it will be second nature.

Oh… Did I not tell you what VO-52 was? It’s an Indian amateur radio satellite that carries a linear transponder: it maps a segment of the 70cm spectrum on its uplink to a portion of the 2m spectrum for its downlink. The nice thing is that it can carry several different conversations at once, either in SSB or in CW.

VO-52, with lots of doppler…

Well, last night I went and programmed in the various doppler shifted frequencies for AO-51 into the new FT-817, and then this morning worked the morning pass half duplex with Leo, W7JPI and W6GMT. The recording of course doesn’t include my own voice, but the audio quality was really good. You can occasionally hear a beep tone, that’s where I hit the up switch on the mic to move to the next pre-programmed Doppler setting. Very nice.

AO-51, Morning of Jan 29, 2008 with the FT-817

Well, I couldn’t stand it anymore. I picked up a new Yaesu FT-817ND to expand my capabilities. It’s a neat little radio, and tunes all the way from 160m up to 70cm, and has SSB, AM and CW capabilities. Neat.

My idea was to try to listen to AO-16: I figured that the Doppler would be easier to handle by hand. I didn’t have much luck though, so I decided to try to write a simple program that interfaced to my Python code to do automatic Doppler correction. Basically, it tunes the radio every couple of seconds according to where it predicts the downlink frequency to be.

Well, it didn’t work that well on the next pass (I’ll try again), but I noted that LO-19 was coming up, and it’s very loud, so I modified the script to track its frequency, and got the following recording:

If you look or listen carefully, you can hear where the receiver retunes (it makes an annoying little weedle, and you can see the frequency jump in the middle of a dash in several places). But overall, the morse stays pretty darn stable in frequency.

Neat for a few minutes of scripting.

The weather here is terrible, and standing outside with an antenna in your hand just isn’t that much fun. But I did manage to handle a few minutes outside. It was rainy, it was cold, but I managed to get WA0D EM12 in Texas before I moved inside (where the noise increased a lot). Not a very pleasant pass to listen to. I think I’ll skip the normal recording.

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.

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.

Couldn’t work the bird at all, it was a low 20 degree pass, and I simply can’t get in when the satellite is crowded like this. Still heard many stations, including N2BX from FN20. I tried to cut in, but I simply got doubled. It would have been a nice DX to West Orange, NJ.

CM87 -> FN20: bearing  70.2° distance: 4139.9 km

Eastern pass of AO-51, I didn’t get in at all. Skip the first minute or two: lots of QRM from something that appears to be active when its cold out.

For the western pass, I got K6RJ Rick DM13 handheld, N6PAA Ron from CM98, some random DTMF codes, WD8PFS from DM12, W5OK came through, I originally said WW5OK, and he never came back (it’s hard to remember what you are saying when operating handheld). I was juggling the Doppler by that time too. Got KF6FNT CM98 also operating portable. Got KE7NLQ DN85, and realized I was off on the Doppler again, but then lost the satellite behind the hills to the north (they fade really quick because of the 25+ degree horizon). That was it for the day.

MP3 of the western, more civilized pass…