Re: [amsat-bb] Oscar 10 help ?

[Mike73@xxxxxxx]

In a message dated 8/3/99 11:26:49 AM Eastern Daylight Time, 
darren.rainer@eyretel.com writes:

> I have listened for OSCAR 10 when it has been in high orbit  
> and been well within its footprint but no signal which I have put down to
> the satellite not beaming in my direction.
> The question I have is how can
>  I find out when OSCAR 10 has its antenna pointing in my direction ?

Hi Darren,

I believe a couple of factors are at work here. Oscar 10 seems to be tumbling 
and its spin rate seems to have decreased. Also remember that AO-10 only 
functions when it has adequate sunlight hitting its solar panels. Its 
batteries stopped working quite a while ago.  Add all this up and you get the 
conditions you are experiencing.

So, is AO-10 workable?? Yes! The best way to work it is to monitor the beacon 
(an unmodulated carrier) at ~145.810 +/- doppler with the second vfo in your 
radio. I switch my 736R B VFO to the beacon and monitor it. When I hear the 
beacon starting to come up, I switch to the A VFO, which I have tuned near 
the center of the transponder and throw out my callsign. The fades right now 
seem to about 20-30 seconds long, with 15-20 second periods of use. I'm using 
switchable CP antennas on both the uplink and downlink which help compensate 
for the varying conditions. Last weekend, I worked a number of DX stations in 
Europe. You have to be quick when it is working, and patient during the fades.

I'm not sure whether the fades are being caused by the bird tumbling and 
thereby pointing its antenna away from me (this would assume it was on its 
directional antenna instead of the omnis) or loss of illumination of the 
solar panels which will shut the bird down. Maybe a combination of both?? I 
did hear some distinct frequency changes, almost as if I had accidentally hit 
my tuning knob. You may experience this as well. Sometimes people will refer 
to this phenomenon as FM'ing. I don't think there is any real harm in the 
type of shift we're hearing right now, however, if you hear the bird 
constantly changing frequency as you uplink, refrain from using it as there 
are several scenarios that could prove to be harmful.

Good Luck,

73,
Mike, N1JEZ
AMSAT #29649
Local Area Coordinator
"A closed mouth gathers no feet."
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