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Re: Has anybody heard AO-10 lately ?



Richard & Peter,
Just an observation on the AO-10 antennas....

I have worked AO-10 on literally hundreds of perigee passes over the last two 
years (my antennas are 2x2, so apogee is beyond my means) and find the 
signals from the satellite absolutely continuous (not counting the infamous 
fades that affect everyone) regardless of elevation angle to my location.  A 
very close perigee pass is under  6,000 km and I can "hear" the bird and work 
into it without losing the signal (as long as I compensate for polarity 
shifts) from horizon to horizon, regardless of elevation.  

Admittedly anecdotal, I still consider this a good argument for believing the 
omni antenna are in use on both the uplink and downlink.  If the high-gain 
antennas were in use, I suspect the narrow beamwidth would leave me out of 
the RF path (either at unfavorable elevations or when the bird wobbled away 
from me) even though I was still in the satellite's "shadow."  

I never heard the bird when it was operating under control, but maybe there 
is an "experienced" user out there who can recall what it was like and 
compare the signals then and now.  It won't prove a thing, but it would be 
interesting to know.  

73,
Jerry, K5OE

> > There is also no guarantee that AO-10 is on the circular polarized beam.
>  > Default value after a reset (or power-down) is the omni antennas. Its a
>  > possibility that the system *might* self-switch to the beams though.
>  
>  This is *not* correct...
>  
>  The Antenna Relays will be in the last state as they were commanded
>  by the computer, even after a power down reset.
>  
>  This was to prevent that the S/C will be in a wrong state after a reset
>  or so..  For example if we are in HiGain-Mode in Apogee and we would
>  reset the computer, it would be then very difficult to command via Omni
>  in an emergency situation. It's better to keep the last state therefor.
>  
>  However, we do not actually now what the current state of both antennas
>  (omni or higain) is, as at least one time a couple of years ago the
>  computer might have started playing piano on the right output ports
>  and switched one or both antennas. Switching Antennas is not just by 
> switching
>  one single output, it is a more complex procedure..
>  
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