[amsat-bb] Re: no go 1.2 on AO-51

Thu Jun 21 12:21:18 PDT 2007


The Doppler runs something like +/- 25 KHz.  From my measurements, and
comments heard, there is an informal consensus that probably the real center
of the uplink is more like 1268.703 or so.  You need to be within about 5
KHz to get in well, and if you are running a lot of power, you can get by a
bit further off.  I am pretty well netted to the uplink, and required power
ranges from 1-2 watts to 80 watts to get a good signal, depending on
location, S/C orientation, and number of trees in the way.  This using about
70' of Heliax to a 32 element M2.  

Guys running without computer control to the TX drop out a lot.  Other
things to check are the pointing accuracy, which becomes more important with
more directive arrays.  One test worth doing, if the situation permits, is
to use a Bird or similar wattmeter and measure the power directly at the
antenna.  I found a big problem that way once, and then worked backward
toward the station to eventually find the bad connector.  WI2W is getting in
with a 10 element yagi and 10 watts, so while more EIRP is definitely
better, it can be done. 


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