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Reason for uplink power!!



Hi sat-ops,
based on the information of the command team, I plotted a comparison for
the U-Band AGC on the orbits 256(1st transponder period) and orbits
330+331 (running xpndr period). 

http://www.physik.unizh.ch/people/avollhar/u_rx_256.jpg
http://www.physik.unizh.ch/people/avollhar/u_rx_330.jpg
http://www.physik.unizh.ch/people/avollhar/u_rx_331.jpg


Many ops complained about the bad rx sensitivity of this 2nd period. The
reason seems to be a non-optimum LEILA2 setting. During first period,
LEILA1 was active and produced mean AGC levels of around 5 dB. With the
actual setting of LEILA2, some hams managed to drive the AGC to 15-20
dB! So remember your uplink pwr from the last couple of days and reduce
10dB.. this will be it after the proper LEILA setting has been loaded!

This is not the fault of the AO-40 RX nor of the cmd teams (by the way:
great job!).
Somebody is just driving the AGC up.. and he won't notice.. because he
is still 7 dB  below the MB (this is how the AGC limit is set..). 

My advice: 
1. find out how long you can increase your ERP while monitoring your
RX-Signal.. 

2. if you found the compression point, go back 1/2 to 1 s-levels.. 

3. this way YOU are not the one driving the AGC.. repeat after every
qso..

Of course, after commisioning of LEILA2, this will be all obsolete.. so
don't flame me to long for this.. ;-)

73s and see you on the bird!
Achim, DH2VA
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