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" <hdefelice@petrexintl.com>
Cc: 'Amsat BB' <amsat-bb@amsat.org>
Subject: RE: [amsat-bb] P3D testing
Date: Tue, 19 Sep 2000 14:48:24 -0400
Return-Receipt-To: Howie DeFelice <hdefelice@petrexintl.com>
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Even with AGC, there will be some limited dynamic range, so there will be a 
min-max gain value. From what I have seen of the bus structure, there are 
also programmable attenuators that can be switched into the transmitters's 
IF input. The initial and final setting of these attenuators will have an 
effect on the gain as well. Since the AGC will control an entire 
transponder I don't see what the problem is, unless the AGC is distributed 
across all active transponders based on the composite IF level of all 
contributing uplinks. This is good for power management, but not so good 
for operators.  It's very likely that the U/V transponder will be heavily 
AGC'd while the L/S will require much less AGC. I don't recall if the IF is 
a common bus or a matrix switch. ..... No matter what, transponder gain, or 
the measurements to derive it, are required to do any link engineering. It 
would be very useful to the entire community to have this information.


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