[amsat-bb] Re: AO7 calibration

[Alan]

Hi Bob,

There are many reasons why the transponder "constant" varies somewhat.  The temperature of the
satellite is somewhat dependent on sun angle, periods of eclipse, etc.  This usually results in a slow
seasonal variation, most frequently seen in SSB satellites, but also in some cases in the FM birds.
In the case of AO-7 there is no battery to stabilize the voltage, so at some (most?) times the 39 year
old arrays may not provide enough power for a completely stable output.  I recall an article on the
subject in the AMSAT Journal, though I don't have it handy.  

73s,

Alan
WA4SCA




<-----Original Message-----
<From: amsat-bb-bounces at amsat.org 
<[mailto:amsat-bb-bounces at amsat.org] On Behalf Of Bob- W7LRD
<Sent: Monday, November 18, 2013 11:00 AM
<To: amsat-bb at amsat.org
<Subject: [amsat-bb] AO7 calibration
<
<Hello...More often than not I have to "adjust" the up link 
<calibration on satpc32 in order to accurately track the sat. 
<It is not always the same adjustment, it can vary from a few 
<cycles to as much as 2.5 khz. Given AO-7 is a grand old lady, 
<is she just being temperamental, or do I have an issue 
<(operator error). 
<73 Bob W7LRD 
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