Re: [amsat-bb] FO-29 Operation sked for Sept-Nov.5 2000

[tlang@xxxxxxxxxxxxxxxxxxxx (Tony Langdon)]

Hello Mike73@aol.com!

30 Aug 00 14:13, you wrote to All:

 M> One thing I've found to be true is that the satellite control ops
 M> always have the best interests of the satellite in mind even if it
 M> conflicts with user wishes. I too was perplexed by the seemingly long
 M> stretches of digitalker mode on FO-29. Personally I'd like to see some
 M> different recordings. I have recorded all of them so far. (cuckoo,
 M> bush warbler, xmas and new years greetings etc.) Even so, I find the
 M> FM signal to be an excellent test tool to check antenna alignment,
 M> antenna sidelobe performance and signal polarity peculiarities at
 M> various points in a pass.

I found FO-29's digitalker a useful tool when I first started out, to
understand path characteristics and the like.  Now, it's a useful beacon for
checking receivers and antennas, especially since satellite activity is in a
bit of a low here.

 M> Anyway, I started looking for possible reasons for the command
 M> decisions. One thing I found was that during these times there was a
 M> high instance of orbital alignment of both FO-20 and FO-29 over the
 M> US, South America and Japan. The footprints of both birds had major
 M> overlap. Seeing as the JA transponders on both birds use the same
 M> frequencies up and down, the switch of FO-29 to digitalker began to
 M> make some sense. During these "aligned" passes, if they were both JA,
 M> it is highly probable that you would be uplinking into both birds
 M> simultaneously. I have no idea if this is the reason for the
 M> digitalker mode. I simply offer it as a "what if" scenario to explain
 M> possible command decisions.

Well, that would make a lot of sense.  Having both in JA mode could be highly
confusing, and adversely affect performance (with 2 signals coming down on
slightly different frequencies...

Tony, VK3JED

.. I am not stubborn.  I am merely correct.
--
|Fidonet:  Tony Langdon 3:633/284.18
|Internet: tlang@freeway.apana.org.au
|
| Standard disclaimer: The views of this user are strictly his own.


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