[amsat-bb] AO-51 and V/S

Andrew Glasbrenner glasbrenner at mindspring.com
Sun May 9 19:00:53 PDT 2010

We made the mode change this evening to V/S on AO-51. I and the rest of 
the command team are a bit concerned that we may not have enough battery 
capacity now to sustain operation through eclipse in V/S mode. We cannot 
PTT the transmitter with PL like the UHF transmitters, nor is there any 
way to lower the downlink power on S. If the battery voltage drops too 
low, the voltage watchdog will shut the S transmitter off and it will 
remain off until commanded back on.

If we cannot make it through eclipse in this mode, we can try to use the 
automatic scheduler to enable the S transmitter at a predicted time upon 
exiting eclipse each orbit. We've not tried to use the scheduler this 
way before, so there may be some time required to get things 
working.This approach will require daily intervention to keep things 

The next four months are going to be challenging keeping AO-51 as 
available as possible.

Please either email me directly, or via -bb, or post to 
http://oscar.dcarr.org/ reception reports for V/S. Send those reports in 
this week please!

73, Drew KO4MA
AMSAT-NA VP Operations

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