[amsat-bb] AO-51 update
glasbrenner at mindspring.com
Sun May 2 20:08:15 PDT 2010
AO-51 has now reentered a period of eclipses that will reach almost 20
minutes by July. Since we've been in an extended period of continuous
illumination and very warm spacecraft temperatures, the next few weeks
will be spent determining what the batteries capacities are now.
Currently we are running 1.01 watt on 435.300 only, with the new PL mode
on. For this summer eclipse season, we are fortunate that the eclipsed
periods are while AO-51 is over mostly unoccupied Antarctica and
surrounding areas. This means when the batteries alone are supporting
the transmitter, there are not likely to be any users.
We have a downlink power management routine that we'll be implementing
over the next week or so. Downlink power may range from 2 watts in
illumination, to maybe as low as 300 milliwatts in eclipse. Using this,
combined with the PL, should mean we can protect the batteries from
over-discharge, while still providing the strongest possible downlink.
I'd like to encourage everyone to use the excellent reporting resource
at http://oscar.dcarr.org/ . I check this page at least 4 times a day to
check the status of AO-51. If the eclipse periods get too long faster
than we can adjust, the repeater may shut off due to a low battery
voltage watchdog. If this happens, please email me directly at
ko4ma at amsat.org, or for those that have my cell phone number already,
please feel free to text me a warning that the satellite repeater is off.
Additionally, the AO51-modes group would like your input on the desired
Field Day mode. We will likely be limited to one transmitter operation.
With AO-27, SO-50, and possibly SO-67 and HO-68 on V/U FM, S band or L/U
operation is looking very promising to provide some variety.
AMSAT-NA VP Operations
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