[amsat-bb] AO-51 now requires 67 Hz PL tone; activity reports appreciated

Mark L. Hammond marklhammond at gmail.com
Thu Apr 21 06:09:04 PDT 2011

Hello AO-51 users,

As you have noticed, AO-51 has recently experienced a few shutdowns
due to a low battery voltage trip.  This is because of increasing
eclipses (now at 20 mins per orbit and increasing), poor sun angles
(still getting worse), and a "weak" battery.

We are now using the 67 Hz PL tone required mode in order to turn the
transmitter(s) OFF when not in use.   The transmitter power is down to
about 550 mW.  We will continue adjusting various parameters,
including transmitter power, trigger voltages, etc. in order to keep
the battery temperatures reasonable. Keep in mind that the power
management feature keeps the transmitter(s) OFF during eclipses, so
you can't bring it up even with a PL tone while the satellite is in

Here is our current schedule, which will continue until further notice:

AO-51 Schedule

Mode V/U FM Voice Repeater (**67 Hz PL tone required**)
Uplink: 145.880 MHz FM (Temporarily from 145.920)
Downlink 435.300 MHz FM

The AO-51 Command Team can use your help!

1-Please make activity reports to: http://oscar.dcarr.org/  This is
very useful to all users.   Until everyone knows that the 67 Hz tone
is required, we might see some conflicting reports.

2-Please help spread the word about needing the 67 Hz tone!


Mark L. Hammond [N8MH]

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