[amsat-bb] AO-73 Lack of transponder activity

Patrick STODDARD (WD9EWK/VA7EWK) amsat-bb at wd9ewk.net
Thu Dec 10 22:40:39 UTC 2015

​i Jeff!

AO-73's transponder normally operates when the satellite is
not in sunlight, and whenever the AO-73 command stations
turn the transponder on all the time (usually during the
weekends and some holidays). The normal schedule is posted
on the FUNcube
web site:


When the command stations put the transponder on all the
time, and then put it back to the normal configuration (on
when the satellite is in darkness),
those items are posted
here on the AMSAT-BB list and also on the @FUNcubeUK Twitter


You'll probably also see mentions of the active transponder
reported on the AMSAT status page:


As W5PFG mentioned, this is an easy satellite to work with
portable stations. I regularly work it with an FT-817ND for
the uplink, and the downlink is handled either with another
FT-817ND or my SDRplay SDR receiver with an 8-inch Windows
10 tablet running HDSDR. At times on high passes, I can cut
my transmitter power down from 5W to 500mW and still have a
readable signal through the transponder. The uplink frequency
you use will probably change from pass to pass, which is why
the recommendations of using manual control when working this
satellite are good. Since this satellite has a sensitive
uplink receiver, it shouldn't be hard to line yourself up on
the transponder.


Twitter: @WD9EWK


> Currently building a portable station and am interested in trying to
> work this bird in the near future. Is the transponder always on or does
> it follow a schedule (i.e., only on during the weekends or when in
> daylight, etc)?

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