[amsat-bb] Re: AO-16 intermittent telem

Mark L. Hammond marklhammond at gmail.com
Fri Jan 1 06:21:11 PST 2010

Hello Auke,

Thank you for your report.

You may remember that the current status of AO-16 is that a hardware
failure causes the satellite to reset itself (which turns off the
transmitter).   The issue appears to be related to the internal
temperature of the satellite.  When the satellite is in continuous
sunlight (no eclipses), the bird warms up and will support continuous
operations.  When the satellite cools down (during periods of
eclipse), it resets itself and turns the transmitter off.   Th
satellite is, and will be for the next several years, in an orbit with
substantial eclipses, so the bird is cool and unable to sustain

What you were hearing was me commanding  ON a transmitter in AO-16,
and then hearing it shut itself OFF.    The satellite will not turn
itself ON; it has to be commanded ON.  Sadly, it will shut itself OFF,
as it has been doing for the last few years.  The satellite will stay
up for only a few minutes at best.  The duration seems very random,
but it's always short...

When AO-16 is commanded ON, it defaults to the digital mode (1200
BPSK), so you'll hear it "humming".   It takes another set of commands
to configure the satellite into voice mode.  Often the satellite turns
itself OFF before it can be configured into voice mode...

I do keep testing the satellite every few weeks to see if conditions
have improved or if the satellite has changed in such a way that would
result in its continuous operation during orbits that include
eclipses.   So, if you are near the east coast of the US, you might
"catch" me testing out the bird and hear it turned OFF and ON. To this
point, nothing has changed for the better.  We can keep hoping :)   It
will something like 10 years before the orbit of AO-16 will have no


Mark Hammond, N8MH
AO-16 command station


AO-16 intermittent telem


Subject: [amsat-bb] AO-16 intermittent telem
From: "Auke de Jong, VE6PWN" <sparkycivic at xxxxxxx>
Date: Thu, 31 Dec 2009 16:37:09 -0700


Hello All,

Today I noticed AO-16 buzzing over NA this afternoon, with it's signal abruptly
cutting off, and later back on a few times for several minutes, as it aproached
the North Pole.

I've no idea of the signifigance, if any that this behaviour indicates about
it's declining health...  or perhaps a command station was working with it at
the time?

Auke de Jong
Edmonton, AB

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