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WHEN AND WHERE TO LISTEN Of course, there is always the possibility
that a battery cell will “open” (similar to
UO-11’s VHF downlink frequency is on what happened to AO-7) so the
145.826 MHz, sending AFSK FM Telemetry command team will regularly attempt
in ASCII format. There are no uplinks. communications with the satellite over
When last heard, the satellite was the coming months and years. Fingers
operating in its default mode, with a cycle crossed that it, too, may someday be
time of 20.7 days; 10.35 days on followed restored to partial, “daylight only” use.
by 10.35 days off.
THE DEMISE OF ARISSAT-1
The easiest way to check whether
OSCAR-11 is operational is to look at Early on the morning of Wednesday,
Clive Wallis’s extensive UO-11 status page January 4, 2012, reception reports
at http://www.g3cwv.co.uk/oscar11.htm. indicated that ARISSat-1 had stopped
I used the excellent information Clive has transmitting and had apparently burned
compiled about UO-11 on that page as up soon thereafter in the atmosphere
background for this column. over the South Atlantic Ocean. The last
full telemetry frames captured and
Clive notes that OSCAR-11’s VHF downlink reported to the ARISSat-1 Telemetry An early full-scale engineering model of
has a unique sound, rather like a raspy website at 06:02:14 UTC on January 4 AMSAT’s FOX-1 satellite. Note the stacked
slow Morse Code signal, sending “di di were received from ground stations as the internal arrangement of circuit boards.
(Courtesy: Keith Baker, VA3KSF/KB1SF)
dah dah dah dah dah dah dah” over a satellite passed over Japan.
period of fve seconds. If you are receiving
a very weak signal, Clive suggests you Those telemetry reports showed that the
switch your receiver to CW or SSB. You temperature aboard ARISSat-1 had been
steadily rising as atmospheric drag began
should hear several sidebands around the to affect the satellite. Indeed, the last
carrier frequency and you should be able telemetry frames indicated that
to hear the characteristic “Morse Code temperatures inside the satellite at the
like” sound on at least one sideband. end of its life well exceeded 190 degrees
Clive also notes that you’ll need a clean Fahrenheit.
(that is “noise-free”) signal to decode
UO-11’s downlink and your receiver must You will recall that Cosmonaut/Flight
be set to NBFM mode for such a decoder Engineers Sergei Volkov and Alexander
to work. However, if you would just like Samokutyaev deployed ARISSat-1 from the
to know what OSCAR-11’s beacon sounds International Space Station (ISS) on
like so you’ll know what to listen for, August 3, 2011 during EVA-29. The satellite
there’s an audio clip of its beacon on carried a student experiment from Kursk
Clive’s UO-11 webpage at: State University in Russia which measured
http://www.g3cwv.co.uk/980214t.wav atmospheric density. Students from A later structural engineering model of FOX-1.
around the world provided the voices for Six ordinary, off-the-shelf, 1.2V Nickel Cadmium
AO-51 GOES SILENT the FM voice announcements. rechargeable batteries will power the satellite.
However, the spacecraft is being specifcally
On November 27, 2011, AMSAT North During its brief lifetime, the Amateur designed to keep working when it is in sunlight
even if one or more batteries were to fail.
America’s Vice-President of Operations, Radio payload aboard ARISSat-1 achieved (Courtesy: Keith Baker, VA3KSF/KB1SF)
Drew Glasbrenner, KO4MA, reported that many “frsts” for Amateur Radio in space.
after a long “illness” due to slow battery These included the frst test of an AMSAT The software also provided a way for
failure, AO-51, up to then, AMSAT’s Software Defned Transponder. That those Amateurs to automatically upload
premiere FM “repeater in the sky” had transponder transmitted an FM voice the data received at their stations via the
ceased transmitting and was also not downlink that cycled between student Internet to the ARISSat engineering team.
responding to ground commands. Drew messages, spoken telemetry and Slow Other “frsts” included a new main
noted that the last telemetry data Scan Television (SSTV) from several onboard computer and a new spacecraft
indicated that the third of six batteries cameras on the space frame. The satellite power management system.
was approaching failure and other also sported a 16 kHz bandwidth linear Soon after ARISSat-1’s demise, AMSAT
observations indicated that the voltage transponder, a CW beacon that contained President Barry Baines, WD4ASW noted
from the satellite’s remaining three cells spacecraft telemetry as well as the call that ARISSat-1 was the prototype for a
was insuffcient to power the UHF signs of selected Radio Amateurs who completely new satellite design that also
transmitters. have made signifcant contributions to captured the attention of national space
Amateur Radio in space. ARISSat-1 also
Soon after AO-51 went silent, dozens of pioneered a robust, forward error agencies around the world for its unique
condolence messages were posted to the correcting 1K bit rate BPSK downlink for educational contributions.
AMSAT Internet Bulletin Board (AMSAT-BB). the satellite’s telemetry He said that, “By designing an educational
Many people fondly remembered their mission aligned with NASA’s Science,
many contacts via this FM “bird” and several ARISSat-1’s ground team also developed Technology, Engineering and Mathematics
thanked the AO-51 all-volunteer operating and then later released a comprehensive (STEM) goals, Amateur Radio operators
team for their work in keeping AO-51 alive piece of free software (ARISSat TLM) for around the world were able enjoy a
both PC and Mac computers which
for so long. Several posters also noted brand new Amateur Radio spacecraft in
that AO-51 was the satellite that brought allowed Amateur stations worldwide to orbit for just the cost of building (versus
reliably copy and then decode the
them into this part of our hobby. the cost of building and launching) the
satellite’s BPSK and CW telemetry.
satellite.”
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