Satellite Communications
AO-51
Telemetry that I downloaded
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My first big project with Amateur Radio was Low Earth
Orbit (LEO) Satellite Communications. I made hundreds of contacts on
UO-14 before it went silent in the summer of 2003. I was taught how to
do this by my friend Cal, N3CAL.
My primary setup was a handheld "Arrow Antenna"
and Kenwood
TH-F6A Dual Band HT.
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Most of the time, I use the Arrow Antenna in a handheld
configuration for ease of movement, unlike the tripod mount shown.
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AJ3U-3
Satellite Gateway
AJ3U-6
Mobile position via ISS
Tips for Satellite Operating
1) When working a bird for the first time, just listen. You will soon
notice that there are different operating practices on different birds.
The FM birds will be the most different from the others. Part of this
is due to their short access time over a particular area and partly
because only one person can talk through them at a time. You will hear
the exchanges of callsigns just like you did on HF but you will also
hear something like EM77 or FN41. These are known as gridsquares and
are collected by some for awards such as VUCC. You can think of VUCC
similar to DXCC but oriented for VHF/UHF.
2) Satellites pass over your horizon at different angles from the
horizon. When first working a bird, look at working with the higher
passes so you will have more of a clear shot at "seeing" the bird. As
you become more comfortable with working a particular bird, you can
work progessively lower and lower passes. The clearer your path to the
horizon will make it easier for you to work a bird as its pass gets
lower to the horizon.
3) If you are starting out with a hand held beam similar to the Arrow
Antenna, get a compass for a sporting goods store and use that to find
where on the horizon that satellite will appear (AOS - Aquisition of
Signal) and where it will disappear on the horizon (LOS - Loss of
Signal). You can get these numbers for a particular pass from some of
the satellite pass prediction software packages such as Nova or from
web sites such as
http://www.heavens-above.com.
Check each of the settings several times before the pass you want to
work the bird so that you become familiar with where the bird will
appear and disappear from your field of view.
4) When working with pre-amps to boost the received signal, place them
as close to the antenna is possible. Part of why you are using the
pre-amps is to make up for the signal loss in the cable that you are
connecting the antenna and the radio together with. Use the best cable
you can get. Low Loss cable such as
Low Loss 400
is popular.
5) When operating handheld, logging contacts may be a challenge. I have
found that using a micro-cassette recorder and let it hear what I am
hearing from the receiver and playing it back after the pass is over
will help your sanity in working the satellites.
6) To keep up with the constantly changing state of some of the
satellites, subscribe to the
Amsat-BB
reflector. You will find a good collection of fellow operators here who
can help answer your questions. You will also find that a condition
change of a satellite will show up on the reflector before you may see
it change on the
Amsat
Satellite Status page.
7) To really work the satellites easily, you will need to run in
full-duplex mode or in other words, you will need to hear your signal
on the downlink. While you can get away from this to a degree on the FM
birds, it will be easier and more fun to work the birds when you can
hear how well you are getting into the birds. This will mean some type
of headset plugged into the receiver so that the built in speaker
doesnt feed back into the microphone for the uplink. You don't have to
get fancy but do get something that will be comfortable to wear.
