Satellites; Amateur & Otherwise
Learn how to make radio or visual contacts with them
Last revised: July 20, 2007
Many amateur radio operators enjoy the multiple interests of our
hobby. One is communications from ground based stations to
satellites flying overhead. Amateur radio operators from around
the world have contributed to designing, building and launching amateur
radio satellites. At last count over 100 since the
space program began with the Russian Sputnik.
Having worked both ARISS and AO-51, I would like to pass on
my knowledge on how you can do it with a little "on the job" training.
I'm suggesting 3-4 classes which will lead you to making
contact with one of the "birds" voice repeater. In the
class, one student will call another station
via satellite. Beyond that, who knows, maybe you'd like to
involve one of our local schools and NASA's program?
Since learning to plot satellite orbits is needed for both radio and
visual viewing, we learn both using the same tools.
Before and after contact attempts, we'll have a campfire which we can
gather around telling radio stories
and warming up. Lots of things have to come together for outdoor
sessions so a need to be flexible is important. We should always
have plenty of lead time to plan the sessions but the weather could
cancel well intended plans the last minute. For visual
observation we need good clear skys after dark but radio contacts can
be made anytime as long as its not raining or windy.
- First session will be indoors with Internet terminals
available. Ideally as many as we have students. We learn
why satellites orbit the earth and introduce you to one of
many tracking programs. Emphasis will be on learning how to find
a satellite that will be in visual or radio range. Where to get
Keplarian elements and online support. Homework on your home
computer will be assigned. Session may be held in the PA library.
- This session will be outdoors, probably in my backyard in which
we will try our skill at visual and radio reception of a passing
"bird". All students should have done the homework to propose observing
time and sky coordinates. Radio reception will be on UHF using a
high gain homebuilt antenna. Homework will be assigned for next session.
- If students become comfortable with computer planning and
we'll move to attempting transmission on VHF. If not, we'll have
one more session on planning receive only.
Uplink will use a high gain homebuilt VHF antenna. Session
outdoors. Radio equipment can be yours or mine. Issue homework for
- Set up two way
communications by plotting targeted "bird" beforehand and
as a team, try your hand at making contact. Working as a team of
three handling two antennas, doppler correction and the third
operating the radio. Session outdoors.
Class #1 Outline
- Orbital mechanics
- Finding a weeks worth of ISS passes from Heavens-Above
- Showing visual passes
- Discuss "Iridium Flairs". More on this at session #4
- Demo of Satellite tracking program
- Where do I get program and Keplarians. What are they?
- Online and resident
- Optimum parameters
- Azmith referenced to true north
- Height should reach at least 60 degrees
- Have good time reference
- Discuss AMSAT... bring it up online
- Radio status and modes of the "birds"
- What "birds" are we compatable with?
- Packet store and forward
- Concentrate on AO-51 (echo)
- Radio requirements
- FM VHF/UHF
- Turn off "squelch"
- Split band ideal, otherwise two radios
- What is Doppler shift?
- About antennas
- Yagi is still king
- Circular polarized--why?
- Tracking--students are cheaper than automated equipment
- Some words about making visual observations
- What do you look for; sun position
- Where do I go for Iridium Flare data?
- Assign homework, for next session
- Find good radio pass of AO-51 over the next two weeks
- Likely location you'll be working from: 48.1368º N,
- Print 2 minute increments during pass
- Plan how you will shift for doppler
- Where should antenna be pointed vs time
- What makes a good pass?
Class #2 Outline
- Be sure we all agree on previous homework results
- Set up equipment for reception on designated pass
- Observe antenna performance during pass and doppler....
- This will be a "doing" class
- Discuss added equipment for class #3 if students are ready,
otherwise, have one more planning and reception class to build
Class #3 Outline
- May be a repeat of class #2 or move on to class #4 material if
- Plan a visual viewing session
- Have a rehearsal for class #4, team of three participants
Class #4 Outline
- Using previously calculated data, prepare for a full duplex
transmission using FM voice on AO-51.
- If you provide your own radio, have earphones available.
- After pass, discuss results and how we could improve
- Discuss Packet modes on some satellites
- Who's going to be the first to make a packet connection?
- What about ARISS
- Talking to an Astronaut
- Involving schools
- You now have all the skills needed
Classes will usually be held in evening hours or during the day
(radio only) on weekends, TBD. Mostly determined by orbital plots of
- Mostly just a sincere interest in the subject
- Ability to use the Internet with printer
- Knowing how to operate a VHF/UHF FM transceiver in VFO mode
- Being attracted to the technical side of amateur radio and how
things work. A desire to learn
- Three out of four class sessions will be outdoors, dressing for
cool weather at times will be needed but a campfire should be available
unless the wind is excessive
- Flexibility in scheduling outdoor sessions. It
depends upon the "birds". May be anytime but summer evenings
If interested, who do I contact?
The decision as to wheither I hold this class will depend upon level
Prepared by Neil