Satellites; Amateur & Otherwise

Learn how to make radio or visual contacts with them

Last revised: July 20, 2007

Summary:

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 third 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.

Class Sessions:

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 reception, 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 final class.
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.

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.

Class #1 Outline

Objectives
Orbital mechanics
Finding a weeks worth of ISS passes from Heavens-Above

Showing visual passes

Why are some visual?

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

Calibrate with GPS

Discuss AMSAT... bring it up online

Radio status and modes of the "birds"
What "birds" are we compatable with?
Packet store and forward
UTC
Telemetry
Concentrate on AO-51 (echo)

Radio requirements

FM VHF/UHF
Turn off "squelch"
Earphones
Split band ideal, otherwise two radios

What is Doppler shift?

What do I do about it?

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?

Daytime flares

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, 123.5276º W
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

Learn about the antennas

Observe antenna performance during pass and doppler.... familiarity
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 experience

Class #3 Outline

May be a repeat of class #2 or move on to class #4 material if all are ready
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
Packet
Involving schools
You now have all the skills needed

When

Classes will usually be held in evening hours or during the day (radio only) on weekends, TBD. Mostly determined by orbital plots of the targeted "birds".

Prerequisites

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 preferred.

If interested, who do I contact?

neil@robin-wood.com

The decision as to wheither I hold this class will depend upon level of interest.

Prepared by Neil Robin, WA7NBF