Working the HAM Satellites 38 page Guide

Working The Satellites
Most of the information, photos
and diagrams in this presentation
were obtained from various
websites. I just assembled it for
presentation.
Overview
Satellite 101
Equipment
Where and When Are They ?
Operating A Pass
Why Do It ?
Questions
Satellites 101
Complicated subject but you only need the
basics to start having fun
History
Sputnik 1 – Oct 4, 1957
First AMSAT – OSCAR 1 – Dec 12 1961
OSCAR = Orbiting Satellite Carrying Amateur Radio
570 Hams in 28 countries worked OSCAR 1 during 22
day life
Currently about 35 AMSATs still working
http://www.amsat.org/amsat-new/satellites/status.php
You need to know a few terms and principles
Orbits
Three Pass Plot
Basic Equipment Required
Antenna
Dual Band Radio – HT (or two single band)
Computer with Internet Access
Tracking Software
Small Tape or Digital Recorder (or a partner
to record contacts)
Compass & Inclinometer (If directionally
challenged)
Antenna
Directional with gain
Polarization changes as satellite passes
Capable of tracking during pass
Workable with HT whip held at angle
Handheld Yagi is better, tripod mounted to free
hands
Base antenna
Bi-directional rotator (true tracking)
Fixed at specific angle (30 degrees?)
Azimuth tracking (rotator)
Omni (non-tracking)
Recommend an Arrow Antenna for starters
Arrow Antenna on Tripod
Base Antenna
Radio Requirements
Dual band or two units
HT or mobile VHF/UHF
Uplink (TX) & downlink (RX) frequencies
Programmable memory channels
Need to quickly adjust for Doppler during pass
Low power OK – desired, in fact
Dual band HT @ 5 watts works fine for FM voice
Satellite capable HF radio to work other modes
All The Toys
Dual Band HT Works Also
What Birds To Work
Satellites operate in various modes.
Get to know and love WWW.AMSAT.ORG
MODES & BANDS
•MODES
•FM Voice Repeaters- 2meter / 70 cm
•SSB / CW
•APRS
•PACKET (Store and forward)
•BEACONS
•Telemetry / Data
•BANDS
International Space Station
The ISS’s FM Repeater has been off the air for several
months. They still make school contacts. See website for
current status.
(Reverse for V/U)
Start Simple
Several VHF/UHF FM capable birds
AO-27, SO-50, AO-51, ARISS
Relatively easy to work with handheld equipment
Program Uplink and Downlink Frequencies for each
into Memory Channels
Transmit (Uplink) on Band A and Listen (Downlink)
on Band B
Run an open squelch on Downlink side
Adjust for Doppler on Downlink side thru the pass
DOPPLER EFFECT
(Recall the train whistle)
When a satellite is approaching the received frequency is
higher than the frequency that was transmitted.
When the satellite is receding, the received frequency is
lower than the frequency that was transmitted.
At the 2m uplink frequency, the Doppler range is less than the
5KHz bandpass, so no adjustment of the transmitter
frequency is needed for FM capture by the satellite.
At 440 MHz, the Doppler shift is three times greater, with the
received signal appearing up to about 10KHz higher than
nominal as the satellite rises on approach (Acquisition of
Signal, or AOS), and up to 10 KHz lower than nominal as the
satellite recedes and sets (Loss of Signal, or LOS).
You need to retune the receiver (one 5 KHz click at a time
lower) during the pass as the signal begins to sound "ragged"
going out of the channel passband into the next lowerfrequency channel.
Doppler Diagram
Uplink and Downlink Frequencies
HT Programmed
When and Where Are They?
Most Amateur Radio satellites travel in
low Earth orbits.
At these altitudes, a satellite completes
one orbit every 90 to 120 minutes.
At the same time, the Earth is turning
beneath the satellite.
Ground stations may have several 10 to15
minute periods to work a satellite each
day – each called a “pass”.
Pass Variables
Date and Time
Azimuth (Which direction)
Elevation (How high)
Pass Duration
Operational Status and Mode
So, how do we know where and when to listen?
When are we in the “Footprint”?
Footprint of AO-51 Pass
Pass Diagram & Terms
•Peak Elevation (ZZ Degrees)
•Ending Azimuth
(XXX Degrees)
•Starting Azimuth
(YYY Degrees)
Calculating Passes
Review Your
Orbital Physics
Start with
Keplerian
Elements
Run the
numbers
starting with
Keplerian Elements
Predicting A Pass
Use free Tracking Software
Computers and the Internet make it easy
Free Software – The best kind!
Ham Radio Deluxe
AMSAT website
Orbitron
SatScape
Determine your location and generate a
schedule for various satellites on various
dates
SatScape Tracking Software
SatScan Pass Predictions
Pass Schedule
Work The Pass
Check current operational status and mode of satellite
(Is it working on FM v/u or u/v mode)
Printout the tracking data for the pass
Have your radio batteries charged
Check your watch against WWV
Use a compass to determine the direction the satellite
will rise, transverse (peak azimuth) and set
Keep your DL Squelch OFF - listen for quieting
Use headphones (Can’t record)
Work The Pass Continued
Know your grid square (EM20)
Point antenna toward AOS azimuth and start listening
Track satellite path with antenna (rotate for polarization)
Listen for signals to clear up (should hear by TCA)
If using an HT with whip antenna tilt the HT to the same
amount as the satellite elevation
Adjust DL freq. for the Doppler Shift during pass
Work The Pass Continued
Listen to who is talking - Note callsign
Make a short call to a strong station or
Give your callsign and grid square
Have a method to record contacts
Have patience
LEO satellites are busy, so it may take a few
passes until you make a contact
Why Do It?
Provides a new learning experience
It’s something many people have not done
Excuse to buy more toys
Impress your friends and family
Contest & awards – work the grids squares
Because it’s fun !!!
Contacts Made
This Pass
4
1
2
3
Links
AMSAT
http://www.amsat.org/amsat-new/index.php
OSCAR Satellite Status
http://www.amsat.org/amsat-new/satellites/status.php
International Space Station
http://www.rac.ca/ariss/oindex.htm
http://www.amsat.org/amsat-new/ariss/
SatScape Tracking Software
http://www.satscape.co.uk/main/modx/index.php?id=50
Orbitron Tracking Software
http://www.stoff.pl/
Arrow Antenna
http://www.arrowantennas.com/
QUESTIONS & COMMENTS ?