1. Operating the Amateur Radio Satellites
Presentation for AEA Amateur Radio Club W6AGO
Ryan Noguchi, AI6DO
Nov 2018

2. Outline Background Operating Concepts Satellite Types References
Making Contacts
Equipment
References

3. Background First amateur radio satellite (OSCAR I) launched Dec 1961
OSCAR: Orbiting Satellite Carrying Amateur Radio
Lead organization is AMSAT-NA, headquartered near Washington, D.C.
Other AMSAT organizations established around the world
Satellites with a primarily educational purpose are able to use amateur radio frequencies if properly coordinated
Control operators must be licensed amateur stations
Frequencies used for data downlink, telemetry, and commanding
Some of these satellites also carry communications subsystems that can be utilized by licensed amateur stations for two-way amateur communications

4. Why Operate Satellites?
Propagation not constrained by ionospheric conditions
All US-licensed amateurs can participate
All current satellites’ uplink frequencies are within Technician privileges
Not much equipment needed to start
Very amenable to portable operation
Friendly community
Extension of what we do at Aerospace
Fun!

5. Operating Concepts Uplink Downlink
Amateur radio satellites are like terrestrial repeaters, except…
Cross-band – uplink and downlink on different bands
Quickly moving across the sky
Tracking
Footprint
Polarization
Doppler
Operators exchange Maidenhead grid squares
Logging and QSLs are the norm

6. Operating Concepts - Frequencies
Satellite repeaters are cross-band to avoid self-interference
Most satellites are Mode B Uplink 70cm, Downlink 2m
Oldest working satellite also has Mode A Uplink 2m, Downlink 10m
Older satellites were often Mode J Uplink 2m, Downlink 70cm
Most packet satellites operate simplex Uplink 2m, Downlink 2m
FalconSat-3 packet satellite operates in Mode J
AO-92 also offers Mode L/V Uplink 23cm, Downlink 2m
Typically in Mode L/V for 24 hrs from ~0200Z Sat to ~0200Z Sun
Some future satellites including Mode L/V, including Fox-1C launching soon

7. Operating Concepts – Satellite Tracking
Omnidirectional antennas not optimal—low gain
Directional antennas need to be slewable to track satellite’s trajectory
Computer or mobile device apps provide real-time satellite azimuth and elevation
Portable ops manually track the antenna
Fixed station ops use computer-controlled rotors
Antennas tradeoff between gain and beamwidth
High gain antennas must be pointed more accurately
ISS Detector app on Android phone

8. Operating Concepts - Satellite Footprints
The stations you can contact via satellite change during the pass
Higher altitudes increase footprint
To work DX, you need to be able to work lower elevations
Clear path to the horizon
Longer path length often requires more gain to close link
Satellites with larger footprint
Use satmatch.com calculator to identify pass intersections with other stations
SATPC32 screenshot showing FO-29 satellite footprint

9. Operating Concepts - Antenna Polarization
Amateur satellites typically use linearly polarized antennas
Usually uplink and downlink antennas are mounted parallel
Mismatched polarization reduces link margin
Ground stations must compensate for antenna polarization shifts as the satellite’s orientation changes
Portable antennas rotated about boom axis
Peak signal strength received on the downlink
Rotate if needed to peak signal strength for uplink
Fixed stations often switch between RHCP and LHCP

10. Operating Concepts - Doppler Shift
Relative motion shifts received frequency
Moving toward—frequency shifts up
Moving apart—frequency shifts down
Operators need to make frequency corrections during the pass
Computer-control enables adjusting both links
Manually adjust only highest frequency link
Magnitude of shift proportional to frequency
FM: Use VFO or separate memory channels
Linear: Smoothly adjust VFO for Doppler
- 10 kHz
- 5 kHz
Nominal
+ 5 kHz
+ 10 kHz

11. Operating Concepts - Maidenhead Grid Squares
The Maidenhead Locator System establishes one’s position on the Earth’s surface through a hierarchical coordinate system
VHF simplex and satellite operators exchange grid squares
4-digit locators
1° latitude, 2° longitude box
We are in grid DM03
Announce your grid along with your call at the start of a QSO

12. Satellite Types FM Repeater Satellites Digital Satellites
Linear Transponder Satellites

13. Satellite Types – FM Repeater Satellites
Easiest to work, lowest barrier to entry
One or two FM radios: HT, mobile, or base station
Four operational satellites
SaudiSat 1C (SO-50) – Mode J
Fox-1A (AO-85)
Fox-1B (AO-91)
Fox-1D (AO-92) – Mode B and Mode L/V
Sometimes ISS is active on FM
Repeater hasn’t been operational in a while
Astronauts make scheduled and unscheduled contacts

14. Making Contacts on FM Satellites
Satellite passes are short, so speed is essential
Avoid a lot of chitchat unless the satellite is empty (wee hours)
Don’t call CQ!
Use phonetics the first time you send your call
Typical flow of an FM satellite QSO:
AI6DO DM03
AI6DO AE0RO DM78
AE0RO QSL AI6DO DM03

15. Satellite Types – Packet Satellites
Moderate equipment needs
Kenwood TH-D7, TH-D72A, TH-D74A for handheld operation
FM radio(s) with external TNC(s) for keyboard operation
Three operational satellites
FalconSat-3
ISS
PSAT (NO-84)
Others recently launched but not yet operational for amateur use
CubeBel-1 (BSUSat-1)
Diwata-2

16. Making Contacts on Packet Satellites
Send your APRS beacon to “call CQ”
Message text might read “CQ APRS AI6DO DM03”
Respond to other operators by sending them APRS message packets
Program “macros” to be copied/pasted into APRS message text field
Make sure your APRS settings are correct for the satellite
Standardized for ISS, NO-84, and other 1200 bps packet satellites
Use ARISS or APRSAT alias as path
DO NOT include terrestrial digipeaters in path if operating satellite digipeater
DO NOT include satellite digipeaters in path if operating an unattended beacon
Different for FalconSat-3 (9600 bps)

17. Satellite Types – Linear Transponder Satellites
Multiple QSOs can occur simultaneously across the passband
Most action is near center of passband
CW typically in the bottom half of downlink
SSB typically in the top half of downlink
Most challenging, most expensive equipment needed to work
Two all-mode (SSB) radios, at least one able to transmit
Tune VFO continuously during the pass to locate signals in the passband and adjust for Doppler
Eleven operational satellites workable from DM03
AMSAT-Oscar 7 (AO-7) – Mode B and Mode A
JAS-2 (FO-29) – Mode J
CAS-3A through -3F (XW-2A, XW-2B, XW-2C, XW-2D, XW-2F)
CAS-4A and CAS-4B
FUNcube-1 (AO-73) – only active during eclipse and most weekends, except when in full sun
Nayif-1 (EO-88) – only active during eclipse

18. Making Contacts on Linear Transponder Satellites
Operating full-duplex is essential when not computer-controlled
Need to hear yourself on the downlink to match Rx and Tx frequencies
Exception is Mode J, where one could operate half-duplex
Some ops use CW keys to send stream of dits to tune
Others just try to tune to their voice
Calling CQ is the norm
Need to speak long enough for you to find yourself and for other stations to find you
Spread out on the passband if needed

19. Equipment for Portable Satellite Operating
Antenna(s)
Radio(s)
Diplexer
Other stuff

20. Antennas for Portable Satellite Operating
Arrow II
Commercial antennas are ~$
Arrow II 146/ dual-band Yagi
Elk 2M/440L5 dual-band Log Periodic
You could also build your own antenna
pdf/cheapyagi.pdf
%20Antennas-LEOs.pdf
tape-measure-yagi-antenna/
Elk

21. Radios for Portable Satellite Operating
Full duplex operation is best
Provides feedback to correct antenna pointing, polarization, Doppler
Know when someone else already has the repeater occupied
Many just use two radios
A few handheld radios are able to do full-duplex on FM
Kenwood TH-D72A, TH-D7A
Alinco DJ-G7T (Mode B only, Mode J often unusable due to desense)
Dual-band mobile FM radios capable of crossband repeating can be used full-duplex
For linear satellites, need at least one all-mode transceiver to Tx
Most portable ops use Yaesu FT-817, FT-818, FT-857, FT-897
Need an all-mode receiver to Rx, could be transceiver or a Rx-only SDR
Kenwood TH-D74A also works well, TH-F6A is marginal

22. Diplexers for Portable Satellite Operating
To operate satellites, you need antennas for two bands
Exception are the simplex packet satellites
A diplexer may be needed to connect radio(s) to antenna(s)
Elk antenna has a single feedpoint
You need a diplexer if you need to connect it to two radios
Arrow antenna has two feedpoints
You need a diplexer if you need to connect to a single radio
A diplexer or filter sometimes needed on Mode J to mitigate desense
Transmitting on 2m produces interfering harmonics on 70cm

23. Other Stuff for Portable Satellite Operating
Satellite tracking app is a must
ISS Detector is what I use and recommend (available on Android and iOS)
GoSatWatch is most commonly used on iOS
A velcro armband holds your phone for easy viewing for tracking
Voice recording is optional
Many use a separate recorder connected to the receive radio to record the downlink audio for later review and logging
Can also use recording app on the smartphone
Earbud/mic set or headset is helpful to keep a hand free for logging and reduce the risk of audio feedback

24. Getting Started The FM satellites are the easiest to get started
Listen to several passes before transmitting
Get familiar with the operating rhythm and tracking the satellite
Keep squelch completely open
When ready, pick a station you’ve heard on that pass and call them
Pick one that’s getting into the satellite well and hearing others well
If at all possible, try to keep your writing hand free when not transmitting to log callsigns and grids in real-time during the pass
Reading a callsign off paper is easier than having to remember it
Even if you’re recording the audio, sometimes audio recordings fail

25. Satellite Status
Crowdsourced operational status updates

26. QUESTIONS?