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

Outline Background Operating Concepts Satellite Types References Making Contacts Equipment References

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

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!

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

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

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

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

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

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

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

Satellite Types FM Repeater Satellites Digital Satellites Linear Transponder Satellites

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

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

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

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)

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

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

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

Antennas for Portable Satellite Operating Arrow II Commercial antennas are ~$100-150 Arrow II 146/437-10 dual-band Yagi Elk 2M/440L5 dual-band Log Periodic You could also build your own antenna https://www.wa5vjb.com/yagi- pdf/cheapyagi.pdf http://www.wa5vjb.com/references/Cheap %20Antennas-LEOs.pdf http://km4lgm.com/2015/07/dual-band- tape-measure-yagi-antenna/ Elk

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

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

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

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

Satellite Status Crowdsourced operational status updates

QUESTIONS?