Ham Radio Satellite Operating: Getting Started With Amateur Sats

Talking through a satellite 400 km above the Earth with a handheld radio and a handheld antenna sounds improbable. But it's exactly what thousands of hams do regularly. Amateur radio satellites are accessible with modest equipment — you don't need a dish antenna or a NASA-grade tracking station.

If you can hit a local repeater, you can probably work an FM satellite with the equipment you already own plus a better antenna.

The Amateur Satellite Landscape (2026)

FM Satellites (Easiest)

FM amateur satellites work like flying repeaters. Transmit on one frequency (uplink), the satellite receives it and retransmits on another frequency (downlink). Anyone in the satellite's footprint can hear you.

Current/Recent FM satellites:

• ISS (ARISS): The International Space Station has an FM cross-band repeater (145.990 downlink, 437.800 uplink) that's periodically activated
• SO-50 (SaudiSat-1C): 145.850 down / 436.795 up. PL tone 67.0 Hz required. The longest-serving amateur FM satellite.
• TEVEL satellites: Constellation of FM transponder cubesats
• PO-101 (Diwata-2B): FM repeater satellite
• IO-117 (GreenCube): Digipeater (packet, not voice FM)

FM satellites are first-come-first-served. One station transmits, everyone in the footprint hears. Gets crowded on popular passes.

Linear Transponder Satellites (More Capable)

Linear transponder satellites retransmit a band segment (typically 40-80 kHz wide) rather than a single FM channel. Multiple simultaneous QSOs happen on different frequencies within the passband.

Current/Recent linear transponders:

• RS-44 (DOSAAF-85): Very popular, VHF up / UHF down
• QO-100 (Es'hail-2): Geostationary (!) narrowband transponder. Always available from Africa/Europe/Asia. 2.4 GHz up / 10.5 GHz down.
• CAS-4A/4B: Linear transponders on Chinese amateur satellites
• XW-2 series: Chinese microsatellites with linear transponders

Linear transponders allow SSB and CW — weaker signals work, less competition for access.

Digital Satellites

Some satellites support packet radio, APRS, or other digital modes:

• ISS APRS digipeater (when active)
• IO-117 GreenCube: UHF digipeater
• Various cubesats with experimental digital payloads

Equipment for FM Satellites

Minimum Equipment (Handheld)

• Dual-band HT (2m/70cm): Yaesu FT-70D, Icom ID-52A, Kenwood TH-D75A, or similar. Must transmit on one band while receiving on the other (full duplex is ideal but not essential for FM sats).
• Arrow Antenna or Elk log-periodic: A handheld directional antenna that you point at the satellite manually. $80-130.
• Tracking app: ISS Detector, AMSAT app, or Heavens-Above on your phone.

That's it. An HT, a handheld Yagi, and a phone app to know when/where to point. Total additional cost beyond your existing HT: about $100.

Better Equipment (Home Station)

• Two radios (one transmit, one receive) — OR one radio with full-duplex capability
• Separate VHF and UHF antennas on a az/el rotator (or a dual-band cross-Yagi)
• Computer tracking with rotator control (SatPC32, GPredict)
• Automatic Doppler correction via CAT control

This setup allows hands-free operation. The computer points the antenna and corrects Doppler. You just make contacts.

The Doppler Problem

Satellites move fast (7.5 km/sec in low Earth orbit). This causes Doppler shift:

• As the satellite approaches, frequencies shift UP
• As it recedes, frequencies shift DOWN
• Maximum shift on 70cm: ±10 kHz
• Maximum shift on 2m: ±3.5 kHz

For FM satellites: The satellite's downlink drifts in frequency during the pass. You compensate by tuning your RECEIVE frequency during the pass. Start above nominal frequency, end below.

For linear transponders: Both uplink and downlink shift. You must correct on at least one side (typically transmit) to keep your signal from drifting across the transponder passband.

Practical approach for FM: Program several memory channels spaced 5 kHz apart around the downlink frequency. Switch channels as the satellite passes overhead when the signal drifts off. Crude but works for beginners.

Making Your First FM Satellite Contact

Step 1: Find a Pass

Use a tracking app or website (n2yo.com, amsat.org/track) to find when a FM satellite passes over your location. Look for passes above 20° maximum elevation — higher passes give stronger signals and longer windows.

A typical pass lasts 8-12 minutes from horizon to horizon. The usable window (above about 10° elevation where signal is strong enough) is 6-8 minutes.

Step 2: Prepare Frequencies

• Program the satellite's uplink and downlink frequencies into your radio
• Set appropriate PL tone for uplink (SO-50 requires 67.0 Hz)
• If your radio supports it, set up satellite mode (transmit on one band, receive on other simultaneously)

Step 3: Aim and Listen

When the satellite rises above the horizon:

1. Point your arrow antenna at the satellite's predicted position
2. Listen on the downlink frequency (adjust for Doppler)
3. You should hear stations calling or the satellite's beacon

If you hear nothing, adjust antenna pointing and frequency. The signal might be weaker than expected — satellites are small and far away.

Step 4: Call

When you hear a clear moment (no one else transmitting):

1. Keep your antenna pointed at the satellite
2. Transmit your callsign and grid square: "W6ABC CM87"
3. Listen for a response
4. Exchange callsign, grid, signal report
5. Confirm and move on (keep contacts SHORT — the window is brief and others are waiting)

Critical etiquette: FM satellite contacts must be brief. The pass is 8 minutes, one station at a time. Extended ragchewing is antisocial. Exchange calls, grids, signal reports, and clear. 30 seconds per contact is the target.

Step 5: Confirm

Log the contact with time, date, satellite name, grids exchanged. Satellite contacts count for VUCC (VHF/UHF Century Club) and satellite-specific awards from AMSAT.

Tips for Success

Power Control

Don't blast 50W at a satellite designed for 5W uplinks. Excessive power:

• Captures the transponder (on linear sats, your signal drowns others)
• Causes AGC issues on FM sats (your signal gets retransmitted louder than others)
• May damage satellite receivers (they're small, sensitive equipment)

Start with 5W on an HT with a gain antenna. If you're hearing the satellite well, you probably have enough uplink power.

Full Duplex Advantage

If you can hear the satellite's downlink while you transmit (full duplex), you can hear your own signal being retransmitted. This confirms:

• Your signal is reaching the satellite
• Your frequency is correct
• Your power level is appropriate

Some HTs support full duplex (Kenwood TH-D74, Icom ID-52 in some configurations). Alternatively, use two separate radios — one for TX, one for RX.

Antenna Pointing

A handheld arrow antenna gives roughly 10 dBd gain. Mispoint by 20° and you lose signal rapidly. Practice tracking before the pass — move the antenna smoothly following the predicted satellite path.

Overhead passes require fast antenna movement as the satellite crosses zenith. Lower-elevation passes (30-60° max) are actually easier to track because the angular rate is lower.

Operating Window

The best contacts happen in the middle of the pass (highest elevation, strongest signal). The first and last minute of a pass typically have weak signals and more fading. Don't waste the prime middle minutes calling CQ — listen first, then call during a clear moment.

Linear Transponder Operating

Linear transponder satellites are more complex but more rewarding:

• Multiple QSOs simultaneously (like a band segment in the sky)
• SSB and CW modes available
• Weaker signals work (SSB has narrower bandwidth than FM)
• Doppler compensation is critical (your signal drifts across the passband)

Key concept: Inverting transponder. Most linear transponders are inverting: if you transmit on the lower edge of the uplink passband, your signal appears at the upper edge of the downlink passband. Tuning up on transmit means tuning down on receive.

Doppler technique for linear: Tune your downlink to find your own signal (if full duplex). Adjust transmit frequency to keep your downlink signal stationary. The computer/software does this automatically in a proper satellite station.

QO-100: The Game Changer

QO-100 (Es'hail-2) is a geostationary satellite with an amateur radio transponder. This is revolutionary:

• Always available (it doesn't set or rise — it's geostationary)
• No Doppler correction needed (it's not moving relative to you)
• Covers Africa, Europe, Middle East, and South/Central Asia
• SSB and CW narrowband transponder plus a wideband transponder for digital/video

Equipment needed: a 2.4 GHz uplink (WiFi dish modified or purpose-built) and a 10 GHz downlink receiver (modified satellite TV LNB). The total cost for a receive-only setup is under $100. Transmit capability adds a few hundred dollars.

QO-100 has made satellite operating accessible to anyone in its footprint who can point a small dish at it.