Satellites and orbital operating

Amateur satellites (and the ISS) reward portable operators: a handheld yagi, a dual-band radio, and a clear horizon. Orbital work is parallel to POTA/SOTA — you can combine a satellite pass with a park activation for grid/rare-DX fun, but satellite QSOs do not replace park program rules unless the specific award says so.

Intro: Easy Portable Satellite Operation (PDF) · AMSAT · field tracking deep-dive: N5DUX Satellite Guide — Tracking

FM vs SSB transponders

FM is the on-ramp: one contact through the bird proves your setup. SSB linear transponders behave like a moving passband — tune both uplink and downlink. Start on FM before you graduate to linear birds; you will make fewer mistakes on a crowded SSB passband once your arm (or rotator) already knows how to track.

Minimum portable FM kit

From Ham Sat Tracker equipment guide and common field practice:

• Dual-band HT or dual-VFO mobile (true full-duplex HT like TH-D72/D74 class is ideal; half-duplex works with practice)
• Handheld yagi (Arrow II or Elk log periodic — 2 m + 70 cm on one boom)
• Pass predictor app (Look4Sat, Ham Sat Tracker, SatSat, and others)
• Headphones — satellite downlink in a noisy park is painful without them

Power: 5 W is enough on FM with a good antenna. More power can desense the transponder for everyone (QRP satellite ops).

Tracking — the skill that matters most

If you do not know when and where to point, the pass is over before you find the bird. Lucky listening exists; deliberate tracking is more fun. The notes below paraphrase and update the practical framing from N5DUX’s tracking page for getontheair / POTA parking-lot ops.

Tools (web and phone)

Most phone apps cache TLEs (two-line elements). When the park has no cell, you can still track if you refreshed data before you left pavement. On a boat or deep-woods hike, that pre-download is the whole plan.

Feature comparison wiki (apps): linked from the N5DUX tracking page resources.

Azimuth (compass heading)

Azimuth is degrees from north: 0° N, 90° E, 180° S, 270° W, then back toward 360°/0°. Cardinal words are fine for hiking; satellite pointing wants numbers. For handheld work you only need to be close enough — a 10° error in arm pointing is normal and usually still works on FM birds. Memorize the four primary points and the midpoints (45° = NE, etc.) so a glance at the app becomes muscle memory.

In a POTA parking lot: stand where you have the clearest horizon toward the predicted AOS azimuth, phone compass calibrated (away from the truck’s steel), and face that heading before the bird rises. Trees, the visitor-center roof, and a motorhome beside you all eat low-elevation passes — walk twenty steps if the lot allows.

Elevation (up from the horizon)

Elevation (altitude) is the angle up from the horizon: 0° on the horizon, 90° straight up, 45° halfway. Tracking apps draw a polar map with concentric rings — commonly 90° at center, then rings for 60° / 30° / 0° (horizon). When the path crosses into the outer usable ring you are near AOS; when it exits the horizon ring you are at LOS.

AOS / LOS and obstacles

AOS = Acquisition of Signal; LOS = Loss of Signal. Those times assume a mathematical horizon at 0° elevation. They do not know about your oak tree, ridge line, or the pavilion roof. Expect real AOS later and real LOS earlier whenever terrain or structures block the path. From a typical park lot, treat published AOS as “start listening and pointing,” not “guaranteed audio.”

Max elevation — don’t worship the overhead pass

Maximum elevation is the highest point of that pass for your location. A near-overhead (~90°) pass feels easy to work; it is not inherently “better.” Low passes stretch the footprint — a bird skimming 15° on your eastern horizon is still high for someone far west of you. Operators chasing Satellite Worked All States and long-haul contacts deliberately work those horizon grazers. For first FM QSOs from a park, pick something with max elevation above ~15–20° and a clear sector; once you are comfortable, chase the low ones for distance.

Pass workflow

1. Predict: pick pass with max elevation above ~15–20° for first tries; ISS passes above 60° for SSTV/HT-only attempts.
2. Setup early: 5 minutes before AOS, antenna compass direction, radio memories programmed.
3. Acquire: listen on published downlink; adjust for Doppler (shift downlink as bird approaches/recedes).
4. Call: brief CQ with grid — satellite QSOs are short by physics.
5. Log: satellite name, mode, uplink/downlink freqs, grid if exchanged.

Doppler (practical)

Uplink and downlink both shift as the satellite moves. FM ops often pre-load three memories (high → nominal → low). SSB ops continuously tune uplink while keeping downlink stable — skill builds with reps.

Numbers, not vibes: LEO birds at VHF can move several kHz over a pass. Pre-load high / mid / low memories from the current AMSAT / tracker card for that object — published Doppler tables change when the bird is replaced. FM: start a few kHz high at AOS, click toward the mid memory as elevation rises, click low toward LOS. Linear birds: lock the downlink in the ears (or on a second VFO / 9700 full duplex) and walk the uplink so your own signal stays in the passband. If you cannot hear yourself through the bird, you are off frequency or underpowered — stop calling and listen.

Parking-lot habit: phone tracker cached TLEs before you lose cell, compass calibrated away from the truck steel, yagi on the AOS azimuth five minutes early. HF mast stays down until LOS so you do not spear the yagi.

Antenna pointing — you are the rotator (until you aren’t)

Rotate the yagi in azimuth; adjust elevation by tilting the boom. Practice without transmitting first — hearing the bird is half the battle. From a POTA lot, a quick mental map helps:

• Note AOS azimuth and LOS azimuth from the app before the pass.
• Track the path across the sky; elevation rises toward mid-pass, then falls.
• Keep the boom pointed at the bird, not at the truck antenna you meant to use for HF later.

Arm fatigue is real on long linear passes. That is where a portable rotator earns its keep.

Portable rotator: WA4MCM PSR-100 Mk2

WA4MCM (Don Friend) sells the PSR-100 Mk2 — a portable, lightweight satellite antenna rotor kit built for Arrow / Elk-class handheld yagis, not permanent tower installs. It is weather-susceptible by design (portable first); do not leave it bolted outside like a Yaesu G-5500.

What field / rover / park ops care about (from the product page and Mk2 manual):

• Mounts on a camera tripod (¼-20) — easy to stage beside a picnic table or parking-lot pad
• Max antenna weight ~2 lb (900 g) — standard Arrow / Elk class; the heavier Arrow Alaskan is too much
• Removable boom mount sized for Arrow ¾″ square boom or Elk log periodic (choose mount; both available)
• Wi‑Fi to any 2.4 GHz network; control and calibration via a web browser (Mk2 dropped the old Windows-only companion app)
• Talks to tracking software over UDP — protocols include Yaesu GS-232B, EasyComm II, and direct CSN Technologies S.A.T. Box
• Works with SatPC32, SkyRoof, HRDSatTrack, Gpredict, MacDoppler, PstRotator, and similar via the included serial-to-UDP bridge where needed
• Field power: a small ~3 Ah LiFePO4 is a common pairing (battery not in the kit); wall supply included for bench test/calibration
• Flip mode for passes that cross north through the azimuth stop; park position to stow between birds

How rovers use it: assemble the tripod and rotor before AOS, snap on the Arrow/Elk, join the rotor’s Wi‑Fi (or your phone hotspot / local network), open the web UI, run calibration if you moved the mount, then let Gpredict / SatPC32 / the S.A.T. Box drive az/el while you work the radio. You get two free hands for logging, Doppler, and half-duplex juggling — useful in a POTA parking lot where you also need to watch for cars and keep coax out of the lane.

It is not a substitute for learning handheld tracking. Learn with your arm first; add the PSR-100 when pass rate and fatigue justify the kit cost and setup time. Purchase is typically via WA4MCM’s contact/purchase-request flow (hamfest-oriented sales), not a random cart checkout — confirm current price and shipping on wa4mcmkits.com.

Combining with POTA / SOTA

Legal and practical separation:

• POTA credit requires HF/VHF simplex QSOs per program rules — not via terrestrial repeaters. Satellite QSOs are their own pursuit; check whether your activation logger should tag them separately.
• Grid: satellite grids are valuable for grid chasers; your activator grid still comes from the park pin for MY_GRIDSQUARE on POTA uploads.
• Time budget: a 10-minute FM pass fits before or after a HF activation; do not miss minimum QSOs chasing a low-elevation pass.
• Horizon: pick the side of the lot with the open sky toward AOS; a vertical HF mast on the hitch can wait until after LOS.

SOTA on summits: FM satellite from a peak is classic; watch weight and keep AZ boundaries in mind. A tripod rotator may be overkill on a short summit stay — handheld still wins for grams.

ISS and special events

ISS voice and SSTV events use published schedules (ARISS). SSTV downlink 145.800 MHz FM — see SSTV for decode setup.

Etiquette

• One contact per pass segment when crowded — do not hog the transponder.
• Identify clearly; satellite pileups are fast.
• If you cannot hear yourself through the bird (half-duplex), listen for others working you before you call again.
• Keep power reasonable; the bird is a shared resource.

Habits / gotchas / checklist (satellites)

• Predict a pass with max el ≳ 15–20° for the first FM QSO. TLEs refreshed before you leave pavement.
• Dual-band radio + handheld yagi + headphones. 5 W is enough on FM; more can desense the transponder.
• Doppler memories loaded. Linear: downlink stable, uplink walked. Full duplex (9700 / dual-VFO) beats half-duplex guesswork.
• POTA 10 still needs simplex QSOs per current program rules — confirm satellite credit on docs.pota.app. WWFF-KFF has treated satellites as repeating devices — confirm the national FAQ.
• Grid in the sat log is the exchange; MY_GRIDSQUARE for a park upload is still the picnic pin.
• Horizon toward AOS. HF hitch mast after LOS. Coax out of the travel lane.

Related

• SSTV · Planning (grid pin)
• RV & camping setups (rooftop / lot passes)
• Resources — N5DUX tracking · WA4MCM PSR-100