How to Use Ham Sat Tracker

From location entry to working the pass

Ham Sat Tracker is designed to be fast to use in the field. This page walks through the full workflow — from entering your location to handing off a pass to AntTrack for real-time antenna pointing.

New to satellite operations entirely? Start with the Beginner's Guide first, then come back here.

Step 1 — Enter Your Location

Your location is used to calculate when satellites will be above your horizon. You have two options:

  • Maidenhead grid square — the preferred format for ham radio. Four characters (e.g. FN25) gives a good result; six characters (e.g. FN25dg) gives higher precision. Most hams know their grid square.
  • Decimal coordinates — enter as latitude, longitude (e.g. 45.4215, -75.6972 for Ottawa).

Tap the 📍 locate button to use your device's GPS instead of typing. On first use your browser will ask for location permission — allow it for the most accurate results.

Your location is saved automatically between sessions so you don't have to re-enter it each time.

Step 2 — Set Your Options

Minimum Elevation

The slider sets the minimum elevation angle for a pass to be shown. The default is 10°. Low passes (under 10°) are often blocked by trees, buildings, or terrain — especially relevant when operating portable or from a condo. Raise this to 20° or 30° for a cleaner list of worthwhile passes only.

Time Range

Sets how far ahead to predict passes. The default is 24 hours. Longer ranges (48h, 72h, 7 days) are available with AntTrack Pro.

Date Picker (Pro)

AntTrack Pro users can select a specific future date to see passes for that day. Useful for planning a portable activation in advance — pick the date, set your time range, and see exactly what's coming over during your operating window.

Step 3 — Calculate Passes

Tap Calculate Passes. Within a second or two you'll see a list of all upcoming passes sorted by time, with a summary showing how many passes were found across how many satellites.

Each pass card shows:

  • Satellite name and mode (FM or SSB)
  • AOS time and azimuth — when and where the satellite rises
  • TCA time, elevation, and azimuth — the peak of the pass
  • LOS time and azimuth — when and where it sets
  • Pass duration
  • Doppler-corrected frequencies — uplink and downlink at AOS, TCA, and LOS
  • CTCSS tone where required (SO-50, ISS)
  • Operating notes for satellites with special requirements
  • Skyview polar plot — a top-down diagram of the satellite's path across your sky

AOS, TCA, and LOS stand for Acquisition of Signal, Time of Closest Approach, and Loss of Signal respectively.

Step 4 — Read the Doppler Frequencies

The frequency table is the key feature of Ham Sat Tracker. For each pass you get the uplink and downlink frequencies corrected for Doppler shift at three points:

  • AOS — set these frequencies as you wait for the satellite to rise. The satellite is approaching, so the downlink is slightly high and uplink slightly low.
  • TCA — at closest approach the Doppler shift is near zero, so these are closest to the nominal frequencies.
  • LOS — as the satellite recedes, the downlink drops and uplink rises. By LOS the shift is the reverse of AOS.

For FM satellites: tune to the AOS downlink frequency, listen for the satellite, and tune the downlink slowly downward throughout the pass as you hear the audio shift. Adjust your uplink in step.

For SSB/linear transponder satellites (FO-29, RS-44, AO-7): the Doppler correction is more critical. Use the AOS frequencies to start, and track the downlink continuously. Tune your uplink to keep your own downlink signal in the correct position on the transponder passband.

Step 5 — Filter and Sort (optional)

The filter bar above the results lets you narrow passes by satellite, mode (FM/SSB), or minimum elevation. Useful if you're only set up for FM today, or only want to see high-elevation passes worth working.

Step 6 — Set a Pass Alert (Pro)

Each pass card has a 🔔 Alert button. Tap it to arm a 5-minute countdown — when the time comes, an amber banner appears at the top of the page and a three-tone chime plays to let you know the satellite is about to rise.

The button turns amber and shows 🔔 Armed to confirm it's set. Tap it again to cancel. You can arm multiple passes at once — each runs its own independent timer.

Alerts require the page to stay open in your browser. If you close or leave the tab the timer is lost, so keep Ham Sat Tracker open while you wait for the pass.

Mobile note: if the chime doesn't play on the first try, arm the alert and tap any button elsewhere on the page before the timer fires — this confirms the audio context to the browser and resolves the issue.

Step 7 — Track the Pass with AntTrack

AntTrack is a real-time antenna pointing tool built into Ham Sat Tracker. It uses your phone's compass and tilt sensor to show you exactly where to point your antenna during the pass.

Manual launch

Tap AntTrack (manual) on any pass card to open AntTrack. You'll need to enter the pass details manually on the setup screen.

One-tap handoff (Pro)

AntTrack Pro users see a 📡 Track This Pass button on each pass card. Tap it and AntTrack opens pre-loaded with all the pass data — AOS azimuth, maximum elevation, LOS azimuth, and duration. No manual entry required.

Before you launch — compass calibration

Phone compasses need to be calibrated periodically, especially after being indoors or near metal objects. Before opening AntTrack, wave your phone in a figure-8 pattern for a few seconds. This resets the magnetometer and gives you the most accurate compass readings. Do this outdoors away from vehicles and metal structures.

AntTrack shows a CMPS indicator in the status bar with a colour-coded accuracy reading (iOS only):

  • 🟢 ±10° or better — compass is reliable, proceed with confidence
  • 🟡 ±11–20° — marginal, a figure-8 calibration gesture may help
  • 🔴 ±20° or worse — close the app, do the figure-8 gesture, reopen

If compass accuracy is poor when GPS first locks, AntTrack will show an amber warning banner prompting you to calibrate before the pass.

Elevation calibration

When you enter the tracking screen, a calibration overlay appears showing a live tilt reading in degrees. Point your antenna boom at the horizon (0° elevation), watch the number settle near 0°, then tap Calibrate. The display turns green and shows "✓ LEVEL" when you're within 1° of level — that's the right moment to tap. This zeros the tilt sensor for your specific phone mounting position.

Using AntTrack

  1. Complete the elevation calibration — wait for the live tilt reading to settle near 0° before tapping Calibrate
  2. Check the compass dot — confirm CMPS shows green before the pass starts
  3. Point at AOS azimuth — before the pass starts, rotate to face the AOS compass bearing shown on screen
  4. Watch the indicators — as the pass progresses, the delta bars show how far off you are in azimuth and elevation
  5. Follow the satellite — keep the delta bars centred throughout the pass

AntTrack works best with an external directional antenna. For a handheld yagi, hold the phone alongside the boom and use the compass heading to rotate — the elevation indicator tells you how high to tilt.

TLE Data and Offline Use

Ham Sat Tracker fetches current orbital element (TLE) data from CelesTrak every time you load the app. The data is also cached locally in your browser, so the app works in the field without an internet connection.

The Update TLEs button in the header forces a fresh fetch. The TLE age is shown in the header — predictions are reliable for several days after the last fetch, but accuracy degrades with older data.

For portable use: open the app and tap Update TLEs before leaving home. If you end up without cell service in the field, the cached data will cover you.

If the app detects it's working offline, an amber banner appears showing how old the cached data is.

Tips for Portable Operations

  • Update TLEs before you leave home — cached data is good for several days
  • Add to home screen — on Android and iOS you can add Ham Sat Tracker to your home screen as a web app for quick access
  • Check passes the night before — use the date picker (Pro) or the 24h range to plan your operating session
  • Set minimum elevation to 20°+ when operating from a restricted site — low passes are rarely worth the effort if you have obstructions
  • Calibrate AntTrack fresh each session — do a figure-8 gesture with your phone before opening AntTrack, then complete the elevation calibration when prompted. Compass accuracy degrades indoors and near metal.
  • Note the AOS azimuth before the pass — be ready to point before AOS, not after
  • High-elevation passes are forgiving — a pass above 50° max elevation is a good one to practice on as there's less rushing to track

Frequently Used Satellites

Quick reference for the five free-tier satellites:

  • SO-50 — FM, uplink 145.850 (67 Hz CTCSS required), downlink 436.795. Activate with a 74.4 Hz tone burst if no response — the satellite has an on-timer that can go to sleep.
  • AO-91 — FM, uplink 145.960, downlink 435.250. Sunlight-only operation — passes in eclipse won't work.
  • ISS — FM, uplink 145.990 (67 Hz CTCSS), downlink 437.800. The repeater is not always active — check ARISS for current status.
  • FO-29 — SSB/CW linear transponder, uplink 145.900–146.000, downlink 435.800–435.900 (inverting). Tune your downlink and adjust uplink until you hear your own signal.
  • RS-44 — SSB linear transponder, uplink 145.935–145.965, downlink 435.610–435.640 (inverting). One of the most active SSB birds currently.

Questions or Problems?

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73 de VE3AKK