How to decode ACARS

Option 1: the radio way

ACARS goes out over the air, so you can catch it yourself. It is a genuinely fun project, and it costs about as much as a nice dinner.

1. 1. Get a receiver. An RTL-SDR dongle and a basic VHF antenna are enough to start.
2. 2. Tune the ACARS band. In most regions the traffic sits in the 129 to 137 MHz range, with a few common channels around 131 MHz.
3. 3. Run a decoder. Software like acarsdec or ACARSDeco2 turns the noise into readable messages. Many hobbyists also feed what they catch to a community network so others can see it.

The trade-off is range. You only receive aircraft near your antenna, and the raw output is full of shorthand you learn to read over time.

Option 2: the app way

If you just want to read the messages, skip the radio. Open Flight Deck, tap a flight, and the decoded ACARS is already there, sorted and explained, next to the plane on the map. No dongle, no frequency hunting. And instead of the aircraft over your own roof, Flight Deck pulls ACARS from across the world and filters tens of thousands of messages down to what is worth reading, so you catch the diversion or the emergency without watching a raw feed scroll past.

Which should you pick?

Want the hobby? Build the radio. Want the answer about your flight right now? Use the app. If you are still hazy on the basics, read what ACARS is first.