spot nearby planes with acars when you're bored
May 3, 2026
There was a time when I liked aircraft a lot. Like a really lot. But you know what is even more cool than flying a plane? To me, it is the understanding of aircraft communication systems, avionics and embedded systems and the overall engineering efforts applied to these amazing flying beasts!
The ADS-B detour
My RTL-SDR is an old v2 dongle, and it just doesn't do a good job at 1090 MHz, which is what you need for ADS-B. I didn't
feel like buying a v3/v4 just to get that one band, so instead I went down a small rabbit hole with
adsb_deku, a Rust ADS-B decoder. The plan was to feed it from dump1090_rs
pointed at a SoapySDR remote endpoint instead of the dongle directly:
dump1090_rs --driver "remote, remote=tcp://127.0.0.1:55132, remote:driver=rtlsdr"Honestly, I never confirmed whether the remote/SoapySDR hop was actually necessary for what I was doing, or just a leftover from an earlier experiment — but I kept the command around, along with the RTL-SDR wiki, in case I revisit it with better hardware.
ACARS: works with (basically) anything
Where the dongle has no trouble at all is VHF, and that's exactly where ACARS lives (airlines still send a lot of short operational messages — gate info, weather, position reports — over VHF datalinks in the 130-137 MHz range). On my MacBook Air, I fed acarsdec live from SoapySDR across the usual set of international ACARS channels, and it picked up traffic right away:
acarsdec --output full:file --soapysdr driver=rtlsdr 131.450 131.525 131.550 131.725 131.825No fiddling required — it just worked, which was a nice change of pace after the ADS-B detour above.
acars_deku, someday
adsb_deku decodes and renders ADS-B frames so nicely that it left me wanting the same thing for ACARS — something
like acars_deku, parsing and rendering the messages acarsdec spits out instead of just logging them to a file.
Nothing built yet, just an idea sitting in my someday-maybe pile.