Abstract ACARSDeco2 is a software-based decoder for VHF ACARS (Aircraft Communications Addressing and Reporting System) messages, designed for the Windows operating system. Originally developed in the early 2000s, it remains a lightweight, command-line tool for aviation enthusiasts, researchers, and light-duty monitoring stations. This paper examines its signal processing pipeline, input/output modes, performance characteristics, and limitations in modern computing environments. 1. Introduction ACARS is a digital datalink system used to transmit short messages between aircraft and ground stations, typically over VHF (118–137 MHz) using amplitude modulation (AM). Decoding these messages requires converting raw audio from a receiver into bitstreams and then parsing them according to ACARS frame structures.
: No support for HF‑ACARS (which uses PSK or 1800 Hz FSK). No built‑in receiver control (e.g., frequency scanning). Cannot decode ACARS over satellite (Inmarsat). 6. Comparison with Other Windows ACARS Decoders | Feature | ACARSDeco2 | MultiPSK | PlanePlotter | dumpvdl2 (via Cygwin) | |--------------------------|----------------|-------------------|--------------------|----------------------| | GUI | No (CLI) | Yes | Yes | No | | Live audio support | Yes (MME) | Yes (MME, ASIO) | Yes (MME) | Yes (RTL‑SDR only) | | WAV playback | Yes | Yes | No | No | | Bitstream recording | Raw hex | Full demodulated | Raw I/Q | Raw frames | | Label translation | Basic | Extensive | Medium | None | | Network output (UDP) | No | Yes | Yes | Yes | | Resource footprint | Very low | High (many modes) | Medium | Low | | OS support up to | Windows 10 (32/64)| Windows 11 | Windows 11 | Windows 10 (64 with workarounds) | acarsdeco2 windows
Decoding a WAV file:
| Metric | Result | |--------------------------------|-------------------------------------| | CPU usage (live decoding) | ~2–5% on legacy hardware, <1% modern | | Decode success rate (clean signal) | >95% | | Decode success rate (noisy SDR) | ~70% (no forward error correction) | | Max sustained frame rate | ~10–15 messages/sec (depends on load) | | Latency (live) | <50 ms from audio to output | Abstract ACARSDeco2 is a software-based decoder for VHF
