manta

Open-source wideband CW skimmer. Every CW signal in an SDR passband, decoded at once, emitted as RBN-compatible spots.

manta is a headless daemon written in Rust. It takes wideband IQ from a commodity SDR, a KiwiSDR over the network, or a WAV file, channelizes the whole passband with a polyphase filterbank, runs an independent CW decoder on every signal it finds, validates the callsigns, and emits spots. Output is the standard DX de cluster format over telnet plus a JSON Lines stream, so existing aggregators (including the Reverse Beacon Network) and modern consumers (such as cqdx) can ingest it without changes.

No GUI. CLI, a config file, and metrics.

Why

The Reverse Beacon Network is infrastructure the whole amateur radio hobby leans on for CW spotting, contest scoring, propagation awareness, and antenna testing. It runs almost entirely on CW Skimmer, a closed-source, Windows-only program maintained by a single author. That is a single point of failure for a shared resource. manta is an open, cross-platform replacement with documented, testable algorithms.

Installation

No Rust toolchain, no cloning the source. Pick one:

Download a prebuilt binary from the Releases page — macOS (Intel or Apple Silicon), Windows, or Linux (x86_64 or arm64, including Raspberry Pi OS 64-bit). Unpack the archive and run the manta binary inside it. Linux binaries need libasound2 installed (audio input is an unconditional dependency, even if you only ever use file, KiwiSDR, or HPSDR input) — sudo apt install libasound2 on Debian/Ubuntu/Raspberry Pi OS, or the equivalent ALSA runtime package on other distros; without it the binary fails to start.

Or run the Docker image (works anywhere Docker does, linux/amd64 and linux/arm64):

docker run --rm ghcr.io/hagaletechnologies/manta:latest --help

When running as a long-lived server (not --help), stop it with docker stop -t 30 <container> — Docker's own default 10-second grace period before SIGKILL is shorter than manta's supported drain window for a slow client's final write (up to 25s), so the default can cut a graceful shutdown off mid-drain.

Both are built by .github/workflows/release-publish.yml directly from each tagged release's commit — every published binary traces to a specific, auditable source revision. (If the image above returns an authorization error, the GHCR package needs its one-time "make public" step in GitHub's package settings after the first real release — see MAN-65. Windows binaries need the Visual C++ Redistributable installed if it isn't already.)

Building from source (if you're developing manta itself, or need a platform/feature combination the release matrix doesn't cover — the soapy feature below, for instance, isn't in the official release binaries since it needs the SoapySDR system library) still works exactly as before, and is what the rest of this Quickstart assumes:

Quickstart

Requires Rust 1.85 or newer.

# Build
cargo build --release -p manta-cli

# Decode a synthetic golden vector from a file (deterministic, no hardware)
manta gen v1 --out /tmp/v1
manta decode /tmp/v1/v1.wav

# Copy live CW from a public KiwiSDR on 40 m
manta listen --kiwi-host kiwi.example.org --kiwi-freq 7030000

# Copy from a local SDR via SoapySDR (build with --features soapy)
manta listen --soapy-driver driver=rtlsdr --soapy-freq 7030000 --soapy-rate 240000

# Copy from the default audio input (rig audio passband, 48 kHz)
manta listen

# Any of the above as JSON Lines instead of text
manta listen --json --kiwi-host kiwi.example.org --kiwi-freq 7030000

manta --help lists every subcommand and flag.

Inputs

Source	How	Status
IQ / audio WAV file	decode, listen --source	Working
Sound card (rig audio passband)	listen --device	Working, 48 kHz input only
KiwiSDR over the network	listen --kiwi-host	Working
RTL-SDR, Airspy, SDRplay, HackRF, and anything else SoapySDR drives	listen --soapy-driver, feature soapy	Working, needs hardware soak

Targets Linux (x86-64 and ARM, Raspberry Pi 4 class), macOS, and Windows. The CPU budget is a full 192 kS/s passband inside one Raspberry Pi 4 core, enforced by criterion benches.

Outputs

• Decoded text or JSON Lines on stdout today.
• RBN-format DX de spots over the DX cluster telnet protocol (port 7300) and a JSON Lines / WebSocket stream (port 7301): in progress, see ROADMAP.md milestone M3.

The decode path is deterministic: the same file in produces byte-identical spot logs out. That is a hard requirement, and CI enforces it with golden test vectors.

Status

Pre-1.0. What exists and what does not:

• Done: single-signal decode from files and live audio (M1); the full wideband pipeline of polyphase channelizer, detector, track manager, and decoder pool, with SoapySDR and KiwiSDR inputs (M2 sub-projects); callsign validation, CQ/DE parsing, cty.dat and SCP cross-checks, dedupe, wired into the engine (M3, in part).
• Open acceptance gates: the Raspberry Pi 4 CPU-budget measurement and a 24 h live-SDR soak both need physical hardware.
• Next: the telnet and JSON spot servers, TOML config, metrics, and an RBN parity benchmark on recorded contest IQ.
• Known limits: the classical decoder loses copy under heavy HF fading on a few golden vectors (issues #25 and #28). Closing that gap is the M4 ML fusion stage, gated on beating the classical baseline under simulated fading.

ROADMAP.md has the milestone breakdown with acceptance criteria.

Non-goals

• Not an interactive receiver or panadapter. Use SDR++ or similar for a waterfall.
• Not a general digital-mode skimmer. FT8 and RTTY are out of scope for 1.0, though the channelizer architecture does not preclude them later.
• Not a cluster network. manta is a spot source, not an aggregator.
• Not a logger. No QSO state.
• Not a multi-process Windows orchestrator. manta is a single Rust binary; there is no companion-program sprawl to sequence-launch.
• No CW Skimmer-style dual MME/WDM soundcard configuration surface, and no CAT/rig control to align a narrowband receiver with the channelizer. manta does ingest a local audio device (listen/listen --device, rig-audio passband) — this is about the legacy Windows driver-selection and band-scope-alignment machinery around that, not the input itself, which the wideband sources (OpenHPSDR/Hermes, SoapySDR, KiwiSDR) don't need at all since the channelizer already covers the whole passband at once.

Documentation

• ARCHITECTURE.md: the seven-crate workspace, data flow, and the channelizer, decoder, validation, and output design.
• docs/SPEC-decode-core.md: the implementation-level algorithm spec. Channelizer constants, noise-floor estimator, track state machine, decoder equations, confidence formulas, determinism rules, golden vectors, and the config-key table.
• ROADMAP.md: milestones M0 to M4 with acceptance criteria.
• docs/DECISIONS/: dated design decisions and implementation pins.
• wiki/INDEX.md: accumulated gotchas and cross-references.

Related projects

• coppa: manta reuses its FFT and its AWGN / Watterson HF channel models for the DSP core and test harness.
• dit: manta's decoder is the wideband, headless evolution of dit's single-channel CW engine.
• cqdx: manta's JSON spot stream is designed as a first-class cqdx ingest source.

Contributing

Open an issue or a pull request. Main moves only by PR, CI must be green, and the golden-vector determinism tests are the bar every decoder change has to clear. See SECURITY.md for vulnerability reporting.

License

MIT OR Apache-2.0, at your option. Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this project shall be dual licensed as above, without any additional terms or conditions.