sigil.radio

Documentation

The full user guide ships alongside 1.0 — the essentials are below

Sigil is a native Mac instrument for radio signals: live spectrum and waterfall from your SDR, burst capture to SigMF, and an analysis workbench that takes an unknown signal apart — symbols, bits, decoded messages. This page gets you from install to first decode; anything it doesn't answer, support does.

Requirements

macOS 14 Sonoma or later, Apple Silicon or Intel. Builds are signed, notarized, and update themselves. During the beta, the app is unlocked with a personal beta key from your invite.

Open a recording — no radio needed

Drag an IQ recording onto Sigil (or File ▸ Open) and it lands in analysis mode: full-capture waterfall, spectrum, and the analysis dock. Sigil reads .sigmf, .fc32/.cf32, .cs16/.sc16, .cu8, .cs8, .wav, BLUE (.cdif/.blue), .sdvr, and headerless .raw.

SigMF, WAV, and BLUE files carry their sample rate and center frequency. For headerless formats Sigil reads rtl_433-style filenames (like g003_315M_250k.cu8); anything it had to assume is flagged in the inspector's File section, where you can correct it.

Connect an SDR

Each device's free, open-source library installs with one Homebrew command — Sigil finds it at runtime:

brew install librtlsdr   # RTL-SDR
brew install hackrf      # HackRF One
brew install uhd         # USRP
brew install soapysdr    # anything with a Soapy module

Plug the device in and it appears in the sidebar; select it and start streaming. (HydraSDR RFOne uses the vendor's libhydrasdr — follow its install instructions.)

Capture a burst

On the live spectrum or waterfall, ⇧-drag a box around the signal — on the waterfall the box also selects a time slice, and it rides down the display with its data. Press R (or the toolbar capture button) and Sigil cuts that slice from its rolling history into a SigMF recording and opens it for analysis. The SDR keeps streaming while you analyze; switching back shows what scrolled past in the meantime.

Analyze and decode

The dock at the bottom of analysis mode is the workbench. ⇧-drag a selection around the signal of interest first — every tool honors it.

• Decoder — run a protocol decoder (or Analyze for a blind modulation verdict). When a decoder finds nothing it reports which stage gave up and what to try.
• Symbols — blind carrier/baud/constellation recovery, eye diagrams, channel measurements.
• Demod — a manual OOK/FSK demodulator with draggable threshold and bit-phase controls, when you want to do it by hand.
• Bits — carve decoded bits into fields, read them as hex/decimal/binary/ASCII, identify CRCs, undo line coding, and diff bursts.

Every shortcut and gesture is listed in Help ▸ Keyboard & Mouse Shortcuts. The in-app walkthroughs (Help menu) teach the whole flow on bundled practice captures — start there.

Listen

Click-to-tune VFO on the live spectrum with NBFM, WFM, AM, and USB/LSB demodulation, squelch, and one-click recording of the audio to WAV.

Getting help

Support has the FAQ and contact details, and Help ▸ Report an Issue in the app is the fastest way to send us a bug.