Standalone FT8/FT4 web decoder

podsdr-digimodes-web is a separate single-page app that decodes FT8, FT4 and FT2 in the browser using PodSDR’s parallel decoder — no radio, proxy session or WSJT-X required. It is the digimode companion to the main clients (which have no built-in FT8 decoding).

Running it

From a source checkout:

./run-digimodes-web.sh [port]     # builds the WASM app and serves it on :8080

Then open http://localhost:8080.

Using it

The Controls panel on the left:

• Source — where the audio comes from:
  • KiwiSDR — connect to a public KiwiSDR over WebSocket. Pick one of the presets (SK3W Sweden, Hack Green UK, NA5B Washington DC, Hungary, Various) or enter any host/port; a status line and Reconnect button track the link.
  • Microphone — decode whatever your sound card hears (e.g. a receiver’s speaker output or an audio cable from your rig).
• Mode — FT8 (15 s cycles), FT4 (7.5 s) or FT2 (30 s). Decoding is aligned to real UTC cycle boundaries, marked as white lines on the waterfall.
• Waterfall — Min/Max dB sliders for display contrast.

The central panel is a GPU waterfall of the audio passband. Click or drag on the spectrum to select a frequency band (highlighted yellow): decodes are then split into All Decodes and Filtered Decodes columns. Each decode line shows time, SNR, time offset and audio frequency alongside the message text.