FT8/FT4 Browser Decoder

Decode FT8 and FT4 amateur radio signals from browser audio in real-time

FT8/FT4 Browser Decoder decodes amateur radio FT8 and FT4 signals directly from browser tab audio. Works great with WebSDR and KiwiSDR sites, with no external radio software or virtual audio cable required. FEATURES: • Real-time FT8 and FT4 decoding using WebAssembly • Optional persistent Chrome side panel for longer monitoring sessions • Waterfall spectrum display for the 200-3000 Hz audio passband • Automatic time synchronization for FT8/FT4 slot timing • CSV export of decoded messages • CQ-only message filter • Local browser-based processing USAGE: 1. Open a regular WebSDR/KiwiSDR/audio tab. Chrome internal pages such as chrome:// pages cannot be captured. 2. Tune to an FT8/FT4 frequency: - FT8: 7.074, 10.136, 14.074 MHz USB - FT4: 7.0475, 10.140, 14.080 MHz USB 3. Make the WebSDR/audio tab active. 4. Click the extension icon. 5. Click Start to decode the active tab audio. 6. Optional: click Panel to open the longer-running side panel UI. DETAILS: • Target decode sample rate: 12000 Hz • Slot time: 15s (FT8) / 7.5s (FT4) • Decoder: WebAssembly FT8/FT4 decoder • Supported UI: popup plus optional Chrome side panel PRIVACY: • No data collection • No tracking or analytics • No account required • Audio is processed locally in your browser • Time synchronization uses a public UTC time endpoint only for clock offset estimation OPEN SOURCE: MIT License - Contributions welcome https://github.com/Transwarp8/ChromeFT8