An HF weather-fax (WEFAX, ITU-R F.343 / WMO) receiver and decoder for Northwood (GYA), DWD and other international stations.
It listens to a sound-card input, finds each transmission automatically and decodes it, correcting tuning offset, slant and tears. It then cleans and sharpens the chart, names it from the broadcast schedules, saves it to disk and shows it in a browser page. With SDR Console’s CAT port it can also retune the radio through the day to collect the most important charts.
Python 3 or later is required on your machine with the small Python server running. Follow the install instructions in the readme.md file. The app runs in a browser window on port 8730.
Features
- Automatic detection of start tone, phasing and stop tone (IOC 576 and 288; 60, 90, 120 and 240 LPM).
- AFC with drift tracking, a correlation FM discriminator that is robust to fades and QRN, and slant correction from the phasing lines.
- A flywheel that uses the PC clock to detect and fill audio lost by the sound card, plus image-based repair of torn charts.
- Enhancement that removes noise streaks and rebuilds broken chart lines without distorting them, with an FSRCNN x2 upscale. Clean charts get only light processing.
- Chart identification from the OpenCPN worldwide schedule file, giving file names such as
20261011_1800Z_DWD_surface-pressure-analysis.png. - SDR Console control over a Kenwood TS-2000 CAT port: frequency read-back, tuning, and an auto-scheduler. You choose the 1st and 2nd priority stations, DX stations fill the gaps, and it learns which frequencies work at each time of day.
- A browser page with the following:
- a live view of the chart as it arrives (green while receiving, orange “NO SIGNAL” when a chart is due but not heard, red when idle);
- a thumbnail strip for each day;
- Raw and Enhanced views, mouse-wheel zoom, and rotation.
Screenshots
