Phase 1 preview

HF propagation, computed on your device

ITU-R P.533 compiled to WebAssembly. Nothing is computed on a server, your location never leaves the browser, and once loaded it works offline.

Tools

Path planner Pick two points, get 24 hours × nine bands of SNR margin. Computes live in this browser in about a third of a second. live engine · ~11 MB first load Reach map Where any station can be heard, with a day/night overlay. Computes across worker threads and fills the map in as it goes — coarse first, then sharper. live engine · pan & zoom Style guide Every design token in all three themes. The reskin test: one token file drives the whole app. design system
What is real here, and what is not.
Predictions come from the ITU's own reference implementation and are verified numerically identical to a native build of it. Distances, bearings, MUF and the diurnal behaviour all check out against reality.
The engine's reliability output is a known open defect — it reads zero for every circuit tested and ignores the required-SNR input — so nothing here displays it. What you see is SNR margin, which is verified responsive.
The A-score described in the design docs does not exist yet. It is meant to be a calibrated probability, and calibrating it depends on resolving that defect first.
Reach maps are computed for whatever transmitter you pick, at 100 W into an isotropic antenna. Your own power and antenna are applied on top as an exact offset. Antenna figures are peak gain applied flat, so beams read optimistic on paths whose take-off angle they do not favour. Coarse passes paint each sample across the block it stands for, so an early frame is a sketch until the finer passes land.
Solar activity is a fixed placeholder (effective sunspot number 60) until the space-weather pipeline is wired in. Predictions do not yet respond to today's conditions.

Why it is built this way