HF WATCH prediction engine (vendor/p533/p533.mjs, p533.wasm)

WATCHMAN's HF WATCH runs the ITU-R P.533-14 HF propagation method (ITURHFProp, libp533 and libp372,
release v14.3) compiled to WebAssembly by the OpenHamClock project, and its month coefficient files
(data/p533/). The engine runs on the user's own computer; no prediction is sent anywhere.

ITU-R P.533 / ITURHFProp: ITU-R Study Group 3 (https://github.com/ITU-R-Study-Group-3/ITU-R-HF).
Developed by Behm and Engelbrecht. The ITU states it may be used by implementers free from any
copyright assertions, provided AS IS.

WebAssembly build and the input/report format used by WATCHMAN's wrapper: OpenHamClock
(https://github.com/accius/OpenHamClock), released under the MIT License:

MIT License

Copyright (c) 2024-2026 OpenHamClock Contributors

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

Predicted sunspot numbers (data/p533/predicted-solar-cycle.json): NOAA Space Weather Prediction
Center, public domain.
