Radiowave Propagation Center
- High frequecy and VHF radio propagation data, solar and geomagnetic real-time and historic data, sunspot activity reports, as well as forecasts. A comprehensive propagation resource compiled by Tomas Hood, editor of the propagation columns of CQ, CQ VHF, Popular Communications, and Monitoring Times magazines.
- WSPR implements a protocol designed for probing potential propagation paths with low-power transmissions. Stations with internet access can automatically upload their reception reports to a central db