Long-delayed echoes are radio echoes which return to the sender several seconds after transmission.
NOAA / Space Weather Prediction Center, Geomagnetic K-indices and Running A-indices, Local Noon Solar Radio Flux, Daily Solar Indices with SSN
Long path hf radio propagation is sometimes the best path to work dx, since the shortest path is not always the best path.
Display a table of last 30 days sunspots reports.
Prepared by the U.S. Dept. of Commerce, NOAA, Space Environment Center
This map can be used to determine the frequencies that will always be returned to the Earth. Transmitted frequencies higher than the indicated contours (which are given in MHz) may penetrate the ionosphere, resulting in lost power to space.
The map shows the radio auroral zones as green bands near the northern and southern poles.
An international Radar network for studying the Earth\'s upper atmosphere, ionosphere, and connection into space.
Current status, prediction, solar weather for the solar cycle 24 by VE3EN
This article will help to unravel some of the mysteries as well as giving useful operating tips to maximize your chances of working that rare station by G4UCJ
William Hepburn's Daily Tropospheric Ducting Forecast.
DX Propagation by DR2W! High resolution SNR maps in pseudo color. Propagation based on the actual sunspot number.
Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center
Exaustive introduction to radio wave propagation, includes a very detailed glossary on common propagation terms, composed by AE4TM.
Propagation in the LF-Band
Experimental maps that show real-time VHF propagation derived from analyzing data gathered from the APRS-IS network.
Collection of real time solar data by CT1BOH
Automatic 144MHz E-skip Warnings via Email for European Region
The Report and Forecast of Solar and Geophysical Activity is the primary daily report prepared by SEC. It provides a summary and analysis of solar and geomagnetic activity during the previous 24 hours as well as the most recent solar indices. It also provides a forecast of activity and indices for the next 3 days.
This is about Small Antenna types and their properties which can help choosing proper
antenna for high-frequency wireless communications as: two-way radio, microwave short links,
repeaters, radio beacons or wireless telemetry
160 Meter Radio Propagation Prediction Table