HF Propagation Explained

Skywave is the mode of propagation in which the radio signals return to Earth by multi-refractions in the ionosphere. It is most effective at frequencies beween 3 and 30 MHz thus enabling long-range communication. This phenomenon occurs in the ionospheric layers E, F1, and F2. There are sometimes ducting effects. The ionization levels, influenced by solar activity, can change rapidly. Tools like real-time maps and charts and/or watching explanatory videos can improve understanding HF radio propagation. See also an index for HF Radio Propagarion.