HF Propagation

From The RadioReference Wiki

Radio and TV signals aren't always limited to traveling line of sight distances. On HF this is commonly caused by refraction (bending) of the signal at the upper layers of the atmosphere known as the ionosphere. On frequencies higher than this, while solar activity plays a role, Earth based weather events are the most common cause of propagation. These links explore several sites, and software, that can be used to help predict how a HF signal will propagate. For propagation topics above 30 Mhz, please see our DXing Above 30 Mhz article.

Links and Online Maps

Online Maps