Fading is, in general terms, the decrease in strength or loss of quality of a signal.

Fading may either be due to multipath propagation, referred to as multipath-induced fading, weather (rain), or shadowing from obstacles affecting the wave propagation, sometimes referred to as shadow fading.

Skywaves will fade at any distance. Sky waves are reflected by the ionosphere. The ionosphere doesn’t have an equal reflection efficiency, which means that the reflected signal can change and cause fading.

The most intense type of fading is when both the skywaves and the groundwaves arrive with the same strength at the receiver.