Fresnel zones are used by propagation theory to calculate reflections and diffraction loss between a transmitter and receiver. Fresnel zones are numbered and are called ‘F1’, ‘F2’, ‘F3’ etc.

There are an infinite number of Fresnel zones, however, only the first 3 have any real effect on radio propagation.
In RMpath allows the display of the following fresnel zones:

• 0,6
• 1
• 2

Also it displays the line or zone of the earth clearance. This line is required to calculate the 'fresnel clearence'