User's Manual

605-0000-706 ProST Installation User Guide-Rev H
20
Fresnel Zones define the amount of clearance required from obstacles. These zones are
composed of concentric ellipsoid areas surrounding the straight-line path between two
antennas. Thus, the zone affects objects to the side of the path and those directly in the path.
The first Fresnel Zone is the surface containing every point for which the distance from the
transmitter to any reflection point on the surface point and then onto the receiver is one-half
wavelength longer than the direct signal path.
One method for clearing the Fresnel Zone is by increasing the antenna height.
The first Fresnel Zone radius is calculated by the following equation:
Typically, at least 60% clearance of the first Fresnel Zone is considered as LOS. To ensure the
ground does not enter into the first Fresnel Zone, both antennas (i.e. at Base Station and
subscriber) must be mounted at least 0.6 x r meters above ground level (or clutter level).
Examples, using the formula above,