User's Manual

Hardware Installation Guide Radio Site Planning
02030311-07 Airspan Networks Inc. 5-3
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. For calculating Fresnel Zone, refer to the ASWipLL System Description.
5.3. Multipath Fading
Some of the transmitted signals may be reflected from a nearby building, by water
under the signal path, or from any other reflectors. This reflected ("bounced") signal
can then be received by the radio receiving the signal and superimposed on the main
received signal, thereby degrading the signal strength.
To avoid multipath fading from nearby buildings etc., Airspan recommends
installing the outdoor radios at the rear end of the buildings instead of at the front.
When you install at the rear end of the building, the front-end of the building blocks
incoming signals from multipath reflections.
Figure 5-2: Radios mounted at rear, blocking multipath reflection