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Cisco Aironet 1520, 1130, 1240 Series Wireless Mesh Access Points, Design and Deployment Guide, Release 6.0
OL-20213-01
Site Preparation and Planning
Figure 21
Point-to-Point Link Fresnel Zone
Figure 22
Typical Obstructions in Fresnel Zone
It is possible to calculate the radius of the Fresnel zone (in feet) at any particular distance along the path
using this equation:
F1 = 72.6 X square root (d/4 x f)
where
F1 = the first Fresnel zone radius in feet
D = total path length in miles
F = frequency (GHz)
Normally, 60 percent of the first Fresnel zone clearance is recommended, so the above formula for
60 percent Fresnel zone clearance can be expressed as: 0.60 F1= 43.3 x square root (d/4 x f). These
calculations are based on a flat terrain.
shows the removal of an obstruction in the Fresnel zone of the wireless signal.
Figure 23
Removing Obstructions in Fresnel Zone
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