Nortel 6220 User Manual page 162

FRESNEL ZONE
For a link to truly be line-of-sight, no objects such as buildings, cars, etc.
or the ground may be within a certain height perpendicular to the line of
sight path called the first fresnel (pronounced fray-nell) zone.
This height of the fresnel zone H (in feet) is specified by the equation
below.
H = 43.3 x sqrt (D/ (4xF))
D: distance in miles between antennas
F: Frequency in GHz
Case Study
D: 10
F: 2.4
H = 43.3 x sqrt (10/ (4x2.4))
H = 44.19 feet
HF = 44.19 * 0.6 = 26.5 feet
If 60 percent of the FRESNEL ZONE is free from obstructions the link
will generally behave as LOS (Line of sight).
Figure A.6
FRESNEL ZONE
WLAN Cable Access Point 6220 CSU NTPM99CA Rel 2.0 Issue 5 Dec 2005
167