Installation Instructions

Q2. How to calculate the minimum mounting height of

the devices?

In order to maximize the received signal strength of the devices,

installers need to minimize the eect of the out-of-phase signals,

which is caused by obstacles in the path between the transmitter and

the receiver. Fresnel Zone is a usual method to calculate this path, as

shown in the formula and the gure below.

where,

r = Fresnel zone radius in meters

c = 3x10

m/s, speed of light

f = operating frequency of the devices in Hz

d1 & d2 = the distances between the point

and the devices in meters

h = the height of

obstacle at this point

H h+r

(1 40%)

(H is the height of the CPE)

For example, assume d1 is 2km, d2 is 8km, and f is 2.4GHz, then r

would be 14.142m. Considering a toleration of 40%, allowable radius

would be 8.485m. Assume h is 10m, then the result of the minimum

mounting height based on this point would be 18.485m. Similarly,

calculate the results based on all the points where there are obstacles,

and the maximum value would be the nal result.

For more information, please refer to:

http://en.wikipedia.org/wiki/Fresnel_zone

r ⋅