124
PRO 11 SERIES WIRELESS ETHERNET
•
Interference
Interference may be caused by another system on the same frequency range,
external noise, or some other co-located system.
L
INE OF
S
IGHT
An optical line of sight exists if you can see one antenna from the other.
Clear Line of Sight
A clear line of sight exists when no physical objects obstruct viewing one antenna
from the location of the other antenna.
A radio-wave clear line of sight exists if a defined area around the optical line of
sight (Fresnel Zone) is clear of obstacles.
Fresnel Zone
The Fresnel zone is the area of a circle around the line of sight. The Fresnel Zone
is defined as follows:
Figure D-7. Fresnel Zone.
R =
1
⁄
2
√
(
λ ×
D)
R: radius of the first Fresnel zone
λ
: wavelength
D: distance between sites
When at least 80% of the first Fresnel Zone is clear of obstacles, propagation loss is
equivalent to that of free space.
Transmitter
(Site A)
Receiver
(Site B)
R
Summary of Contents for LW0050A
Page 2: ......
