Alvarion BreezeNET DS.11 User Manual page 23

Physical Obstacles
Any physical object in the path between two bridges can cause signal attenuation.
Common obstructions are buildings and trees. Any buildings or other physical
structure such as trees, mountains or other natural geographic features higher than
the antenna and situated in the path between the two sites can constitute
obstructions. Install outdoor antennas high enough to avoid any obstacles, which
may block the signal.
Minimal Path Loss
Path loss is determined mainly by several factors:
Distance between sites – Path loss is lower and system performance better
when distances between sites are shorter.
Clearance – Path loss is minimized when there exists a clear line of sight. The
number, location, size, and makeup of obstacles determine their contribution
to path loss.
Antenna height – Path loss is lower when antennas are positioned higher.
Antenna height is the distance from the imaginary line connecting the antennas
at the two sites to "ground" level. "Ground" level in an open area is the actual
ground. In dense urban areas, "ground" level is the average height of the
buildings between the antenna sites.
BreezeNET BU-DS.11/RB-DS.11
2-7
Installation
User's Guide