Programming instructions

Installation
2-5
Alvarion
Outdoor Installation
Considerations
This chapter describes various considerations to take into account
when planning an outdoor installation including site selection, antenna
alignment, antenna polarization, antenna seal, and cell size.
Collocating DS.5800 Outdoor Units
Up to four BU-DS.5800 units using sector antennas, at least 1 m apart
can be collocated on the same building top or tower. Collocating more
then four units may decrease performance depending upon the type of
antenna and its direction. Each unit should be assigned to one of the
non-overlapping channels: 1, 6, 11 or 14.
Site Selection Factors
When selecting a location for outdoor units and external antennas,
remember to take into consideration the following guidelines:
! Minimum distance between sites.
! Maximum height above the ground.
! Maximum line of sight clearance.
Path of Clearest Propagation
A propagation path is the path that signals traverse between the
antennas of any two units. The “line” between two antenna sites is an
imaginary straight line, which may be drawn between the two antennas.
Any obstacles in the path of the “line” degrade the propagation path.
The best propagation path is, therefore, a clear line of sight with good
clearance between the “line” and any physical obstacle.
Physical Obstacles
Any buildings or other physical structures such as trees, mountains or
other geographic features higher than the antenna and situated in the
path between the two sites can constitute obstructions and cause signal
attenuation. Install outdoor antennas high enough to avoid any
obstacles, which may block the signal.
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.