D-Link Collocating DWL-1800 Outdoor Units, Site Selection Factors, Physical Obstacles

2.3.1 Collocating DWL-1800 Outdoor Units

Up to three DWL-1800B units with integrated antennas (the exact number depends on the number of non-overlapping channels available in the relevant regulatory domain) can be collocated on the same building top or tower. Collocating more then three 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, 7, or 13 in ETSI or 1, 6 or 11 in FCC.

2.3.2 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 physic al 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.

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