Hewlett Packard Enterprise Company AP175SDR Manual Do Utilizador
8
Aruba AP-175 Outdoor Access Point
| Installation Guide
Identifying Known RF Absorbers/Reflectors/Interferences Sources
Identifying known RF absorbers/reflectors/interference sources while out in the field during the installation
phase is critical. Even though outdoor environments consist of fewer RF absorbers/reflectors/interference
sources compared to indoor environments, ensure that these sources are identified and taken into
consideration when installing and mounting an AP to its fixed outdoor location.
phase is critical. Even though outdoor environments consist of fewer RF absorbers/reflectors/interference
sources compared to indoor environments, ensure that these sources are identified and taken into
consideration when installing and mounting an AP to its fixed outdoor location.
RF Absorbers
Cement/Concrete
Natural Items: Trees/vegetation
Brick
RF Reflectors
Metal Objects: Roof-installed air-conditioning equipment, chain link fences (depending on aperture
size), other wire fences, or water pipes
size), other wire fences, or water pipes
RF Interference Sources
Other 802.11a/b/g/n or broadband access equipment operating nearby
Industrial RF welding equipment or other Industrial, Scientific and Medical (ISM) equipment that utilizes
RF to heat or alter the physical properties of materials
RF to heat or alter the physical properties of materials
Military, Commercial Aviation or Weather Radar Systems
Line of Sight (Radio Path Planning)
A wireless bridge or mesh link requires a “radio line of sight” between the two antennas for optimum
performance. The concept of radio line of sight involves the area along a link through which the bulk of the
radio signal power travels. This area is known as the first Fresnel Zone of the radio link. For a radio link, no
object (including the ground) must intrude within 60% of the first Fresnel Zone.
performance. The concept of radio line of sight involves the area along a link through which the bulk of the
radio signal power travels. This area is known as the first Fresnel Zone of the radio link. For a radio link, no
object (including the ground) must intrude within 60% of the first Fresnel Zone.
Figure 4
illustrates the concept of a good radio line of sight.
Figure 4 Line of Sight
If there are obstacles in the radio path, there may still be a radio link but the quality and strength of the
signal will be affected. Calculating the maximum clearance from objects on a path is important as it directly
affects the decision on antenna placement and height. It is especially critical for long-distance links, where
the radio signal could easily be lost.
signal will be affected. Calculating the maximum clearance from objects on a path is important as it directly
affects the decision on antenna placement and height. It is especially critical for long-distance links, where
the radio signal could easily be lost.
When planning the radio path for a wireless bridge or mesh link, consider these factors:
Avoid any partial line of sight between the antennas
Be cautious of trees or other foliage that may be near the path, or may grow and obstruct the path.
Radio Line of Sight
Visual Line of Sight