Cisco Aironet 1300 Serie Instructions De Montage page 10

Choosing a Mounting Location
Antenna Polarization
The integrated antenna radiates and receives vertically polarized radio signals. Polarization helps reduce
interference because the antenna tends to reject cross-polarized signals from other sources.
For the multi-point links, Cisco recommends that you use vertical polarization on all antennas; however,
Note
on point-to-point links you can also use horizontal polarization on both ends of the link. To operate
correctly, the antennas at each end of the wireless link should have the same polarization.
The following lightweight access point antenna is vertically polarized:
5.2-dBi omni-directional antennas
•
The following lightweight access point antennas can be vertically or horizontally polarized depending
on their mounting orientation:
10-dBi a yagi antennas
•
9-dBi patch wall-mount antenna
•
Signal Path Clearance
A radio beam travels from the access point to another in a straight line. Therefore, the path between the
antennas must be free of major obstacles. The effects of obstacles and terrain, both along and near the
path, have a significant bearing on the propagation of radio signals and can cause both interference and
signal cancellation.
When choosing a site, consider the effects of the following common obstacles:
• Trees and large plants
A tree directly in the path can totally block the signal. With clearance above the trees there are
usually no secondary effects, but you should allow for future tree growth.
Man-made obstacles
•
A large round container such as a gas storage reservoir or water tower that is partially in the path
causes some blocking. These obstacles may also reflect some energy, which can interfere with other
receivers. Square or rectangular objects in or near the path have rectangular surfaces that can block
and diffract signals over and around them.
• Internal building obstacles
When mounting the access point in an indoor location, the signal can be block obstructions, such as
walls, office cublicles, steel file cabinets, metal ducts, and metal shelving. These obstacles can also
reflect some energy, which can interfere with radio receivers.
For tower installations, you may need to climb the tower to the proposed mounting location to verify a
clear path to the other site. If trees are in the line of signal propagation, leave extra clearance above
them for future growth into the signal path.
Physical Site Inspection
Perform a visual inspection of the site to ascertain and document the physical characteristics of the site
and to ensure that all requirements are met for the proper installation and operation of the system.
Cisco Aironet 1300 Series Lightweight Outdoor Access Point Mounting Instructions
10
78-17634-01B0