minimize damage from lightning strikes. A lightning arrestor, properly grounded and installed at each building in the topology, will protect networking equipment in the building, as well as the people working there, from
ALIGNMENT
Position bridges so that they are aimed at each other wherever possible. While maintaining a direct line of sight between antennas helps to ensure a strong signal, it is not strictly necessary, nor is it always possible. Conditions such as long distances, mountainous regions, and architectural barriers could make a direct line of sight nearly impossible to achieve.
In a campus setting, where buildings are short distances apart, and especially in a
POLARIZATION
Polarization is a physical phenomenon of radio signal propagation. In general, any two antennas that are to communicate with each other must be set for the same horizontal or vertical polarization. If polarization on both antennas does not
■Vertical polarization is preferred for
■For
■Unidirectional antennas that link with omnidirectional antennas should always be oriented for vertical polarization.
RESTRICTIONS ON ANTENNA USE
The following restrictions apply to the use of the bridge’s 18 dBi antenna:
■FCC regulations require that in the United States, use of channels 12 and 13 in conjunction with an 18 dBi antenna is allowed only at very reduced power, which the 3Com unit sets automatically.
■The highest allowable power level is set automatically when the country selection is made from the pulldown menu in the configuration tool.
■To work properly with 18 dBi antennas, bridges must be separated by at least 61 Meters (200 Feet).
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