Quidway WB2011, Руководство пользователя

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Bridge Link Planning
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Radio Path Planning
Although the wireless bridge uses IEEE 802.11a radio technology, which is capable
of reducing the effect of multipath signals due to obstructions, the wireless bridge
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 radio link path 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 not to be affected by obstacles along
its path, no object, including the ground, must intrude within 60% of the first Fresnel
Zone.
The following figure illustrates a good radio 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.
Visual Line of Sight
Radio Line of Sight