Cambium Networks PMP/PTP 450i Series, Руководство пользователя

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Chapter 3: System planning
Page 3-15
Site planning
•
If the tower is greater than 61 m (200 ft
)
in height, the drop cable shield must be grounded at the tower midpoint,
and at additional points as necessary to reduce the distance between ground cables to 61 m (200 ft) or less.
•
In high lightning-prone geographical areas, the drop cable shield must be grounded at spacing between 15 to 22 m
(50 to 75 ft
)
. This is especially important on towers taller than 45 m (150 ft).
For roof installations ( Figure 29 ), use the following additional criteria:
•
The drop cable shield must be bonded to the building grounding system at its top entry point (usually on the roof).
•
The drop cable shield must be bonded to the building grounding system at the entry point to the equipment room.
Lightning Protection Unit(LPU) location
Find a location for the bottom LPU that meets the following requirements:
•
The bottom LPU can be connected to the drop cable from the ODU.
•
The bottom LPU is within 600 mm (24 in) of the point at which the drop cable enters the building, enclosure or
equipment room within a larger building.
•
The bottom LPU can be bonded to the grounding system.