Cambium Networks PMP 450 AP, Планирование и руководство по установке

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Chapter 3: System planning Site planning
Page
3-16
•
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 48 ), 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.