Cambium Networks PMP/PTP 450i Series, Руководство пользователя

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Chapter 3: System planning Site planning
Page 3-11
Site grounding system
Confirm that the site has a correctly installed grounding system on a common ground ring with access points for
grounding PMP/PTP 450 platform equipment.
If the outdoor equipment is to be installed on the roof of a high building ( Figure 29 ), confirm that the following
additional requirements are met:
•
A grounding conductor is installed around the roof perimeter to form the main roof perimeter lightning
protection ring.
•
Air terminals are installed along the length of the main roof perimeter lightning protection ring, typically every
6.1m (20ft).
•
The main roof perimeter lightning protection ring contains at least two down conductors connected to the
grounding electrode system. The down conductors should be physically separated from one another, as far as
practical.
ODU and external antenna location
Find a location for the ODU (and external antenna for connectorized units) that meets the following requirements:
•
The equipment is high enough to achieve the best radio path.
•
People can be kept a safe distance away from the equipment when it is radiating. The safe separation
distances are defined in
Calculated distances and power compliance margins on page 4-24.
•
The equipment is lower than the top of the supporting structure (tower, mast or building) or its lightning air
terminal.
•
If the ODU is connectorized, select a mounting position that gives it maximum protection from the elements,
but still allows easy access for connecting and weatherproofing the cables. To minimize cable losses, select a
position where the antenna cable lengths can be minimized. If diverse or two external antennas are being
deployed, it is not necessary to mount the ODU at the midpoint of the antennas.
ODU ambient temperature limits
Select a location where the ODU can operate within safe ambient temperature limits. The following points need to
be considered while selecting a location for the ODU:
•
The ODU must be mounted in a Restricted Access Location (as defined in EN 60950-1) if the operating
ambient temperature may exceed 40°C, including solar radiation.
•
If the ambient temperature never exceeds 40°C, the temperature of the external metal case parts of the ODU
will not exceed the touch temperature limit of 70°C.
•
If the ambient temperature never exceeds 60°C, the temperature of the external metal case parts of the ODU
will not exceed the touch temperature limit of 90°C.
A restricted access location is defined (in EN 60950-1) as one where access may only