Site survey
FiberPatrol Site Planning & Installation Guide
Page 31
Deploying the sensor cable
There are two standard methods of deploying FiberPatrol sensor cable.
1. The cable drum can be mounted on a cable stand and then pulled around the perimeter.
2. The cable drum can be mounted on a reel trailer or a truck, which lays out the cable on the
ground as it moves around the perimeter.
Refer to the site plan and pull back and lay out sufficient sensor cable to cover the site specific
features (gates, bypasses, service loops, sensitivity loops, isolation loops, fiber access points).
The following factors must be considered when deploying FiberPatrol sensor cable along the
inside of the perimeter fence:
•
The length of the section of sensor cable being deployed.
•
Clearance and access along side the fence.
•
Service loops, sensitivity loops, isolation loops, splice loops, gate coverage.
•
Site-specific features such as cable bypasses for gates and other structures on the perimeter.
•
The location of splices.
Sensor cable splices
At all designated splice points, each section of sensor cable requires a 10 m (33 ft.) service loop.
The service loops at splice points allows the sensor cable and splice enclosure to be attached/
removed from the fence fabric for splicing. Inside the splice tray, sensor fibers S1 and S2 and any
dark fibers that are designated for use must be fusion spliced. When dressing the bare fibers,
ensure that the turn radius is kept above a minimum bend radius of 32 mm (1.25 in.). Any tighter
bend radius may lead to optical fiber damage and an increased loss at the splice location. Once
the field splices are complete, and the sensor cable is installed, the loss must be measured from
both ends of the cable to ensure the quality of each splice. The average loss for the full length of
sensor cable must be 0.3 dB per km or less, and the maximum event loss is 0.1 dB. The fusion
splices at the start module and the end module are made once the field splices have passed the
OTDR measurement test.
Note
Install FiberPatrol sensor cable on the side of the fence that is opposite
the threat (the secure side of the fence).
Figure 39 Cable splice service loops and buried isolation loop at fully closed perimeter start/end point
service loops (10 m cable length, 60 cm diameter)
splice
enclosure
conduit
buried 13 m
isolation loop
