User's Manual

22
External Radio Unit Installation Guide
Estimating cable requirements
Once you have selected the installation site, you must decide where you want the
cable to enter the building and estimate how much cable you are going to need.
Cable restrictions
You must use RG-6/U coaxial cable to connect the ERU to the SOMAport. One
coaxial cable runs from the ERU to a ground block. A second coaxial cable,
which connects to the first at the ground block, runs to the SOMAport. The total
length of the two coaxial cables must not exceed 45 m (150 feet). You cannot use
a line amplifier.
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To estimate how much cable is required
1
Identify where the SOMAport is located.
2
Locate the central building ground.
The following ground points are acceptable:
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Grounded metallic service raceway
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Grounded electrical service panel enclosure
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A 2.5-m (8-foot) grounding rod driven into the ground and bonded to the
central building ground by #6 or heavier bonding wire
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Grounded water pipe, if it complies with section 250.53[D] of the NEC, which
requires new installations to verify the conductivity of the electrode and add a
supplemental ground electrode
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Other acceptable grounding electrodes that comply with sections 250 and 810
of the NEC, Section 10 of the CEC, or the electrical code of the country in
which you are installing the ERU
3
Choose a location to mount the ground block.
The ground block should be as close as possible to the point where the coaxial
cable will enter the building.