User's Manual

MM102554V1 REV B

grounding through in-building cable routes, etc. This subject is to be discussed with microwave provider

and must conform to local installation regulations.

5.4.3.3 Fiber Optic

It is a requirement that the demarcation point for fiber optic cable is the fiber optic interface on the

multiplexer. If the multiplexer is not equipped with such an interface, a fiber optic line driver will be

provided and will be the point to which the cable is to be connected.

All other considerations are as for Microwave.

5.5 PROTECTIVE GROUNDING

For information on protective grounding outside the equipment room and general information for internal

grounding refer to the Site Grounding and Lightning Protection Standard manual AE/LZT123 4618/1.

However, a general rule for the external grounding system is that the resistance to ground should be five

(5) ohms or less, as measured with a Biddle DET2/2 Megger or equivalent, per IEEE STD 81-1983 or

local equivalent.

All equipment that is within the site must be connected to an internal halo ground of No. 2 AWG copper

wire six (6) inches below the ceiling. This interior halo ground must be connected to the external ground

system at each corner, using separate No. 2 AWG copper wires. The halo may be mounted on the cable

ladder, in the ducting or beneath the false floor.

All metal (electrically conductive) objects within the equipment room must be grounded. These objects

are divided into the following three (3) groups.

• Room Fixtures

• Power Supply

• RF equipment

All metallic fixtures and room parts, such as doorframes, sheet metal, ventilation louvers, air conditioning

units, light fixtures, etc., should be connected to the internal halo ground.

In addition to all other AC power protection, the AC power must be equipped with a Jocelyn AC

protector, or equivalent, placed immediately after the main disconnect switch. This protector must be

connected to the external ground system using a separate No. 2 AWG copper wire.

All equipment cabinets, cable trays, and protectors for cables connecting to this equipment must be

connected to a single grounding plate or bulkhead panel mounted on the wall where the antenna cables

enter the equipment room. This grounding plate must be connected to the external ground system using

two (2), two-inch wide copper strapping, or equivalent. A separate No. 6 AWG copper wire must be used

for each cabinet, each cable tray/ladder, and each group of cable protectors.

A few general rules of thumb are as follows:

• Make ground wires as short as possible and direct as possible - avoid bends if possible - absolutely no

bends with a radius of less than eight (8) inches.

• Surface area of ground wires is more important than cross sectional area.

• All connections must be clean, free of non-conductive coatings, and be coated with an anti-oxidant.