User's Manual

Altai A8n (ac) Series Super WiFi Base Station

Installation Guide

A typical lightning protection system for A8n (ac) series base station is

shown in Figure 24. It consists of 5 parts:

 Lightning Rod

 Ground Conductor

 Grounding Plate

 Earth Termination

 External Lightning Protectors

Lightning Rod

A lightning rod (air terminal) neutralizes the downward lightning strike

by launching an upward ionized path. The lightning current will follow

this path and is thus diverted away from personnel and electronic

equipment. The lightning rod must be constructed of steel with a

pointed tip and welded to a ground conductor.

The lightning rod must be installed at top of the mounting post or tower

higher than the highest portion of equipment it protects. For A8n (ac)

base station installation, the 4-sector antennas are usually the highest

points and usually protrude away from the post. Suppose the horizontal

distance from the post to the top outer most point of antenna is d, the

minimum height of the tip of lightning rod above the highest point of

antenna (H) is recommended to be at least 2d such that a cone of

protection of 60 degree is ensured around the pole or tower. In areas

of high lightning activities, the height H should be increased to 5d.

Ground Conductor

A ground conductor is a metal strip or rod usually made of copper or

similar conductive metal linking the lightning rod to the earth. The

prime purpose of the ground conductor is to conduct lightning current

from the lightning rod to the earth termination. It also provides

connection to a metal grounding plate so that the equipment under

protection can be connected to at the shortest distance possible.

A ground conductor must be installed straight and vertical without

bends such that it connects to the earth termination at the shortest

and direct path. As a rule of thumb, a minimum 50 mm

in cross

sectional area or AWG 0 copper conductor is recommended for the

ground conductor. Aluminum or iron conductor can also be used but

with poorer conductivity. Minimum cross sectional area of copper,

aluminum and iron ground conductor are 16, 25 and 30 mm

respectively.