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Altai A8n (ac) Series Super WiFi Base Station
Installation Guide
Altai Technologies Ltd. All rights reserved
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
2
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
2
respectively.
