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6193-5201
The gains and losses of typical antennas are
Antenna
Gain (dBi)
Dipole
2
Collinear
5 or 8
Directional
10 – 28
Cable type
Loss (dB per 10 m / 30 ft)
RG58 Cellfoil
-6
RG213
-5
LDF4-50
-1.5
The net gain of the antenna/cable configuration is determined by adding the antenna gain
and the cable loss. For example, a 5dBi antenna with 10 metres of Cellfoil has a net gain
of -1 dB (5dB – 6dB).
Installation tips
Connections between the antenna and coaxial cable should be carefully taped to prevent
ingress of moisture. Moisture ingress in the coaxial cable is a common cause for prob-
lems with radio systems, as it greatly increases the radio losses. We recommend that the
connection be taped, firstly with a layer of PVC Tape, then with a vulcanizing tape such as
“3M 23 tape”, and finally with another layer of PVC UV Stabilized insulating tape. The first
layer of tape allows the joint to be easily inspected when trouble shooting as the vulcan-
izing seal can be easily removed.
Where antennas are mounted on elevated masts, the masts should be effectively earthed
to avoid lightning surges. For high lightning risk areas, surge suppression devices between
the module and the antenna are recommended. If the antenna is not already shielded
from lightning strike by an adjacent earthed structure, a lightning rod may be installed
above the antenna to provide shielding.