Manual

WI-I/O 9-x_WI-I/O-EX-1-S-x 2.16 Page 13
Cable type Loss (dB per 30 ft / 10 m)
RG58 -5
RG213 -2.5
Cellfoil -3
The net gain of the antenna/cable configuration is determined by adding the antenna gain and the cable
loss. For example, a 6 element Yagi with 70 feet (20 metres) of Cellfoil has a net gain of 4dB (10dB –
6dB).
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 problems 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 vulcanising tape such as “3M 23 tape”, and finally with another layer of PVC
UV Stabilised insulating tape. The first layer of tape allows the joint to be easily inspected when trouble
shooting as the vulcanising 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.
2.2.1 Dipole and
Collinear antennas.
A collinear antenna
transmits the same amount
of radio power in all
directions - as such that
are easy to install and use.
The dipole antenna with
integral 15 feet cable does
not require any additional
coaxial cable, however a
cable must be used with the
collinear antennas.
Collinear and dipole
antennas should be
mounted vertically,
preferably 1 metre away
from a wall or mast to obtain maximum range.
2.2.2 Yagi antennas.
A Yagi antenna provides high gain in the forward direction, but lower gain in other directions. This
may be used to compensate for coaxial cable loss for installations with marginal radio path.
1m minimum
COLINEAR
ANTENNA
MAST
EARTH STAKE
IF GROUND CONDITIONS ARE
POOR, INSTALL MORE THAN
ONE STAKE
INSTALL AERIAL ABOVE
LOCAL OBSTRUCTIONS
ANT
WI-I/O 9
SURGE
ARRESTOR
(OPTIONAL)
COAXIAL CABLE
WEATHERPROOF
CONNECTORS WITH
“3M 23” TAPE
STRESS RELIEF LOOP
PROVIDE GOOD
GROUND
CONNECTION TO
MAST, MODULE
AND SURGE
ARRESTOR
GND