WI-I/O 9-K
v1.9
Page 26
3.2.1
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 ‘ 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.
3.2.2
Yagi antenna.
Yagi antennas are directional. That is,
they have positive gain to the front of the
antenna, but negative gain in other
directions. This may be used to
compensate for coaxial cable loss for
installations with marginal radio path.
Yagi antennas should be installed with the
central beam horizontal and must be
pointed exactly in the direction of
transmission to benefit from the gain of
the antenna. Also note that Yagi antennas
normally have a drain hole on the folded
element - the drain hole should be
located on the bottom of the installed
antenna.
The Yagi antennas may be installed with
the elements in a vertical plane (vertically
polarised) or in a horizontal plane
(horizontally polarised). For a two station
installation, with both modules using
Yagi antennas, horizontal polarisation is recommended. If there are more than two stations
transmitting to a common station, then the Yagi antennas should have vertical polarisation, and
1m minimum
COLINEAR
ANTENNA
MAST
EARTH STAKE
IF GROUND CONDITIONS ARE
POOR, INSTALL MORE THAN
ONE STAKE
INSTALL ANTENNA ABOVE
LOCAL OBSTRUCTIONS
ANT
WI-I/O
9-K
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
WI-I/O
9K
Antenna installed
with drain holes
down
Coax feed looped
at connection
90
o
Coaxial surge
diverter
