Chapter Three
Operation
Man_805U Rev 1.8
Page
13
as 10D-FB, or a higher gain antenna should be used. Collinear antennas should be mounted
vertically, at least 1 metre away from a wall or mast.
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.
The Yagi gain also acts on the
receiver, so adding Yagi
antennas at both ends of a link
provides a double improvement.
Yagi antennas are directional.
That is, they have positive gain
to the front of the antenna, but
negative gain in other
directions. Hence Yagi
antennas should be installed
with the central beam horizontal
and must be pointed exactly in
805U
Antenna installed
with drain holes
down
Coax feed looped
at connection
90
o
1m minimum
COLINEAR
ANTENNA
MAST
EARTH STAKE
IF GROUND CONDITIONS ARE
POOR, INSTALL MORE THAN
ONE STAKE
INSTALL AERIAL ABOVE
LOCAL OBSTRUCTIONS
ANT
805U
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
