805U-E Wireless Ethernet
User Manual
Man_805U-E Rev 1.5
Page 12
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.
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 the direction of transmission to
benefit from the gain of the antenna. The Yagi antennas may be installed with the elements
in a vertical plane (vertically polarized) or in a horizontal plane (horizontally polarized). For
a two station installation, with both modules using Yagi antennas, horizontal polarization is
recommended. If there are more than two stations transmitting to a common station, then the
Yagi antennas should have vertical polarization, and the common (or “central” station
should have a collinear (non-directional) antenna.
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
