WI-GTWY-9-xxx Wireless Gateway V1.18
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Collinear and dipole antennas should be mounted vertically, preferably no less than 2 ft (0.6
metre) away from a wall or mast to obtain maximum range. The WI-ANT-DPL-0-16 dipole
antenna is the preferred antenna for use in industrial plants and factories.
3.2.2
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.
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.
3.3
Power Supply
The WI-GTWY-9-xxx power supply is a switch-mode design which will accept either AC or DC
supply. The module includes an integral battery charger for a backup battery.
The module accepts supply voltages in the following ranges:
Antenna installed
with drain holes
down
Coax feed looped
at connection
90
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