User manual

105G Wireless Gateway User Manual
Elpro_man_105g_1.18.doc Page 30
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 105G 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:
12 – 24 volts AC RMS or 9 – 30 volts DC at the “supply” terminals, or
10.8 –15 volts DC at the “battery” terminals.
The power supply should be rated at 1.5 Amps and be CSA Certified Class 2. For use in Class 1
Div 2 explosive areas (USA/Canada), the power supply must be approved for Class 1 Div 2 use.
Note: Connect module to the same ground/earth point as the antenna mounting to avoid
differences in earth potential during voltage surges. The modules need an earth connection for
the internal surge protection to be effective.
Module
Antenna installed
with drain holes
dow n
Coax feed
loo
p
ed
90
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