Discrete Wireless MARCUS 3G GPRS Instrukcja instalacji - Strona 7
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3. Antennas
.
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1 General Antenna Guidelines
Introduction
Among all installation variables, antenna location has the greatest impact on the performance of
the radio module. Great care should be taken before selecting and installing the antennas. The
®
standard antenna types that are used with the MARCUS
3G Radio Module are Glass Mount
Antennas. The below is an overview of these types and the recommended installation guidelines
for each.
Glass Mount Antennas
The most popular type of antenna is the glass mount, 1dB gain antenna. This antenna does not
require a mounting hole and is mounted on the inside glass of the vehicle's window. Observe the
manufacturer's precautions when mounting the antenna near defroster wires. The defroster
wires, as well as metal flake-treated windshields, can impede or stop the transfer of radio energy
through the glass.
3.2
GPS Antenna
As a general rule, the placement of the GPS antenna must have a clear view of a large portion of
the sky in order to be able to receive GPS satellite data.
It is recommended that the GPS
antenna have a clear view of at least 40 % of the sky and be as horizontal as possible. Reception
is shielded by metal, but the antenna can be under such non-metallic materials such as plastic,
fiberboard, fiberglass, etc. The GPS antenna should be a + 3.3V active gain (+26 dBm gain)
antenna. You should always refer to the antenna manufacturer's guidelines that will be included
with the antenna packaging.
3.3 RF Antenna
As a general rule, the placement of the Radio Frequency (RF) antenna is as high and vertical as
possible. Windscreens, ladder racks, or other radio transmission antennas should not obstruct
the antennas view of the sky.
If there are other radio antennas on the vehicle, position the
MARCUS RF transmission antenna at least 18 inches away.
You should always refer to the
antenna manufacturer's guidelines that will be included with the antenna packaging.
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