ABB AWIN GW100, User Manual

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ANTENNAS A ND CAB LING WIRELES SHART S YSTEM PLA NNING
22 3BNP1029 12 C
4.4.1 Coaxial cable considerations
The importance of using a low-loss antenna coaxial cable is often neglected during radio in-
stallation. Using the wrong cable can cause huge reductions in efficiency, and these losses
cannot be recovered with any amount of antenna gain or transmitter power.
For every 3 dB of coaxial cable loss, half the transmitter power will be lost before reaching the
antenna. The choice of coaxial cable to use depends on: 1) the length of cable required to
reach the antenna, 2) the amount of signal loss that can be tolerated, and 3) cost considera-
tions. For long-range transmission paths, where signal is likely to be weaker, a low-loss cable
type is recommended.
For a short-range system, or one that requires only a short antenna coaxial cable, a less effi-
cient cable may be acceptable and will cost far less than large diameter cable. Refer to
Table 5
for values that allow judging the effectiveness of various cables at 2.4 GHz.
Table 5: Cable types and signal loss (dB)
Cable type 2.4 GHz loss (dB/100 ft.)
RG-58 25.01
RG-213 12.51
PFP-240 12.76
PFP-400 6.68
PFP-500 5.41
PFP-600 4.37
4.4.2 Antenna mounting considerations
The antenna manufacturer’s installation instructions must be strictly followed for proper op-
eration of a directional or omnidirectional antenna. Using proper mounting hardware and
bracket ensures a secure mounting arrangement with no pattern distortion or detuning of
the antenna. The following recommendations apply to all antenna installations:
– Mount the antenna in the clear, as far away as possible from obstructions such as build-
ings, metal objects, dense foliage, etc. Choose a location that provides a clear path in the
direction of the opposite antenna. If the antenna is co-located with another antenna
(other than second antenna connector on the same radio), try to get at least one foot ver-
tical (31cm) or one foot (31cm) horizontal separation between the two.
– Polarization of the antenna is important. Most systems use a vertically polarized omnidi-
rectional antenna at the master station. Therefore, the remote antennas must also be ver-
tically polarized (elements perpendicular to the horizon). Cross-polarization between sta-
tions can cause a signal loss of 20 dB or more.
– When installed indoors, the radio must be grounded through the DIN rail for DIN rail-
mount versions or using the ground lug on the wall-mount versions. A surge arrestor must
be used on the antenna for outdoor installations.