Specifications

FCS1362 Page 30 of 74 © Nov 2010
4.
Installation procedures
Ensure all component parts of the equipment to be fitted are present and in serviceable condition to
enable the completion of the job.
See section 4.11 regarding de-installation should the installation job involve moving equipment from one
vehicle to another.
4.1. Installation of antenna and coaxial cable
The antenna system and its installation dictate the quality of performance of the mobile communications
equipment.
The manufacturer's instructions, where supplied, should be read and the vehicle manufacturer guidelines
for antenna location and type should be followed as per sections 3.8 and 5.2.
Not all installations will require the fitment of an antenna as it is integral in some mobile equipment (e.g.
GSM phone in-car kit without external antenna connector, Bluetooth hands free, etc.)
4.1.1. Antenna types
It is important to select the correct antenna to best match both the customer requirements and mobile
network coverage.
Also see section 2.8 regarding safety considerations for antenna installation.
Generally mobile radio installations and those of higher power, for example PBR, TETRA, require a more
effective antenna installation.
Table 1 - General table of antenna type to typical network performance
Type
Cellular GSM/3G/ Tracking
Mobile Radio/PBR/TETRA
1 Body Mount
Optimum performance when roof
mounted – recommended
Optimum RF performance when roof mounted
– recommended
2
External
glass mount
Almost as good as body mount for
cellular GSM/3G
Usually gives acceptable RF performance:
VHF - not as good as body mount
UHF – close to body mount subject to
mounting location
3
Internal T bar
glass mount
Fair when positioned high on
screen. Should be vertical
VHF not available due to size
UHF – reduced performance - should be
vertical.
4
Internal tax
disc glass
mount
Default position at base of screen
may give reduced performance
especially in poor signal areas
VHF not available due to size
UHF – very poor performance due to size and
position.
5
Bumper
mount
Location causes antenna to be
very directional - not suitable for
use in poor signal areas
Location causes antenna to be very
directional
VHF very poor performance due to size and
proximity of vehicle body
UHF poor performance due to proximity of
vehicle body. Very directional but can be
acceptable with dual-antenna systems
Antennas for terrestrial radio systems (e.g. cellular GSM/3G and mobile radio) are usually vertically
polarised and need to radiate towards the horizon as the network base station will usually be located on a
mast/tower or building structure relatively close to ground level.
Antennas for GPS and satellite communication systems need to have an unimpeded view to the sky.
The network signal levels from satellite systems are significantly lower than for terrestrial systems so
antenna positioning and orientation is usually more critical to ensure effective operation.