6
68P81124E57-A
June, 2000
Mobile Gain Antennas
Motorola Recommendations for Mobile Antenna Location
To assure optimal radio performance and that human
exposure to radio frequency electromagnetic energy is
within the guidelines referenced in this document,
transmit only when people outside the vehicle are at
least the minimum distance away from a properly
installed, externally-mounted antenna.
Table 2 lists the minimum distance for several different
ranges of rated radio power.
Selecting an Antenna Site
1.
Install the vehicle antenna external to the
vehicle and in accordance with the require-
ments contained in this manual.
2.
The best mounting location for the antenna is
in the center of a large, flat conductive surface.
In almost all vehicles, mounting the antenna
in the center of the roof will satisfy these
requirements. A good alternative location is in
the center of the trunk lid. If you use the trunk
lid, ensure that the trunk lid is grounded by
connecting grounding straps between the
trunk lid and the vehicle chassis.
3.
Ensure the antenna cable can be easily routed
to the radio. Ensure that the antenna cable is
routed separately and not in parallel to any
other vehicle wiring or mobile radio cable
wiring.
4.
Check the antenna location for any electrical
interference.
NOTE
Any two metal pieces rubbing against
each other (such as seat springs, shift
levers, trunk and hood lids, exhaust pipes,
etc.) in close proximity to the antenna can
cause severe receiver interference.
5.
If the vehicle is equipped with an electronic
anti-lock braking system (ABS), mount the
antenna at the center of the roof or trunk lid
and do not route the antenna cable near the
ABS Modulator Box. Mount the radio as far
away from the Modulator Box as physically
possible. This minimizes radio interference to
the modulator box from the radio.
6.
Make sure the mobile radio antenna is
installed at least one foot (30.48cm) away from
any other antenna on the vehicle.
Table 1.
Standard metal passenger vehicles
Center roof or center trunk lid
Vans, pickups, and other light trucks (metal roofs)
Center roof
Heavy duty equipment with metal roofs (heavy duty trucks,
semi-tractors, heavy refuse trucks, cement mixer trucks)
Center cab roof
Specialty vehicles (such as T-roofs, sun roofs, or convertibles)
Center trunk lid – recommended only for transmitter output of
less than 7 W.
Other vehicles
Contact your Motorola Field Technical Representative. Do not
install closer than the distances shown in Table 2, for the rele-
vant transmitter output power, from occupants or without
proper antenna ground plane.
Table 2.
Rated Power and Distance
Rated Power of Vehicle-installed
Mobile Two-Way Radios
Minimum Distance from
Transmitting Antenna
7 to 15 W
1 Foot (30.5cm)
16 to 50 W
2 Feet (61cm)
More than 50 W
3 Feet (91.5cm)
