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7.1.1
Direct Center or Center-Rear of Rooftop
The center of the vehicle’s roof is the best location for the rooftop antenna (
❶
in Figure 7-1). For optimal
performance, the mounting area under the antenna must be a flat with a minimum radius of six (6) inches
of metallized ground plane. It must be located directly in the center of the roof for RF safety. Other
obstructions such as a light bar or another antenna may prevent the antenna from being mounted in the
direct center of the roof. In this case, the antenna should be mounted a minimum of one foot away from
and behind the obstruction but in the middle of the roof with respect to the left and right sides of the
vehicle (
❷
in Figure 7-1).
7.1.2
Center of Trunk Lid
Certain vehicles do not allow for the antenna to be placed in the center or center-rear of the roof. In this
case, the next best location for the antenna is in the direct center of the trunk lid (
❸
in Figure 7-1). In this
case, an elevated-feed-point antenna is recommended. Although this type of antenna does not require a
metallized ground plane, it must be located directly in the center of the trunk lid for RF safety.
WARNING
The antenna cable of M/A-COM approved antennas should
never
be cut to a shorter
length. Instead, excess cable must be tied and stowed. This not only prevents the
antenna from radiating above its intended or configured power, but it also allows for
future installation considerations. Installations requiring longer cables are to be treated
as custom and separately specified.
7.2 ANTENNA INSTALLATION PROCEDURE
NOTE
An antenna
must
be installed before completing the radio installation.
7.2.1
Install and Connect Mobile Radio Antenna
Table 4-2 lists several types of mobile radio antennas available for use with the radio. As presented in the
previous section, various mounting locations exist. Optimal performance is achieved via a rooftop
antenna mounted in the direct center of the motor vehicle’s roof:
1.
Once the mounting location is selected, refer to the antenna manufacturer’s mounting and testing
instructions included with the antenna kit for installation guidance. If necessary, contact M/A-COM’s
Technical Assistance Center (see page 13 for contact information).
2.
Route the cable from the antenna to the rear of the radio. The cable should be kept out of casual
contact from persons within the vehicle. Tie and stow as necessary.
3.
Connect the antenna cable’s TNC plug-type (male) connector to the radio’s TNC receptacle-type
(female) “pigtail” type RF connector at the rear of the radio. Mate the two connectors and turn the
plug clockwise until finger-tight.
This will be a temporary connection until the radio and antenna can be tested after the installation is
complete. The antenna needs to be connected in case of accidental RF transmission.