Jeep 2014 Grand Cherokee Owner's Manual page 563

INSTALLATION OF RADIO TRANSMITTING
EQUIPMENT
Special design considerations are incorporated into this
vehicle's electronic system to provide immunity to radio
frequency signals. Mobile two-way radios and telephone
equipment must be installed properly by trained personnel.
The following must be observed during installation.
The positive power connection should be made directly to
the battery and fused as close to the battery as possible. The
negative power connection should be made to body sheet
metal adjacent to the negative battery connection. This
connection should not be fused.
Antennas for two-way radios should be mounted on the roof
or the rear area of the vehicle. Care should be used in
mounting antennas with magnet bases. Magnets may affect
the accuracy or operation of the compass on vehicles so
equipped.
The antenna cable should be as short as practical and
routed away from the vehicle wiring when possible. Use only
fully shielded coaxial cable.
Carefully match the antenna and cable to the radio to ensure
a low Standing Wave Ratio (SWR).
Mobile radio equipment with output power greater than
normal may require special precautions.
All installations should be checked for possible interference
between the communications equipment and the vehicle's
electronic systems.