Motorola APX Instruction Manual page 42

5-8
As stated above, the antennas have a better ground plane the farther away from the edge of the roof.
The antennas must also be a reasonable distance from each other to minimize the interference
between them.
!
C a u t i o n
July 30, 2014
Avoid using lip-mounted antennas. A lip-mount does not
supply an adequate ground plane for the antennas.
APX Dual-Radio Installation: Antenna Mounting
MN000770A01-AA