You need to mount your antenna in the middle of the vehicle for the best transmit signal or best ground plane effect. If you mount them on the back bumper you will be very directional and will not get out to the sides or rear very well. CB antenna needs to have something to reflect signal off of.

The best place to mount your antenna would be top dead center of your cab using a good quality base load antenna. Stay away from Radio Shack antennas, they are JUNK, IMHO.

Used to install CB's at a radio shop back in the day! Your radio is only as good as your antenna system!!!! If you use a ball type mount, use rg 8x stranded coax cable.

I currently run an Conex 3500 Hi power radio and have co-phased K-40 antennas on my 07 Peterbilt, which seem to work well for me.

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07 Ranger x-cab STX in bright yellow w/ black leather interior, 4.0 liter automatic