Cobra 148GTL-ST Issues

IS the CB radio making the whining noise or is your car stereo? I ask because by sharing a common power point between the two radios you can create an inductive coupling and will hear a ground hum thru the car stereo speakers. This can be fixed by running power and ground for the CB directly to the battery (be sure to fuse the hot side) or installing a choke coil in the power lines to the radio.

 

When you rewire it make sure all the connections are tight and clean to reduce the resistance as much as possible, as this can cause noise. Also, check you antenna and mic cables for damage, especially on the ground shield. By damage I mean loose or bad quality connections, discoloration or corrosion on the terminals or soldered joints, anything that can increase resistance to current flow can cause noise.

Lastly, do you have an external speaker connected to the CB? If you do and have a bad ground it can make noise on transmit just like a bad talkback monitor circuit. Good luck.

 

8 gauge would be what I would use. I've even went to 6 gauge once too.

 

Ground inside yje mic connector sounds like its shorting the audio wire.