Noise

Got an issue just driving me freakin nuts. When the truck is running, I can turn the squelch all the way down…gain all the way up, and I get a “swish swish swish” noise. Every 1/2 second. Only when truck is running. Moves the needle on meter.
General Lee 5 yrs old from Bobs CB. Does it on my back up Cobra night watch also from Bob in 2001. 5’ Wilson tuned tip. 1.3 on ch 1, 1.6 on 40. Wilson gumdrop mount on a heavy duty mount on the metal mirror arm of my 03 FLD. 9’ of fresh Wilson coax.
Mirror arms ground strapped to door, door to cab, cab to frame in 2 places. Stainless ground straps mounted with the paint etched off to give good contact.
I even pulled out the 25’ jumper cables and ground to frame and also to battery and then started touching everything to make ground from frame, to door, to cab. No bueno.
Have 10 gauge power cables coming off deep cells under bunk to cb. Grounded to frame. As it only does it when the truck is running, its getting electrical interference from somewhere but dam med if I can find it.

Any ideas?

 

Will try coax tomorrow

 

Nothing yet. Got home…went camping. Going back to work Friday the 13th. Let ya know then.

 

Am back to work. Will fiddle with it today and report what I find out

 

FINALLY.
I replaced coax…nope
I bonded door, mirror, cab, EVERYTHING….zip
Swapped out cb’s…nada
New power wires…zero

traced the noise to my power relay for my auxiliary batteries. I have a relay that feeds power to my auxiliary batteries when the motor is running so I can use em when I’m stopped for my laptop, bunk heater, ect. That’s where the noise is coming from. Had it grounded to the sleeper frame. Took the ground all the way to the main batteries….problem solved.
What the hell…I needed new coax anyway. Lol