when i was in to my street bassing, i came across alot of issues regarding the set up of the RCA leads, if they are too close to a live or earth cable, when running from the front to the rear, i would get interference.
i was always under the influence that electrical circuits provide a (which i can only describe as ) magnetic force.
seperate / distance and the issues went away.
thinking that the output being generated by the ballasts, against the frame of the vehicle, interfearing with the eletronic / power signal of the aerial, to me makes sense.