Hearing stuff ……….

Its the electronics of the trk...I got same issues...If i drive down the road i can put trk in netural and come off the fuel and radio is almost dead quiet..Back in gear and on the fuel static....
I dont remember clearly the explanation but some how its somethin to do with with rf..Shoot i better not try to go into more detail cause i dont know enough..

 

It is hard to guess at why, mainly because you need to tell us what model truck it is and what year. More likely than not you hear it because the wiper motor is producing the static and it is travelling through the power line to the radio. Another reason is you have leaky coax.

You could try a couple things, one is to find another power source, the other is to hook it up to the batteries - both may work but may not because of the truck itself.

OH you can try to put a ground on the wiper motor itself and/or the antenna.