Do you have horizontal "static" lines running across the screen when the motor is running? I installed the Gentex mirror with the integral backup display. Initially I ran the cable along the passenger side of the car and got "static" with the engine running. Engine off things were clear as a bell. I then went to an Audiovox wireless receiver/transmitter pair like the boyo and got even more interference with the engine running. I then went back to the 20ft extension cable and moved it all around the car and no matter what I did, I still got the horizontal interference. This is even with ferrite chokes installed close to the rearview mirror display and at the camera end. Just for the record, I'm using the Boyo 300C.