A few years ago I installed a back-up camera with a monitor that would handle a second camera. The primary camera was installed near the top of my rear window so it would view the hitch and it works pretty well. I hard-wired a second camera on the rear of my 5er using good quality video cable. It worked but not really well. It seems the long run of cable allowed for too much deterioration of the video quality. Total cable length, because I did not cut it to the exact length needed, was probably around 50 ft. I used the highest quality cable I could find locally, but there may have been something better that I wasn't aware of. That may have made a difference. I took it off when we traded trailers and did not re-install it. The back-up camera on the truck is pretty handy. Hope this helps.