I bought one of these a couple of weeks ago. Like you said, it's wireless. The display is nice, easy to see and you can select either regular or reversed (mirror) view. IMO, the display alone is almost worth the $79 price.
I mounted the camera inside the coach, at the top of the rear window looking down on our tow car. There's a DC power line and an antenna line about 2 ft. long. Of this, the last 1" or so is the actual antenna. I ran this so the antenna portion is horizontal and broadside to the length of the motorhome with as clear a shot as I could find to the receiver on the dashboard.
The display can either be plugged into a cigarette lighter or hard wired in place. Cords are supplied for either option.
The signal reaches the length of our 35' Damon. However, I don't think it will go much further than that. If the signal is too weak the picture becomes snowy or disappears, like a regular TV. I don't know yet how well it will work on the road - whether or not we will experience interference from other users of the spectrum. The 2.4 GHz ISM band is also used by Bluetooth and Wi-Fi devices and in some areas is getting pretty congested. On a side note, it would be wise to be sure the camera is turned off while you're parked in a campground - both from a power consumption standpoint as well as the possibility of degrading any Wi-Fi signals being used either by yourself or your neighbors. There may not be directly observable interference, but every device that is sharing a band raises the noise level a bit for everyone.
The display also accepts a wired video input. I have a wired camera and may replace the wireless one sometime in the future.
