I have the furrion wireless observation camera on the back of my 32' trailer. Works great, can see everything that's behind you and what's coming up along side you. bought it on ebay.
2017 SportTrek 271 VRB 2016 F150 Eco boost with max tow package
The one I have on my TC, I can sit 40 feet from the unit with the cam on and it works fine. I think it has to do with height of the unit and antenna placement (on a wireless unit).
I had a wireless one for our 30 ft. MH and the place I went for installation said that's too much length for wireless. He had tried it on short buses and not a good image.
View my prior posts as I listed what I hard wired for both my 5th and truck campers. Two cameras and only one monitor and power supply. I just unplug when done with one. About $80 for all on Amazon. Cheap wireless just doesnโt have the reception needed.