tony.latham wrote:...people are using standard 12v practice and lugging the negative from lights, etc to the closest metal structural element and creating a sort of faraday cage?
A Faraday cage doesn't need to be grounded. It's just a metal box. I've never grounded my house battery to the frame.
Tony
Yes, what Tony says.
It's an interesting idea, but the cell phone signal is a radio wave and can't penetrate an enclosed metal box very well. Doesn't matter what DC voltage the box is at.
To dig more in depth (than it's worth?) windows are several wavelengths long at cell phone frequencies, so you might do better close to a window. Also, the small amount of oxide on screws and other fasterners holding the metal in the teardrop together typically has a low resistance at DC, but may have a very high resistance at cell phone frequencies and so, ironically, a less well built trailer, mechanically, may have better cell phone properties.
That oxide also can act as a diode, and so if you happen to camp next to an antenna farm (very high power levels) you may find yourself living inside a crystal radio and be "entertained" by a strong station. (Antenna engineers call this the "rusty bolt effect".) That's theory; be interesting if anyone ever actually experienced it in their trailer?
Tom