I swear that TT manufacturers install the fresh water tank assuming that they'll never be used. We have a 2003 Coachman and I think that the water tank is supported by a 1/8" thick piece of Masonite. I have never used it and would never use it withou...
How old is your TT? We have a 2003 and it has a cable connection outside to attach to the CG cable. The cable connection and the roof antenna seem to be wired in parallel.