I first became aware of dowsing a few years ago watching America Unearthed. It's where you take two bare copper wires bent in the shape of an L and hold them parallel. If there is metal or water, they will cross and make an X. I just took some old Romex and took the insulation off and they work great!

I do have a dowser---its in the lamphouse of my portable 35MM projector.You use it to cut light from the projection lamp from getting on the screen unless film is in the projector.Used in projector changeovers from one reel of a movie to another.Requires two projectors.In the digital age not a whole lot of use for dowsers in projectors anymore.And weren't needed in theaters that had one projector fed from a film platter.The reels of the show spliced together and wound onto a platter.The platter serves as the supply-takeup device.No longer used.Never tried the Dowsing you mention.Don't think it would work at the transmitter!!esp with the wire.