Is is possible to non-destructively sense a signal through a wire such as a coax cable or telephone cable? In this case both the send and return wires are bound together and cannot be separated. The answer would seem to be no since the radiation would be quite small and only due to deviations from the idea case.
What I would like to do, just for fun, is non-destructively("remote") sense an audio signal from a coax or telephone wire.