Sounds more like a simple radio reciever, not unlike the simple crystal set many kids make from an old tp roll and wire. You can pick up stations from an incredible distance with such a rig. And it would still be useful in a POW camp just for gathering war news and keeping morale up (provided your on the winning side <img src="images/graemlins/laugh.gif" alt="" />) I know I've got more detailed info on this subject lying around here some place but I haven't had breakfast and the coffee has yet to fully kick in.

Ed