When I was a teen many years ago we used to go camping a couple of miles behind my house. There were massive very high voltage main transmission lines there. We would pack in some wire and coil it under the lines checking the voltage every loop and when we got a voltage reading about 110 volts we would stop and connect our light and a radio to it. We always made sure to take the coil and wire out with us as a small plane flying over the wires could find that coil of wire. Once we slept in late one morning and the plane went over and circled twice over the coil. We got out of there as soon as possible.