Foxhole radios were built by American troops in the 1940s in order to pick up radio transmissions while stationed in the foxholes of Europe. The radios were used mainly for entertainment purposes, but they also brought up-to-date news to the troops if an English station could be found. They were popular because they didn't require batteries or outside electrical sources and were instead self-powered. They could also be made with items most soldiers had access to.
Wind magnet wire around a toilet paper tube 120 times. Attach the coil to the wood block using metal tacks. Place extra tacks several inches from each end of the coil.
Attach copper wire to one end of the coil; this will serve as the ground wire. Run the wire around the extra tack. Place a clothes hanger in the ground and attach the ground wire to it, or hook the wire to another metal object such as a radiator. Run a wire from the other end of the coil for an antenna. Wrap it around the extra tack on that end. The longer this wire the better. Hang this wire out the window if the radio is being used indoors.
Tack a blued or rusted razor blade flat against the block. Run a wire from the tack wrapped with antenna wire to the blade. Open a safety pin and flatten the hooking end. Put a tack through the hole and attach next to the razor blade so that the tip touches the blade. This will adjust to find a station.
Run a wire from the pin to the earphone or speaker jack, and another from the ear phone or speaker jack to the tack that is wrapped with the ground wire.
If a blued or rusted razor blade is not available, you can blue your own at home by heating the steel blade to between 275 and 325 degrees Fahrenheit with a torch.