A foxhole radio is a makeshift radio that was used by soldiers in World War II. The foxhole radio differed from the crystal radio. A razor blade and pencil were used as a diode in a foxhole radio while a piece of crystal is used as a diode in a crystal radio. The foxhole radio is like a crystal set, in that it does not require an external power source. The radio is powered by the radio signal it receives. This made the foxhole radio ideal for prisoners of war (POW). Prisoners of war made these radios to keep up with current events. Generally, this radio named after foxholes—small man-made earthen shelters along defensive lines during the war. So, any radio built during the war could be considered a foxhole radio, ideally so if it doesn’t use semiconductors or a power supply. In 1942, Lieutenant Colonel R. G. Wells—a prisoner of war in Japan—built a foxhole radio to get news about the international situation. The whole POW camp craved news, according to Wells.