POWs were not permitted radios. They were considered contraband, strictly verbotten. But, still, they got radios. How? I know US POWs were sent crystal sets built into cribbage boards. These didn't require electricity to function, thus were almost impossible to detect. In discussion the question arose of POWs building their own sets from scrounged tubes, and spare parts. I do not know of any examples of this, other than in fiction. Does anyone know of either ETO or PTO POWs having vacuum tube radio sets?