This should be must know for every prepper. How to build and use a crystal radio/ Fox hole radio. Sold and homemade by the millions, the inexpensive and reliable crystal radio was a major driving force in the introduction of radio to the public, contributing to the development of radio as an entertainment medium with the beginning of radio broadcasting around 1920. These easy to make DIY radios were built and used in fox holes during WW2 and in concentration camps. Imaging yourself three days into a EMP attack, You never prepared nor thought this would happen… Communications is KEY to survival. If you have this knowledge you will find yourself in a better survival scenario.