Crystal Set – who needs the internet?
Originally uploaded by This Window

Early crystal sets (radio) receives programs broadcast from radio stations. Radio stations convert sound into radio waves and send out the waves everywhere, these waves travel across the crystal radio antenna. Radio waves make radio wave electricity which flows between the antenna wire and the earth (ground) wire. The crystal radio uses a ‘cat’s whisker’ which is a wire, to tune the electricity to receive (select) just one station. Then it uses a crystal detector to convert this radio wave electricity back to sound electricity. The detector can be made from a special rock of galena in a holder (other materials also work including coke [coal]). Earphones are used to convert the sound electricity into audible sound. No batteries or electricity is needed to power these machines.

Later ones use a diode (instead of the mineral holder) and a variable potentiometer. I built one of these after reading BUILD YOUR OWN CRYSTAL SET (The Project Club). The Project Club series of books were published by Wolfe Publishing Limited (For the Dairy Industry). The 1st edition was published in 1970. These were a great series of Paper covered booklets. (6?x5 1/4?). Project book 147, BUILD YOUR OWN CRYSTAL SET in The Project Club series was Illustrated by Peter Loates. I remember being a member of the club, collecting several of the pamphlets in the series.