NATURAL HISTORY MUSEUM, LONDON / SCIENCE PHOTO LIBRARY NATURAL HISTORY MUSEUM, LONDON / SCIENCE PHOTO LIBRARY
Revophone crystal radio. Instructions and controls for a crystal radio set dating from 1923. This is the British Revophone model. The instructions include a diagram showing how to erect an aerial wire, and a diagram of the controls. These include a fine tuning switch (left) and a coarse tuning switch (right). The actual crystal detector consisted of a copper coil (the cat's whisker) next to a galena crystal. The coil was adjusted using the smaller knob at right. Crystal radio sets were an early form of radio, used in the first few decades of the 20th century until they were replaced by vacuum tube technology.
Model release not required. Property release not available.