The rise and Fall of the military wavemeter: British military wavemeters of the 20th century

The instruments used in the 20^th Century to measure and set frequencies for the communications needs of land, sea and air forces are reviewed, with the aid of some examples of historic wavemeters used by British military units. The designs reflect the rapid advances in theory and practice of radio and electronics, stimulated particularly by World War 1, World War 2 and the Cold War, and illustrate how the methods and equipment used for frequency measurement changed dramatically, with progress from spark transmitters to microwave precision navigation systems.