Radar (an American term short for radio detection and ranging) was invented during the 1930s, with most of the major developments taking place in Great Britain and Germany. Originally used in marine navigation (signals), radar, as a means to detect aircraft at altitude and distance, was discovered by Robert Watson Watt and Arnold Wilkins in 1935.
Radar, originally called RDF (range and detection finding), played a vital role in helping the Allies win the Second World War. Canada would provide the second largest contingent of allied radar personnel after Britain. Over 6,000 RCAF service men and hundreds of WAAFs were trained on radar and sent into every theatre of war. This doesn't take into account the hundreds of others participating in Navy and Army operations.
Sworn to an oath of secrecy that was not fully lifted until 1991, it was only recently that these men and women were able to share their experiences. Canadian radar personnel were a crucial part of the war effort. Many of these early radar veterans went on to have leadership roles in the development of radar during the Cold War and in the Canadian electronics and aviation industries.