Radar did not appear suddenly during the Second World War. Its foundations lay in electromagnetic and radio work from the 1860s and 1870s, followed by more recognizable detection concepts in the 1890s. Experimenters encountered relevant effects while developing radio, while radio direction finding matured as a related but distinct technology. Wartime radar sets were the result of decades of linked experiments rather than isolated inventions.
Notable Point · 35:32-37:09
Radar grew from decades of radio experimentation
A short history-of-technology aside traces radar's foundations well before its famous Second World War applications.