Heinrich Hertz in Germany calculated that an electric current swinging very rapidly back and forth in a conducting wire would radiate electromagnetic waves into the surrounding space. Today we would call such a wire an ‘antenna’. He created such a wire in 1886, and detected such oscillations in his lab, using an electric spark, in which the current oscillates rapidly (that is how lightning creates its characteristics crackling noise on the radio!). Today we call such waves ‘radio waves’. At first however they were ‘Hertzian waves’, and even today we honour the memory of their discoverer by measuring frequencies in Hertz (Hz), oscillations per second—and at radio frequencies, in megahertz (MHz). Heinrich Hertz was the first to demonstrate experimentally the production and detection of Maxwell’s waves. This discovery led directly to the invention of the radio.
Sir Robert Alexander Watson Watt (1892-1973) was the Scottish physicist who developed the radar locating of aircraft in England. He was appointed as the director of radio research at the British National Physical Laboratory in 1935, where he completed his research into aircraft locating devices. Radar was patented in Britain in April 1935.
