In the 1930s, Robert Watson-Watt’s invention, radar, was developed into a practical tool for detecting enemy aircraft, codenamed Chain Home. Due to the wavelength used, each transmitter required three massive 90-ton steel towers at each of the tens of coastal sites. Only one tower remains, and that is not in its original site. It was dismantled after the war and moved to Great Baddow, near Chelmsford, for use by The Marconi Company for Cold War research. It is 360 feet tall, very close to the legal drone-flying height limit!
