Radar the acronym stands for Radio Detection And Ranging , detects distant objects such as airplanes or ships by sending pulses of radio waves and measuring the reflected signal. The basic principles needed for radar systems were established in the s, when German physicist Heinrich Hertz first produced and transmitted radio waves across his laboratory. He discovered that the invisible waves were a form of electromagnetic radiation, and noticed that some materials transmit radio waves while others reflect them.
Radio waves were quickly put to use. In , Italian physicist Guglielmo Marconi sent the first wireless radio communication across the Atlantic Ocean. In German engineer Christian Huelsmeyer invented a crude system that used radio waves to prevent boats and trains from colliding on foggy days.
US navy researchers also discovered that they could detect ships using radio wave echoes, but their invention was largely ignored. But the value of the technology was most obvious in Great Britain, which was especially vulnerable to German air attack. He graduated from University College, Dundee, in and then worked as an assistant for Professor William Peddie, who encouraged his fascination with radio waves.
In , Watson-Watt hoped to go to work for the War Office, but no suitable position in communications was available there, so he joined the Meteorological Office. He was put to work developing systems for detecting thunderstorms. Lightning ionizes the air and generates a radio signal, which Watson-Watt could detect to map the positions of thunderstorms.
The Air Ministry had already offered pounds to anyone who could demonstrate a ray that could kill a sheep yards away. In February Watson-Watt demonstrated to an Air Ministry committee the first practical radio system for detecting aircraft.
He then developed a device that could measure the transit time of reflected waves: the telemobiloscope. On 30 April , he took out a patent for the process and is therefore the inventor of radar. Another important discovery during the development of radar was the verification of the Doppler effect.
With this effect, radar can be used to determine whether or not a detected object is moving. It is named after the Austrian physicist and mathematician Christian Doppler, who predicted the effect in They based their new research on radio and electronics experiments that started in the early 20th century. Inventors like Telsa, Butement and Pollard had been working with radio and pulsed modulation to detect ships and other metal objects, which did not attract much interest prior to World War II.
The British and Americans were not the only ones experimenting with radio waves. With tensions in Europe increasing in the mids, interest was renewed in these experiments. Scottish scientist, Robert Watson-Watt, was one of the participants and was a pioneering force behind the British use of radar.
Watson-Watt and several other scientists helped created the Chain Home system, an early warning system on the English Channel, which would become instrumental in British defense during the Second World War. Post war, work on radar technology slowed somewhat.
There was a revival in the ss, and now radar systems and technology are used in thousands of ways in modern society.
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