History of Radar in Timeline

Radar is a radiodetermination system employing radio waves to detect and track objects, determining their range, direction, and radial velocity relative to the radar's location. It's used across various sectors, including aviation, maritime, space exploration, and meteorology, for detecting aircraft, ships, weather formations, and terrain. The system's core function lies in its ability to accurately pinpoint the location and movement of objects through the transmission and reception of radio waves.

April 1904: Hülsmeyer Patents Detection Device

In April 1904, Christian Hülsmeyer obtained a patent for his device detecting distant metallic objects using radio waves. This device could detect a ship in dense fog, but not determine its distance.

September 1904: Hülsmeyer Patents Full Radar System

On September 23, 1904, Christian Hülsmeyer obtained a British patent for a full radar system called a telemobiloscope, operating on a 50 cm wavelength, using a spark-gap to create a pulsed radar signal and featuring a horn antenna with parabolic reflector. Military officials rejected it after practical tests.

1915: Watson-Watt Uses Radio for Thunderstorm Warning

In 1915, Robert Watson-Watt used radio technology to provide advance warning of thunderstorms to airmen.

1922: Taylor and Young Discover Signal Fading

In 1922, U.S. Navy researchers A. Hoyt Taylor and Leo C. Young discovered that ships passing through a radio beam path caused the received signal to fade in and out. Taylor suggested using this phenomenon to detect ships in low visibility.

1928: Alder Patents Naval Radar

In 1928, L.S. Alder took out a secret provisional patent for Naval radar in the UK.

January 1931: First Official Record of Coastal Defence Technology in Great Britain

In January 1931, a writeup on the apparatus developed by W.A.S. Butement and P.E. Pollard was entered in the Inventions Book maintained by the Royal Engineers. It marked the first official record in Great Britain of the technology used in coastal defence, later incorporated into Chain Home as Chain Home (low).

December 1934: Page Demonstrates First Pulsed Radar Apparatus

In December 1934, Robert M. Page at the Naval Research Laboratory demonstrated the first elementary pulsed radar apparatus.

1934: CSF Begins Developing Obstacle-Locating Radio Apparatus

In 1934, the research branch of the Compagnie générale de la télégraphie sans fil (CSF), headed by Maurice Ponte, began developing an obstacle-locating radio apparatus after systematic studies on the split-anode magnetron.

February 1935: Daventry Experiment

On February 26, 1935, the Daventry Experiment was conducted, using a BBC shortwave transmitter as the source and their GPO receiver setup. A bomber was detected, which impressed Hugh Dowding. Funds were then provided for operational development. Watson-Watt's team patented the device in patent GB593017.

May 1935: Germany Tests Surface-to-Surface Radar

In May 1935, Rudolf Kühnhold and GEMA in Germany successfully tested a primitive surface-to-surface radar for aiming coastal battery searchlights at night.

June 1935: UK Team Demonstrates Pulsed System

In June 1935, an Air Ministry team led by Robert Watson-Watt in Great Britain demonstrated a pulsed radar system.

1935: Installation on the Normandie Ocean Liner

In 1935, aspects of the CSF's obstacle-locating radio apparatus were installed on the ocean liner Normandie.

1935: Working Radar Systems Produced

In 1935, the team produced working radar systems and began deployment.

September 1936: Watson-Watt Becomes Superintendent of Bawdsey Research Station

On September 1, 1936, Watson-Watt became superintendent of the new Bawdsey Research Station under the British Air Ministry.

1936: First Chain Home Systems Operational

By 1936, the first five Chain Home (CH) systems were operational.

1938: First Commercial Radar Device Fitted to Aircraft

In 1938, the first commercial device fitted to aircraft was a Bell Lab unit on some United Air Lines aircraft.

1939: Chain Home Operational

By 1939, aircraft detection and tracking stations called "Chain Home" were installed along the East and South coasts of England. This system played a key role for the Royal Air Force in winning the Battle of Britain. The radar formed part of the "Dowding system".

1939: Soviets Produce First Mass Production Radars

In 1939, the Soviets produced their first mass production radars, the RUS-1 and RUS-2 Redut, in collaboration with the Leningrad Electrotechnical Institute.

April 1940: Radar Unit Shown in Popular Science

In April 1940, Popular Science featured an example of a radar unit using the Watson-Watt patent in an article on air defence.

1940: Chain Home Extended Across the UK

By 1940, Chain Home (CH) systems stretched across the entire UK, including Northern Ireland.

1940: Cavity Magnetron Developed in the UK

In 1940, a key development was the cavity magnetron in the UK, which allowed the creation of relatively small radar systems with sub-meter resolution.

1940: RADAR Acronym Coined

In 1940, the United States Navy coined the term RADAR as an acronym for "radio detection and ranging." The term has since been adopted into English and other languages as a common noun.

1941: Watson-Watt Advises on Air Defense

In 1941, Watson-Watt was sent to the U.S. to advise on air defense after Japan's attack on Pearl Harbor. Alfred Lee Loomis organized the MIT Radiation Laboratory.