Robert Watson Watt

Robert Watson-Watt, in 1944.

Robert Alexander Watson-Watt (Brechin, Angus County, Scotland, April 13, 1892-Inverness, December 5, 1973) was a Scottish engineer and physicist, considered the inventor of the radar (development was much earlier). Despite this, his patent on this matter in 1935 led the UK to install the first defense radar network. His research and his management of projects before and during World War II made radar an essential tool for the Allies to achieve final victory.

Youth

Originally he was a descendant of James Watt, the engineer who had invented the steam engine. After studying at Brechin Public School, he was admitted to the University of Dundee (then part of the University of St. Andrews). He graduated with an engineering degree in 1912 and got a job as a research assistant professor with Professor William Peddie, who encouraged him in the study of radio or, as it was then called, wireless telegraphy.

Early career

In 1915, Watson-Watt tried to work in the War Office but there was no infrastructure for telecommunications research. Thus, he began working as an electrical engineer in the Meteorological Service interested in the use of radiodetection of storms. As lightning strikes ionize the air, a radio signal is produced that Watson-Watt believed could be used to warn pilots of danger.

Development of a concept

Already in his first experiments he was able to detect the signal even at a very great distance. However, there were two problems: the direction from which that signal came and how to fix it. The first problem was solved by using a directional antenna that could be manually rotated to maximize signal, thereby pointing towards the storm. The second was solved using a cathode phosphor tube and an oscilloscope, which had just been developed. This system, launched in 1923, represented an important advance in the development of the radar system. However, the emitting part of an impulse was missing and a way to measure the round trip time of the signal to be able to determine the distance to the target.

He initially worked at the Air Ministry Meteorological Office's Aldershot Wireless Station. In 1924 he went to work for the Ministry of Defense.

UK Air Defense

In 1933, the Air Ministry had begun modernizing the UK's air defense structures. During World War I the Germans had used zeppelins as long-distance bombers and their interception by aircraft had failed, and the only thing that had worked had been anti-aircraft artillery. Despite the fact that the zeppelins were hundreds of meters long and traveling at only 100 km/h, the fighters only discovered them three of the 20 times they were used and were never able to attack them.

The bombers that were developed after the war were already capable of flying high above anti-aircraft batteries, posing a great threat. In addition, the enemy airfields were only 20 minutes away, allowing them to hit and run before the fighters could intercept them. The only solution seemed to be to permanently keep a squadron of fighters in the air, which was physically impossible.

Nazi Germany

With the rearmament of Germany at the time of the Nazis, the danger seemed to be getting closer. German propaganda also claimed that they had developed a death ray, which worked with radio waves, and could even destroy cities. H. E. Wimperis, chairman of the committee, visited Watson-Watt at Teddington in 1934 to find out if it was feasible to build a British version of such a death ray. Watson-Watt showed him some calculations that his assistant Arnold Wilkins had already done, demonstrating the impossibility of the concept. This fact allowed the fear of the Nazis to be lowered. However, he noted that his team would work on "the difficult but more real problem of using reflected radio waves to detect and position targets."

Detection and position of aircraft

On February 12, 1935, Watson-Watt sent a memorandum on the proposed system to the Air Ministry entitled Detection and location of aircraft by radio methods. Although not as exciting as the death ray concept, the concept had significant potential and was called for an immediate practical demonstration. As of February 26, it already had two antennas about 10 km from a BBC shortwave antenna in Daventry. In absolute secrecy, Watson-Watt, his assistant Arnold Wilkins and a single member of the committee, A. P. Rowe, attended the demonstration that allowed a bomber to be located several times with the signal emitted. More importantly, Prime Minister Stanley Baldwin was informed of progress in radar development.

Two weeks later, Wilkins left the Radio Research Station with a small group of associates, including Edward George Bowen, to continue their research in Orfordness. On April 2, 1935, Watson-Watt was granted a patent for the radar system (British patent GB593017). As of June, his equipment was already capable of detecting an aircraft at 27 km, which was enough to stop any development or investigation of competing sound localization systems. By the end of that year, the range was already 100 km and in December the plans for five stations covering the possible aerial approach to London were ready.

One such station was located on the coast near Orfordness and became the main center for radar research. There would soon be full-scale tests of the system, later known as Chain Home, in which a bomber had to be located and intercepted before it acted. The tests failed, not because of radar detection but because of the problem of transmitting the information in time. The fighters were out too late and did not see their target until after the bomber had passed through the bombing area. Watson-Watt addressed this problem by staggering the detectors. The reports ended up in the War room in which the observers indicated the position of the enemy on a large map and the coordinators sent the information to the squadrons of fighter planes directly by radio.

In 1937, the first stations were already operational, which made it possible to test their system. The results were conclusive and another twenty stations were commissioned. By the start of World War II, there were 19 built and ready to take a decisive role in the Battle of Britain. At the end of the war there were a total of fifty stations. The Germans knew about the construction of the Chain Home but they didn't really know what it was for. They put their theories to the test by sending the GRAF Zeppelin II but came to the conclusion that the network was a long-distance communication system set up by the British Army.

As early as 1936, the British realized that the Luftwaffe would switch to night bombing raids if daytime expeditions proved unsuccessful. Watson-Watt dedicated another of his assistants at the Radio Research Station, Edward George Bowen, to the development of a radar that could be carried on a fighter. This was because the night visual contact of a bomber was only about 300 meters and the detection Chain Home network was not accurate enough to guide the fighters so close to their targets.

Bowen decided that a radar on an airplane could not weigh more than 90 kg or have a volume of more than 230 L without more than 500 W of power. In order to reduce the trace of the antenna by reducing its diameter, the wavelength of the beam could not be greater than one meter, which was difficult, given the technology of the time. However, that type of system was perfected in the 1940s and proved essential in ending the "Blitz" of 1941. Bowen also mounted such radars on maritime patrol planes in the fight against submarines.

The war and the postwar period

He participated in 1941 in the commissioning of radar systems in the United States. His contribution to the war effort was of such magnitude that he was knighted in 1942. In 1952, the British government paid him £50,000 for his contribution to the development of radar. After the war, he spent much of his life first in Canada and then in the United States where he published Three Steps to Victory in 1958.

He was awarded the Hughes Medal in 1948, awarded by the Royal Society "for distinguished contributions to the physics of the atmosphere and to the development of radar".

Robert Watson-Watt returned to Scotland in the 1960s and died in Inverness.

Work

• Three Steps to Victory. 1957
• The Pulse of Radar. Autobiographie 1959