Developed the theory of the interaction of radio waves.
David Forbes Martyn was born on June 27, 1906, in Cambuslang, Scotland, the son of Dr. Somerville Martyn. He attended Plymouth College and Allan Glen’s School, and then entered the Royal College of Science in London. He received a B.A. in 1926, then in 1929 a Ph.D. degree and in 1936 a D.Sc. degree, all from the Royal College.
During the 1920’s David Forbes Martyn worked on the stability of the triode vacuum tube oscillator, and also developed a new method for measuring extremely small alternating currents. In 1927, the Australian Council for Scientific and Industrial Research (C.S.I.R.) established the Radio Research Board, with Martyn as one of its first four research officers.
After traveling to Australia, Dr. Martyn submitted two proposals to the Board; one suggested reflecting very high-frequency radio waves off of the Moon (echo-pulsing); the second was that Sir Edward Appleton’s frequency-change method of studying the ionosphere might be improved through the transmission of continuous “saw-tooth” shaped frequency sweeps. Martyn’s research convinced him of the supremacy of the “pulse” method.
In 1934, Martyn helped research the newly discovered tendencies, in certain conditions, for the modulation of one radio wave to impose itself on that of another. He and his associate V.A. Bailey showed this was due to a non-linear effect in the ionosphere. With this study of this interaction of radio waves, Martyn became an international expert on the subject.
In early 1939, as tensions between the British Commonwealth and Nazi Germany escalated, the Australian government chose David Martyn to follow up his work with a more technical study to improve radio wave research. He soon discovered the secret radar project being developed in Britain under Sir Robert Watson Watt was using pulse techniques. Martyn shared his earlier research on radio frequency sweeping that supported this approach, which was to play an important role in the successful use of radar by the Allies in World War II, especially during the decisive Battle of Britain in 1940.
Returning to Australia in August 1939, Martyn urged his research into radar be supported by the Australian wartime Cabinet. C.S.I.R. set up a Radiophysics Laboratory, with Dr. Martyn as its Chief just before the outbreak of World War II on September 1, 1939. He oversaw the design of what was called Shore Defense Radar, able to detect and locate surface vessels. This system was successfully integrated with the 9.2-inch and 6-inch coast defense guns.
David Martyn served as Officer-in-charge of the C.S.I.R. Radiophysics Laboratory until 1940 when he became Chief of Division Radiophysics. He was promoted to Director of the Australian Army Operational Research Group in 1942, then in 1944 became Chief Scientific Officer, C.S.I.R./O. Radio Research Board, a position he kept until 1958.
In 1950, because of his work on radio-emission from the sun and in radio astronomy, Dr. Martyn was elected president of the newly formed Radio Astronomy Commission of the International Union of Radio Science (URSI). In 1954, he was the major force in the formation of the Australian Academy of Science. He then took the lead in organizing Australia’s activities in the International Geophysical Year (1957-1958), especially in securing funds for this notable enterprise.
David Martyn next served as Officer-in-charge of the C.S.I.R./O’s Upper Atmosphere Section from 1958 until 1970. During the last three years of his life, Martyn became increasingly concerned with problems of conservation and became one of the leaders of Australia’s environmental movement. His last post was as president of the Australian Academy of Science, from 1969 until his death on March 5, 1970, in Camden, New South Wales.
Dr. David Forbes Martyn received many honors for his research, including the Lyle Medal of the Australian National Research Council, and the Sidey Medal of the Royal Society of New Zealand, both in 1947. In 1950, he received the Burfitt Medal of the Royal Society of New South Wales and was elected a Fellow of the Royal Society of London. In 1954, Dr. Martyn was awarded the Charles Chree Medal of the Physical Society of London.