Sixty years ago this month, the PROCEEDINGS OF THE INSTITUTE OF RADIO ENGINEERS (IRE) included a paper on the theory of radio frequency transformers by Harry Diamond and E.Z. Stowell. Diamond, for whom the Harry Diamond Memorial Award of the IEEE is named, was employed at the National Bureau of Standards in 1928. Stowell recently had joined the Federal Telegraph Company in Palo Alto, CA, after working at the Bureau of Standards. from 1924 to 1927.

In their paper Diamond and Stowell noted that the effect of distributed capacitance coupling between transformer windings typically had been neglected in the analysis of radio frequency amplifiers. They provided equations and graphs which included this effect and stated that their analysis gave better agreement with experimental results than reported previously.

Harry Diamond was born in Quincy, MA, in 1900 and graduated in electrical engineering from the Massachusetts Institute of Technology in 1922. He then worked for General Electric Company for about 18 months before becoming an electrical engineering instructor at Lehigh University, where he taught from 1923 to 1927. He received the M.S. degree in electrical engineering from Lehigh in 1925 and joined the Radio Section of the National Bureau of Standards in July 1927.

Diamond’s first assignment at the Bureau of Standards was to work on the development of radio aids for use in aviation. Subsequently, he designed a system for voice radio communication which enabled pilots to make blind landings. He participated in tests using a Bureau of Standards station in College Park, MD, until the system was turned over to the Department of Commerce in 1933. The College Park facility was closed in 1934, and Diamond was transferred to Washington, DC. He was author or coauthor of nine IRE papers on radio aids to aviation published between 1929 and 1937.

During the 1930’s, Diamond headed a project to develop a high-altitude weather telemetry system for the United States Navy. With colleagues including Francis W. Dunmore and Wilbur S. Hinmann, Jr., Diamond developed what became known as a radiosonde system. They used latex rubber balloons which became available in sizes large enough to lift a small radio transmitter to a great height at reasonable cost by the mid-1930’s. Data from the upper atmosphere were transmitted to ground receivers over distances of up to 200 mi. The transmitters were designed to operate at very low temperature and pressure and to require minimum power. They employed miniature vacuum tubes operated at frequencies of the order of 180 MHz. A similar unit was developed for the Navy to be used as automatic weather stations on islands or other remote locations. By 1940 the radiosondes enjoyed wide use by the United States Weather Bureau and they also were adopted by researchers studying cosmic rays at extreme altitudes. Diamond, Dunmore, and Hinmann published an IRE paper on “radio meteorography” in October 1938.

Beginning in December 1940, Diamond directed a major effort at the Bureau of Standards to develop radio-actuated proximity fuzes for military applications. Diamond and Hinmann invented a detector which would cause detonation when radio waves reflected from a target exceeded a threshold value. The technology was a natural outgrowth of the radiosonde transmitter, and large quantities of several types of proximity fuzes were produced during World War II.

Soon after Diamond’s untimely death in 1948, a number of his friends and colleagues established the Harry Diamond Memorial Award. It was first awarded by the IRE and the IEEE has continued to award it in recognition of “outstanding technical contributions in the field of government service in any country, as evidenced by publication in professional society journals.” Diamond’s close colleague, Wilbur S. Hinmann, Jr. received the Harry Diamond Memorial Award in 1956 for his contributions to radio meteorology and proximity fuzes.

James E. Brittain

School of History, Technology, and Society

Georgia Institute of Technology

Submitted by Dick Reiman, Historian

Copyright 1993 IEEE. Reprinted with permission from the IEEE publication, “Scanning the Past” which covers a reprint of an article appearing in the Proceedings of the IEEE Vol. 81, No.9, September 1993.