Scanning the Past: A History of Electrical Engineering from the Past
Submitted by Bob Morrison, Editor
Copyright 1995 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. 83, No. 4, April 1995.
James K. Clapp
Sixty-five years ago this month, the PROCEEDINGS OF THE INSTITUTE OF RADIO ENGINEERS (IRE) included a paper on antenna-measuring instrumentation by James K. Clapp. At the time he was employed as an engineer with the General Radio Company of Cambridge, MA, where he spent most of his professional career.
Clapp was born in December 1897 in Denver, CO. He worked for the American Marconi Wireless Telegraph Company during 1914-1916. He served in the United States Navy from 1917 to 1919 and worked briefly for the Radio Corporation of America in 1920. He graduated with a degree in electrical engineering from the Massachusetts institute of Technology (MIT) in 1923 and earned an M.S. at MIT in 1926. He taught communications engineering at MIT from 1923-1928. Also, he served as radio editor for the Boston Evening Transcript and as chief engineer of the newspaper’s radio broadcasting station. In 1928 he joined the engineering staff of the General Radio Company and the following year published a Proceedings paper on short-wave radio experiments. One of his first assignments at General Radio was to develop a commercial quartz crystal frequency standard.
In his April 1930 paper, Clapp described a portable instrument which he had designed for the United States Coast Guard to be used to measure the characteristics of shipboard antennas. His instrument relied on a substitution method where measurements on the actual antenna being tested were compared to measurements on a “phantom antenna” with calibrated capacitance and resistance. A variable-frequency vacuum-tube oscillator was used to drive the antenna during testing and a frequency meter covering the range from 90 to 2000 kHz was included in the instrument package. Clapp noted that his instrument could give readings of antenna resistance and capacitance to an accuracy of better than 1% and that an operator with limited skill and experience could use it successfully. He included some data giving experimental results for some antennas he had tested.
In 1933, Clapp designed a transmitter for the United States Naval Observatory for use in transmitting time signals. He also developed a primary frequency standard for the Radio Broadcast Commission of Canada. He was elected a Fellow of the IRE in 1933. Much of his work in the 1930’s was related to applications of quartz crystals and on instruments to measure frequency. He pioneered in developing techniques to extend frequency standards into the microwave region.
Clapp retired from General Radio in 1957 and died in 1965 at age 67.
James E. Brittain
School of History , Technology and Society
Georgia Institute of Technology