View source for Radio Research Laboratory (Harvard)

{{Short description|Secret laboratory during World War II}}
The '''Radio Research Laboratory (RRL)''', located on the campus of [[Harvard University]], was an 800-person secret research laboratory during [[World War II]]. Under the U.S. [[Office of Scientific Research and Development]] (OSRD), it was a spinoff of the [[Radiation Laboratory]] (Rad Lab) at MIT and set up to develop [[electronic countermeasures]] to enemy radars and communications, as well as [[electronic counter-countermeasures]] (ECCM) to circumvent enemy ECM. The RRL was directed by [[Frederick E. Terman]] and operated between 1942 and 1946.

The RRL was engaged in both analysis and hardware development. They made significant contributions to the basic understanding of methods, theories, and circuits at [[VHF|very-high]] and [[UHF|ultra-high frequencies]] for radio systems, particularly in signals intelligence gear and statistical communications techniques. However, unlike the Rad Lab, the RRL never released significant details on its accomplishments; ECM and ECCM have always been closely guarded secrets by all nations.

The RRL conducted considerable work on [[Chaff (countermeasure)|chaff]], light-weight aluminum strips dropped in clouds from aircraft to confuse enemy radars. [[Fred L. Whipple]], an astronomer, made detailed analytical studies of this and devised a formula giving [[radar cross-section]] at a given wavelength per kilogram of chaff.

An example of RRL hardware development was Tuba (aka 'Project Tuba'), a giant ECM system generating continuous 80-kW signals in the range of 300-600&nbsp;MHz to jam German [[Lichtenstein radar]]s. The power tube (called Resnatron) for Tuba was developed at the RRL by David H. Shone and Lauritsen C. Marshall. Tuba used a [[horn antenna]] built of mesh wire 150 feet long and driven through 22- by 6- inch [[waveguides]], possibly the largest ever built. Tuba was placed in operation in mid-1944 on the south coast of England. The radiated energy was such that it lit fluorescent bulbs a mile away and jammed radars throughout Europe.

The RRL staff did document some of the general theory that they developed. After the war, this was released in a two-volume publication ''Very High-Frequency Techniques'', edited by Herbert J. Reich (McGraw-Hill, 1947).

==References==
* Louis Brown, ''A Radar History of World War II'', Inst. of Physics Publishing, p.&nbsp;293, 1999
* Steve Blank, Google Tech Talk: https://www.youtube.com/watch?v=hFSPHfZQpIQ
* Raymond C. Watson Jr.; ''Radar Origins Worldwide'', Trafford Publishing, pp.&nbsp;203–205, 2009
* [http://oasis.lib.harvard.edu/oasis/deliver/~hua09005 United States. Radio Research Laboratory, Harvard University. Records of the Radio Research Laboratory : an inventory], Harvard University Archives

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[[Category:Harvard University]]
[[Category:University and college laboratories in the United States]]
[[Category:Radiation]]
[[Category:Radar]]


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