[Doc Ewen looks into the horn antenna, 1950]
Image courtesy of Doc Ewen


Harvard Cyclotron: 1948-1951

Detection of HI Line: 1951

Harvard 24ft and 60ft and NRAO founding: 1952-1956

1950s and 1960s: Two Roads that Crossed

Microwave & Millimeter Wave Applications in the 1970s and 1980s

Mm Wave Radiometry in the 1990s

May 2001 visit to NRAO Green Bank



[Doc Ewen and horn antenna, 2001]
Image courtesy of Doc Ewen

Doc Ewen: The Horn, HI, and Other Events in US Radio Astronomy

by Doc Ewen, © 2003

Slide 23: Detecting the Interstellar Hydrogen Line, 1951

[Cover of Broad-Band Microwave Noise Source]

A fortuitous event: Report cover of Bill Mumford's gas discharge noise source for noise temperature calibration of the hydrogen line receiver, June 1949. [A Broad-Band Microwave Noise Source, by W.W. Mumford. Bell Telephone System Monograph 1721, also published in Bell System Technical Journal vol. 28, p. 601-618, 1949.] [Photo courtesy of Doc Ewen]

Slide 24
Modified on Monday, 06-Sep-2004 14:24:30 EDT by Ellen Bouton