[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 11: Detecting the Interstellar Hydrogen Line, 1951

[Horn antenna design]

The design of the horn antenna was based on descriptive information presented in the Rad Lab book on Antennas by Sam Silver [Microwave Antenna Theory and Design, edited by Samuel Silver. MIT Radiation Laboratory Series 12, published by McGraw-Hill, 1949; reprinted by P. Peregrinus on behalf of the Institution of Electrical Engineers, 1984]. The maximum size was determined by the geometric constraints of the fourth floor parapet at Lyman Lab. I sent my calculations and sketches to Sam for a sanity check, before sending the build order to the Physics Dept. Model Shop. It was up on the parapet in about three weeks. [Diagrom courtesy of Doc Ewen]

Slide 12
Modified on Monday, 06-Sep-2004 14:06:02 EDT by Ellen Bouton