Type VA-842 klystron

During the early 20th century, scientists developed radar–a means to transmit and then detect radio waves reflected by metal objects. Most radar units used electronic tubes to generate the radio waves and many different types of tubes were invented.
The model VA-842 klystron tube from Varian Corporation is one of the largest radar tubes made. This klystron operated for over 29,000 hours (about four years) in the Ballistic Missile Early Warning System radar at Thule, Greenland. Banks of these klystrons generated the radio waves transmitted by the huge radar in order to detect missiles aimed at North America.
The VA-842 klystron provided 1,250,000 watts peak power output with an average power output of 75,000 watts. The radio waves ranged from 400 to 450 megahertz in frequency. Varian donated the klystron to the Smithsonian in September 1964.
Currently not on view
Object Name
radar tube
pulse amplifier klystron
date made
ca 1960
Varian Associates
Physical Description
steel (overall material)
copper (overall material)
overall: 120 in x 33 in x 24 in; 304.8 cm x 83.82 cm x 60.96 cm
ID Number
catalog number
accession number
model number
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Work and Industry: Electricity
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
from Varian Associates

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