Eimac is a trade mark of Eimac Products, part of the Microwave Power Products Division of
Communications & Power Industries
CPI International, Inc. is the holding company for Communications & Power Industries, the largest manufacturer and rebuilder of electron devices (primarily vacuum tubes) in the United States. CPI was founded in 1995 when Varian Associates sold its ...
. It produces power
vacuum tube
A vacuum tube, electron tube, valve (British usage), or tube (North America), is a device that controls electric current flow in a high vacuum between electrodes to which an electric voltage, potential difference has been applied.
The type kn ...
s for
radio frequency
Radio frequency (RF) is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency range from around to around . This is roughly between the upp ...
applications such as
broadcast
Broadcasting is the distribution of audio or video content to a dispersed audience via any electronic mass communications medium, but typically one using the electromagnetic spectrum ( radio waves), in a one-to-many model. Broadcasting began ...
and
radar
Radar is a detection system that uses radio waves to determine the distance (''ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, w ...
transmitter
In electronics and telecommunications, a radio transmitter or just transmitter is an electronic device which produces radio waves with an antenna (radio), antenna. The transmitter itself generates a radio frequency alternating current, which i ...
s. The company name is an initialism from the names of the founders, William Eitel and Jack McCullough.
History
The
San Francisco Bay
San Francisco Bay is a large tidal estuary in the U.S. state of California, and gives its name to the San Francisco Bay Area. It is dominated by the big cities of San Francisco, San Jose, and Oakland.
San Francisco Bay drains water from a ...
area was one of the early centers of
amateur radio
Amateur radio, also known as ham radio, is the use of the radio frequency spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radiosport, contesting, and emergency communic ...
activity and experimentation, containing about 10% of the total operators in the US. Amateur radio enthusiasts sought
vacuum tube
A vacuum tube, electron tube, valve (British usage), or tube (North America), is a device that controls electric current flow in a high vacuum between electrodes to which an electric voltage, potential difference has been applied.
The type kn ...
s that would perform at higher power and on higher frequencies than those then available from RCA, Western Electric, General Electric, and Westinghouse.
Additionally, they required tubes that would operate with the limited voltages available from typical amateur power supplies.
While employed by the small
San Francisco
San Francisco (; Spanish language, Spanish for "Francis of Assisi, Saint Francis"), officially the City and County of San Francisco, is the commercial, financial, and cultural center of Northern California. The city proper is the List of Ca ...
,
California
California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...
manufacturing firm of Heintz & Kaufman which manufactured custom radio equipment, Bill Eitel (
amateur radio
Amateur radio, also known as ham radio, is the use of the radio frequency spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radiosport, contesting, and emergency communic ...
call sign
In broadcasting and radio communications, a call sign (also known as a call name or call letters—and historically as a call signal—or abbreviated as a call) is a unique identifier for a transmitter station. A call sign can be formally assigne ...
W6UF) and Jack McCullough (W6CHE) convinced company president Ralph Heintz (W6XBB) to allow them to develop a transmitting tube that could operate at lower voltages than those then available to the amateur radio market, such as the
RCA
The RCA Corporation was a major American electronics company, which was founded as the Radio Corporation of America in 1919. It was initially a patent trust owned by General Electric (GE), Westinghouse, AT&T Corporation and United Fruit Comp ...
UV-204A or the 852. Their effort was a success and resulted in production of the HK-354. Shortly after in 1934, Eitel and McCullough left H&K to form Eitel McCullough Corp. in
San Bruno
San Bruno (Spanish for " St. Bruno") is a city in San Mateo County, California, United States, incorporated in 1914. The population was 43,908 at the 2020 United States Census. The city is between South San Francisco and Millbrae, adjacent to Sa ...
California.
[Orr, B (1994). ''Radio FUNdamentals, Do You Want A Kilowatt??'' ic CQ p.60]
The first product produced under the trade mark "Eimac" was the 150T power triode. Later tubes include the 3CX5000A7 power triode and the 4X150D tetrode. The new company thrived during
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
by selling tubes to the U.S. military for use in
radar
Radar is a detection system that uses radio waves to determine the distance (''ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, w ...
equipment.
Charles Litton Sr.
Charles Vincent Litton Sr. (1904–1972) was an engineer and inventor from the area now known as Silicon Valley.
Biography
Early life
Charles Vincent Litton was born on March 13, 1904, in San Francisco, California. His mother was Alice J. Vincent ...
originated
glass lathe techniques which made mass production of reliable high quality power tubes possible, and resulted in the award of wartime contracts to the company.
Mass production
Contracts to provide transmission tubes for radar and other radio equipment during World War II required adaption of mass production, research to improve the reliability of tubes, and development of standardized manufacturing techniques which could be performed by unskilled workers. The workforce expanded from a few hundred to several thousand.
During the war Eimac produced hundreds of thousands of radar tubes.
[How science grew such long arms](_blank)
// ''Aviation Week & Space Technology'', June 3, 1963, v. 78, no. 22, p. 87.
Welfare capitalism
A union organizing drive in 1939-40 by the strong Bay area labor movement was fought off by adoption of a strategy of
welfare capitalism
Welfare capitalism is capitalism that includes social welfare policies and/or the practice of businesses providing welfare services to their employees. Welfare capitalism in this second sense, or industrial paternalism, was centered on industrie ...
which included pensions and other generous benefits, profit sharing, and such extras as a medical clinic and a cafeteria. An atmosphere of cooperation and collaboration was established,
Postwar
![Eimac Tube](https://upload.wikimedia.org/wikipedia/commons/b/b7/Eimac_Tube.jpg)
As wartime orders ceased and a large supply of military surplus transmission tubes flooded the market the firm laid off 90% of its workers and closed its plant in Salt Lake City. Reallocation of the FM band by the FCC in 1945, however, provided an opportunity for the firm to market a superior power
tetrode
A tetrode is a vacuum tube (called ''valve'' in British English) having four active electrodes. The four electrodes in order from the centre are: a thermionic cathode, first and second grids and a plate (called ''anode'' in British English). Th ...
tube which it had developed.
Beginning in 1947, Eimac operated
FM radio station
KSBR
KSBR (88.5 FM, "The SoCal Sound") is a non-commercial educational radio station licensed to Mission Viejo, California and broadcasting to the Orange County area. The station is owned by Saddleback College and airs adult album alternative (AAA) ...
from their plant in
San Bruno, California
San Bruno (Spanish for " St. Bruno") is a city in San Mateo County, California, United States, incorporated in 1914. The population was 43,908 at the 2020 United States Census. The city is between South San Francisco and Millbrae, adjacent to S ...
, one of only two FM stations in the United States to test the new Rangertone
tape recorder
An audio tape recorder, also known as a tape deck, tape player or tape machine or simply a tape recorder, is a sound recording and reproduction device that records and plays back sounds usually using magnetic tape for storage. In its present- ...
s (adapted from the German
Magnetophon
Magnetophone, or simply Magnetophon, was the brand or model name of the pioneering reel-to-reel tape recorder developed by engineers of the German electronics company AEG in the 1930s, based on the magnetic tape invention by Fritz Pfleumer
Fr ...
recorders). In need of more space, the company moved to
San Carlos in 1959. Eimac's San Carlos plant was dedicated on April 16, 1959.
[Eitel-McCullough, Inc. building in San Carlos, 1959](_blank)
/ref> By that time, the company had the following subsidiaries
A subsidiary, subsidiary company or daughter company is a company owned or controlled by another company, which is called the parent company or holding company. Two or more subsidiaries that either belong to the same parent company or having a sa ...
: National Electronics, Inc., Geneva, Illinois
Geneva is a city in and the county seat of Kane County, Illinois, United States. It is located on the western side of the Chicago suburbs. Per the 2020 census, the population was 21,393.
Geneva is part of a tri-city area, located between S ...
, and Eitel-McCullough, S.A., Geneva, Switzerland
Geneva ( ; french: Genève ) frp, Genèva ; german: link=no, Genf ; it, Ginevra ; rm, Genevra is the List of cities in Switzerland, second-most populous city in Switzerland (after Zürich) and the most populous city of Romandy, the French-speaki ...
. During the Cold war era
The Cold War is a term commonly used to refer to a period of geopolitical tension between the United States and the Soviet Union and their respective allies, the Western Bloc and the Eastern Bloc. The term '' cold war'' is used because the ...
, Eimac supplied U.S. military with klystron power tubes and electron power tubes used in the defense communications network, navigation
Navigation is a field of study that focuses on the process of monitoring and controlling the movement of a craft or vehicle from one place to another.Bowditch, 2003:799. The field of navigation includes four general categories: land navigation, ...
, detection, ranging and fire-control radar
A fire-control radar (FCR) is a radar that is designed specifically to provide information (mainly target azimuth, elevation, range and range rate) to a fire-control system in order to direct weapons such that they hit a target. They are sometim ...
s.
In the beginning of May 1959, the company announced its newly-produced giant klystron tube powered the Massachusetts Institute of Technology
The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the ...
’s radar which recently established contact with planet Venus
Venus is the second planet from the Sun. It is sometimes called Earth's "sister" or "twin" planet as it is almost as large and has a similar composition. As an interior planet to Earth, Venus (like Mercury) appears in Earth's sky never fa ...
. The super-power klystron was developed under Rome Air Development Center
Rome Laboratory (Rome Air Development Center until 1991) is the US "Air Force 'superlab' for command, control, and communications" research and development and is responsible for planning and executing the USAF science and technology program.
...
sponsorship. Eimac klystrons also were chosen for NATO
The North Atlantic Treaty Organization (NATO, ; french: Organisation du traité de l'Atlantique nord, ), also called the North Atlantic Alliance, is an intergovernmental military alliance between 30 member states – 28 European and two No ...
's tropospheric scatter
Tropospheric scatter, also known as troposcatter, is a method of communicating with microwave radio signals over considerable distances – often up to and further depending on frequency of operation, equipment type, terrain, and climate facto ...
communications network.
In 1965, Eimac merged with Varian Associates
Varian Associates was one of the first high-tech companies in Silicon Valley. It was founded in 1948 by Russell H. and Sigurd F. Varian, William Webster Hansen, and Edward Ginzton to sell the klystron, the first vacuum tube which could amplify ...
and became known as the Eimac Division. In August 1995, Varian Associates
Varian Associates was one of the first high-tech companies in Silicon Valley. It was founded in 1948 by Russell H. and Sigurd F. Varian, William Webster Hansen, and Edward Ginzton to sell the klystron, the first vacuum tube which could amplify ...
sold the Electron Device Business to Leonard Green & Partners
Leonard Green & Partners ("LGP") is an American private equity investment firm founded in 1989 and based in Los Angeles. The firm specializes in private equity investments. LGP has invested in over 95 companies since its inception, including Petc ...
, a private equity fund, and members of management. Together, they formed Communications & Power Industries
CPI International, Inc. is the holding company for Communications & Power Industries, the largest manufacturer and rebuilder of electron devices (primarily vacuum tubes) in the United States. CPI was founded in 1995 when Varian Associates sold its ...
.
In January 2004, affiliates of The Cypress Group, a private equity fund, acquired CPI.
In February 2011, an affiliate of Veritas Capital, a private equity investment firm acquired CPI.
In 2006 CPI relocated the Eimac facility from 301 Industrial Road, San Carlos to their operation in Palo Alto.
References
10. Eimac building in San Carlos https://ethw.org/File:Eitel_Mccullough.jpg
External links
{{Commons category, Eimac vacuum tubes
Corporate Web site
Electronics companies established in 1934
Vacuum tubes
San Bruno, California
1934 establishments in California