The Holmdel Horn Antenna is a large microwave horn antenna that was used as a satellite communication antenna and radio telescope during the 1960s at the Bell Telephone Laboratories facility located on Crawford Hill in Holmdel Township, New Jersey, United States. This was one of the most important discoveries in physical cosmology since Edwin Hubble demonstrated in the 1920s that the universe was expanding. It provided the evidence that confirmed George Gamow's and Georges Lemaître's "Big Bang" theory of the creation of the universe. This helped change the science of cosmology, the study of the universe's history, from a field for unlimited theoretical speculation into a discipline of direct observation. In 1978 Penzias and Wilson received the Nobel Prize for Physics for their discovery.

Description

250px|thumb|left|Bell Labs' horn antenna, April 2007

The horn antenna at Bell Telephone Laboratories in Holmdel, New Jersey, was constructed on Crawford Hill in 1959 to support Project Echo, the National Aeronautics and Space Administration's passive communications satellites,

The antenna is in length with a radiating aperture of and is constructed of aluminum. The antenna's elevation wheel, which surrounds the midsection of the horn, is in diameter and supports the structure's weight using rollers mounted on a base frame. All axial or thrust loads are taken by a large ball bearing at the narrow apex end of the horn. The horn continues through this bearing into the equipment building or cab. The ability to locate receiver equipment at the horn apex, thus eliminating the noise contribution of a connecting line, is an important feature of the antenna. A radiometer for measuring the intensity of radiant energy is located in the cab.

When not in use, the turntable azimuth sprocket drive is disengaged, allowing the structure to "weathervane" and seek a position of minimum wind resistance. The antenna was designed to withstand winds of , and the entire structure weighs 18 short tons (16 tonnes). It was built by David C. Hogg. It consists of a flaring metal horn with a curved reflecting surface mounted in its mouth at a 45° angle to the long axis of the horn. This triggered a petition to preserve the property as a park, which preservationists preferred over real estate development. The petition was given to township officials in March 2023, having accumulated over 6,900 signatures. That April, township officials filed a lawsuit in the New Jersey Superior Court to clarify who owned the antenna; the site developer, Crawford Hill Holdings claimed that it owned the antenna and would preserve the property. That June, the town moved to acquire the antenna.

In October 2023, the township announced plans to buy and preserve the antenna. The purchase included $5.5 million for of land, which would be converted into a public park. The purchase was finalized in January 2024, when the township announced plans for the park. In May 2025, the Institute of Electrical and Electronics Engineers dedicated a plaque commemorating the antenna.

In 1992 the receiver and calibration equipment were sent to the Deutsches Museum in Munich, the birth city of Penzias, while the antenna remains in Holmdel, New Jersey. The museum also displays the hardware alongside a functional 1:25 scale model of the horn antenna.

See also

  • Andover Earth Station, location of another large Hogg horn antenna
  • National Register of Historic Places listings in Monmouth County, New Jersey
  • List of National Historic Landmarks in New Jersey

References

Footnotes

<!-- The original material in this article was taken from the National Park Service found in Further reading which in turn used the following sources. Ideally these sources should be added as proper citations within the article. -->

  • Aaronson, Steve. "The Light of Creation: An Interview with Arno A. Penzias and Robert W. Wilson." Bell Laboratories Record. January 1979, pp.&nbsp;12–18.
  • Abell, George O. Exploration of the Universe. 4th ed., Philadelphia: Saunders College Publishing, 1982.
  • Asimov, Isaac. Asimov's Biographical Encyclopedia of Science and Technology. 2nd ed., New York: Doubleday & Company, Inc., 1982.
  • Bernstein, Jeremy. Three Degrees Above Zero: Bell Labs in the Information Age. New York: Charles Scribner's Sons, 1984.
  • Chown, Marcus. "A Cosmic Relic in Three Degrees," New Scientist, September 29, 1988, pp.&nbsp;51–55.
  • Crawford, A.B., D.C. Hogg and L.E. Hunt. "Project Echo: A Horn-Reflector Antenna for Space Communication," The Bell System Technical Journal, July 1961, pp.&nbsp;1095–1099.
  • Disney, Michael. The Hidden Universe. New York: Macmillan Publishing Company, 1984.
  • Ferris, Timothy. The Red Limit: The Search for the Edge of the Universe. 2nd ed., New York: Quill Press, 1978.
  • Friedman, Herbert. The Amazing Universe. Washington, DC: National Geographic Society, 1975.
  • Hey, J.S. The Evolution of Radio Astronomy. New York: Neale Watson Academic Publications, Inc., 1973.
  • Jastrow, Robert. God and the Astronomers. New York : W. W. Norton & Company, Inc., 1978.
  • H.T. Kirby-Smith U.S. Observatories: A Directory and Travel Guide. New York: Van Nostrand Reinhold Company, 1976.
  • Penzias, A.A., and R. W. Wilson. "A Measurement of the Flux Density of CAS A At 4080 Mc/s," Astrophysical Journal Letters, May 1965, pp.&nbsp;1149–1154.

Further reading