The AN/APQ-13 radar was an American ground scanning radar developed by

Bell Laboratories Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984), then AT&T Bell Laboratories (1984–1996) and Bell Labs Innovations (1996–2007), is an American industrial research and scientific development company owned by mult ...

Western Electric The Western Electric Company was an American electrical engineering and manufacturing company officially founded in 1869. A wholly owned subsidiary of American Telephone & Telegraph for most of its lifespan, it served as the primary equipment ma ...

, and

MIT 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 mo ...

as an improved model of the airborne

H2X radar H2X, officially known as the AN/APS-15, was an American ground scanning radar system used for blind bombing during World War II. It was a development of the British H2S radar, the first ground mapping radar to be used in combat. It was also known ...

, itself developed from the first ground scanning radar, the British

H2S radar H2S was the first airborne, ground scanning radar system. It was developed for the Royal Air Force's Bomber Command during World War II to identify targets on the ground for night and all-weather bombing. This allowed attacks outside the range ...

. It was used on

B-29 The Boeing B-29 Superfortress is an American four-engined propeller-driven heavy bomber, designed by Boeing and flown primarily by the United States during World War II and the Korean War. Named in allusion to its predecessor, the B-17 Fly ...

s 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 ...

in the

Pacific theater The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

for high altitude area bombing, search and navigation. Computation for bombing could be performed by an impact predictor. A range unit permitted a high degree of accuracy in locating beacons. The

radome A radome (a portmanteau of radar and dome) is a structural, weatherproof enclosure that protects a radar antenna (radio), antenna. The radome is constructed of material transparent to radio waves. Radomes protect the antenna from weather and ...

was carried on the aircraft belly between the bomb bays and was partially retractable on early models. The radar operated at a frequency of 9375 ± 45 megahertz and used a

superheterodyne receiver A superheterodyne receiver, often shortened to superhet, is a type of radio receiver that uses frequency mixing to convert a received signal to a fixed intermediate frequency (IF) which can be more conveniently processed than the original carr ...

Weather radar use

The AN/APQ-13 radar was the first military radar converted to civilian use as a weather warning radar. About 30 systems were converted, starting in late 1945. They were installed in the aircraft at military bases.Historical Electronics Museu

. The last operational APQ-13 was removed from the

Fort Sill, Oklahoma Fort Sill is a United States Army post north of Lawton, Oklahoma, about 85 miles (136.8 km) southwest of Oklahoma City. It covers almost . The fort was first built during the Indian Wars. It is designated as a National Historic Landmark ...

post weather station in October 1977 for display at what is now the

National Museum of the United States Air Force The National Museum of the United States Air Force (formerly the United States Air Force Museum) is the official museum of the United States Air Force located at Wright-Patterson Air Force Base, northeast of Dayton, Ohio. The NMUSAF is the ...

. The museum intended to display it in its original configuration as a navigation and bombing radar, but would note the radar's much longer history as an operational weather radar.Roger C. Whiton, et al. "History of Operational Use of Weather Radar by U.S. Weather Services. Part I: The Pre-NEXRAD Era." Weather and Forecasting: Vol. 13, No. 2, pp. 219–243. 19 February 1998. American Meteorological Society. 5 April 200

The AN/APQ-13 weather radars were generally replaced by the

AN/CPS-9 The AN/CPS-9 radar, the first radar specifically designed for meteorological use, was produced in the United States around 1949 and unveiled by the Air Weather Service (now the Air Force Weather Agency) in 1954.NOAA Legacy Timeline - 1900–196 A ...

, which was specifically designed as a weather radar.

References

Aircraft radars Military radars of the United States World War II radars Weather radars Radars of the United States Air Force Boeing B-29 Superfortress Military equipment introduced from 1940 to 1944 {{Technology-stub