AN/APQ-13
USAAF WWII-era aircraft bombsight radar
The AN/APQ-13 radar was an American ground scanning radar developed by Bell Laboratories, Western Electric, and MIT as an improved model of the airborne H2X radar, itself developed from the first ground scanning radar, the British H2S radar. It was used on B-29s during World War II in the Pacific theater 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 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.
In accordance with the Joint Electronics Type Designation System (JETDS), the "AN/APQ-13" designation represents the 13th design of an Army-Navy airborne electronic device for radar special equipment. The JETDS system also now is used to name all Department of Defense electronic systems.
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.
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