The first operational set was installed aboard the heavy cruiser USS Augusta in April 1942.

The radar was developed by Raytheon under the guidance of the MIT Radiation Laboratory and Naval Research Laboratory using the cutting-edge multicavity magnetron technology developed in Britain and brought to the US by the Tizard Mission.

[2] The prototype was tested at sea aboard the destroyer USS Semmes in May 1941.

[2] Designed for installation on destroyers and larger ships to search for low-flying warplanes and surface ships, it achieved greatly improved surface coverage and detection of aircraft compared with previous lower frequency radars.

[2] It also proved a superior navigation aid, making possible the detection of buoys and shoreline at night or bad weather.