[2] The first six units RCA produced (delivered in 1940) were denoted "CXAM" and were a fusion of XAF and CXZ technologies.

These were installed on the battleship California, the aircraft carrier Yorktown (in September 1940), and the heavy cruisers Pensacola, Northampton, Chester, and Chicago.

These were installed on the battleships Texas (in October 1941), Pennsylvania, West Virginia, North Carolina, and Washington; on the aircraft carriers Lexington, Saratoga, Ranger, Enterprise, and Wasp; on the heavy cruiser Augusta; on two light cruisers; and on the seaplane tender Curtiss.

Surface ships are more difficult to detect due to a number of factors such as signal return from waves (called in general ground clutter), distance to the horizon (due to the curvature of the Earth), elevation of the radar antenna, height of the target above the sea surface, and water vapor in the air.

Lexington's CXAM-1 detected the incoming Japanese carrier aircraft strike at a range of 68 miles (109 km) during the battle of the Coral Sea.