SM was an American made fighter-direction radar used for the ship ground-controlled interception (GCI) during World War II by the United States Navy.

[1] Microwave set with three axis stabilized antenna, installed on aircraft carriers to search for enemy planes, particularly low-flying and shadow planes, and to supply height, speed and course data so that a Fighter Director Officer can direct fighters to an interception.

SM is correlated with search sets, such as SK, and with radio communication to planes.

The largest unit is the antenna mount, at 131 in (3.3 m) high, with a diameter of 67 in (1.7 m) at base, and weighing about 4,600 lb (2,100 kg).

Minimum operators per shift required are two, plus one assistant radar officer.