SD radar

SD radar

Various masts and equipment of the USS Sculpin in 1943. The SD radar mast in designated as item 10.
Country of origin	United States
Manufacturer	RCA Victor Division of RCA[1]
Designer	US Naval Research Laboratory[2]
Introduced	1941[2]
No. built	400+[2]
Frequency	114 MHz[2]
PRF	60 Hz
Beamwidth	40° (horizontal)
Pulsewidth	8.5 µs
RPM	4
Range	20 mi (32 km)[3]
Altitude	1,000 ft (300 m)[3]
Azimuth	360º
Precision	450 m (1,480 ft)[4]
Power	100 kw (SD-5 130 kw)[2]

The SD radar was an early form of radar developed by the United States Naval Research Laboratory between 1940 and 1941. It was installed on submarines to provide warning of enemy aircraft. Its omnidirectional antenna, however, prevented it from being able to provide bearing information, and it was used as a proximity radar.^[2] Its range was directly affected by the aircraft's size and altitude. Large aircraft with an altitude above 1000 feet AGL could be detected between twelve and twenty miles, and small aircraft at the same altitude between eight and fifteen miles, while aircraft flying lower could avoid detection altogether.^[3] Another disadvantage was the enemy's ability to use the SD radar signal to locate and target submarines, leading submarine commanders to only use the SD radar intermittently so as not to disclose their location.^[5]

See also

• SJ radar

References

1. List of Naval Radio, Radar, and Sonar Equipment Arranged by Navy Model Letters (PDF). Washington D.C.: US Navy. January 1945. p. 106.
2. Gebhard, Louis A. (1979). Evolution of Naval Radio-Electronics and Contributions of the Naval Research Laboratory. Washington, D.C.: Naval Research Laboratory. p. 186. Retrieved 13 July 2021.
3. Radar Operator's Manual. United States Navy. 1944. p. 266. Retrieved 13 July 2021.
4. "SD". Radar Tutorial. Retrieved 14 July 2021.
5. Lockwood, Charles A. (1951). Sink 'Em All (2nd ed.). New York: E.P. Dutton & Co. p. 204. ISBN 1258432366. Retrieved 13 July 2021.