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SG Surface Search Radar


Photograph of SG radar antenna

National Archives #19-N-40832.

Cropped by author.


Specifications:


Wavelength 10 cm
Pulse Width 2 microsecond
Pulse Repetition Frequency     
775, 800 or 825 Hz
Scan rate 4, 8, or 12 rotations per minute
Power 50 kW
Range 15 nautical miles (30 km) (low-altitude bomber)
22 nautical miles (41 km) (battleship)
15 nautical miles (30 km) (destroyer)
Antenna
48" by 15" (122cm by 38cm) cut parabola
Scope
9" (23cm) PPI
5" (13 cm) A scope
Accuracy 200 yards/2 degrees
180 meters/2 degrees
Resolution 400 yards/2 to 3 degrees
370 meters/2 to 3 degrees
Weight 3000 lbs
1350 kg
Production: First available in the Pacific in October 1942 and installed on all cruisers and destroyers by early 1943. 955 were produced by 11/43.


The SG was a vast improvement over SC radar when it was first introduced in 1942. It was standard on cruisers and destroyers by early 1943.  Early models did not have the full 50kW power, but all models had a 9" (23 cm) PPI display with 15,000 and 75,000 yard (13,700 and 69,000 meter) range scales as well as a 5" (13 cm) "A" scan.

The radar was initially buggy and sensitive to shock, and the set on Honolulu at the Battle of Tassafaronga seems to have performed poorly. However, later sets proved sturdy, compact, and dependable. It was well-suited for navigation, being capable of easily distinguishing ships from islands.

Starting in 1944, the radar was equipped with antijamming features.

References

Buderi (1998)

Crenshaw (1995)

Frank (1990)

Friedman (1981)
Guerlac (1987)

Morison (1950)

Roberts (1982)



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