# SG radar

> Mediated Wiki article. Canonical URL: https://mediated.wiki/source/SG_radar
> Markdown URL: https://mediated.wiki/source/SG_radar.md
> Source: https://en.wikipedia.org/wiki/SG_radar
> Source revision: 1335156623
> License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/)

American surface-search radar

SG radar SG (at the top of the mast) and SK-1 (below and to the left of the SG) radar antennas of USS Astoria Country of origin United States Designer Raytheon MIT Radiation Laboratory Naval Research Laboratory Introduced 1942 No. built 955 Type Surface-search radar Frequency 3 GHz PRF 775, 800, or 825 Beamwidth 5.6° (horizontal) 15° (vertical) Pulsewidth 1.3–2 μs RPM 4, 8, or 12 Range 15 nmi (28 km; 17 mi) Precision 200 yd (180 m) Power 50 kW

The **SG radar** was a [US Navy](/source/US_Navy) [surface-search radar](/source/Surface-search_radar) for large warships developed during the [Second World War](/source/Second_World_War). The first operational set was installed aboard the [heavy cruiser](/source/Heavy_cruiser) [USS *Augusta*](/source/USS_Augusta_(CA-31)) in April 1942.[1] It was the first Navy radar to use [S-band](/source/S-band) ([microwave](/source/Microwave)) frequencies [2] and the first surface-search radar to be equipped with a [plan position indicator](/source/Plan_position_indicator) (PPI), the ancestor of virtually all modern radar displays.

The radar was developed by [Raytheon](/source/Raytheon) under the guidance of the [MIT Radiation Laboratory](/source/MIT_Radiation_Laboratory) and [Naval Research Laboratory](/source/Naval_Research_Laboratory) using the cutting-edge [multicavity magnetron](/source/Cavity_magnetron) technology developed in Britain and brought to the US by the [Tizard Mission](/source/Tizard_Mission).[2] The prototype was tested at sea aboard the [destroyer](/source/Destroyer) [USS *Semmes*](/source/USS_Semmes_(DD-189)) in May 1941.[3] It saw extensive use during [World War 2](/source/World_War_2), particularly in the Pacific Theater, with about 1000 units produced during the war, and remained in service for about 2 decades.[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.

Operating console.  The three large round displays are *(left to right)*: "A display" of return signal versus time, gyrocompass readout, and PPI (Plan Position Indicator) display

## Notes

1. **[^](#cite_ref-f8_1-0)** Friedman, p. 148

1. ^ [***a***](#cite_ref-Gebhard_2-0) [***b***](#cite_ref-Gebhard_2-1) [***c***](#cite_ref-Gebhard_2-2) [***d***](#cite_ref-Gebhard_2-3) Gebhard, Louis A. (1979). [*Evolution of Naval Radio-electronics and Contributions of the Naval Research Laboratory*](https://books.google.com/books?id=8pOPvqSkcCYC&pg=PA187&dq=sg+radar). US Naval Research Laboratory. p. 187.

1. **[^](#cite_ref-3)** Watson, p. 212

## Bibliography

- Brown, Louis (1999). *A Radar History of World War II: Technical and Military Imperatives*. Bristol and Philadelphia: Institute of Physics Publishing. [ISBN](/source/ISBN_(identifier)) [0-7503-0659-9](https://en.wikipedia.org/wiki/Special:BookSources/0-7503-0659-9).

- Friedman, Norman (1981). *Naval Radar*. London: Conway Maritime Press. [ISBN](/source/ISBN_(identifier)) [0-85177-238-2](https://en.wikipedia.org/wiki/Special:BookSources/0-85177-238-2).

- Watson, Raymond C. Jr. (2009). *Radar Origins Worldwide: History of Its Evolution in 13 Nations Through World War II*. Trafford. [ISBN](/source/ISBN_(identifier)) [978-1-4269-2111-7](https://en.wikipedia.org/wiki/Special:BookSources/978-1-4269-2111-7).

## Further reading

- ["US Radar: Operational Characteristics of Radar Classified by Tactical Application"](https://www.history.navy.mil/content/history/nhhc/research/library/online-reading-room/title-list-alphabetically/u/operational-characteristics-of-radar-classified-by-tactical-application.html). Naval History and Heritage Command. Retrieved 2022-02-18.

---
Adapted from the Wikipedia article [SG radar](https://en.wikipedia.org/wiki/SG_radar) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/SG_radar?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.