SK was an American-made air-search radar used during

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

by the

United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

. Models include SK-1, SK-2 and SK-3.

Overview

Long wave In radio, longwave, long wave or long-wave, and commonly abbreviated LW, refers to parts of the radio spectrum with wavelengths longer than what was originally called the medium-wave broadcasting band. The term is historic, dating from the e ...

search set for large ships. Furnishes range and bearing of surface vessels and aircraft, and can be used for control of interception. Set has both "A" and PPI scopes, provisions for operating with remote PPI's and for

IFF In logic and related fields such as mathematics and philosophy, "if and only if" (shortened as "iff") is a biconditional logical connective between statements, where either both statements are true or both are false. The connective is bicon ...

connections, and built-in BL and BI

antennas In radio engineering, an antenna or aerial is the interface between radio waves propagating through space and electric currents moving in metal conductors, used with a transmitter or receiver. In transmission, a radio transmitter supplies a ...

. Reliable maximum range, with antenna at , is on medium bombers at altitude. Range accuracy is ± .

Azimuth An azimuth (; from ar, اَلسُّمُوت, as-sumūt, the directions) is an angular measurement in a spherical coordinate system. More specifically, it is the horizontal angle from a cardinal direction, most commonly north. Mathematicall ...

accuracy, ± 3°. There is no elevation control, but elevation can be estimated roughly from positions of maximum, and minimum signal strength. Shipment includes spares, with tubes for 400 hours, and separate generator if ship's power is DC. Not air transportable. SK has 10 components weighing approximately . Heaviest unit, at , is the antenna assembly. Antenna measures x . Antenna should be or more above water. Minimum operators required are one per shift. Primary power required is 3500

kilowatts The watt (symbol: W) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantify the rate of energy transfer. The watt is named after James Wa ...

, 115

volts The volt (symbol: V) is the unit of electric potential, electric potential difference (voltage), and electromotive force in the International System of Units (SI). It is named after the Italian physicist Alessandro Volta (1745–1827). Definit ...

, 60 Hz. Source of power is ship's power of 115 volts, 60 Hz. During the later stages of the war, a

parabolic antenna A parabolic antenna is an antenna that uses a parabolic reflector, a curved surface with the cross-sectional shape of a parabola, to direct the radio waves. The most common form is shaped like a dish and is popularly called a dish antenna or pa ...

called SK-2 would then replace the SK-1.

Onboard ships

United States

Midway-class aircraft carrier *

Essex-class aircraft carrier The ''Essex'' class was a class of aircraft carriers of the United States Navy. The 20th century's most numerous class of capital ship, the class consisted of 24 vessels, which came in "short-hull" and "long-hull" versions. Thirty-two ships wer ...

Independence-class aircraft carrier The ''Independence''-class aircraft carriers were a class of light carriers built for the United States Navy that served during World War II. Development Adapted from the design for the light cruisers, this class of ship resulted from the i ...

* USS ''Enterprise'' (CV-6) * USS ''Saratoga'' (CV-3) *

Casablanca-class escort carrier The ''Casablanca''-class escort carrier were a series of escort carriers constructed for the United States Navy during World War II. They are the most numerous class of aircraft carriers ever built. Fifty were laid down, launched and commissione ...

Bogue-class escort carrier The ''Bogue'' class were a class of 45 escort carriers built in the United States for service with the US Navy and the Royal Navy, through the Lend-Lease program, during World War II. Following the war, ten ''Bogue''-class ships were kept in ser ...

Iowa-class battleship The ''Iowa'' class was a class of six fast battleships ordered by the United States Navy in 1939 and 1940. They were initially intended to intercept fast capital ships such as the Japanese while also being capable of serving in a traditional ba ...

* South Dakota-class battleship * North Carolina-class battleship *

Colorado-class battleship The ''Colorado''-class battleships were a group of four United States Navy super-dreadnoughts, the last of its pre-Treaty battleships. Designed during World War I, their construction overlapped the end of that conflict and continued in its i ...

Tennessee-class battleship The ''Tennessee'' class consisted of two super-dreadnought battleships— and —built for the United States Navy in the late 1910s, part of the standard-type battleship, "standard" series. The ship class, class was in most respects a repeat of ...

* USS ''Pennsylvania'' (BB-38) * USS Augusta (CA-31) steaming off Portland, Maine (USA), on 9 May 1945 (NH 97932)

Nevada-class battleship *

New York-class battleship The ''New York'' class was a pair of super-dreadnought battleships built for the United States Navy between 1911 and 1914. The two ships of the class, and , saw extensive service beginning in the occupation of Veracruz, World War I, and World ...

* USS ''Arkansas'' (BB-33) *

Alaska-class cruiser The ''Alaska'' class were six very large cruisers ordered before World War II for the United States Navy, of which only two were completed and saw service late in the war. The US Navy designation for the ships of this class was 'large cruiser ...

Des Moines-class cruiser ''Italic text'' The ''Des Moines''-class cruisers were a trio of very large U.S. Navy heavy cruisers commissioned in 1948 and 1949. They were the last of the all-gun heavy cruisers, exceeded in size in the American navy only by the s that straddl ...

Oregon City-class cruiser The ''Oregon City'' class was a class of heavy cruisers of the United States Navy. Although ten ships of this class were planned, only four were completed – one of those as a command ship. The three ships completed as cruisers were in commiss ...

Baltimore-class cruiser The ''Baltimore''-class heavy cruisers were a large class of heavy cruisers in the United States Navy commissioned during and shortly after World War II.The ''Baltimore''-class were the largest cruisers of World War II by tonnage. Fourteen ''B ...

* USS ''Wichita'' (CA-45) *

Fargo-class cruiser The ''Fargo''-class cruisers were a modified version of the design; the main difference was a more compact pyramidal superstructure with single trunked funnel, intended to improve the arcs of fire of the anti-aircraft (AA) guns. The same type o ...

Cleveland-class cruiser The ''Cleveland'' class was a group of light cruisers built for the U.S. Navy during World War II. They were the most numerous class of light cruisers ever built. Fifty-two were ordered, and 36 completed, 27 as cruisers and 9 as light aircraft ...

New Orleans-class cruiser The ''New Orleans''-class cruisers were a class of seven heavy cruisers built for the United States Navy (USN) in the 1930s. These ships participated in the heaviest surface battles of the Pacific War. ''Astoria'', ''Quincy'', and ''Vincenne ...

* Brooklyn-class cruiser * Portland-class cruiser *

Northampton-class cruiser The ''Northampton''-class cruisers were a group of six heavy cruisers built for the United States Navy, and commissioned between 1928 and 1931. The ''Northampton''s saw much action in World War II. Three (''Northampton'', ''Chicago'', and ''Hou ...

* Pensacola-class cruiser * Omaha-class cruiser * Currituck-class seaplane tender * Appalachian-class command ship * Mount McKinley-class command ship

United Kingdom

* Ruler-class escort carrier * HMS ''Boxer'' (F121)

Gallery

File:Grumman Avenger landing on HMS Trumpeter WWII IWM A 24282.jpg, SK-1 aboard HMS Trumpeter File:Battleship Texas - exterior - DSCN0165.JPG, SK-1 aboard USS Texas File:USS Wichita (CA-45) underway in the Central Pacific on 2 May 1944.jpg, SK-1 aboard USS Wichita File:USS Alabama - Mobile, AL - Flickr - hyku (195).jpg, SK-2 aboard USS Alabama File:USS Macon (CA-132) underway off the Philadelphia Navy Yard on 29 October 1946.jpg, SK-2 aboard USS Macon File:Radars of USS Princeton (CV-37) in 1952.jpg, SK-3 aboard USS Princeton

Citations

References

Norman Friedman Norman Friedman (born 1946) is an American internationally known author and analyst, strategist, and historian. He has written over 30 books and numerous articles on naval and other military matters, has worked for the U.S. Navy and Marine Corps ...

(2006).
The Naval Institute Guide to World Naval Weapon Systems
'.

Naval Institute Press The United States Naval Institute (USNI) is a private non-profit military association that offers independent, nonpartisan forums for debate of national security issues. In addition to publishing magazines and books, the Naval Institute holds se ...

. * Buderi, Robert (1998). ''The Invention That Changed the World: How a Small Group of Radar Pioneers Won the Second World War and Launched a Technical Revolution.'' Touchstone. * Hezlet, Arthur (1975). ''Electronics and Sea Power. New York: Stein and Day''. {{ISBN, 0-8128-1811-3 Naval radars World War II radars Military equipment introduced from 1940 to 1944 Military radars of the United States