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

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

by the

United States Navy The United States Navy (USN) is the naval warfare, maritime military branch, service branch of the United States Department of Defense. It is the world's most powerful navy with the largest Displacement (ship), displacement, at 4.5 millio ...

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

Overview

SK was a very high frequency search set for large ships. It furnished range and bearing of surface vessels and aircraft, and it could be used for control of interception. The set had both "A" and PPI scopes, provisions for operating with remote PPIs and for

IFF In logic and related fields such as mathematics and philosophy, "if and only if" (often shortened as "iff") is paraphrased by the biconditional, a logical connective between statements. The biconditional is true in two cases, where either both ...

connections, and built-in BL and BI

antennas In radio-frequency engineering, an antenna (American English) or aerial (British English) is an electronic device that converts an alternating electric current into radio waves (transmitting), or radio waves into an electric current (receivi ...

. With the antenna at , SK could detect

medium bomber A medium bomber is a military bomber Fixed-wing aircraft, aircraft designed to operate with medium-sized Aerial bomb, bombloads over medium Range (aeronautics), range distances; the name serves to distinguish this type from larger heavy bombe ...

s at altitude at . Range accuracy was ± and

azimuth An azimuth (; from ) is the horizontal angle from a cardinal direction, most commonly north, in a local or observer-centric spherical coordinate system. Mathematically, the relative position vector from an observer ( origin) to a point ...

accuracy ± 3°. There was no elevation control, but elevation could be estimated roughly from positions of maximum and minimum signal strength. Shipment for SK included spares, with tubes for 400 hours, and a separate generator if the ship's power is DC. SK was not air transportable. SK had 10 components weighing approximately . The heaviest unit, at , was the antenna assembly. The antenna measured x . It was mounted or more above water. The minimum operators required were one per shift. Primary power required was 3500

watts Watts is plural for ''watt'', the unit of power. Watts may also refer to: People *Watts (surname), a list of people with the surname Watts Fictional characters *Albie Watts, a fictional character in the British soap opera ''EastEnders'' *Angie ...

, 115

volt The volt (symbol: V) is the unit of electric potential, Voltage#Galvani potential vs. electrochemical potential, electric potential difference (voltage), and electromotive force in the International System of Units, International System of Uni ...

s, 60 Hz. The source of power is ship's power of 115 volts, 60 Hz. During the later stages of

, 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 p ...

called SK-2 replaced the SK-1.

On board ships

United States

* * * USS ''Enterprise'' (CV-6) * USS ''Saratoga'' (CV-3) * * * * ''South Dakota''-class battleship * * * * USS ''Pennsylvania'' (BB-38) * * * USS ''Arkansas'' (BB-33) * * * * * USS ''Wichita'' (CA-45) * * * * * * * * * * * * ''Commencement Bay''-class escort carrier

United Kingdom

* * HMS ''Boxer'' (F121)

Gallery

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

Citations

References

Norman Friedman Norman Friedman (born 1946) is an American author, 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, and has appeared on tel ...

(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