SM was an American made fighter-direction

radar Radar is a detection system that uses radio waves to determine the distance ('' ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, we ...

used for the ship ground-controlled interception (GCI) 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 opposing ...

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 ...

. Variation included the SM-1.

SM radar

Microwave Microwave is a form of electromagnetic radiation with wavelengths ranging from about one meter to one millimeter corresponding to frequencies between 300 MHz and 300 GHz respectively. Different sources define different frequency ra ...

set with three

axis An axis (plural ''axes'') is an imaginary line around which an object rotates or is symmetrical. Axis may also refer to: Mathematics * Axis of rotation: see rotation around a fixed axis * Axis (mathematics), a designator for a Cartesian-coordinat ...

stabilized antenna, installed on aircraft carriers to search for enemy planes, particularly low-flying and shadow planes, and to supply height, speed and course data so that a Fighter Director Officer can direct fighters to an interception. Can also be used to search for ships and periscopes. SM is correlated with search sets, such as SK, and with radio communication to planes. Has provisions for A and G-band

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 ...

, and a built-in BO antenna. For night interception,

AIA AIA or A.I.A. or Aia may refer to: Aia * Aia, a small town in the Basque province of Gipuzkoa, Spain * Aia, current Kutaisi, ancient capital of Colchis * Aia, another name for Aea (Malis), an ancient town in Greece * ''Aia'', the collected ed ...

is required in planes. SM has a reliable detection range of on a

medium bomber A medium bomber is a military bomber aircraft designed to operate with medium-sized bombloads over medium range distances; the name serves to distinguish this type from larger heavy bombers and smaller light bombers. Mediums generally carrie ...

above optical horizon as surfaced submarines can be followed to horizon.

Periscope A periscope is an instrument for observation over, around or through an object, obstacle or condition that prevents direct line-of-sight observation from an observer's current position. In its simplest form, it consists of an outer case with ...

s can be seen or more, and buoys can be seen up to horizon. Range can be determined to ± , or 1/4%, whichever is greater. Bearing can be determined to ± 1/2 °. Elevation can be determined to ±1/3° if airplane is 21/2° or more above optical horizon. If plane is lower, data is less reliable. Accuracy of range difference between two targets is ± for separation of . Elevation limit is 90°. Spares, testing equipment and separate generator supplied. SM has 23 components weighing a total of about 9

ton Ton is the name of any one of several units of measure. It has a long history and has acquired several meanings and uses. Mainly it describes units of weight. Confusion can arise because ''ton'' can mean * the long ton, which is 2,240 pounds ...

s. Largest unit is the antenna mount, at high, with a diameter of at base, and weighing about . The antenna is in diameter; antennas will be installed on later sets. The console, in dimensions and in weigh, splits into 3 parts for installation. Minimum operators per shift required are two, plus one assistant radar officer. Recommended personnel: 15 per day. Power required is 45-65 KW, 440 V 3-phase 60 Hz, supplied by motor generator set, or, in emergencies, from ship's supply. USS ''Lexington'' (CV-16) was equipped with the first prototype of SM radar in March 1943, while USS ''Enterprise'' (CV-6) and USS ''Bunker Hill'' (CV-17) were equipped with the first two production models in October of the same year. 26 SM-1 variants were all produced and

leased A lease is a contractual arrangement calling for the user (referred to as the ''lessee'') to pay the owner (referred to as the ''lessor'') for the use of an asset. Property, buildings and vehicles are common assets that are leased. Industrial ...

to the

Royal Navy The Royal Navy (RN) is the United Kingdom's naval warfare force. Although warships were used by English and Scottish kings from the early medieval period, the first major maritime engagements were fought in the Hundred Years' War against ...

. SM was developed from the

SCR-584 radar The SCR-584 (short for '' Set, Complete, Radio # 584'') was an automatic-tracking microwave radar developed by the MIT Radiation Laboratory during World War II. It was one of the most advanced ground-based radars of its era, and became one of th ...

Onboard ships

United States

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 ...

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

United Kingdom

* HMS ''Boxer'' (F121) File:USS Enterprise (CV-6), port amidships, at the Puget Sound Naval Shipyard, Washington (USA), on 19 October 1943 (NH 81080).jpg, SM aboard USS Enterprise File:USS Saratoga (CV-3) at Pearl Harbor 1945.jpg, SM aboard USS Saratoga File:USS Bunker Hill (CV-17) in a photo most likely taken in or after October 1945..jpg, SM aboard USS Bunker Hill File:HMS Boxer.jpg, SM-1 aboard

HMS Boxer Several ships of the British Royal Navy have been named HMS ''Boxer'', named after the competitor in a boxing match. * was an launched in 1797 and sold in 1809. * was a launched in 1812 that the US Navy captured in 1813 during the War of 1812 ...

SP radar

SP or CXDT was the lightweight version of the SM radar. It replaced the SK radar in the later stages of the war.

Onboard ships

United States

Saipan-class aircraft carrier The ''Saipan''-class aircraft carriers were a class of two light carriers and built for the United States Navy during World War II. Like the nine light carriers, they were based on cruiser hulls. However, they differed from the earlier li ...

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 ...

Commencement Bay-class escort carrier The ''Commencement Bay''-class escort aircraft carriers were the last class of escort carriers built for the US Navy in World War II. The ships were based on the Maritime Commission type T3 Tanker hull, which gave them a displacement of appr ...

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 b ...

* North Carolina-class battleship * USS ''California'' (BB-44) * USS ''Pennsylvania'' (BB-38) *

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 ...

Gearing-class destroyer The ''Gearing'' class was a series of 98 destroyers built for the U.S. Navy during and shortly after World War II. The ''Gearing'' design was a minor modification of the , whereby the hull was lengthened by at amidships, which resulted in mo ...

Porter-class destroyer The ''Porter''-class destroyers were a class of eight 1,850-ton large destroyers in the United States Navy. Like the preceding , their construction was authorized by Congress on 26 April 1916, but funding was delayed considerably. They were desi ...

Buckley-class destroyer escort The ''Buckley''-class destroyer escorts were 102 destroyer escorts launched in the United States in 1943–44. They served in World War II as convoy escorts and anti-submarine warfare ships. The lead ship was which was launched on 9 January 1 ...

* Adirondack-class command ship * Mount McKinley-class command ship

France

* ''Jean Bart'' (1940) File:USS Buckley (DE-51), following her conversion to a radar picket ship, circa in late 1945 (NH 107405).jpg, SP aboard USS Buckley File:USS Pocono (AGC-16) at anchor on 28 August 1956 (6929433).jpg, SP aboard USS Pocono File:Radars of USS Newport News (CA-148) c1952.jpg, SP aboard USS Newport News File:USS Vesole (DD-878) underway c1946.jpg, SP aboard USS Vesole

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

SM radar

Onboard ships

United States

United Kingdom

SP radar

Onboard ships

United States

France

See also

Citations

References