SK (radar)

SK-1 aboard USS Long Island
Country of origin	United States
Manufacturer	General Electric
Introduced	1944
Type	Air-search radar
Frequency	VHF band
Beamwidth	10°
Pulsewidth	5 μs
Range	160.9 km (86.9 nmi)
Azimuth	± 3 °
Precision	± 100 yd (91 m)
Power	250 kW[1]

SK was an American-made air-search radar used during World War II by the United States Navy. Models included SK-1, SK-2 and SK-3.^[2]

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 connections, and built-in BL and BI antennas.^[3]

With the antenna at 100 ft (30 m), SK could detect medium bombers at 1,000 ft (300 m) altitude at 100 miles (160 km). Range accuracy was ± 100 yards (91 m) and azimuth accuracy ± 3°. There was no elevation control, but elevation could be estimated roughly from positions of maximum and minimum signal strength.^[3]

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 5,000 lb (2,300 kg). The heaviest unit, at 2,400 lb (1,100 kg), was the antenna assembly. The antenna measured 15 ft (4.6 m) x 16 ft 9 in (5.11 m). It was mounted 100 ft (30 m) or more above water. The minimum operators required were one per shift. Primary power required was 3500 watts, 115 volts, 60 Hz. The source of power is ship's power of 115 volts, 60 Hz.^[3]

During the later stages of World War II, a parabolic antenna called SK-2 replaced the SK-1.^[1]

• 

  Midway-class aircraft carrier
• Essex-class aircraft carrier
• Independence-class aircraft carrier
• USS Enterprise (CV-6)
• USS Saratoga (CV-3)
• Casablanca-class escort carrier
• Bogue-class escort carrier

• 

  Iowa-class battleship
• South Dakota-class battleship
• North Carolina-class battleship
• Colorado-class battleship
• Tennessee-class battleship
• USS Pennsylvania (BB-38)

• 

  Nevada-class battleship
• New York-class battleship
• USS Arkansas (BB-33)
• Alaska-class cruiser
• Des Moines-class cruiser
• Oregon City-class cruiser
• Baltimore-class cruiser
• USS Wichita (CA-45)
• Fargo-class cruiser
• Cleveland-class cruiser
• New Orleans-class cruiser
• Brooklyn-class cruiser
• Portland-class cruiser
• Northampton-class cruiser
• Pensacola-class cruiser
• Omaha-class cruiser
• Currituck-class seaplane tender
• Appalachian-class command ship
• Mount McKinley-class command ship
• Commencement Bay-class escort carrier

• Ruler-class escort carrier
• HMS Boxer (F121)

• 
  SK-1 aboard HMS Trumpeter
• 
  SK-1 aboard USS Texas
• 
  SK-1 aboard USS Wichita
• 
  SK-2 aboard USS Alabama
• 
  SK-2 aboard USS Macon
• 
  SK-3 aboard USS Princeton

• List of radars
• Radar configurations and types
• Air-search radar

• Norman Friedman (2006). The Naval Institute Guide to World Naval Weapon Systems. Naval Institute Press. ISBN 978-1-55750-262-9
• 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. ISBN 0-684-83529-0
• Hezlet, Arthur (1975). Electronics and Sea Power. New York: Stein and Day. ISBN 0-8128-1811-3