Type 984 was a

Royal Navy The Royal Navy (RN) is the naval warfare force of the United Kingdom. It is a component of His Majesty's Naval Service, and its officers hold their commissions from the King of the United Kingdom, King. Although warships were used by Kingdom ...

radar Radar is a system that uses radio waves to determine the distance ('' ranging''), direction ( azimuth and elevation angles), and radial velocity of objects relative to the site. It is a radiodetermination method used to detect and track ...

system introduced in the mid-1950s, designed by the Admiralty Signals and Radar Establishment. Type 984 was a 3D S band system used for both ground controlled interception (GCI) and as a secondary

early warning An early warning system is a warning system that can be implemented as a Poset, chain of information communication systems and comprises sensors, Detection theory, event detection and decision support system, decision subsystems for early identi ...

system.

Description

The Type 984 was different from most radars in a number of ways. For one, it used a lens made of metal tubes in place of the more traditional parabolic reflector, which made it look like a circular plate rather than the open framework typical of the era. It was mounted on a fully stabilized platform, allowing it to produce a steady image in all but the highest sea states. It also used a unique system for vertical scanning, feeding the output of four cavity magnetrons into four moving feedhorns, each scanning about 5 degrees vertically. Other 3D radars of the era generally picked one solution or the other, using a network of separate feedhorns or a single vertically scanning feed. The use of four magnetrons gave it better range performance; against large high-flying aircraft it had a typical range of , although this fell to as short as against small low flying aircraft. A key part of the overall Type 984 installation was the Comprehensive Display System (CDS), an electromechanical computer that developed "tracks" for aircraft in a semi-automated fashion. This greatly reduced operator workload, allowing the overall system to track many dozens of formations of aircraft while continuing to scan for new contacts, what would today be known as track while scan (TWS). In several tests against

US 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 ...

aircraft during

military exercise A military exercise, training exercise, maneuver (manoeuvre), or war game is the employment of military resources in Military education and training, training for military operations. Military exercises are conducted to explore the effects of ...

s, the combination of the 984's high scanning rates and the CDS' tracking made the ships impossible to approach without being intercepted. CDS also allowed the 984 to be used both for interception control, as well as day-to-day

air traffic control Air traffic control (ATC) is a service provided by ground-based air traffic controllers who direct aircraft on the ground and through a given section of controlled airspace, and can provide advisory services to aircraft in non-controlled air ...

around the fleet

aircraft carrier An aircraft carrier is a warship that serves as a seagoing airbase, equipped with a full-length flight deck and hangar facilities for supporting, arming, deploying and recovering carrier-based aircraft, shipborne aircraft. Typically it is the ...

s. The original design called for a maximum weight of , and a maximum turning circle while scanning of . Many Navy designs of the early 1950s intended to mount the 984, and some sported two installations, fore and aft. As the design matured its weight continued to grow, ultimately reaching , making it too heavy for most ships. At the same time, the Navy's inventory of large ships was shrinking. Ultimately it was mounted on only the aircraft carriers , and .

References

External links

* * {{Cite web , title=Type 984: A massive radar which only the might of a carrier could carry , website=HMS Collingwood Collection , url=http://www.rnmuseumradarandcommunications2006.org.uk/TYPE_984.html , archiveurl=https://web.archive.org/web/20170808083148/http://www.rnmuseumradarandcommunications2006.org.uk/TYPE_984.html , archivedate=8 August 2017 Naval radars Cold War military equipment of the United Kingdom Royal Navy Radar Military equipment introduced in the 1950s