Type 277 radar

Type 277 radar was a crucial S band surface warning and target indication radar developed in the United Kingdom during the latter stages of the Second World War. Designed to replace the earlier Type 273 radar, it provided Royal Navy vessels with vastly improved detection of surface targets and low-flying aircraft. Its distinctive "cheese" antenna and high power output made it a mainstay of British and Commonwealth naval fleets well into the Cold War.

Development and design

The development of the Type 277 was driven by the operational limitations of its predecessor, the Type 273 radar, which operated in the metric P band and suffered from poor accuracy and resolution. Spearheaded by the Admiralty Signal Establishment, the project aimed to harness the superior capabilities of the S band for naval surface search. Key design work was conducted at the Telecommunications Research Establishment, leveraging advances in cavity magnetron technology pioneered for systems like the H2S radar. The antenna was a horizontally mounted "cheese" antenna, a type of parabolic reflector, which produced a narrow, fan-shaped beam ideal for surface warning. This design allowed for accurate bearing determination and good discrimination against sea clutter, a significant improvement over earlier sets.

Technical specifications

Operating in the S band at a frequency of approximately 3000 MHz, the Type 277 utilized a peak power output of 500 kW. Its "cheese" antenna, with dimensions of approximately 8 feet by 3 feet, generated a beam width of about 1.5 degrees in azimuth and 12 degrees in elevation. This configuration provided a maximum range of around 25 nautical miles against surface targets like U-boats or small ships, and was also effective for detecting the low-flying aircraft that threatened Allied convoys. The display system typically used a Plan Position Indicator, giving operators a clear map-like view of surrounding contacts. The radar's components, including the powerful magnetron and sturdy waveguide system, were engineered for the harsh environment of naval warfare in theaters such as the Battle of the Atlantic.

Operational history

The Type 277 entered service with the Royal Navy in 1944, seeing action in the final year of the Second World War. It was rapidly fitted to a wide range of vessels, including destroyers, frigates, and larger fleet units like the ''King George V''-class battleships, significantly enhancing their situational awareness. Its performance proved invaluable for anti-submarine warfare in the North Atlantic and for fleet operations in the Pacific War. Post-war, the Type 277 remained a standard fit throughout the Royal Navy and was widely exported to Commonwealth navies, including the Royal Canadian Navy and Royal Australian Navy. It saw continued use during the Korean War and the early decades of the Cold War, serving on ships like the HMCS ''Bonaventure'' before being gradually supplanted by newer models such as the Type 293 radar.

Variants

Several key variants of the radar were produced to meet different operational requirements. The Type 277P was a modified version with a power output increased to 1 MW, offering greater range and detection capability. The Type 277Q incorporated a different antenna mounting and display system optimized for specific classes of smaller escorts. For height-finding purposes, the system was sometimes integrated with the Type 293 radar, which used a similar "cheese" antenna but was mounted to scan in elevation. These adaptations ensured the Type 277 family could be deployed effectively across the diverse fleet of the Royal Navy and allied services.

See also

* Type 293 radar * Type 273 radar * H2S radar * Cavity magnetron * Royal Navy

Category:World War II radars Category:Royal Navy Category:Radar