Radar, Anti-Aircraft No. 4 Mk. 7

Last updated
AA No.4 Mk.7
Country of originUK
Type tactical control
FrequencyS band, 3 GHz
PRF 700 to 800
Beamwidth 5º horizontal, ~30º vertical
Pulsewidth1.25 μS
RPM15
Range120,000 yd (110,000 m)
Altitude60,000 ft (18,000 m)
Diameter45 ft (14 m)
Azimuth 360º
Precision500 yd (460 m) in range, 1.75º azimuth
Power1 MW

Radar, Anti-Aircraft Number 4 Mark 7, or AA No.4 Mk.7 for short, was a mobile medium-range tactical control radar used by the British Army. It was intended to rapidly scan the sky and quickly indicate targets that could then be handed off to anti-aircraft artillery batteries who would then aim their own gun laying radars like the AA No. 3 Mk. 7 using the image provided from the No. 4 on a remote Adjacent Display (AD) unit. The Mk.7/1 added support for IFF Mark X, and the Mk.7/2 was modified for use with surface-to-air missiles.

The system used a unique antenna system designed to be compact and robust. It consisted of a cheese antenna mounted flat on the roof of the operations trailer, and a semi-parabolic reflector in front of it. The cheese produces a signal that is narrow side-to-side, about 5 degrees in this system, but very wide vertically. This signal was then further shaped by the reflector to lessen the vertical angle. The assembly was mounted on a pole that ran through the roof of the trailer and into a bearing on the floor where it was rotated by a motor. For transport, the reflector was folded down on top of the cheese, the assembly moved to center it over the top of the trailer, and then grate-like covers on the sides of the trailer were raised and folded over the top of the antenna system to protect it.

The system was normally operated by a crew of two. Air conditioning was supplied to cool the equipment and the trailer as a whole, with the power and air conditioning systems taking up about half of the trailer and the radar systems the other half. Power was supplied by an external Meadows 27.5 kVA 415/240V three phase 50 Hz generator on a skid that was normally carried in the towing vehicle and then set on the ground during setup. The eight-wheeled trailer massed 10 tons.

Related Research Articles

SCR-268 radar U.S. Armys first radar system

The SCR-268 was the United States Army's first radar system. Introduced in 1940, it was developed to provide accurate aiming information for antiaircraft artillery and was also used for gun laying systems and directing searchlights against aircraft. The radar was widely utilized by both Army and Marine Corps air defense and early warning units during World War II. By the end of World War II the system was already considered out of date, having been replaced by the much smaller and more accurate SCR-584 microwave-based system.

SCR-584 radar

The SCR-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 the primary gun laying radars used worldwide well into the 1950s. A trailer-mounted mobile version was the SCR-784.

Armament of the <i>Iowa</i>-class battleship Armament of WWII battleship

The Iowa-class battleships are the most heavily armed gunships the United States Navy has ever put to sea, due to the continual development of their onboard weaponry. The first Iowa-class ship was laid down in June 1940; in their World War II configuration, each of the Iowa-class battleships had a main battery of 16-inch (406 mm) guns that could hit targets nearly 20 statute miles (32 km) away with a variety of artillery shells designed for anti-ship or bombardment work. The secondary battery of 5-inch (127 mm) guns could hit targets nearly 9 statute miles (14 km) away with solid projectiles or proximity fuzed shells, and was effective in an anti-aircraft role as well. Each of the four battleships carried a wide array of 20 mm and 40 mm anti-aircraft guns for defense against enemy aircraft.

Radar in World War II greatly influenced many important aspects of the conflict. This revolutionary new technology of radio-based detection and tracking was used by both the Allies and Axis powers in World War II, which had evolved independently in a number of nations during the mid 1930s. At the outbreak of war in September 1939, both Great Britain and Germany had functioning radar systems. In Great Britain, it was called RDF, Range and Direction Finding, while in Germany the name Funkmeß (radio-measuring) was used, with apparatuses called Funkmessgerät . By the time of the Battle of Britain in mid-1940, the Royal Air Force (RAF) had fully integrated RDF as part of the national air defence.

Blue Joker was an experimental moored balloon-mounted, airborne early-warning radar project developed by the Royal Radar Establishment (RRE) starting in 1953. The idea was to position the radar high in the air in order to extend its radar horizon and allow it to see low-flying aircraft. Ground reflections were filtered out using a moving target indicator (MTI) system. Two examples were built and tested in the late 1950s, but the project was cancelled in 1960 as part of the Linesman/Mediator efforts.

Foster scanner

The Foster scanner, or Variable Path scanner, is a type of radar system that produces a narrow beam that rapidly scans an area in front of it. Foster scanners were widely used in post-World War II radar systems used for artillery and mortar spotting. Modern radars in this role normally use electronic scanning in place of a Foster scanner for this purpose.

Type 271 radar British WWII naval surface search radar

The Type 271 was a surface search radar used by the Royal Navy and allies during World War II. The first widely used naval microwave-frequency system, it was equipped with an antenna small enough to allow it to be mounted on small ships like corvettes and frigates, while its improved resolution over earlier radars allowed it to pick up a surfaced U-boat at around 3 miles (4.8 km) and its periscope alone at 900 yards (820 m).

AI Mk. IV radar Operational model of the worlds first air-to-air radar system

Radar, Airborne Interception, Mark IV, or AI Mk. IV for short, was the world's first operational air-to-air radar system. Early Mk. III units appeared in July 1940 on converted Bristol Blenheim light bombers, while the definitive Mk. IV reached widespread availability on the Bristol Beaufighter heavy fighter by early 1941. On the Beaufighter, the Mk. IV arguably played a role in ending the Blitz, the Luftwaffe's night bombing campaign of late 1940 and early 1941.

AI Mk. VIII radar

Radar, Airborne Interception, Mark VIII, or AI Mk. VIII for short, was the first operational microwave-frequency air-to-air radar. It was used by Royal Air Force night fighters from late 1941 until the end of World War II. The basic concept, using a moving parabolic antenna to search for targets and track them accurately, remained in use by most airborne radars well into the 1980s.

GL Mk. I radar

Radar, Gun Laying, Mark I, or GL Mk. I for short, was an early radar system developed by the British Army to provide range information to associated anti-aircraft artillery. There were two upgrades to the same basic system, GL/EF and GL Mk. II, both of which added the ability to accurately determine bearing and elevation.

Radar, Anti-Aircraft No. 3 Mk. 7

Radar, Anti-Aircraft Number 3 Mark 7, also widely referred to by its development rainbow code Blue Cedar, was a mobile anti-aircraft gun laying radar designed by British Thomson-Houston (BTH) in the mid-1940s. It was used extensively by the British Army and was exported to countries such as Holland, Switzerland, Sweden Finland and South Africa. In British service, it was used with the 5.25 inch and QF 3.7 inch AA guns, as well as the Brakemine missile.

GL Mk. III radar

Radar, Gun Laying, Mark III, or GL Mk. III for short, was a radar system used by the British Army to directly guide, or lay, anti-aircraft artillery (AA). The GL Mk. III was not a single radar, but a family of related designs that saw constant improvement during and after World War II. These were renamed shortly after their introduction in late 1942, becoming the Radar, AA, No. 3, and often paired with an early warning radar, the AA No. 4, which was also produced in several models.

AIRPASS

AIRPASS was a British airborne interception radar and fire-control radar system developed by Ferranti. It was the world's first airborne monopulse radar system and fed data to the world's first head-up display. The name is an acronym for "Airborne Interception Radar and Pilot's Attack Sight System". In the Royal Air Force (RAF) it was given the official name Radar, Airborne Interception, Mark 23, normally shortened to AI.23. AIRPASS was used on the English Electric Lightning throughout its lifetime.

Type 277 radar

The Type 277 was a surface search and secondary aircraft early warning radar used by the Royal Navy and allies during World War II and the post-war era. It was a major update of the earlier Type 271 radar, offering much more power, better signal processing, new displays, and new antennas with greatly improved performance and much simpler mounting requirements. It allowed a radar with performance formerly found only on cruisers and battleships to be fitted even to the smallest corvettes. It began to replace the 271 in 1943 and was widespread by the end of the year.

Searchlight Control radar

Searchlight Control, SLC for short but nicknamed "Elsie", was a British Army VHF-band radar system that provided aiming guidance to an attached searchlight. By combining a searchlight with a radar, the radar did not have to be particularly accurate, it only had to be good enough to get the searchlight beam on the target. Once the target was lit, normal optical instruments could be used to guide the associated anti-aircraft artillery. This allowed the radar to be much smaller, simpler and less expensive than a system with enough accuracy to directly aim the guns, like the large and complex GL Mk. II radar. In 1943 the system was officially designated Radar, AA, No. 2, although this name is rarely used.

AMES Type 82

The AMES Type 82, also widely known by its rainbow codename Orange Yeoman, was an S-band 3D radar built by Marconi and used by the Royal Air Force (RAF), initially for tactical control and later for air traffic control (ATC).

Radar, Anti-Aircraft, or simply AA radar for short, was a classification system for British Army radars introduced in 1943 and used into the 1960s when these systems were replaced by missiles with their own integral radar systems. The classification included subcategories, Number 1 through 8, as well as the many individual systems which were assigned Marks.

AMES Type 80

The AMES Type 80, sometimes known by its development rainbow code Green Garlic, was a powerful early warning (EW) and ground-controlled interception (GCI) radar developed by the Telecommunications Research Establishment (TRE) and built by Decca for the Royal Air Force (RAF). It could reliably detect a large fighter or small bomber at ranges over 210 nautical miles, and large, high-flying aircraft were seen out to the radar horizon. It was the primary military ground-based radar in the UK from the mid-1950s into the late 1960s, providing coverage over the entire British Isles.

The AR-3D was a military air traffic control and early warning radar developed by Plessey and first produced in 1975. It used a pencil beam and simple frequency scanning system known as "squint scan" to produce a low-cost 3D radar system that was also relatively mobile. About 23 were produced in total and found sales around the world into the early 1980s.

References