The HF200 is a
height finder radar
A height finder is a ground-based aircraft altitude measuring device. Early height finders were optical range finder devices combined with simple mechanical computers, while later systems migrated to radar devices. The unique vertical oscillating ...
designed and first built by
Decca Radar
The Decca Radar company was a British manufacturer of radar systems. There were originally two divisions, Marine and Heavy Radar, with separate product lines. The latter was sold to Plessey in 1965, and the term "Decca Radar" normally refers to ...
in 1957, and continuing sales into the 1970s after the division was purchased by
Plessey
The Plessey Company plc was a British electronics, defence and telecommunications company. It originated in 1917, growing and diversifying into electronics. It expanded after World War II by acquisition of companies and formed overseas compani ...
in 1965. It was one of the company's successful heavy radar projects, winning the contract for many of the
ROTOR
Rotor may refer to:
Science and technology
Engineering
*Rotor (electric), the non-stationary part of an alternator or electric motor, operating with a stationary element so called the stator
* Helicopter rotor, the rotary wing(s) of a rotorcraft ...
stations in the UK and additional sales around the world with a total production run of about 40 examples. These served into the 1980s, and in one case, 1993, before
3D radar
3-D, 3D, or 3d may refer to:
Science, technology, and mathematics Relating to three-dimensionality
* Three-dimensional space
** 3D computer graphics, computer graphics that use a three-dimensional representation of geometric data
** 3D film, a ...
s removed the need for separate height-finders.
History
Decca Heavy Radar won the contract to build the production models of the
Green Garlic radar system developed by the
Air Ministry
The Air Ministry was a department of the Government of the United Kingdom with the responsibility of managing the affairs of the Royal Air Force, that existed from 1918 to 1964. It was under the political authority of the Secretary of State ...
's
Telecommunications Research Establishment
The Telecommunications Research Establishment (TRE) was the main United Kingdom research and development organization for radio navigation, radar, infra-red detection for heat seeking missiles, and related work for the Royal Air Force (RAF) d ...
(TRE) in the early 1950s. This was just prior to the TRE's merger with their
British Army
The British Army is the principal land warfare force of the United Kingdom, a part of the British Armed Forces along with the Royal Navy and the Royal Air Force. , the British Army comprises 79,380 regular full-time personnel, 4,090 Gurk ...
counterparts to form the
Radar Research Establishment
The Royal Radar Establishment was a research centre in Malvern, Worcestershire in the United Kingdom. It was formed in 1953 as the Radar Research Establishment by the merger of the Air Ministry's Telecommunications Research Establishment (TRE) a ...
in 1953. Decca's version of the Green Garlic was given the name
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 f ...
and was among the most powerful radars of its era; the Mark III versions had a detection range against bomber-sized targets of at least whilst having enough resolution to directly guide
interceptor aircraft
An interceptor aircraft, or simply interceptor, is a type of fighter aircraft designed specifically for the defensive interception role against an attacking enemy aircraft, particularly bombers and reconnaissance aircraft. Aircraft that are cap ...
from its radar displays.
Key to the success of the Mark III was a new 2.5 MW
cavity magnetron
The cavity magnetron is a high-power vacuum tube used in early radar systems and currently in microwave ovens and linear particle accelerators. It generates microwaves using the interaction of a stream of electrons with a magnetic field while ...
developed at Decca. With the completion of development of the Type 80, Decca turned its attention to other roles that might make use of the same electronics. Decca had contacts with the French company
SNERI who had developed a
radar clutter
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, weat ...
suppression system. This was considered for inclusion on a number of Decca radars of the era, notably their
Decca Hydra Decca may refer to:
Music
* Decca Records or Decca Music Group, a record label
* Decca Gold, a classical music record label owned by Universal Music Group
* Decca Broadway, a musical theater record label
* Decca Studios, a recording facility in We ...
military
early warning radar
An early-warning radar is any radar system used primarily for the long-range detection of its targets, i.e., allowing defences to be alerted as ''early'' as possible before the intruder reaches its target, giving the air defences the maximum t ...
. SNERI had also been working on a system to extract height information from a horizon-scanning radar like the Hydra. This generated considerable interest at Decca, but was ultimately proven not to be useful and was not employed.
This left an obvious hole in the UK market for a high-power height-finder with range that matched that of the Type 80, compared to the
WWII
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 opposin ...
-era
AMES Type 13
Ames may refer to:
Places United States
* Ames, Arkansas, a place in Arkansas
* Ames, Colorado
* Ames, Illinois
* Ames, Indiana
* Ames, Iowa, the most populous city bearing this name
* Ames, Kansas
* Ames, Nebraska
* Ames, New York
* Ames, Ok ...
which had an effective range perhaps of the Type 80. Converting the Type 80 electronics to height-finding was straightforward, the main effort would be the development of a suitable antenna with a very narrow vertical beamwidth that would provide accurate measures of the vertical angle.
Around this time the
Ministry of Defence
{{unsourced, date=February 2021
A ministry of defence or defense (see spelling differences), also known as a department of defence or defense, is an often-used name for the part of a government responsible for matters of defence, found in states ...
(MoD) reached the same conclusions about their existing height-finders, and began looking for options. Decca decided to risk the development of the system as a private venture. In addition to the UK market,
NATO
The North Atlantic Treaty Organization (NATO, ; french: Organisation du traité de l'Atlantique nord, ), also called the North Atlantic Alliance, is an intergovernmental military alliance between 30 member states – 28 European and two No ...
was undertaking its "high performing reporting post" program which would emerge as the
NADGE
The NATO Integrated Air Defense System (short: NATINADS) is a command and control network combining radars and other facilities spread throughout the NATO alliance's air defence forces. It formed in the mid-1950s and became operational in 1962 as ...
system. Decca ultimately dropped out of NADGE, and their needs were filled by a system from
Marconi Electronic Systems
Marconi Electronic Systems (MES), or GEC-Marconi as it was until 1998, was the defence arm of General Electric Company (GEC). It was demerged from GEC and bought by British Aerospace (BAe) on 30 November 1999 to form BAE Systems. GEC then renam ...
. The MoD then took over funding of further development of the Decca unit to replace the Type 13 as well as the
General Electric AN/FPS-6 Radar
The AN/FPS-6 Radar was a long-range height finding radar used by the United States Air Force's Air Defense Command. The AN/FPS-6 radar was introduced into service in the late 1950s and served as the principal height-finder radar for the United Sta ...
which were being used in some number.
The first example of the HF200 was completed in 1957 and set up behind Decca's development site on Davis Road in
Chessington
Chessington is an area in the Royal Borough of Kingston upon Thames within Greater London. Historically part of Surrey, today it is the largest salient of Greater London into that county. At the 2011 census it had a population of 18,973. Th ...
on the outskirts of
London
London is the capital and largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary down to the North Sea, and has been a majo ...
. By this time the MoD began working on their new
Linesman/Mediator
Linesman/Mediator was a dual-purpose civil and military radar network in the United Kingdom between the 1960s and 1984. The military side (Linesman) was replaced by the Improved United Kingdom Air Defence Ground Environment (IUKADGE), while the ...
network. Linesman included the new
AMES Type 85
The AMES Type 85, also known by its rainbow code Blue Yeoman, was an extremely powerful early warning (EW) and fighter direction (GCI) radar used by the Royal Air Force (RAF) as part of the Linesman/Mediator radar network. First proposed in early ...
radar, a
3D radar
3-D, 3D, or 3d may refer to:
Science, technology, and mathematics Relating to three-dimensionality
* Three-dimensional space
** 3D computer graphics, computer graphics that use a three-dimensional representation of geometric data
** 3D film, a ...
that performed height-finding as well as PPI, so the need for HF200 was reduced. But the plans also called for a number of sites in the network that would not receive the Type 85 and retain their Type 80s, and those were to be upgraded with the HF200.
As part of this program, HF200's were eventually installed two-each at
RAF Boulmer
Royal Air Force Boulmer or RAF Boulmer is a Royal Air Force station near Alnwick in Northumberland, England, and is home to Aerospace Surveillance and Control System (ASACS) Force Command, Control and Reporting Centre (CRC) Boulmer.
The Scho ...
,
RAF Saxa Vord
Remote Radar Head Saxa Vord or RRH Saxa Vord (aka RAF Saxa Vord), is a Royal Air Force radar station located on the island of Unst, the most northern of the Shetland Islands in Scotland. As of July 2019 it is once more a fully operational radar ...
,
RAF Staxton Wold
Remote Radar Head Staxton Wold or RRH Staxton Wold is an air defence radar station operated by the Royal Air Force, located near Scarborough in North Yorkshire, England. As it has been a radar site continuously since 1939, it has a claim to be t ...
and three at
RAF Bishops Court
Royal Air Force Bishopscourt or more simply RAF Bishopscourt is a former Royal Air Force airfield, radar control and reporting station located on the south east coast of Northern Ireland, approximately from Downpatrick, County Down, Northern Ir ...
. Additional units were sent to the 280 Signals Unit on
RAF Cape Gata and
RAF Troodos
Royal Air Force Troödos, commonly known as RAF Troödos, is a Royal Air Force station in the Republic of Cyprus.
RAF Troödos is a remote Signals Station run by 27 personnel from Golf Section, Joint Service Signal Unit (Cyprus), and also cont ...
in
Cyprus
Cyprus ; tr, Kıbrıs (), officially the Republic of Cyprus,, , lit: Republic of Cyprus is an island country located south of the Anatolian Peninsula in the eastern Mediterranean Sea. Its continental position is disputed; while it is geo ...
and another at
RAF Bukit Gombak in
Singapore
Singapore (), officially the Republic of Singapore, is a sovereign island country and city-state in maritime Southeast Asia. It lies about one degree of latitude () north of the equator, off the southern tip of the Malay Peninsula, borde ...
. Foreign sales followed, three to
Finland
Finland ( fi, Suomi ; sv, Finland ), officially the Republic of Finland (; ), is a Nordic country in Northern Europe. It shares land borders with Sweden to the northwest, Norway to the north, and Russia to the east, with the Gulf of B ...
, eight to
Sweden
Sweden, formally the Kingdom of Sweden,The United Nations Group of Experts on Geographical Names states that the country's formal name is the Kingdom of SwedenUNGEGN World Geographical Names, Sweden./ref> is a Nordic country located on ...
, ten to
Iran
Iran, officially the Islamic Republic of Iran, and also called Persia, is a country located in Western Asia. It is bordered by Iraq and Turkey to the west, by Azerbaijan and Armenia to the northwest, by the Caspian Sea and Turkmeni ...
, four to
South Africa
South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring countri ...
, one to India and three to
Burma
Myanmar, ; UK pronunciations: US pronunciations incl. . Note: Wikipedia's IPA conventions require indicating /r/ even in British English although only some British English speakers pronounce r at the end of syllables. As John Wells explai ...
.
Westinghouse Electric
The Westinghouse Electric Corporation was an American manufacturing company founded in 1886 by George Westinghouse. It was originally named "Westinghouse Electric & Manufacturing Company" and was renamed "Westinghouse Electric Corporation" in ...
also purchased eight units for the US.
The HF200's generally went out-of-service as newer radars replaced the Type 80s. The last operational example appears to be the unit at Saxa Vord, which was installed beginning in 1977 and became operational in 1979. It remained in service until 1993 when the station's Marconi S649 radar was replaced by the
AMES Type 93, a 3D radar.
Description
The system was designed to work with the Type 80 or similar
plan-position indicator
A plan position indicator (PPI) is a type of radar display that represents the radar antenna in the center of the display, with the distance from it and height above ground drawn as concentric circles. As the radar antenna rotates, a radial tra ...
(PPI) radars; when an operator on the PPI wanted to measure the altitude of a given ''blip'' on their screen, they would press a button as the radar swept by the target, sending the angle of the target to a separate height-finder operator. The operator would then accept the angle coordinate and slew the HF200's antenna to that angle. The HF200 would then begin "nodding" up and down to measure the altitude.
The returns were displayed as blips on a
HR scope, which displays range along the X-axis and vertical angle along the Y-axis. The operator moved a cursor, or ''strobe'' in UK parlance, so it laid under the selected target, which limited the nodding to a small angle on either side of the target. The altitude was measured compared to a curved line that represented the curvature of the Earth, as targets seen at longer distances would be at higher altitudes compared to closer ones due to this curvature.
Once the cursor was properly positioned, the operator pressed another button which calculated the resulting altitude and sent the value back to the original PPI operator, where it appeared on a secondary display beside the primary PPI.
The antenna used the "orange peel" design, generating a beam about 3º wide and º high. The antenna was nodded and rotated hydraulically. The system was normally mounted on a truncated cone with the radio equipment in the base. A prominent
waveguide
A waveguide is a structure that guides waves, such as electromagnetic waves or sound, with minimal loss of energy by restricting the transmission of energy to one direction. Without the physical constraint of a waveguide, wave intensities de ...
carried the signal to and from the antenna
feedhorn
A feed horn (or feedhorn) is a small horn antenna used to couple a waveguide to e.g. a parabolic dish antenna or offset dish antenna for reception or transmission of microwave. A typical application is the use for satellite television recept ...
through a rotating joint behind the antenna.
References
Citations
Bibliography
*
*
* {{cite book
, first=Jack , last=Gough
, title=Watching the skies: a history of ground radar for the air defence of the United Kingdom by the Royal Air Force from 1946 to 1975
, publisher=HMSO
, isbn=978-0-11-772723-6
, date=1993
, url=https://books.google.com/books?id=VHcfAQAAIAAJ
Military radars of the United Kingdom
Height-finding radars
Decca