HISTORY
AARMS
Vol. 7, No. 1 (2008) 175–185
British radar in WWII
ATTILA GULYÁS
Hungarian Defense Forces, 34. Special Operations Forces Battalion, Szolnok, Hungary
This article is a short essay of the British radar’s wartime history from its first usage
until the end of World War II. This new development was used against Italian warships
and coastlines as well as German U-boats. Especially crucial was the application of
“Elsie” radar in combination with the Ack-Ack (Anti-Aircraft) gun during the Blitz that
rendered the Allies possible to rule the Atlantic and in the end won the WWII.
“This was a secret war, whose battles were lost or
won unknown to the public; and only with difficulty
is it comprehended, even now, by those outside the
small high scientific circles concerned. No such
warfare had ever been waged by mortal men.”
WINSTON CHURCHILL
The history of Radari
Several inventors, scientists, and engineers contributed to the development of radar. The
first to use radio waves to detect “the presence of distant metallic objects via radio
waves” was Christian Hulsmeyer, who in 1904 demonstrated the feasibility of detecting
the presence of a ship in dense fog, but not its distance. He received for his pre-radar
device in April and on November 11. Nikola Teslaii in August 1917, first established
principles regarding frequency and power level for the first primitive radar units. Before
the Second World War, developments by the Americans (Dr. Robert M. Page tested the
first monopulse radar in 1934), the Germans, the French and mainly the British who
were the first to fully exploit it as a defence against aircraft attack by Robert WatsonWatt in 1935, led to the first real radars. In the same vein, the Hungarian inventor,
Zoltan Bay produced a working model by 1936 at the Tungsram laboratory. In 1934,
Émile Girardeau was working with the first French radar systems, stating he was
building radar systems “conceived according to the principles stated by Tesla”.
i
M. HOLLMAN: Radar Development in England (Christian Huelsmeyer), 2007.
(http://www.radarworld.org/huelsmeyer.html)
ii
Nicola Tesla, croatian (Austro-Hungarian Monarchy) inventor (1856–1943).
Received: January 28, 2008
Address for correspondence:
ATTILA GULYÁS
E-mail: [email protected]
A. GULYÁS: British radar in WWII
The Radar won World War II
In the technical sense, one of the most important factors in winning the World War II
for the Allies was the use of Radar. The word, which is perhaps of American naval
origin, is the equivalent of the older term radiolocation. Former President Truman
himself recently cited radar as one of the three principal benefits received by the United
States from England under Reverse Lease-Lend Act.iii Practical naval experiment in
radar began nearly 100 years ago before the War began, when it was in use by Royal
Navy, thought in an elementary form. Echo-sounding was one of the first applications
of radar. It was discovered that sounding by this means, was simpler, quicker and more
reliable than by the older methods.iv
Since those first steps were taken radar has made giants strides. It is no exaggeration
to say that it completely transformed the face of naval and air warfare. The Admiralty
scientists and technical officers devised important improvements in collaboration with
Army and Air Force experts. Much of the experimental work has been carried out at the
Telecommunication Research Establishmentv under conditions of utmost secrecy.
To understand how radar works, one first must understand that short wave radio
waves behave similarly to light, and in fact travel at the same speed. Short wave radio
waves can be focused in a beam in just the same way and can be reflected off of solid or
liquid surfaces. Where radar has the advantage of over light is in its ability to penetrate
fog, clouds and smoke radar also can cover far greater distances than the human eye.
Additionally, radio impulses are much more easily controlled than beams of light.
Radar has gone far to provide the sailor with sixth sense, enabling him to see in the
dark as well as daylight. In simple terms, radar projects an electromagnetic beam which,
on coming in contract with an object, returns an echo, which is reproduced visually on
the radio operators’ screen. In range-finding, to take only one example, this amounts to
nothing less than a revolution.vi
It is a curious thing that Germans, for all their boasted scientific ability, should have
failed to make any corresponding progress in this field of research. Throughout the War
they seem to have been content to lag behind in radar development; when hostilities ceased
the Krauts were still far short of the stage, which had been reached by the Royal Navy.vii
iii E. STALEY: The Economic Implications of Lend-Lease, The American Economic Review, 33(1/2) (Mar.,
1943) 362–376.
iv R. J. JAMES: A History of Radar. 1989, pp. 343–349.
v G. C. CLARK: Deflating British Radar Myths of World War II. 1997, pp. 5–8.
vi
P. HAINING: World War II Stories. 2007, pp. 197–199.
vii
J. WOOD: A radar history of World War II: Technical and military imperatives, p. 29.
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British Radar during the Blitz
Radar was especially crucial during the German Blitz. The brain-child of Sir Robert
Watson Watt, scientific adviser of on telecommunication to the War Cabinet of Great
Britain and colleague of the other radio back-room-boys, began radar research for the
British Army under conditions of great secrecy on October 31, 1936, under special care
of two of Sir Robert Watt’s scientists, Mr. H. Dewhurst and Mr. W. S. Eastwood. As
their work progressed, their secret laboratory was moved to Dunkirk, near Canterbury.
They were joined and reinforced by workers from the War Office, and soon after the
laboratory’s first product came into being. This development was known by the magic
letters “G.L.” or Gun and Light Laying.viii
Three experimental models of the first radar apparatus for automatically spotting the
position of an enemy aircraft for A.A. gunners were made. On June 20, 1939, Mr.
Churchill inspected the first working G.L. radar for A.A guns. This gave a bearing
accuracy of about one degree on either side of the possible target in the night skies and
a pick-up range for “first warning” of about ten miles.ix
In the early months of the War, residents at the edge of green spaces around London
were puzzled by the sudden appearance of U.S. bulldozers, the crews of which swiftly
leveled the ground. After the bulldozers came about two acres of wire-netting, erected
on low posts as a giants spiders’ web close to the ground. In the centre of the web was a
small wooden hut. It is now commonly known that these webs were the centres of the
G.L. system, which very rapidly helped the A.A. gun-network to beat back the German
Blitz. Mr. Bedford, a private scientist working for a television manufacturer, was the
first to suggest that the elevation-finding attachment could be fitted to early models of
the G.L.’s. It was necessary to measure the elevation angle above a smooth surface
because the irregularities in the ground had to be smoothed out.
Radar as first used by the British Ack-Ack crewsx had the disadvantage that false
positive radio echoes were being picked up after reflecting off the British balloon
barrage. It was analogous to a powerful but dispersed searchlight trained on a forest in
the hope of spotting a man walking between the trees. There was another snag in the
manual controls had to be used with the first Army radar equipment to keep the
invisible beam fixed on the invisible target.
viii N.
F. EVANS: British Artillery in WWII., Sights & Laying (2003).
GALLAND: The First and the Last: The Rise and Fall of the German Fighter Forces, 1938–1945.
x
Ack Ack crew: Air artillery machine gun, Glossary of Army Slang, American Speech, 16(3) (Oct. 1941)
163–169.
ix A.
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Looking at an unseen target
But by the summer of 1940, scientists working in laboratories of the Ministry of
Aircraft Production had produced a “radio-theodolite”xi with a very narrow beam.
German aircraft could now be spotted between the wires of British balloon barrages and
the new apparatus could train itself on the targets at about 30.000 yards. Additionally,
the new system kept the aerials fixed on the bombers no matter how they weaved
through the clouds.
Canadian scientists were also at work during 1940 and soon Canadian workshops
produced an independently designed version of G.L. Interestingly, this Canadian
version was actually in production before the British set.xii
Within the next 24 months amazing progress was made with the “continuous
follow” device, so that G.L. radar aerials were able to keep themselves automatically in
line with the enemy bombers. One of the scientists who worked on this gear remarked
that it was “an impressive and at first uncanny experience to see the aerial system
‘looking’ at an unseen target miles away (maybe in cloud, or so far distant that it cannot
be distinguished by eye) and following the evolutions of the target unerringly and
automatically, its movements to keep the target in ‘view’ being used to inform the gun
predictor, without human intervention, of the target position and velocity.”xiii
Behind the scenes, scientists in other laboratories had been striving to use shorter
wavelengths, on the scale of centimeters instead of the more familiar meter-length
waves of ordinary radio. These yield a much narrower radar waves. The truth was that
the Allies were too near the front line. Enemy bombing meant that the Ack-Ack radar
posts were in use night and day. They could neither manufacture the latest gadgetry
which scientists had invented nor stop the war machine long enough to install the new
parts. They had, however, sent a mission to Washington D.C. at an early stage in the
war and had told the U.S. experts all they knew about radar.xiv
xi The
air defence of Great Britain, 1920–1940: an operational research perspective. 1962.
R. SHOCK: The US Army Barrage Balloon Program. 1978.
xiii
Scope of the Collections for British Military History 1801–1945. pp. 187–192.
xiv
The War Illustrated. April 26, 1940, p. 34.
xii J.
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Figure 1. “Elsie” radar equipment with Ack-Ack searchlight gunxv
United States copied the British ideas, improved on them, and brought British
aspirations to reality. While this was blow to national pride, when the V1 flying-bomb
campaign began, Britain had good reason to be grateful to the American enterprise. As
the menace began, the coastline of Britain became dotted with tiny, efficient mobile
American radar systems, the only visible sign of which was huge wire-mesh basket
shaped like a rose-bowl and facing towards the launching sights of the flying bombs.
Immediately after each bomb was launched from the Calais coast the radar vans picked
xv
Photo of British Official, P.N.A., Keystone 1945, pp. 299–301.
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A. GULYÁS: British radar in WWII
up the bombs’ signals, and the wire-basket aerials turned themselves in the direction of
the bombs’ flight. These amazing robots could actually feed the rates of target
movement directly into gun predictor.xvi
“This combination led to our remarkable success in shooting down the flying
bomb”xvii the scientists stated and together with the work of fighter aircraft (which used
the British airborne radar weapons) fully prevent 80% of the missiles from reaching
their targets.xviii
Long before the V1 menace, some scientists experienced the devastation during the
first violent raid on Christ-church (on the night of June 20, 1940). The scientists were
anxious at the way searchlight operators had to grope and search ineffectively about the
skies while the bombers droned overhead unseen. This night was the turning point in
yet another amazing new device to help the gunners. Its official code name was
S.L.C.,xix but this did not remain for long before being changed affectionately and
unofficially to “Elsie”.
Contributions by Japanese inventors
“Elsie” used five aerials. An individual close to a large searchlight battery might have
seen the wire-mesh circles behind the little groups of sticks, which were sufficient for
the aerials to employ using the tiny wavelength of about ten feet. The five aerials give a
pair each for “up and down” and “left and right” direction sense, with a fifth of
transmits to steady radar beam. These aerials known as “Yagi” were the only material
contribution Japanese inventors made to radar.xx
First tests with “Elsie” were so startling and successful that a private message was
sent to Mr. Churchill. Lord Cherwellxxi and Watson Watt gave a report of what “Elsie”
could do against the night bombers. Britain was already committed to an overwhelming
radio programme, but with characteristic decision Mr. Churchill ordered that a
maximum number of sets should be produced with all speed and that “Elsie” should
xvi T.
R. PERKINS: Nonlinear Prediction Concept for Improving Gun Accuracy. 1991, pp. 13–16.
P. G. COOKSLEY: Flying Bomb. New York: Charles Scribner’s Sons, 1979; F.R. ILLINCWORTH: Flying
Bombs, the Story of V.1 and V.2 (London n.d.), p. 32.
xviii
The War Illustrated. No. 241, June 1945, p. 298.
xix
S.L.C. Searching Control.
xx The Yagi antenna is credited to Hidetsugu Yagi, a Japanese physicist. The Yagi was designed to improve
the gain of the antenna concentrated in one direction. The directivity is accomplished with added elements
called directors and reflectors. In simple unidirectional antennas like the Yagi, frequency bandwidth is
inversely proportional to antenna gain. The greater the conductor diameter, the wider the band with increased
conductor diameter also has a second benefit, it increases the physical strength of the antennas.
xxi
Churchill’s scientific advisor
xvii
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become a top priority job. If it was not for “Elsie”, Britain might have been bombed to
it surrender point.
Eighteen sets were produced in a few weeks and they were mostly made from bits and
pieces of other equipment by the most intense day and night effort of men and women in
the factories. Apart from a few failures, the majority of sets worked well and yet another
weapon had been born. The searchlight was capable of being directed at the enemy with
the certainty of illuminating him immediately, coining the order “Expose.”xxii
“Elsie” was use in the North African campaign and played a big part in the Sicilian
landings. The Allies had to land on steeply sloping beaches and some form of radar
predictor for the guns was necessary to protect the friendly armies during the critical
hours immediately following the landing. The standard G.L. was too large for this
purpose, so the War Office sent specially adapted “Elsies” out to Sicily. This would
give sufficiently good guidance to the Allies Ack-Ack at short ranges, giving rise to the
portable gun-laying version of “Elsie”.
As troops assaulted the Sicilian shores, the concealed and camouflaged devices gave
warning of Italian and Luftwaffe fighters overhead. The secret radar “Elsie” that had
shielded London from the full force of Goering’s hatred, also most ably protected the
first British invasion forces in the North African campaign. The supreme example of
radar in defensexxiii was at Malta when the enemy fighters became so worn down
almost nothing remained.
Italian surprise
One of the first notable cases in which radar proved of inestimable service to the Allied
cause was during the Battle of Cape Matapan, March 28, 1941.xxiv Thought the type of
radar in use in Mediterranean Fleet at that date would be regarded as crude and
elementary in comparison with the highly efficient sets now in service, it enabled Sir
Arthur Cunningham to locate the Italian fleet and open up with deadly fire upon it out
of the darkness. Three big enemy cruisers and three destroyers were sunk without being
able to retaliate. In subsequent attacks by the British Forces on enemy convoys
proceeding at night from Italy to Libya, equally surprising results were obtained with
the help of radar. Had radar been installed in the Grand Fleet at Jutland (western,
continental part of Denmark) in 1916, the Germans would never have succeeded in
xxii The
War Illustrated. April 28, 1940, p. 694–695.
The Idea of Radar in defence. Sir Arthur Tedder (British Air Chief Marshall), August 14, 1945.
xxiv
Peloponnesian coast of Greece.
xxiii
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extricating themselves from battle under cover of mist and darkness, and the partial
night action which ensued would have gone very differently.xxv
By means of radar, station keeping at night or in fog is rendered comparatively
simple; this has been a great boon to convoys proceeding to North Russia. It was the
prime cause of the destruction of the German battleship Scharnhost when she attacked a
convoy off the North Cape in December 1943. Every time she tried to break off the
action with the escorting cruisers and destroyers, radars followed her movements and
contact was maintained until H.S.M. Duke of Yorkxxvi arrived on the scene. The British
battleship’s gunfire -accurately directed by the same means- quickly scored a disabling
hit, after which the Scharnhost’s end was inevitable.
Fight with the U-boats
Though undisclosed at the time for security reasons, radar had an important share in
locating the Bismarck and bringing her to action with H.M.S. King George V and the
H.M.S. Rodney in May, 1941.xxvii During the Battle of the Atlantic, radar also played a
prominent part. It was able to detect enemy submarines on the surface in time for
convoys to take evasive action. Meanwhile, the escort vessels would close in on the
submarines with unerring direction. The U-boats were forced either to dive and be
exposed to depth-charge attack, or fight it out on the surface. In either contingency, the
convoy was able to proceed unharmed.xxviii During the Allies landing in North Africa,
ships of the U.S. Navy fitted with radar engaged the French battleship Jean Bart at
Casablanca,xxix at a range of 20 miles. She was disabled without a chance to hit back
and other French warships, which offered opposition, were equally unlucky.
xxv
A. M. SCALZO: Battle of Cape Matapan, Italian Naval Massacre. 1946.
means Her\His majesty’s ship or submarine.
xxvii
M. WALSH: Round One for the Barbarians. British Library Catalogue, 2005.
xxviii
The War Illustrated. March 8, 1940, p. 37.
xxix
J. L. MOONEY: Dictionary of American Naval Fighting Ships. 1969, pp. 4–6.
http://www.militaryhistoryonline.com/wwii/articles/capitalshipsurfaceactions.aspx
xxvi H.S.M.
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Figure 2. Portable type radarxxx
In this way the radar proved a more efficient substitute for the human eye in
gunnery fire control. It has been particularly valuable for anti-aircraft purposes. So
highly developed is the type of radar now installed in Her Majesty’s Ships that it is
possible to locate almost anything on the surface of the sea ranging in size from a
seagull to an iceberg. Though the exact shape of an object is not shown on the screen,
its size can be determined. In navigation, the value of this hardly needs stressing, for
shoals, buoys and other ships can be avoided with little difficulty.
Some go so far as to predict early abolition of that time-honored friend of the
mariner: the sextant. Navigation specialists are inclined to dissent, maintaining that the
sextant will always be needed, if only for use during emergency.xxxi Certainly
castaways in an open boat would require one to find their position in the absence of a
portable radar set. Already sets small enough to be included in the equipment of aircraft
xxx
B.A. AUSTIN: Radar in World War II: the South African contribution. Science and Education Journal,
1(3) (Jun 1992) 121–130.
xxxi
P. IFLAND: The History of the Sextant. Course of the Celestial Navigation. University of Coimbra, TX,
(3 October 2000).
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are in fairly general use; so it should be merely a question of time before ships’ lifeboats
carry something similar.
During the invasion of Normandy, radar was use to guide the landing craft to ensure
that they made no mistake in selecting a landing beach as well as many other purposes.
Later, when the tide of invasion had reached Antwerp, the British ships were able to
proceed up the Scheldtxxxii River of northern France in fog at a good speed, radar picking
out the varying configuration of the banks as well as every obstacle in the estuary.
A new innovation from which navigation benefited was a special type of buoy fitted
with a device that emitted radio signals in response to radar. Through this facility a ship’s
position in a buoy-marked channel can be exactly defined without the possibility of error.
According to its exponents, radar is still far from attaining its full degree of development,
so its present performances may soon be surpassed. In fact, radar was a vigorous and
growing branch of science for which new uses are constantly being found.xxxiii
Conclusions
The advent of repulsing beam theory and the invention of radar equipment profoundly
affected the course of world wartime history. It allowed the British to win their great
battle in the air and on the sea and gave the nations of the world greatly increased
offensive and defensive power. After the World War II, radar technology was rapidly
developed and enhanced in order to utilize it for civilian and military life. But as is the
human nature, we can not get enough of it and day in day out we are endeavouring to
apply this technology to new places. This very reason has led to more sophisticated and
specialized uses, which are still in the process of being improved.
The following periods excess equipment and extensive knowledge of radar sets led
to its use in weather forecasting, police and law enforcement, large scale mapping of
areas and further improvements in military applications. Its ability to track objects was
employed in air traffic control and many safety systems. Research in different areas of
radar is actively taking place in all parts of the world. However, at the early stages of
development of radar, research was targeted at increasing frequencies and reducing size,
today although these goals exist, research is concentrated on expanding its boundaries
in terms of different applications and economic means of production and usage of such
devices. It still remains to be seen, what further areas radar can capture and how
Hulsmeyer’s invention contributes to every individual’s day-to-day life in the future. So
xxxii The
Scheldt (Dutch: Schelde, French Escaut, Latin Scaldis) is a 350 km long river in northern France,
western Belgium and the southwestern part of the Netherlands.
xxxiii
H. DEESE: Radar in WWII. The Battle of the Beams (January 1, 2007).
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the development of modern radar equipment – particularly of the techniques of three
dimensional radar systems (3D) such as multi-beam radar developments or
ARTISAN,xxxiv MRRxxxv and STAR,xxxvi SMART-S Mk2xxxvii- is unceasingly
building up the industries not only of belligerent nations but also in every field of
science. This process is thriving with no limit in sight for air and radio navigation.
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xxxiv
ARTISAN, Advanced Radar Target Indication Situation Awareness and Navigation 3D (BAE Systems
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xxxv
MRR, Medium Range Radar (Lockheed Martin).
xxxvi
STAR, Surveillance and Threat Alert Radar (Elta System).
xxxvii SMART-S Mk2, 3D multi-beam radar (E/F band) for medium-to-long range surveillance (250 km) and
target indication, optimised for accurate operation in littoral environments. The radar matches the full
performance of surface-to-air missiles such as ESSM.
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