Johannes Plendl
Encyclopedia
Johannes "Hans" Plendl (6 December 1900 – 1992), German
radar
pioneer, was the scientist whose radio navigation techniques made possible the early German bombing successes in World War II
.
, German Empire
to parents from Northern Bavaria. His surname is most likely a truncated Bavarian
dialect
form of "Plendlein." Plendl served briefly in the Imperial Kriegsmarine (Navy) during World War I
. Shortly thereafter, Plendl began his career as a radio and beam engineer for Telefunken
corporation. His early research into meter-wave propagation and radar beams necessitated additional names for newly discovered levels of the Earth's atmosphere
, and Plendl is generally credited with coining the term ionosphere
. In the early 1930s, Plendl worked on developing the radio communications used in flights by civilian aircraft and the Hindenburg
zeppelin.
Around 1933, as Nazi Germany
rearmed, Dr. Plendl and others saw the possibilities of using radio beams to guide bombers to their target, and they began to develop a system under the code name “X-System” (X-Verfahren). . Using technology previously used for the Lorenz beam
landing system, he developed a system that would guide planes to their target, and which improved the accuracy of bombing at night or in poor weather conditions. This work was conducted for the German Airforce (Luftwaffe) at the Airforce Experimental Station (Erprobungstelle der Luftwaffe) at Rechlin, Germany. At the same time the system code named "Knickebein" was developed by the Telefunken electronics firm. Although it could use the Lorenz landing system for guidance, it was less accurate and more prone to jamming.. Both systems employed transmitter towers on the English channel
and the North Sea
to transmit radar beams over targets in England. German bombers carried primitive radar detectors and complex timing devices, also invented by Dr. Plendl, to lead them on the correct path and to guide the timing of the release of their bombs.
When Germany invaded Poland, the X-System was used effectively against military targets, but on a limited basis, due to the few number of planes equipped with the X-Device (X-Gerät, the electronic component of the system carried in the plane.) and the short duration of the campaign. During the air war over the England and Scotland known as The Battle of Britain
the Knickebein, X-System and Y-System were all used extensively, but their effectiveness was diminished by countermeasures developed by Reginald Victor Jones
and others, who were able use electronic countermeasures to redirect or jam the radio signals of the navigation systems in what has become known as the Battle of the Beams
.
Dr. Plendl was awarded the honorary title of Prussian Councilman (Preußischer Staatsrat) by Hermann Göring
for his work. He was named National Director of High Frequency Research (Bevollmächtigten der Hochfrequenzforschung). He held that position for only about a year. It may be noted that Plendl helped Karl-Otto Kiepenheuer
to establish a Europe-wide network of stations observing the solar activity in order to predict disturbances of the Ionosphere
that interrupted the military radio connections. Plendl and Kiepenheuer may so be seen as the fathers of the science now called space weather
, A considerable part of their network prevailed after the war in one or another organisation.
Plendl´s career ended after a heavy british ride upon Hamburg that had used a special counterradar
technique called Windows by the british. As responsible for this desaster Plendl was dismissed from his office and was replaced by Abraham Esau
at the end of 1943.
At the end of the war, Plendl surrendered to the Americans. Like other German scientists, Plendl was invited to come to the United States to aid in American weapons development, as part of "Operation Paperclip
." U.S. government records noted that he had regularly voiced opposition to the Nazi regime. Particularly noteworthy was the fact that Plendl had saved a number of people, including many Jews, from the Dachau
concentration camp, under the guise of needing them to work on his projects. Many of these individuals had no scientific background. In this manner, Plendl differed from other German scientists, who voiced no opposition to the regime.
The most notable figure who Plendl saved was Hans Mayer
, the author of the Oslo Report
. In sending this report to the British Government in November 1939 just after the beginning of the war, Mayer had performed perhaps the most serious breach of German security in World War II, although this was not known to his colleagues (or the Gestapo) at that time. Mayer had been the Director of the Siemens Research Laboratory in Berlin up to the time of his arrest in 1943, for listening to the BBC and criticism of the Nazi regime. Plendl appointed Mayer to head a radio laboratory even though Mayer's expertise was in telephony, and not in radio.
Plendl finished his military career working for the United States Air Force
, at their Cambridge Research Laboratory. He specialized in the field of solid-state physics
.
In 1970, Plendl retired to Europe, taking residence in Italy. R.V. Jones, the British scientist who had worked on the other end of the channel to jam Plendl's beams, became a good friend, and the two corresponded regularly and collaborated on several books. Johannes Plendl died in 1992.
Germans
The Germans are a Germanic ethnic group native to Central Europe. The English term Germans has referred to the German-speaking population of the Holy Roman Empire since the Late Middle Ages....
radar
Radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...
pioneer, was the scientist whose radio navigation techniques made possible the early German bombing successes in World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
.
Biography
Plendl was born in 1900 in MunichMunich
Munich The city's motto is "" . Before 2006, it was "Weltstadt mit Herz" . Its native name, , is derived from the Old High German Munichen, meaning "by the monks' place". The city's name derives from the monks of the Benedictine order who founded the city; hence the monk depicted on the city's coat...
, German Empire
German Empire
The German Empire refers to Germany during the "Second Reich" period from the unification of Germany and proclamation of Wilhelm I as German Emperor on 18 January 1871, to 1918, when it became a federal republic after defeat in World War I and the abdication of the Emperor, Wilhelm II.The German...
to parents from Northern Bavaria. His surname is most likely a truncated Bavarian
Austro-Bavarian
Bavarian , also Austro-Bavarian, is a major group of Upper German varieties spoken in the south east of the German language area.-History and origin:...
dialect
Dialect
The term dialect is used in two distinct ways, even by linguists. One usage refers to a variety of a language that is a characteristic of a particular group of the language's speakers. The term is applied most often to regional speech patterns, but a dialect may also be defined by other factors,...
form of "Plendlein." Plendl served briefly in the Imperial Kriegsmarine (Navy) during World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...
. Shortly thereafter, Plendl began his career as a radio and beam engineer for Telefunken
Telefunken
Telefunken is a German radio and television apparatus company, founded in Berlin in 1903, as a joint venture of Siemens & Halske and the Allgemeine Elektricitäts-Gesellschaft...
corporation. His early research into meter-wave propagation and radar beams necessitated additional names for newly discovered levels of the Earth's atmosphere
Atmosphere
An atmosphere is a layer of gases that may surround a material body of sufficient mass, and that is held in place by the gravity of the body. An atmosphere may be retained for a longer duration, if the gravity is high and the atmosphere's temperature is low...
, and Plendl is generally credited with coining the term ionosphere
Ionosphere
The ionosphere is a part of the upper atmosphere, comprising portions of the mesosphere, thermosphere and exosphere, distinguished because it is ionized by solar radiation. It plays an important part in atmospheric electricity and forms the inner edge of the magnetosphere...
. In the early 1930s, Plendl worked on developing the radio communications used in flights by civilian aircraft and the Hindenburg
Hindenburg class airship
The two Hindenburg-class airships were passenger carrying rigid airships built in Germany in the 1930s and named in honor of Paul von Hindenburg. They were the last such aircraft ever built, and in terms of their length and volume, the largest aircraft ever to fly...
zeppelin.
Around 1933, as Nazi Germany
Nazi Germany
Nazi Germany , also known as the Third Reich , but officially called German Reich from 1933 to 1943 and Greater German Reich from 26 June 1943 onward, is the name commonly used to refer to the state of Germany from 1933 to 1945, when it was a totalitarian dictatorship ruled by...
rearmed, Dr. Plendl and others saw the possibilities of using radio beams to guide bombers to their target, and they began to develop a system under the code name “X-System” (X-Verfahren). . Using technology previously used for the Lorenz beam
Lorenz beam
The Lorenz beam blind landing system was an air radio navigation system in use from the late 1930s. The name refers to the company that produced the system; Lorenz referred to it simply as the Ultrakurzwellen-Landefunkfeuer, German for "ultra-short-wave landing radio beacon", or LFF...
landing system, he developed a system that would guide planes to their target, and which improved the accuracy of bombing at night or in poor weather conditions. This work was conducted for the German Airforce (Luftwaffe) at the Airforce Experimental Station (Erprobungstelle der Luftwaffe) at Rechlin, Germany. At the same time the system code named "Knickebein" was developed by the Telefunken electronics firm. Although it could use the Lorenz landing system for guidance, it was less accurate and more prone to jamming.. Both systems employed transmitter towers on the English channel
English Channel
The English Channel , often referred to simply as the Channel, is an arm of the Atlantic Ocean that separates southern England from northern France, and joins the North Sea to the Atlantic. It is about long and varies in width from at its widest to in the Strait of Dover...
and the North Sea
North Sea
In the southwest, beyond the Straits of Dover, the North Sea becomes the English Channel connecting to the Atlantic Ocean. In the east, it connects to the Baltic Sea via the Skagerrak and Kattegat, narrow straits that separate Denmark from Norway and Sweden respectively...
to transmit radar beams over targets in England. German bombers carried primitive radar detectors and complex timing devices, also invented by Dr. Plendl, to lead them on the correct path and to guide the timing of the release of their bombs.
When Germany invaded Poland, the X-System was used effectively against military targets, but on a limited basis, due to the few number of planes equipped with the X-Device (X-Gerät, the electronic component of the system carried in the plane.) and the short duration of the campaign. During the air war over the England and Scotland known as The Battle of Britain
The Battle of Britain
The Battle of Britain was the fourth of Frank Capra's Why We Fight series of seven propaganda films, which made the case for fighting and winning the Second World War...
the Knickebein, X-System and Y-System were all used extensively, but their effectiveness was diminished by countermeasures developed by Reginald Victor Jones
Reginald Victor Jones
Reginald Victor Jones, CH CB CBE FRS, was a British physicist and scientific military intelligence expert who played an important role in the defence of Britain in -Education:...
and others, who were able use electronic countermeasures to redirect or jam the radio signals of the navigation systems in what has become known as the Battle of the Beams
Battle of the beams
The Battle of the Beams was a period early in the Second World War when bombers of the German Air Force used a number of increasingly accurate systems of radio navigation for night bombing. British "scientific intelligence" at the Air Ministry fought back with a variety of increasingly effective...
.
Dr. Plendl was awarded the honorary title of Prussian Councilman (Preußischer Staatsrat) by Hermann Göring
Hermann Göring
Hermann Wilhelm Göring, was a German politician, military leader, and a leading member of the Nazi Party. He was a veteran of World War I as an ace fighter pilot, and a recipient of the coveted Pour le Mérite, also known as "The Blue Max"...
for his work. He was named National Director of High Frequency Research (Bevollmächtigten der Hochfrequenzforschung). He held that position for only about a year. It may be noted that Plendl helped Karl-Otto Kiepenheuer
Karl-Otto Kiepenheuer
Karl-Otto Kiepenheuer was a German astronomer and astrophysicist. His research focused on the Sun, and for that purpose he initiated construction of several solar telescopes and founded the Kiepenheuer Institute for Solar Physics.-Life and work:Kiepenheuer was born in 1910 in Weimar, Germany, as a...
to establish a Europe-wide network of stations observing the solar activity in order to predict disturbances of the Ionosphere
Ionosphere
The ionosphere is a part of the upper atmosphere, comprising portions of the mesosphere, thermosphere and exosphere, distinguished because it is ionized by solar radiation. It plays an important part in atmospheric electricity and forms the inner edge of the magnetosphere...
that interrupted the military radio connections. Plendl and Kiepenheuer may so be seen as the fathers of the science now called space weather
Space weather
Space weather is the concept of changing environmental conditions in near-Earth space or thespace from the Sun's atmosphere to the Earth's atmosphere. It is distinct from the concept ofweather within the Earth's planetary atmosphere...
, A considerable part of their network prevailed after the war in one or another organisation.
Plendl´s career ended after a heavy british ride upon Hamburg that had used a special counterradar
Radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...
technique called Windows by the british. As responsible for this desaster Plendl was dismissed from his office and was replaced by Abraham Esau
Abraham Esau
Robert Abraham Esau was a German physicist.After receipt of his doctorate from the University of Berlin, Esau worked at Telefunken, where he pioneered very high frequency waves used in radar, radio, and television, and he was president of the Deutscher Telefunken Verband...
at the end of 1943.
At the end of the war, Plendl surrendered to the Americans. Like other German scientists, Plendl was invited to come to the United States to aid in American weapons development, as part of "Operation Paperclip
Operation Paperclip
Operation Paperclip was the Office of Strategic Services program used to recruit the scientists of Nazi Germany for employment by the United States in the aftermath of World War II...
." U.S. government records noted that he had regularly voiced opposition to the Nazi regime. Particularly noteworthy was the fact that Plendl had saved a number of people, including many Jews, from the Dachau
Dachau
Dachau is a town in Upper Bavaria, in the southern part of Germany. It is a major district town—a Große Kreisstadt—of the administrative region of Upper Bavaria, about 20 km north-west of Munich. It is now a popular residential area for people working in Munich with roughly 40,000 inhabitants...
concentration camp, under the guise of needing them to work on his projects. Many of these individuals had no scientific background. In this manner, Plendl differed from other German scientists, who voiced no opposition to the regime.
The most notable figure who Plendl saved was Hans Mayer
Hans Ferdinand Mayer
Hans Ferdinand Mayer was a German mathematician and physicist and perhaps most notable for the Oslo Report which revealed German technological secrets to the British Government shortly after the start of World War II.-Biography:Hans Ferdinand Mayer studied mathematics, physics and astronomy at...
, the author of the Oslo Report
Oslo report
The Oslo Report was one of the most spectacular leaks in the history of military intelligence. Written by German mathematician and physicist Hans Ferdinand Mayer on November 1 and 2, 1939 during a business trip to Oslo, Norway, it described several German weapons systems, current and future.Mayer...
. In sending this report to the British Government in November 1939 just after the beginning of the war, Mayer had performed perhaps the most serious breach of German security in World War II, although this was not known to his colleagues (or the Gestapo) at that time. Mayer had been the Director of the Siemens Research Laboratory in Berlin up to the time of his arrest in 1943, for listening to the BBC and criticism of the Nazi regime. Plendl appointed Mayer to head a radio laboratory even though Mayer's expertise was in telephony, and not in radio.
Plendl finished his military career working for the United States Air Force
United States Air Force
The United States Air Force is the aerial warfare service branch of the United States Armed Forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on September 18, 1947 under the National Security Act of...
, at their Cambridge Research Laboratory. He specialized in the field of solid-state physics
Solid-state physics
Solid-state physics is the study of rigid matter, or solids, through methods such as quantum mechanics, crystallography, electromagnetism, and metallurgy. It is the largest branch of condensed matter physics. Solid-state physics studies how the large-scale properties of solid materials result from...
.
In 1970, Plendl retired to Europe, taking residence in Italy. R.V. Jones, the British scientist who had worked on the other end of the channel to jam Plendl's beams, became a good friend, and the two corresponded regularly and collaborated on several books. Johannes Plendl died in 1992.