Oslo report
Encyclopedia
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 mailed the report anonymously in the form of two letters to the British
Embassy in Oslo, where they were passed on to MI6 in London
for further analysis, and proved to be an invaluable resource to the British in developing counter-measures, especially to navigational and targeting radar
s, and contributed to the British winning the Battle of Britain
.
) laboratory, he joined Siemens AG
in 1922. He became interested in telecommunications and joined Siemens' communication research laboratory, becoming its director in 1936. Because of this position, he had contacts all over Europe and the United States and had access to a wide range of information about electronics development in Germany, especially in the military sector.
After Hitler invaded Poland on September 1, 1939, Mayer decided to divulge to the British as much as he could about military secrets to defeat the Nazi regime. He arranged a business trip to Scandinavia
in late October 1939. He arrived at his first scheduled stop, Oslo
, Norway
, on October 30, 1939 and checked into the Hotel Bristol.
Mayer borrowed a typewriter from the hotel, and typed the seven-page Oslo Report in the form of two letters over two days. He mailed the first on November 1, which asked the British military attaché to arrange for the BBC World Service to alter the introduction to its German language programme if he wished to receive the Report. This was done, and he sent the Report along with a vacuum tube from a prototype proximity fuze
.
He also wrote a letter to his longtime British friend Henry Cobden Turner, asking him to communicate with him via their Danish colleague Niels Holmblad. This indirect communication path was required since Britain and Germany were at war, but Denmark
was at that time neutral. Mayer continued his travels to Denmark
to visit Holmblad, asking if he could relay information between himself and Turner. Holmblad readily agreed, but once Hitler invaded Denmark on April 9, 1940, this communication route was no longer feasible. Mayer then returned to Germany. Although Mayer was arrested by the Gestapo
in 1943 and was imprisoned in concentration camps until the war ended, the Nazis never knew of the Oslo Report.
's German language broadcast to be changed to "Hullo, hier ist London". This was done, and resulted in the delivery of a parcel a week later which contained a typewritten document and a type of vacuum tube
, a sensor for a proximity fuze
for shells or bombs. The typewritten document accompanying it became famous after its existence was revealed in 1947 and would go down in history as the "Oslo Report".
Boyes quickly appreciated the Report's potential importance and had a member of the embassy staff make a translation which he forwarded to MI6 in London along with the original.
The Oslo Report was received with indifference or even disbelief by British Intelligence, with the notable exception of Dr. R.V. Jones
, a young Ph.D. physicist who had recently been put in charge of a new field called "Scientific Intelligence". Jones argued that despite the breadth of information and a few inaccuracies, the technical details were correct and argued that all the electronic systems divulged therein be further explored. In a 1940 report, Jones summarized his thoughts.
In his 1989 book, Jones summarized the importance of the Oslo Report as follows:
While Jones took the Oslo Report very seriously, the Admiralty for one thought that the Report was "too good to be true" and therefore had to be a devious deception by the Abwehr
, with its fantastic claims written by psychological warfare experts. An additional argument raised by the doubters was that no single person could have such wide knowledge of weapons technology as discussed in the Report. This was mainly because interforce co-operation, e.g. between the Navy and Air Force, was at the time poor in both Britain and the US, and it was known that in Germany the two organisations were virtually at war between themselves.
In fact, the Oslo Report is strongly focused - on electronic technology - and several major German companies were involved in such projects for all three armed forces; some scientists in these companies would indeed have had a wide-ranging overview.
is one of the carbon copies and lacks the sketches that were apparently included in Mayer's original. A typed copy in German can also be found in the Public Records Office., while the Report has been published twice in English translation.F.H. Hinsley (1979), Appendix 5.
The section headings given here correspond to those in the Report. Some of the information Mayer heard was second-hand and later proved to be incorrect.
, and was expected to be finished in April 1940. The carrier was referred to as Franken.
It is sometimes suggested that Mayer was mistaken and that he was instead identifying the carrier Graf Zeppelin
. However, the construction of Graf Zeppelin was well known to Allied navies. Following Kriegsmarine ship naming policy, this carrier was assigned her name on being launched on 8 December 1938; previously she was known as "Flugzeugträger A". A second carrier known as "Flugzeugträger B
" was also laid down in Kiel in 1938 with a launch date planned for July 1940, possibly to be named as Peter Strasser. Work on this second carrier was halted in September 1939 and she was broken up the following year. It is possible that Mayer misinterpreted the construction of the large naval tanker Franken for this second aircraft carrier and wanted to alert the Allies to this development. The naval tanker Franken (launched on 8 March 1939) was in the process of being built right next to the Graf Zeppelin, itself still under construction.
, or if the wingspan alone is considered, it could have referred to the Henschel Hs 293
design, controlled with an FuG 203 Kehl transmitter in the deploying aircraft, and an FuG 230 Straßburg receiver in the ordnance.
, but the German text clearly states that a rocket was meant. This is also clear from the remark that the projectile is highly unstable when fired, while artillery shells would be spin-stabilized, or fin-stabilized in the case of mortar
projectiles.
The mentioned size of 80 cm (31.5 in) calibre was seen as a curious item at the time; even by 1943 British rocket developers were focused on solid fuels, and thinking in diameters of around 3 in (7.6 cm); a solid fuel rocket of more than ten times this diameter would have caused a credibility gap
, which did in fact happen when more information later became available to British intelligence. With hindsight, the description can be recognised as the A8 rocket, which had a diameter of 78 cm (30.7 in).
The one crucial item of information missed out by the author of the Oslo Report was the use of liquid fuels in the German ballistic rocket program.
is a small town located on the Lake Müritz
north of Berlin
, with the turf-covered airfield some 4.5 km (2.5 miles) directly north of the 21st century Rechlin-Lärz airfield
being the core of the Luftwaffe's central Erprobungstelle aviation test facility. The facility's main turf surface airfield, set up in the manner of a pre-WW II aerodrome without clearly defined runways, was bounded by a roughly hexagonal-layout perimeter road that still exists. Mayer noted that the Luftwaffe
's laboratories and research centers were there, and that it was a "worthwhile point of attack" for bombers. The entire system of Erprobungstellen facilities was commanded by Luftwaffe Oberst Edgar Petersen
for a time during the later years of the war.
in 1939, Polish bunkers were attacked using smoke shell which forced their crews to withdraw deeper into the bunkers, following which soldiers armed with flame throwers attacked under cover of the smoke. Revealing these tactics employed by the Wehrmacht is perhaps the most mundane information provided by the Oslo Report.
in September 1939 was detected while the aircraft were 120 km (74.6 mi) from the German coast using radar
. He also gives the technical characteristics of the German early-warning radar systems- power
, pulse duration
, and range were described in some detail, along with counter-measures that could exploit the radar system's vulnerabilities. However, Mayer did not know the last critical piece of information: the wavelength
.
He also noted that the system was being installed on Ju 88 bombers, the first instance of an airborne radar.
Again, he mentioned the date of April 1940 as the deadline for installation of this radar. He described a similar second system that was under development at the time that operated at a 50 cm wavelength. The wavelengths for both the FuG 200 Hohentwiel ASV airborne maritime search radar, and the FuG 202 Lichtenstein AI night fighter radar both operated at low-UHF band, 490 to 550 MHz frequencies, both in the general neighborhood of the 50 cm wavelength.
The section of the report revealed Mayer's depth of knowledge of radar technology. The operational radar principle he revealed - a short burst of transmitted energy, measuring the time-of-flight and calculating range from it - was known by the British and was in fact being used in the Chain Home
early warning radar.
Revealing the details of the system under development allowed the British to invent a simple countermeasure they called Window
, already known to the Germans as Düppel, which consisted of long strips of aluminium foil of a length designed to optimally reflect the German 50 cm radar signals, jamming
them. It turned out that 50 cm was a standard wavelength that all German defensive radars used, which made Window a very effective way of blinding all their defensive radar systems following its introduction in the Hamburg raid of 24 July 1943 (see Operation Gomorrah).
aid installed at many German airports. Mayer gave the wavelength as 6m (50MHz).
The first was designed to be used from distances of 10 km (6.2 mi). It was intended to be steered into rough proximity to a convoy using a long wave radio receiver, when two acoustic receivers in the head of the torpedo would take over when it came within a few hundred metres of a ship. See Acoustic torpedo
.
The second type of torpedo (mentioned as the same type that was used to sink HMS Royal Oak in 1939), was described as having a magnetic fuze
designed to detect the deviations in the Earth's magnetic field
caused by a ship's metal hull and explode beneath its keel. Mayer described the general principle of the fuze and suggested that it could be defended against by generating a suitable magnetic field.
s for artillery shells were being discontinued in favour of electrical fuzes, and mentioned that all bombs already had electrical fuzes. Mayer described the working of bomb fuzes and described electrical time fuzes.
Mayer also mentioned an idea for a proximity fuze
, i.e. a fuze that detonates a warhead at a set distance from a target. The fuze he described sensed its target by changes in partial capacitances, which in practice turned out to be impracticable. He also not only mentioned its anti-aircraft applications, but also its application to anti-personnel artillery shells, an application which was later employed by the Allies.
Mayer concluded with mentioning that the fuzes were manufactured by Rheinmetall
in Sömmerda
, Thüringen
.
that publicly revealed for the first time the existence and importance of the Oslo Report.
This part of his talk caught the eye of the press and it was widely publicized.
He revealed some of the Report's contents, holding back many details to test anyone claiming authorship.
But neither Henry Cobden Turner nor Mayer heard of the talk at the time.
By chance, both Turner and Jones were on the same voyage of the Queen Mary
in 1953, and one evening, they sat at the same dinner table.
They found much in common and Jones invited Turner to a dinner at his London club.
On December 15, 1953 the dinner was arranged, during which one of Jones's friends, Professor Frederick Norman of King's College London
, excitedly shouts "Oslo!!".
Turner and Norman privately tell Jones over after-dinner drinks that Turner had heard from his old German friend, Hans Ferdinand Mayer, at the beginning of the war in a letter written from Oslo.
Upon learning of Mayer's background and position at Siemens
, Jones decided to open a correspondence with Mayer using Turner as a middleman.
Jones and Mayer met at a 1955 radar conference in Munich
and had dinner with Turner at Mayer's house.
Jones quickly determined that Mayer had indeed written the Oslo Report.
They agreed that immediately divulging who had written the Oslo Report would serve no purpose and both agreed to silence.
They continued to exchange letters, with Mayer providing more details about how he wrote it.
Jones decided to write a book about his wartime scientific intelligence work for MI6, but it did not appear until 1978.
In it, he discussed how he used the Oslo Report, but did not reveal the author.
Mayer died in 1980 without being publicly acknowledged as the author.
Jones's sequel, published in 1989, revealed the author's identity.
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...
on November 1 and 2, 1939 during a business trip to Oslo
Oslo
Oslo is a municipality, as well as the capital and most populous city in Norway. As a municipality , it was established on 1 January 1838. Founded around 1048 by King Harald III of Norway, the city was largely destroyed by fire in 1624. The city was moved under the reign of Denmark–Norway's King...
, Norway
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...
, it described several German
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...
weapons systems, current and future.
Mayer mailed the report anonymously in the form of two letters to the British
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
Embassy in Oslo, where they were passed on to MI6 in London
London
London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...
for further analysis, and proved to be an invaluable resource to the British in developing counter-measures, especially to navigational and targeting 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...
s, and contributed to the British winning the Battle of Britain
Battle of Britain
The Battle of Britain is the name given to the World War II air campaign waged by the German Air Force against the United Kingdom during the summer and autumn of 1940...
.
Background
Hans Ferdinand Mayer received his doctorate in physics from the University of Heidelberg in 1920. After spending two years as a research associate there in his doctoral supervisor's (Philipp LenardPhilipp Lenard
Philipp Eduard Anton von Lenard , known in Hungarian as Lénárd Fülöp Eduárd Antal, was a Hungarian - German physicist and the winner of the Nobel Prize for Physics in 1905 for his research on cathode rays and the discovery of many of their properties...
) laboratory, he joined Siemens AG
Siemens AG
Siemens AG is a German multinational conglomerate company headquartered in Munich, Germany. It is the largest Europe-based electronics and electrical engineering company....
in 1922. He became interested in telecommunications and joined Siemens' communication research laboratory, becoming its director in 1936. Because of this position, he had contacts all over Europe and the United States and had access to a wide range of information about electronics development in Germany, especially in the military sector.
After Hitler invaded Poland on September 1, 1939, Mayer decided to divulge to the British as much as he could about military secrets to defeat the Nazi regime. He arranged a business trip to Scandinavia
Scandinavia
Scandinavia is a cultural, historical and ethno-linguistic region in northern Europe that includes the three kingdoms of Denmark, Norway and Sweden, characterized by their common ethno-cultural heritage and language. Modern Norway and Sweden proper are situated on the Scandinavian Peninsula,...
in late October 1939. He arrived at his first scheduled stop, Oslo
Oslo
Oslo is a municipality, as well as the capital and most populous city in Norway. As a municipality , it was established on 1 January 1838. Founded around 1048 by King Harald III of Norway, the city was largely destroyed by fire in 1624. The city was moved under the reign of Denmark–Norway's King...
, Norway
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...
, on October 30, 1939 and checked into the Hotel Bristol.
Mayer borrowed a typewriter from the hotel, and typed the seven-page Oslo Report in the form of two letters over two days. He mailed the first on November 1, which asked the British military attaché to arrange for the BBC World Service to alter the introduction to its German language programme if he wished to receive the Report. This was done, and he sent the Report along with a vacuum tube from a prototype proximity fuze
Proximity fuze
A proximity fuze is a fuze that is designed to detonate an explosive device automatically when the distance to target becomes smaller than a predetermined value or when the target passes through a given plane...
.
He also wrote a letter to his longtime British friend Henry Cobden Turner, asking him to communicate with him via their Danish colleague Niels Holmblad. This indirect communication path was required since Britain and Germany were at war, but Denmark
Denmark
Denmark is a Scandinavian country in Northern Europe. The countries of Denmark and Greenland, as well as the Faroe Islands, constitute the Kingdom of Denmark . It is the southernmost of the Nordic countries, southwest of Sweden and south of Norway, and bordered to the south by Germany. Denmark...
was at that time neutral. Mayer continued his travels to Denmark
Denmark
Denmark is a Scandinavian country in Northern Europe. The countries of Denmark and Greenland, as well as the Faroe Islands, constitute the Kingdom of Denmark . It is the southernmost of the Nordic countries, southwest of Sweden and south of Norway, and bordered to the south by Germany. Denmark...
to visit Holmblad, asking if he could relay information between himself and Turner. Holmblad readily agreed, but once Hitler invaded Denmark on April 9, 1940, this communication route was no longer feasible. Mayer then returned to Germany. Although Mayer was arrested by the Gestapo
Gestapo
The Gestapo was the official secret police of Nazi Germany. Beginning on 20 April 1934, it was under the administration of the SS leader Heinrich Himmler in his position as Chief of German Police...
in 1943 and was imprisoned in concentration camps until the war ended, the Nazis never knew of the Oslo Report.
British reaction
On 4 November 1939, Captain Hector Boyes, the Naval Attaché at the British Embassy in Oslo, received an anonymous letter offering him a secret report on the latest German technical developments. To receive the report, all he had to do was arrange for the usual announcement of the BBC World ServiceBBC World Service
The BBC World Service is the world's largest international broadcaster, broadcasting in 27 languages to many parts of the world via analogue and digital shortwave, internet streaming and podcasting, satellite, FM and MW relays...
's German language broadcast to be changed to "Hullo, hier ist London". This was done, and resulted in the delivery of a parcel a week later which contained a typewritten document and a type of vacuum tube
Vacuum tube
In electronics, a vacuum tube, electron tube , or thermionic valve , reduced to simply "tube" or "valve" in everyday parlance, is a device that relies on the flow of electric current through a vacuum...
, a sensor for a proximity fuze
Proximity fuze
A proximity fuze is a fuze that is designed to detonate an explosive device automatically when the distance to target becomes smaller than a predetermined value or when the target passes through a given plane...
for shells or bombs. The typewritten document accompanying it became famous after its existence was revealed in 1947 and would go down in history as the "Oslo Report".
Boyes quickly appreciated the Report's potential importance and had a member of the embassy staff make a translation which he forwarded to MI6 in London along with the original.
The Oslo Report was received with indifference or even disbelief by British Intelligence, with the notable exception of Dr. R.V. 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:...
, a young Ph.D. physicist who had recently been put in charge of a new field called "Scientific Intelligence". Jones argued that despite the breadth of information and a few inaccuracies, the technical details were correct and argued that all the electronic systems divulged therein be further explored. In a 1940 report, Jones summarized his thoughts.
The contribution of this source to the present problem may be summarised in the statements that the Germans were bringing into use an R.D.F. [ Radio Direction Finding, the British name for radar] system similar to our own,...
A careful review of the whole report leaves only two possible conclusions: (1) that it was a "plant" to persuade us that the Germans were as well advanced as ourselves or (2) that the source was genuinely disaffected from Germany, and wished to tell us all he knew. The general accuracy of the information, the gratuitous presentation of the fuse, and the fact that the source made no effort, as far as it is known, to exploit the matter, together with the subsequent course of the war and our recent awakening with Knickebein, weigh heavily in favour of the second conclusion. It seems, then, that the source was reliable, and he was manifestly competent.
In his 1989 book, Jones summarized the importance of the Oslo Report as follows:
It was probably the best single report received from any source during the war.
...Overall, of course, the contributions from other sources such as the Enigma decryptsCryptanalysis of the EnigmaCryptanalysis of the Enigma enabled the western Allies in World War II to read substantial amounts of secret Morse-coded radio communications of the Axis powers that had been enciphered using Enigma machines. This yielded military intelligence which, along with that from other decrypted Axis radio...
, aerial photographs, and reports from the ResistanceResistance during World War IIResistance movements during World War II occurred in every occupied country by a variety of means, ranging from non-cooperation, disinformation and propaganda to hiding crashed pilots and even to outright warfare and the recapturing of towns...
, outweighed the Oslo contribution, but these were all made from organizations involving many, sometimes thousands of individuals and operating throughout most of the war. The Oslo Report, we believed, had been written by a single individual who in one great flash had given us a synoptic glimpse of much of what was foreshadowed in German military electronics.
While Jones took the Oslo Report very seriously, the Admiralty for one thought that the Report was "too good to be true" and therefore had to be a devious deception by the Abwehr
Abwehr
The Abwehr was a German military intelligence organisation from 1921 to 1944. The term Abwehr was used as a concession to Allied demands that Germany's post-World War I intelligence activities be for "defensive" purposes only...
, with its fantastic claims written by psychological warfare experts. An additional argument raised by the doubters was that no single person could have such wide knowledge of weapons technology as discussed in the Report. This was mainly because interforce co-operation, e.g. between the Navy and Air Force, was at the time poor in both Britain and the US, and it was known that in Germany the two organisations were virtually at war between themselves.
In fact, the Oslo Report is strongly focused - on electronic technology - and several major German companies were involved in such projects for all three armed forces; some scientists in these companies would indeed have had a wide-ranging overview.
Report Contents
The original typed report was seven pages long. It was retyped, with a number of carbon copies being made for distribution. A specimen of the original translation is unobtainable, and the German version held by the Imperial War MuseumImperial War Museum
Imperial War Museum is a British national museum organisation with branches at five locations in England, three of which are in London. The museum was founded during the First World War in 1917 and intended as a record of the war effort and sacrifice of Britain and her Empire...
is one of the carbon copies and lacks the sketches that were apparently included in Mayer's original. A typed copy in German can also be found in the Public Records Office., while the Report has been published twice in English translation.F.H. Hinsley (1979), Appendix 5.
The section headings given here correspond to those in the Report. Some of the information Mayer heard was second-hand and later proved to be incorrect.
1. Ju 88 Program
The Junkers 88 light bomber production levels are stated to be probably 5,000 per month, with a total of over 25-30,000 predicted to be produced by April 1940. This was an exaggeration of production levels and total production.2. The "Franken"
The report states that the German navy's first aircraft carrier is at KielKiel
Kiel is the capital and most populous city in the northern German state of Schleswig-Holstein, with a population of 238,049 .Kiel is approximately north of Hamburg. Due to its geographic location in the north of Germany, the southeast of the Jutland peninsula, and the southwestern shore of the...
, and was expected to be finished in April 1940. The carrier was referred to as Franken.
It is sometimes suggested that Mayer was mistaken and that he was instead identifying the carrier Graf Zeppelin
German aircraft carrier Graf Zeppelin
German aircraft carrier Graf Zeppelin was the lead ship in a class of two carriers ordered by the Kriegsmarine. She was the only aircraft carrier launched by Germany during World War II and represented part of the Kriegsmarine's attempt to create a well-balanced oceangoing fleet, capable of...
. However, the construction of Graf Zeppelin was well known to Allied navies. Following Kriegsmarine ship naming policy, this carrier was assigned her name on being launched on 8 December 1938; previously she was known as "Flugzeugträger A". A second carrier known as "Flugzeugträger B
Flugzeugträger B
The Flugzeugträger B was the sister ship of the Kriegsmarine's only launched aircraft carrier, the Graf Zeppelin....
" was also laid down in Kiel in 1938 with a launch date planned for July 1940, possibly to be named as Peter Strasser. Work on this second carrier was halted in September 1939 and she was broken up the following year. It is possible that Mayer misinterpreted the construction of the large naval tanker Franken for this second aircraft carrier and wanted to alert the Allies to this development. The naval tanker Franken (launched on 8 March 1939) was in the process of being built right next to the Graf Zeppelin, itself still under construction.
3. Remote controlled gliders
This section of the report described remote-controlled gliders of 3 m (9.8 ft) wingspan and 3 m (9.8 ft) length, carrying an explosive charge, and fitted with an altimeter intended to maintain them at an altitude of 3 m (9.8 ft) above the water, the horizontal stage of their flight to be powered by a rocket engine. This description is similar to the ultimately unsuccessful Blohm & Voss Bv 143Blohm & Voss BV 143
The Blohm & Voss BV 143 was an early prototype rocket-assisted glide bomb developed by the German Luftwaffe during World War II.-Design:By 1941, Allied merchant ships were slow and easy targets for German coastal bombers, but were proving increasingly well-equipped with anti-aircraft artillery,...
, or if the wingspan alone is considered, it could have referred to the Henschel Hs 293
Henschel Hs 293
The Henschel Hs 293 was a World War II German anti-ship guided missile: a radio-controlled glide bomb with a rocket engine slung underneath it. It was designed by Herbert A. Wagner.- History :...
design, controlled with an FuG 203 Kehl transmitter in the deploying aircraft, and an FuG 230 Straßburg receiver in the ordnance.
4. Autopilot
Here, Mayer briefly described another remote-controlled system, this time for an aircraft instead of for a rocket.5. Remote-controlled projectiles
The German word Geschoss was used in the report, which can also be translated to mean artillery shellShell (projectile)
A shell is a payload-carrying projectile, which, as opposed to shot, contains an explosive or other filling, though modern usage sometimes includes large solid projectiles properly termed shot . Solid shot may contain a pyrotechnic compound if a tracer or spotting charge is used...
, but the German text clearly states that a rocket was meant. This is also clear from the remark that the projectile is highly unstable when fired, while artillery shells would be spin-stabilized, or fin-stabilized in the case of mortar
Mortar (weapon)
A mortar is an indirect fire weapon that fires explosive projectiles known as bombs at low velocities, short ranges, and high-arcing ballistic trajectories. It is typically muzzle-loading and has a barrel length less than 15 times its caliber....
projectiles.
The mentioned size of 80 cm (31.5 in) calibre was seen as a curious item at the time; even by 1943 British rocket developers were focused on solid fuels, and thinking in diameters of around 3 in (7.6 cm); a solid fuel rocket of more than ten times this diameter would have caused a credibility gap
Credibility gap
Credibility gap is a political term that came into wide use during the 1960s and 1970s. At the time, it was most frequently used to describe public skepticism about the Lyndon B. Johnson administration's statements and policies on the Vietnam War...
, which did in fact happen when more information later became available to British intelligence. With hindsight, the description can be recognised as the A8 rocket, which had a diameter of 78 cm (30.7 in).
The one crucial item of information missed out by the author of the Oslo Report was the use of liquid fuels in the German ballistic rocket program.
6. Rechlin
RechlinRechlin
Rechlin is a municipality in Mecklenburg-Western Pomerania, Germany. The town's airport has a long history and was the Luftwaffe's main testing ground for new aircraft designs during the Third Reich....
is a small town located on the Lake Müritz
Müritz
Müritz is a former Kreis in the southern part of Mecklenburg-Vorpommern, Germany. It is named after the lake Müritz. Neighboring districts were Demmin, Mecklenburg-Strelitz, the district-free city Neubrandenburg, the district Ostprignitz-Ruppin in Brandenburg, Parchim and Güstrow...
north of Berlin
Berlin
Berlin is the capital city of Germany and is one of the 16 states of Germany. With a population of 3.45 million people, Berlin is Germany's largest city. It is the second most populous city proper and the seventh most populous urban area in the European Union...
, with the turf-covered airfield some 4.5 km (2.5 miles) directly north of the 21st century Rechlin-Lärz airfield
Rechlin-Lärz Airfield
Rechlin-Lärz Airfield is an airfield in the village of Rechlin, Mecklenburg-Western Pomerania, Germany, which is certified for aviation equipment up to 14 tons weight...
being the core of the Luftwaffe's central Erprobungstelle aviation test facility. The facility's main turf surface airfield, set up in the manner of a pre-WW II aerodrome without clearly defined runways, was bounded by a roughly hexagonal-layout perimeter road that still exists. Mayer noted that the Luftwaffe
Luftwaffe
Luftwaffe is a generic German term for an air force. It is also the official name for two of the four historic German air forces, the Wehrmacht air arm founded in 1935 and disbanded in 1946; and the current Bundeswehr air arm founded in 1956....
's laboratories and research centers were there, and that it was a "worthwhile point of attack" for bombers. The entire system of Erprobungstellen facilities was commanded by Luftwaffe Oberst Edgar Petersen
Edgar Petersen
Edgar Petersen was a German Luftwaffe bomber pilot and recipient of the Knight's Cross of the Iron Cross during World War II. The Knight's Cross of the Iron Cross was awarded to recognise extreme battlefield bravery or successful military leadership...
for a time during the later years of the war.
7. Methods of attacks on bunkers
Mayer noted during the invasion of PolandInvasion of Poland (1939)
The Invasion of Poland, also known as the September Campaign or 1939 Defensive War in Poland and the Poland Campaign in Germany, was an invasion of Poland by Germany, the Soviet Union, and a small Slovak contingent that marked the start of World War II in Europe...
in 1939, Polish bunkers were attacked using smoke shell which forced their crews to withdraw deeper into the bunkers, following which soldiers armed with flame throwers attacked under cover of the smoke. Revealing these tactics employed by the Wehrmacht is perhaps the most mundane information provided by the Oslo Report.
8. Air raid warning equipment
Mayer mentions that the British air raid on WilhelmshavenWilhelmshaven
Wilhelmshaven is a coastal town in Lower Saxony, Germany. It is situated on the western side of the Jade Bight, a bay of the North Sea.-History:...
in September 1939 was detected while the aircraft were 120 km (74.6 mi) from the German coast using 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...
. He also gives the technical characteristics of the German early-warning radar systems- power
Power (physics)
In physics, power is the rate at which energy is transferred, used, or transformed. For example, the rate at which a light bulb transforms electrical energy into heat and light is measured in watts—the more wattage, the more power, or equivalently the more electrical energy is used per unit...
, pulse duration
Pulse duration
In signal processing and telecommunication, the term pulse duration has the following meanings:#In a pulse waveform, the interval between the time, during the first transition, that the pulse amplitude reaches a specified fraction of its final amplitude, and the time the pulse amplitude drops,...
, and range were described in some detail, along with counter-measures that could exploit the radar system's vulnerabilities. However, Mayer did not know the last critical piece of information: the wavelength
Wavelength
In physics, the wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the wave's shape repeats.It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a...
.
He also noted that the system was being installed on Ju 88 bombers, the first instance of an airborne radar.
Again, he mentioned the date of April 1940 as the deadline for installation of this radar. He described a similar second system that was under development at the time that operated at a 50 cm wavelength. The wavelengths for both the FuG 200 Hohentwiel ASV airborne maritime search radar, and the FuG 202 Lichtenstein AI night fighter radar both operated at low-UHF band, 490 to 550 MHz frequencies, both in the general neighborhood of the 50 cm wavelength.
The section of the report revealed Mayer's depth of knowledge of radar technology. The operational radar principle he revealed - a short burst of transmitted energy, measuring the time-of-flight and calculating range from it - was known by the British and was in fact being used in the Chain Home
Chain Home
Chain Home was the codename for the ring of coastal Early Warning radar stations built by the British before and during the Second World War. The system otherwise known as AMES Type 1 consisted of radar fixed on top of a radio tower mast, called a 'station' to provide long-range detection of...
early warning radar.
Revealing the details of the system under development allowed the British to invent a simple countermeasure they called Window
Chaff (radar countermeasure)
Chaff, originally called Window by the British, and Düppel by the Second World War era German Luftwaffe , is a radar countermeasure in which aircraft or other targets spread a cloud of small, thin pieces of aluminium, metallized glass fibre or plastic, which either appears as a cluster of secondary...
, already known to the Germans as Düppel, which consisted of long strips of aluminium foil of a length designed to optimally reflect the German 50 cm radar signals, jamming
Radar jamming and deception
Radar jamming and deception is the intentional emission of radio frequency signals to interfere with the operation of a radar by saturating its receiver with noise or false information...
them. It turned out that 50 cm was a standard wavelength that all German defensive radars used, which made Window a very effective way of blinding all their defensive radar systems following its introduction in the Hamburg raid of 24 July 1943 (see Operation Gomorrah).
9. Aircraft rangefinder
Mayer described a system being developed at Rechlin for navigating German bombers to their targets, which used a single radio transmission to accurately locate a bomber's range from the transmitter. This was the X-Gerät (X-device), which was based on the prewar Lorenz blind-landingInstrument Landing System
An instrument landing system is a ground-based instrument approach system that provides precision guidance to an aircraft approaching and landing on a runway, using a combination of radio signals and, in many cases, high-intensity lighting arrays to enable a safe landing during instrument...
aid installed at many German airports. Mayer gave the wavelength as 6m (50MHz).
10. Torpedoes
Mayer described two new types of torpedoes in service with the German navy.The first was designed to be used from distances of 10 km (6.2 mi). It was intended to be steered into rough proximity to a convoy using a long wave radio receiver, when two acoustic receivers in the head of the torpedo would take over when it came within a few hundred metres of a ship. See Acoustic torpedo
Acoustic torpedo
An acoustic torpedo is a torpedo that aims itself by listening for characteristic sounds of its target or by searching for it using sonar. Acoustic torpedoes are usually designed for medium-range use, and often fired from a submarine....
.
The second type of torpedo (mentioned as the same type that was used to sink HMS Royal Oak in 1939), was described as having a magnetic fuze
Magnetic pistol
Magnetic pistol is the term for the device on a torpedo or naval mine that detects its target by its magnetic field, and triggers the fuse for detonation...
designed to detect the deviations in the Earth's magnetic field
Earth's magnetic field
Earth's magnetic field is the magnetic field that extends from the Earth's inner core to where it meets the solar wind, a stream of energetic particles emanating from the Sun...
caused by a ship's metal hull and explode beneath its keel. Mayer described the general principle of the fuze and suggested that it could be defended against by generating a suitable magnetic field.
11. Electric fuzes for bombs and shells
The final section of the report described how mechanical fuzeFuze
Fuze Beverage, commercially referred to as just Fuze , is a manufacturer of teas and non-carbonated fruit drinks enriched with vitamins. Currently the brand consists of five vitamin-infused lines: Slenderize, Refresh, Tea, Defensify, and Vitalize...
s for artillery shells were being discontinued in favour of electrical fuzes, and mentioned that all bombs already had electrical fuzes. Mayer described the working of bomb fuzes and described electrical time fuzes.
Mayer also mentioned an idea for a proximity fuze
Proximity fuze
A proximity fuze is a fuze that is designed to detonate an explosive device automatically when the distance to target becomes smaller than a predetermined value or when the target passes through a given plane...
, i.e. a fuze that detonates a warhead at a set distance from a target. The fuze he described sensed its target by changes in partial capacitances, which in practice turned out to be impracticable. He also not only mentioned its anti-aircraft applications, but also its application to anti-personnel artillery shells, an application which was later employed by the Allies.
Mayer concluded with mentioning that the fuzes were manufactured by Rheinmetall
Rheinmetall
Rheinmetall AG is a German automotive and defence company with factories in Düsseldorf, Kassel and Unterlüß. The company has a long tradition of making guns and artillery pieces...
in Sömmerda
Sömmerda
Sömmerda is a town near Erfurt in Thuringia, Germany, on the Unstrut river. It is the capital of the district of Sömmerda.-History:Archeological digs in the area that is now Sömmerda, formerly Leubingen, have uncovered prominently buried human remains dating to around 2000 BCE...
, Thüringen
Thuringia
The Free State of Thuringia is a state of Germany, located in the central part of the country.It has an area of and 2.29 million inhabitants, making it the sixth smallest by area and the fifth smallest by population of Germany's sixteen states....
.
Divulging the Report and the Author
On February 12, 1947, Jones gave an invited talk to the Royal United Service InstitutionRoyal United Services Institute
The Royal United Services Institute for Defence and Security Studies , officially still known by its old name, the Royal United Services Institution, is a British defence and security think tank. It was founded in 1831 by The Duke of Wellington.RUSI describes itself asIt won Prospect Magazine's...
that publicly revealed for the first time the existence and importance of the Oslo Report.
This part of his talk caught the eye of the press and it was widely publicized.
He revealed some of the Report's contents, holding back many details to test anyone claiming authorship.
But neither Henry Cobden Turner nor Mayer heard of the talk at the time.
By chance, both Turner and Jones were on the same voyage of the Queen Mary
RMS Queen Mary
RMS Queen Mary is a retired ocean liner that sailed primarily in the North Atlantic Ocean from 1936 to 1967 for the Cunard Line...
in 1953, and one evening, they sat at the same dinner table.
They found much in common and Jones invited Turner to a dinner at his London club.
On December 15, 1953 the dinner was arranged, during which one of Jones's friends, Professor Frederick Norman of King's College London
King's College London
King's College London is a public research university located in London, United Kingdom and a constituent college of the federal University of London. King's has a claim to being the third oldest university in England, having been founded by King George IV and the Duke of Wellington in 1829, and...
, excitedly shouts "Oslo!!".
Turner and Norman privately tell Jones over after-dinner drinks that Turner had heard from his old German friend, Hans Ferdinand Mayer, at the beginning of the war in a letter written from Oslo.
Upon learning of Mayer's background and position at Siemens
Siemens
Siemens may refer toSiemens, a German family name carried by generations of telecommunications industrialists, including:* Werner von Siemens , inventor, founder of Siemens AG...
, Jones decided to open a correspondence with Mayer using Turner as a middleman.
Jones and Mayer met at a 1955 radar conference in Munich
Munich
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...
and had dinner with Turner at Mayer's house.
Jones quickly determined that Mayer had indeed written the Oslo Report.
They agreed that immediately divulging who had written the Oslo Report would serve no purpose and both agreed to silence.
They continued to exchange letters, with Mayer providing more details about how he wrote it.
Jones decided to write a book about his wartime scientific intelligence work for MI6, but it did not appear until 1978.
In it, he discussed how he used the Oslo Report, but did not reveal the author.
Inevitably, the question will be asked regarding my own ideas about the identity of the Oslo author.
I believe that I know, but the way in which the identity was revealed to me was so extraordinary that it may well not be credited.
In any event, it belongs to a later period, and the denouement must wait until then.
Mayer died in 1980 without being publicly acknowledged as the author.
Jones's sequel, published in 1989, revealed the author's identity.