Japan shares it's cavity magnetron with German in 1940?

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stg 44
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Japan shares it's cavity magnetron with German in 1940?

Post by stg 44 » 30 Aug 2017 18:03

https://en.wikipedia.org/wiki/Yoji_Ito#Magnetron
Shigeru Nakajima,[4] a younger brother of Yoji Ito and a scientist at the Japan Radio Company (JRC), was also investigating magnetrons, primarily for the medical dielectric heating (diathermy) market. An alliance was made between NTRI and JRC for further magnetron development. In early 1939, led by Yoji Ito they built a 10-cm (3-GHz), stable-frequency Mandarin-type magnetron (No. M3) that, with water cooling, could produce 500-W power.[2]
In late 1940 Commander Ito led a technical-exchange mission to Germany. Fluent in the German language and holding a doctorate from Dresden Technische Hochschule, he was well received. Staying several months, he became aware of their pulse-modulated radio equipment for detecting and ranging, and immediately sent word back to Japan that this technology should be incorporated in the NTRI-JRC effort. On August 2, 1941, even before Ito returned to Japan, funds were allocated for the initial development of a pulse-modulated Radio Range Finder (RRF – the Japanese code name for a radar).

The Germans had not yet developed a magnetron suitable for use in such systems, so their equipment operated in the VHF region. At the NTRI, they followed the Germans and built a prototype VHF set operating at 4.2 m (71 MHz) and producing about 5 kW.
What if Commander Ito, rather than keeping mum about the development of a cavity magnetron, instead shared it with the Germans in an Axis Tizard mission? The power of the 1939 Japanese magnetron was equivalent to the power of the 1941 vintage British airborne intercept radar's magentron.

What impact would it have on the war if then the Germans had access to equivalent functional cavity magnetron technology as the British and US as of late 1940-early 1941? Historically they only gained access to a captured British unit in early 1943 and took a while to understand how the technology worked, only producing a few dozen copies by the end of the war. In this scenario the Germans would have access not just to a physical unit, but Japanese theoretic research and understanding of the workings of the technology, thus not having to replicate it themselves in a costly development program, they could just continue advancing research on their own or with an exchange with the Japanese, who developed powerful magnetrons throughout the war:
In parallel with the VHF work, Yoji Ito also returned to the magnetron applications, resulting in Japan’s first pulse-modulated microwave RRF set. It operated at 10 cm (3 GHz) and produced a peak-power of 2.0 kW. A prototype was tested in October 1941, and several versions for surface ships and submarines were soon put into production. Naval officials favored the microwave sets because with very narrow beams they were less vulnerable to interception.

A special laboratory was set up near Shimada, in the Shizuoka Prefecture, for developing a high-power magnetron that, if not as powerful as Tesla had boasted, might at least incapacitate an aircraft. A number of Japan’s leading physicists were involved. A 20 cm magnetron producing 100 kW was achieved, and by the end of the war a 1000 kW (1 MW) unit was undergoing preliminary testing.[6] At that time, the development was terminated and the hardware as well as all documentation was destroyed.[8]

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Re: Japan shares it's cavity magnetron with German in 1940?

Post by T. A. Gardner » 30 Aug 2017 18:53

I'd expect the Germans to largely ignore this development. Radar in 1939 - 40 wasn't a high priority. Göring, in particular, was pretty adverse to the whole electronics field up to discovering the Allies had gotten way ahead of the Germans. I think that Nazi racism would have played a role in downplaying its significance until the Germans discover the Allies are using the technology. Then it'd be a game of trying to catch up. But, that would have given them millimeter radar and detection equipment early in 1943 instead of mid 1944, so they gain a year or year and a half.

It's interesting to note that Japan had a working magnetron ahead of Britain but production limitations... the Japanese radar program was split between the Navy and Army with almost zero cooperation between the two and both had just a few hundred employees for most of the war... kept them from deploying a working microwave radar until 1944.

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Re: Japan shares it's cavity magnetron with German in 1940?

Post by stg 44 » 30 Aug 2017 19:36

T. A. Gardner wrote:I'd expect the Germans to largely ignore this development. Radar in 1939 - 40 wasn't a high priority. Göring, in particular, was pretty adverse to the whole electronics field up to discovering the Allies had gotten way ahead of the Germans. I think that Nazi racism would have played a role in downplaying its significance until the Germans discover the Allies are using the technology. Then it'd be a game of trying to catch up. But, that would have given them millimeter radar and detection equipment early in 1943 instead of mid 1944, so they gain a year or year and a half.
If the Germans weren't interested in radar, why did they spend so much money and effort developing it prior to 1943? They built many thousands of units prior to 1943:
https://en.wikipedia.org/wiki/Radar_in_ ... II#Germany
In 1940, Josef Kammhuber used Freyas in a new air-defense network extending through the Netherlands, Belgium, and France. Called the Kammhuber Line by the Allies, it was composed of a series of cells code-named Himmelbett (four-poster bed), each covering an area some 45 km wide and 30 km deep, and containing a radar, several searchlights, and a primary and backup night-fighter aircraft. This was relatively effective except when the sky was overcast. A new gun-directing radar was needed to cover this deficiency and the Luftwaffe then contracted with Telefunken for such a system.
https://en.wikipedia.org/wiki/Kammhuber_Line

They abandoned focus on the cavity magnetron in 1935 due to the phase shift problem, which the Japanese had solved with their design and created a device capable of producing more power than the most powerful klystrons in the world. I cannot see how the Germans could ignore it, especially from such a well received engineer as Commander Ito, who spoke fluent German and got his engineering degree form a German technical university. If anyone would be listened to it would be Ito especially if demonstrating the power of his device. It certainly would be embarrassing in terms of race, but the Japanese were declared 'aryan' by the Nazis and allied with Germany, while the Germans did request and accept Japanese technology at other times, including their air deployed torpedoes.

Why would it take until 1943 to develop? Ito's mission was in late 1940. The device is ready to go and when he got back home, with a much less developed electronics industry he had mated the cavity magnetron to German radar technology to create the first Japanese radar system:
https://en.wikipedia.org/wiki/Yoji_Ito
The Germans had not yet developed a magnetron suitable for use in such systems, so their equipment operated in the VHF region. At the NTRI, they followed the Germans and built a prototype VHF set operating at 4.2 m (71 MHz) and producing about 5 kW. This was completed on a crash basis, and in early September 1941, the set detected a bomber at a range of 97 km (61 mi). The system, Japan’s first full radar, was designated Mark 1 Model 1 and quickly went into production.[6]

RRF
In parallel with the VHF work, Yoji Ito also returned to the magnetron applications, resulting in Japan’s first pulse-modulated microwave RRF set. It operated at 10 cm (3 GHz) and produced a peak-power of 2.0 kW. A prototype was tested in October 1941, and several versions for surface ships and submarines were soon put into production. Naval officials favored the microwave sets because with very narrow beams they were less vulnerable to interception.
The Germans with a much more advanced radar program should be able to integrate the cavity magnetron into their existing systems FAR more quickly than they did with the captured British magnetron due to not having to 'recreate the wheel' as the Japanese could share their theoretical knowledge as well as the blue prints.

If they follow same time line of capture/reception of technology to fielding it as the historical captured British unit starting from late 1940 they should have it in service as of late 1942 instead of the Lichtenstein airborne radar system:
https://en.wikipedia.org/wiki/FuG_240_Berlin
The inevitable occurred on 2 February 1943, when a Short Stirling Pathfinder was downed near Rotterdam. German forces examining the wreckage found an apparatus which they called the "Rotterdam Gerät" (Rotterdam Device). They quickly determined it to be a centimeter wavelength generator.

The captured magnetron was sent to Berlin. The electronic group Telefunken used it as a basis for a German version of the device and an AI radar based on it. The system which Telefunken developed was similar to its British counterpart, differing largely in the display system. Given the limited number of changes, it is unclear why it took so long to get into production, over two years. Production units were not ready until the spring of 1945, and were not installed in German aircraft until April, just before the war ended.
It is unlikely that the Germans would need two years with the Japanese magnetron, given that they don't need to do a bunch of testing to understand the technology first before being able to copy it, plus they wouldn't be facing the same level of bombing of industry in 1940-41 as in 1943-45.
Much more likely is that by late 1941 they'd have had a system using it for ground radar and by 1942 instead of the Lichtenstein system they'd have a cavity magnetron based system:
The German Luftwaffe first introduced an airborne interception radar in 1942, the FuG 202 "Lichtenstein B/C" and its direct follow-on version, the FuG 212 Lichtenstein C-1. Both units operated at 490MHz, in the low UHF band with a wavelength of 0.61 meter. Radar antennas are sized roughly to the operational wavelength, or a fraction thereof, so the FuG 202 and 212 required large, 32-dipole Matratze (mattress) antenna arrays that projected in front of the aircraft and caused considerable drag.

Cavity Magnetron
The Berlin N-2 model was installed primarily in Junkers Ju 88G-6 night-fighters, behind a plywood radome. This so greatly reduced drag compared to the late-model Lichtensteins and Neptun that the fighters regained their pre-radar speeds. The power output of the N-2 radar was 15 kW, and was effective against bomber-sized targets at distances of up to 9 kilometers, or down to 0.5 kilometer, which eliminated the need for a second short-range radar system. The N-3 version used an updated display system that featured a C-scope output, which simplified the intercept.
T. A. Gardner wrote: It's interesting to note that Japan had a working magnetron ahead of Britain but production limitations... the Japanese radar program was split between the Navy and Army with almost zero cooperation between the two and both had just a few hundred employees for most of the war... kept them from deploying a working microwave radar until 1944.
Yeah the Japanese had a lot better research establishment that most people realize, it was the bureaucratic divisions/infighting and the problems with industry that prevented it from achieving nearly as much as it could have.

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Re: Japan shares it's cavity magnetron with German in 1940?

Post by sitalkes » 31 Aug 2017 00:45

Interesting, I had no idea Japanese radar development was so advanced. I think that if the Japanese had shared their "long lance" torpedo, air launched torpedo technology, and landing craft technology (like they did with their aircraft carriers) that would have had greater impact. If the Germans had a respectable number of air-launched torpedoes at the start of the war and working submarine torpedoes that also gave their T-boats (which were the size of Hunt destroyer) and destroyers an advantage like the Japanese had, there would have been significant early war consequences.

The Japanese had a very sophisticated set of landing craft designs, culminating in a design very similar to the landing ships used by today's US marines with some aircraft launching capability. This also meant that the Japanese Army had its own navy!! They also performed the first modern amphibious landings in 1937.

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Re: Japan shares it's cavity magnetron with German in 1940?

Post by stg 44 » 31 Aug 2017 01:24

sitalkes wrote:Interesting, I had no idea Japanese radar development was so advanced. I think that if the Japanese had shared their "long lance" torpedo, air launched torpedo technology, and landing craft technology (like they did with their aircraft carriers) that would have had greater impact. If the Germans had a respectable number of air-launched torpedoes at the start of the war and working submarine torpedoes that also gave their T-boats (which were the size of Hunt destroyer) and destroyers an advantage like the Japanese had, there would have been significant early war consequences.

The Japanese had a very sophisticated set of landing craft designs, culminating in a design very similar to the landing ships used by today's US marines with some aircraft launching capability. This also meant that the Japanese Army had its own navy!! They also performed the first modern amphibious landings in 1937.
http://www.historynet.com/world-war-ii- ... onvoys.htm
It was a historic moment. I-30 was the first Japanese submarine to arrive in Europe. As befitted such an important occasion, Grand Admiral Erich Raeder, head of the Kriegsmarine; Admiral Karl Dönitz, commander of the U-boat force; and Captain Tadao Yokoi, Japanese naval attaché to Berlin, were on hand to greet Endo and his crew. The Lorient station band played martial music, and an attractive young woman presented Endo with the bouquet of flowers traditionally given to successful U-boat commanders. While U-boat men fted the Japanese sailors, the sub’s cargo of 3,300 pounds of mica and 1,452 pounds of shellac was unloaded along with engineering drawings of the Japanese Type 91 aerial torpedo.

Kriegsmarine submarine experts examined the Japanese boat thoroughly and concluded that its noise levels were unreasonably high by their standards. They believed that an enemy destroyer’s hydrophones could easily pick up I-30‘s location. If they did not, then radar-equipped Allied air patrols most likely would. To counter this, the Germans fitted a Metox ‘Biscay Cross passive radar detector to the bridge of the Japanese sub. They also removed its 25mm Type 96 anti-aircraft guns and replaced them with a quick-firing Mauser quadruple 20mm anti-aircraft mount.

The visit came to an end on August 22, when I-30 slipped out of the sub pen and began its journey home. Its cargo included a complete Würzburg air defense ground radar with blueprints and examples of German torpedoes, bombs and fire control systems. Perhaps most important of all, the submarine also carried industrial diamonds valued at one million yen and 50 top-secret Enigma coding machines.

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Re: Japan shares it's cavity magnetron with German in 1940?

Post by thaddeus_c » 03 Sep 2017 02:46

how big an improvement for naval radar?

my understanding of radar development is limited, looking at the array in nose of JU-88 pictured it seems something could be provided to the S-boat fleet and concealed on auxiliary raiders?

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Re: Japan shares it's cavity magnetron with German in 1940?

Post by stg 44 » 03 Sep 2017 03:02

thaddeus_c wrote:how big an improvement for naval radar?

my understanding of radar development is limited, looking at the array in nose of JU-88 pictured it seems something could be provided to the S-boat fleet and concealed on auxiliary raiders?
Pretty massive for all radar. Ship borne picket radar could be seriously enhanced:
https://en.wikipedia.org/wiki/German_ni ... essel_Togo

Check out British and US cavity magnetron based microwave radar for examples of what could be possible.
https://en.wikipedia.org/wiki/Radar_in_ ... Royal_Navy
https://en.wikipedia.org/wiki/Radar_in_ ... Centimeter

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Re: Japan shares it's cavity magnetron with German in 1940?

Post by thaddeus_c » 03 Sep 2017 16:48

stg 44 wrote:
thaddeus_c wrote:how big an improvement for naval radar?

my understanding of radar development is limited, looking at the array in nose of JU-88 pictured it seems something could be provided to the S-boat fleet and concealed on auxiliary raiders?
Pretty massive for all radar. Ship borne picket radar could be seriously enhanced:
https://en.wikipedia.org/wiki/German_ni ... essel_Togo

Check out British and US cavity magnetron based microwave radar for examples of what could be possible.
https://en.wikipedia.org/wiki/Radar_in_ ... Royal_Navy
https://en.wikipedia.org/wiki/Radar_in_ ... Centimeter
thanks! very interesting

found a nice chronology on Navweaps site also http://www.navweaps.com/Weapons/WNGER_Radar.php

noted that Prince Eugen got the most advanced set, of course later in the war. my question would be any effects on their naval construction program if they had developed cavity magnetron themselves , earlier?

if they had or felt they had advantage in radars to build small(er), faster (attempted that) ships instead of hodgepodge.

if advances in radar "gifted" to them via Japanese? they convert a large number of the large fleet tenders (diesel powered) and historical Sperrbrecher to direction ships or some type of AA ship/direction ship.

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Re: Japan shares it's cavity magnetron with German in 1940?

Post by stg 44 » 03 Sep 2017 17:23

thaddeus_c wrote: noted that Prince Eugen got the most advanced set, of course later in the war. my question would be any effects on their naval construction program if they had developed cavity magnetron themselves , earlier?

if they had or felt they had advantage in radars to build small(er), faster (attempted that) ships instead of hodgepodge.

if advances in radar "gifted" to them via Japanese? they convert a large number of the large fleet tenders (diesel powered) and historical Sperrbrecher to direction ships or some type of AA ship/direction ship.
Thanks for the link.
https://en.wikipedia.org/wiki/FuG_224_B ... velopments
Why would it impact naval construction? They could see more clearly, perhaps further out, but the naval construction imperative was based on need to fight a specific type of war, which was against the Allied merchant fleet, which means Uboats. Now microwave radar would mean early detection equipment to spot aircraft, so perhaps significantly less losses to them.
In terms of AA ship...I think an early warning radar ship might be possible to supplement the land based ones, but I do wonder if an AWACS system might be viable, given that the Germans did develop one at the end of the war:
https://en.wikipedia.org/wiki/FuG_240_Berlin#Berlin
The N-4 was a further development of the N-3; it rotated the antenna in the horizontal plane under an FuG 350 Naxos-antenna style teardrop housing atop the aircraft fuselage. The result was a 360-degree image of the sky around the aircraft that was presented on a plan position indicator (PPI). This version was later renamed the FuG 244 "Bremen", but was not approved for production. The Bremen was one of the first airborne early warning (AEW) systems to be developed, although no production units were produced.

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Re: Japan shares it's cavity magnetron with German in 1940?

Post by thaddeus_c » 04 Sep 2017 04:36

stg 44 wrote:
thaddeus_c wrote: noted that Prince Eugen got the most advanced set, of course later in the war. my question would be any effects on their naval construction program if they had developed cavity magnetron themselves , earlier?

if they had or felt they had advantage in radars to build small(er), faster (attempted that) ships instead of hodgepodge.

if advances in radar "gifted" to them via Japanese? they convert a large number of the large fleet tenders (diesel powered) and historical Sperrbrecher to direction ships or some type of AA ship/direction ship.
Thanks for the link.
https://en.wikipedia.org/wiki/FuG_224_B ... velopments
Why would it impact naval construction? They could see more clearly, perhaps further out, but the naval construction imperative was based on need to fight a specific type of war, which was against the Allied merchant fleet, which means Uboats. Now microwave radar would mean early detection equipment to spot aircraft, so perhaps significantly less losses to them.
In terms of AA ship...I think an early warning radar ship might be possible to supplement the land based ones, but I do wonder if an AWACS system might be viable, given that the Germans did develop one at the end of the war:
https://en.wikipedia.org/wiki/FuG_240_Berlin#Berlin
great minds! was looking for article or mention if AWACS type aircraft had been conceived of during WWII-era. have always looked at the early German advantage in high altitude flight with JU-86 as lost opportunity. wonder if they could have married the two technologies?

my mention of alternative naval construction probably a non-starter, meant NOT building historical 4 BBs or carrier(s) but rather lighter armored ships reliant on advanced radar and speed (saving all the expensive Krupp armor.)

historically they DID gamble on high parameter steam engines and had magnetic mines nearly ready at the onset of war, marry those to advanced radar in 4,000 - 5,000t ship would at least be an interesting scenario.

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Re: Japan shares it's cavity magnetron with German in 1940?

Post by stg 44 » 04 Sep 2017 18:45

thaddeus_c wrote: great minds! was looking for article or mention if AWACS type aircraft had been conceived of during WWII-era. have always looked at the early German advantage in high altitude flight with JU-86 as lost opportunity. wonder if they could have married the two technologies?

my mention of alternative naval construction probably a non-starter, meant NOT building historical 4 BBs or carrier(s) but rather lighter armored ships reliant on advanced radar and speed (saving all the expensive Krupp armor.)

historically they DID gamble on high parameter steam engines and had magnetic mines nearly ready at the onset of war, marry those to advanced radar in 4,000 - 5,000t ship would at least be an interesting scenario.
Don't forget that the first historical AWACS was a British aircraft:
https://en.wikipedia.org/wiki/Airborne_ ... evelopment

The US Navy developed one too to fight Japanese low flying aircraft.

As to the BBs, the POD in this situation comes in 1940, so too late to save on the BBs, especially given the inherent conservatism of the KM.

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Re: Japan shares it's cavity magnetron with German in 1940?

Post by Hop » 05 Sep 2017 17:00

stg 44 wrote:
Shigeru Nakajima,[4] a younger brother of Yoji Ito and a scientist at the Japan Radio Company (JRC), was also investigating magnetrons, primarily for the medical dielectric heating (diathermy) market. An alliance was made between NTRI and JRC for further magnetron development. In early 1939, led by Yoji Ito they built a 10-cm (3-GHz), stable-frequency Mandarin-type magnetron (No. M3) that, with water cooling, could produce 500-W power.[2]
What if Commander Ito, rather than keeping mum about the development of a cavity magnetron, instead shared it with the Germans in an Axis Tizard mission? The power of the 1939 Japanese magnetron was equivalent to the power of the 1941 vintage British airborne intercept radar's magentron.
Randall and Boot's magnetron operated at 400w on its first run. The third prototype reached 3kw in June 1940, the fourth reached 15kw with a greatly increased lifespan. By the end of 1940 power was over 100kw. (source: The GEC Research Laboratories, 1919-1984, Sir Robert Clayton, p129)

The reason the UK built microwave radar before anyone else is because other magnetron designs could not deliver the necessary power. 500w is wholly inadequate for an operational radar (and most magnetrons were research devices only, not suitable for field use).

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Re: Japan shares it's cavity magnetron with German in 1940?

Post by stg 44 » 05 Sep 2017 17:50

Hop wrote: Randall and Boot's magnetron operated at 400w on its first run. The third prototype reached 3kw in June 1940, the fourth reached 15kw with a greatly increased lifespan. By the end of 1940 power was over 100kw. (source: The GEC Research Laboratories, 1919-1984, Sir Robert Clayton, p129)

The reason the UK built microwave radar before anyone else is because other magnetron designs could not deliver the necessary power. 500w is wholly inadequate for an operational radar (and most magnetrons were research devices only, not suitable for field use).
That is equivalent to the British lab radar. When they actually started mating it to production radar they boosted the power output, which the Germans can do with the Japanese magnetron. The Japanese version was very similar to the British one and slightly ahead given that it was producing greater power than the first run Randall-Boot model a year earlier, their problem was they weren't actually doing research into all the other parts of radar, just working on the magnetron. The Germans had all other the radar stuff, they didn't have a stable magnetron to work with; give them a magnetron, like the British did in 1943, and they can mate it with their existing radar equipment and produce very powerful results; the problem with the OTL situation for the Germans is that they had to figure out how the captured magnetron worked and how to copy it before they could actually do anything with it, which would not be a problem with the Japanese model, as they'd turn over the engineering documents and research developments, saving the Germans at least a year's worth of reserve engineering time to get to a working microwave radar.

Also it should be noting that the British magnetron wasn't production capable either, they had to turn it over to the US via the Tizard Mission to get Bell Labs to actually make it more than a laboratory curiosity.
https://en.wikipedia.org/wiki/Cavity_magnetron#History
Because France had just fallen to the Nazis and Britain had no money to develop the magnetron on a massive scale, Churchill agreed that Sir Henry Tizard should offer the magnetron to the Americans in exchange for their financial and industrial help (the Tizard Mission). An early 10 kW version, built in England by the General Electric Company Research Laboratories, Wembley, London (not to be confused with the similarly named American company General Electric), was given to the US government in September 1940.
....
The Bell Telephone Laboratories made a producible version from the magnetron delivered to America by the Tizard Mission, and before the end of 1940, the Radiation Laboratory had been set up on the campus of the Massachusetts Institute of Technology to develop various types of radar using the magnetron. By early 1941, portable centimetric airborne radars were being tested in American and British aircraft.[28]
So basically the TL would be very similar for the Japanese magnetron given to the Germans, except their magnetron would have been weaker than the one given to the US. Ito's mission to Germany was in late 1940 and lasted into 1941, so if he gave it over toward the end of the year the Germans would have it only a couple of months later than the US. At that time German radar developments were in advance of the US AND UK except for the magnetron. The US despite their relative lagging in the international radar scene were able to quickly turn that 10kw magnetron into a portable airborne radar a few months later. The Germans, if then given the Japanese 500w magnetron and all the info behind it could then develop it into something more powerful than the Japanese did; the Germans didn't invest to figure out how to solve the multicavity resonating bit, which the Japanese did and the German electronics industry was significantly far in advance of the Japanese except in investment into the magnetron, so they could develop it much further with that key issue worked out; the German military didn't want to invest in fixing the 1935 domestic design's phase shift issue, but with the Japanese presenting them with one that already had that issue worked out, just needing more power, they could tackle the problem much more easily than the Japanese could, who would go on to fix the power issue themselves:
https://en.wikipedia.org/wiki/Yoji_Ito#Laboratory
A special laboratory was set up near Shimada, in the Shizuoka Prefecture, for developing a high-power magnetron that, if not as powerful as Tesla had boasted, might at least incapacitate an aircraft. A number of Japan’s leading physicists were involved. A 20 cm magnetron producing 100 kW was achieved, and by the end of the war a 1000 kW (1 MW) unit was undergoing preliminary testing.[6] At that time, the development was terminated and the hardware as well as all documentation was destroyed.[8]

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Re: Japan shares it's cavity magnetron with German in 1940?

Post by Hop » 05 Sep 2017 18:27

That is equivalent to the British lab radar. When they actually started mating it to production radar they boosted the power output, which the Germans can do with the Japanese magnetron.
Do you have a source to support that? AFAIK the British developed microwave radar first, other countries only built microwave radar after being gifted, or capturing, British magnetrons.
The Japanese version was very similar to the British one and slightly ahead given that it was producing greater power than the first run Randall-Boot model a year earlier
Lots of people produced magnetrons before Randall and Boot. They struggled for years to increase the power by tens of watts. Randall and Boot turned their prototype over to GEC who engineered production models with outputs of 10kw or more within weeks.
Also it should be noting that the British magnetron wasn't production capable either, they had to turn it over to the US via the Tizard Mission to get Bell Labs to actually make it more than a laboratory curiosity.
No, GEC turned it into a service model in 1940. It entered large scale production in the UK in 1941.

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Re: Japan shares it's cavity magnetron with German in 1940?

Post by stg 44 » 05 Sep 2017 18:37

Hop wrote: Do you have a source to support that? AFAIK the British developed microwave radar first, other countries only built microwave radar after being gifted, or capturing, British magnetrons.
http://ieeexplore.ieee.org/document/6735528/
https://en.wikipedia.org/wiki/Yoji_Ito
till in the Navy, Yoji Ito was sent to Germany for graduate study where he was a student of Heinrich Barkhausen at the Dresden Technische Hochschule. Upon completing his Doctor of Engineering degree there in 1929, he was promoted to the rank of Commander and assigned as a researcher at the Naval Technology Research Institute (NTRI) in the Meguro area of Tokyo. The NTRI had been formed in 1922, and was just becoming fully operational when Ito was sent there. Here first-rate scientists, engineers, and technicians were engaged in a wide variety of activities for advancing naval capabilities.[2]

At NTRI, Ito became involved with analyzing long-distance radio communications, and wanted to investigate the interaction of microwaves with the Kennelly-Heaviside layer (the ionosphere). He started a project using a Barkhausen-Kurz tube, then tried a split-anode cavity magnetron developed by Kinjiro Okabe at Tohoku University, but the frequency was too unstable. In late 1932, believing that the magnetron would eventually become the primary source for microwave power, he started his own research in this technology, calling the device a magnetic electric tube.
Partnerships

Tsuneo Ito (no relationship to Yoji Ito) at Tokoku University developed an 8-split-anode magnetron that produced about 10 W at 10 cm (3 GHz). Based on its appearance, it was named Tachibana (or Mandarin, an orange citrus fruit). Tsuneo Ito joined the NTRI and continued his research on magnetrons in association with Yoji Ito. In 1937, they developed the technique of coupling adjacent segments (calling it push-pull), resulting in frequency stability, an extremely important magnetron breakthrough.[2][3]

Shigeru Nakajima,[4] a younger brother of Yoji Ito and a scientist at the Japan Radio Company (JRC), was also investigating magnetrons, primarily for the medical dielectric heating (diathermy) market. An alliance was made between NTRI and JRC for further magnetron development. In early 1939, led by Yoji Ito they built a 10-cm (3-GHz), stable-frequency Mandarin-type magnetron (No. M3) that, with water cooling, could produce 500-W power.[2]

The configuration of the M3 magnetron was essentially the same as that used later in the device developed by Boot and Randall in early 1940, including the improvement of strapped cavities. Unlike the high-power magnetron in Great Britain, however, the initial device from the NTRI generated only a few hundred watts.[5]
I misremembered this detail and thought the magnetron, while the layout was about the same, was weaker than the Randall/Boot model.


Edit:
http://www.armms.org/media/uploads/06_a ... burman.pdf
However, in about 1940 this research resulted in the development of the M312 water
cooled 4 cavity RCM which generated about 400 Watts at 9.6 cm. Under pulse
conditions the output was about 6 KW and the valve was used operationally in the
type 22 radar fitted to a few capital ships and submarines
Hop wrote: Lots of people produced magnetrons before Randall and Boot. They struggled for years to increase the power by tens of watts. Randall and Boot turned their prototype over to GEC who engineered production models with outputs of 10kw or more within weeks.
The Japanese ended up making a 1000KW model.
Hop wrote: No, GEC turned it into a service model in 1940. It entered large scale production in the UK in 1941.
Source?

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