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.
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:
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.
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:
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.
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.