Japanese get ship-based radar 1940

Deleted member 1487

Why not have the Japanese follow up their own actual research instead?
Because their work was quite behind IOTL until they had a technology exchange with Germany in 1940-1:
https://en.wikipedia.org/wiki/Yoji_Ito#VHF

Germany had radar by 1938 and installed air intercept and gunfire surface radars on their ships by 1940. Lets have Japan get German sets for all its aircraft carriers by the end of 1940.
Move up Ito's trip to 1938:
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. 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]

It would help too if Ito shared his work on the magnetron in the exchange to get the Germans working in that direction and maintain the technology exchange into and during the war.
 
I don't know where you are getting your information from but your assertion is totally inaccurate. IJN strategy was based on the Decisive Battle concept. The IJN envisioned their submarines, land-based aircraft and aircraft carriers as a means to locate and attrit the US battle fleet as it came across the Pacific. There were to be night engagement with cruisers and destroyers using the Long Lance torpedoes to further attrit the US battle fleet. Once, it had been reduced sufficiently, the main IJN battle squadrons (ie, battleships) were then to engage and destroy their opposing numbers. It never worked out that way but that was their strategy and their tactics were developed to support that strategy. It wasn't until Midway that the IJN that aircraft carriers could be considered the decisive combat force as opposed to the battleship.
Compare that with other countries doctrine. See which gives the carriers a more important and decisive role.
Nobody had a pure carrier centred doctrine in 1941. All the navies that had carriers and battleships had doctrines that rellied on a combination of both, with the accepted wisdom being that in the end the battleships would have to be destroyed by other battleships. The conceptual jump to a carrier centred navy had not been made yet.
But the IJN was the only one that grouped all its fleet carriers in a permanent strike force, fully supported and operating independently in an offensive role. Six fleet carriers, with close to 400 aircraft.
The altricional concept, that was in actual planning abandoned in favor of a carrier led preemptive strike, was a clever compromise that allowed the navy to focus on its carriers and submarines while keeping the battleship faction happy.
Compare that with the way the RN used its carriers or the way the USN planned to use theirs before they lost their battle line.
Was that plain in black and white on policy papers? Not really, but policy papers are for politicians and journalists. Military staffs work with budgets. And the real money in the IJN went for six fleet carriers and state of the art aircraft. The Battleships got a few rebuilds and two large battleships. The Italian navy spent more on battleships than the IJN did, with more extensive rebuilds and four new battleships.
The plan can be resumed as:
First we'll fight an atricional battle with submarines and carriers.
Then we'll fight an atricional battle with long range aircraft
Then we'll fight a night torpedo battle
Then, if there are enemy ships left, the battleships will finish them off.
Does this sound like the plan of a battleship obsessed admiral?

And they didn't even follow it. In practice, until Midway, the carriers led and the battleships provided distant cover.

I'm not saying that the IJN had a purely carrier centred doctrine. Nobody had. What I'm saying is that within a very divided navy, the carrier faction of the IJN secured a more relevant and conceptually advanced role for its carrier force than any other navy in the world.
So if they were the conservatives in 1940, who were the progressives?
 

SsgtC

Banned
I don't know where you are getting your information from but your assertion is totally inaccurate. IJN strategy was based on the Decisive Battle concept. The IJN envisioned their submarines, land-based aircraft and aircraft carriers as a means to locate and attrit the US battle fleet as it came across the Pacific. There were to be night engagement with cruisers and destroyers using the Long Lance torpedoes to further attrit the US battle fleet. Once, it had been reduced sufficiently, the main IJN battle squadrons (ie, battleships) were then to engage and destroy their opposing numbers. It never worked out that way but that was their strategy and their tactics were developed to support that strategy. It wasn't until Midway that the IJN that aircraft carriers could be considered the decisive combat force as opposed to the battleship.
Honestly, it sounds like it's coming from Newt Gingrich's Days of Infamy alternate history novels. They're good books. Unless you know anything about the Pacific War and how Japan actually thought.
 
Not enough said actually. What's your point?

The point is actually there was room for a useful technology exchange on both sides and also that had the Japanese pursued their research earlier they would likely have been less behind the Germans. Carl Schwamberger did a useful study of the likely engagements that might have been affected by radar for the Japanese so it is not by any means a war winner. That said alternative history is as much about exploring minor differences as major ones.

So I would agree more German radar technology transfer is one potential POD, bilateral tech transfer another and Japan's Navy (in this instance) pursuing earlier interest a third.
 
Honestly, it sounds like it's coming from Newt Gingrich's Days of Infamy alternate history novels. They're good books. Unless you know anything about the Pacific War and how Japan actually thought.
Read my post above. The IJN expected to win an attricional campaign before a finishin action with the battleships. In the final versions the Kongos were expected to support the torpedo attacks and regarded as expendable. The whole concept moves away from a single decisive battle and conceived an extended campaign. That is a step forward from the "winning the war in an afternoon" decisive battle plan.
And no, I haven't read the novels you mention.
 
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Deleted member 1487

The point is actually there was room for a useful technology exchange on both sides and also that had the Japanese pursued their research earlier they would likely have been less behind the Germans. Carl Schwamberger did a useful study of the likely engagements that might have been affected by radar for the Japanese so it is not by any means a war winner. That said alternative history is as much about exploring minor differences as major ones.

So I would agree more German radar technology transfer is one potential POD, bilateral tech transfer another and Japan's Navy (in this instance) pursuing earlier interest a third.
Agreed and after an edit that I wrote as you were posted I said something similar. If anything though the bigger impact would be the Japanese sharing their work on the cavity magnetron pre-war with the Germans, that really opens up a huge can of worms (I did a thread on that). As you say, not war winning necessarily, but even relatively minor PODs can generate interesting what ifs even if the outcome is still basically the same.

As to the Japanese developing it earlier themselves due to greater interest, it seems some other posters think that there were enough problems within Japanese R&D that it would have been hard to pull off without a pretty significant POD. Even IOTL with German help:
https://en.wikipedia.org/wiki/Radar_in_World_War_II#Japan
Japanese radar technology was 3 to 5 years behind that of America, Great Britain, and Germany throughout the war.[35]
Compton, K. T.; "Mission to Tokyo", The Technology Review, vol. 48, no. 2, p. 45, 1945

If there was pre-war cooperation though and development of cavity magnetron based radar in coordination (the Japanese developed their M3 magnetron before Booth and Randall), perhaps by the time the Pacific War starts Japanese radar could have been at or better than US standards at the time, as American hadn't developed a working cavity magnetron until the Tizard mission, so would be behind to some extent until MIT's Radlab got rolling.
 
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In 1929 Rudolf Kuhnhold of the German Navy Signals Research Division began work on an air 'echo sounder' and in 1933 was suggesting research on centimetric waves to detect aircraft and ships. He was using Phillips magnetrons and Yagi directional antenna with a 13cm wavelength. The experiments were promising so he went to Telefunken in 1934. He spoke to mid-level manager Wilhelm Runge who was working on decimeter wavelengths. Knowing no one at Telefunken was working on centimetric waves Runge told Kuhnhold that he had neither the funds nor staff to spare to collaborate with the Navy. Kuhnhold took this as a rejection by the whole company and so left the navy and went off to form GEMA, a company to continue radar work for the navy. This took some years to set up and produced the early Seetakt radars but an early opportunity to collaborate on powerful radar systems was missed by a misunderstanding.

I think the Japanese would be interested in radio detection of aircraft.

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This leads to the same outcomes for the carrier battles of Coral Sea, Midway, Santa Cruz, The surface actions vary; The night cruiser action 'Savo Island' does not change much. The Allied cruiser force was caught by surprise, even without Japanese radar.

At Cape Esperance October OTL a night battle the USN cruisers located the Japanese force with its radar, tracked it & reached a decent tactical position, and seems to have better opening accuracy. If the IJN only has radar on its BB at this point then no change from OTL as there were no BB present. If one or more of the IJN heavy cruisers has radar then they are not tactically surprised & in theory their opening salvos are more accurate.

Alternately the Night Action of 12-13 November may be more of a defeat for the USN,since the Krishna at least would have radar. OTL the USN had a advantage with its radar, but doctrinal decisions and tactical errors lost much of the advantage. Spotting the US cruisers early with the radar probably gives advantage to R Adm Kondo. Maybe that leads to the same confusion and error on the US side, maybe not.

Similarly the first battleship vs battleship action of the Pacific war, 14-15 Nov started with a radar blessed tactical advantage & surprise to the USN. Presumably the Hiei with radar spots the US squadron & the start is more even. However Japanese radar does not waive away the electrical failure of the South Dakota, & probably not the momentary masking of the Washington by the S Dakota. Assuming the same courses the SD masks the Washington from radar as well as visual identification. So Kondo & his captains may be just as confused at targeting as OTL & miss the Washington to their loss.

Tassafaronga night 30 November OTL had the Japanese cruiser squadron running close inshore & there fore masked by the radar returns from Guadalcanals forested hills. They spotted the US cruiser squadron visually in good time and achieved good tactical surprise, getting a salvo of 70+ torpedoes in the water & damaging hits on four US cruisers. Even if the IJN cruisers here had radar nothing may change since the dispositions of R Adm Tanaka make sense with radar as well as with visual spotting.

So, thats at least one action where the outcome is likely to change with IJN radar. The 14-15 November battle might change with IJN radar, but the variables alter a lot if Kondo deploys differently due to having radar on the Hiei. In the first & last battles the IJN beat a radar equipped enemy with out that gizmo. If possessing radar alters their doctrine, tactics, or decisions enough then in theory they might do worse in those two.
There were also the Battles of the Eastern Solomons and Santa Cruz. In your opinion, would the results of those battles have been significantly different if the Japanese had had radar?
 
There were also the Battles of the Eastern Solomons and Santa Cruz. In your opinion, would the results of those battles have been significantly different if the Japanese had had radar?

They had radar at Santa Cruz and it detected the incoming American attacks and Shokaku had damage control crews in place when the dive bombers arrived on scene and that may have saved the ship.

At Eastern Solomons it won't make a difference, Ryujo was overwhelmed.
 
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