This is another thread on Imperial Japanese radar countermeasures in WW2.

This thread will also include the US inter-service intelligence/classification/budget wars between the Joint Chiefs & MacArthur's Section 22 radar hunters.
1/ Image
The information in this thread is coming from a 28 May 1945 training document from Boca Raton Army Air Field.

William Cahill of the Sec 22 Special Interest Group found it in Late Feb 2021. 2/ ImageImage
What Cahill found in RCM Digest 14 was yet another bit of Japanese radar countermeasures.

One utterly unique in the history of electronic warfare. 3/
It was an air dropped radar dipole reflector that was neither window, nor rope.

It was a wire corner reflector assembly. It had a parachute to slow and stabilize the assembly while a hydrogen gas generator filled a balloon that would keep the decoy airborne for a 1/4 hour(+) 4/ Image
I mentioned the Japanese use of balloon born dipole reflectors in Section 22 Week. This wasn't that. (See photo)

It was aircraft dropped to inflate & was not released from the ground.

The Kriegsmarine, USN & Royal Navy had nothing like it. 5/ Image
The US Navy's "NAVTECHJAP" investigative mission said nothing about it after the WW2.

This willful exclusion of Japanese RCM technology was par for the WW2 US Navy's course under COMINCH Adm. King. 6/ Image
What stood out about this bit of RCM kit was there is no record of its existence in Section 22 records.

The US Navy held back information on IJN doxing Allied IFF signals starting in March 1944 to Sept 1944 & on IJN airborne radar after Iwo Jima to the end of WW2. 7/
In fact, the USN was holding out on itself on Japanese RCM tactics in WW2. See pg 248 of 328, paragraph 35, in the attached document "Report on the Capture of the Marianas" below.

Enemy RCM tactics were a step below sigint, but above that ships crews were authorized to know. 8/ Image
This lack of intelligence information made things rather difficult for US Navy and USMC radar operators.
9/
The 1st use I can find of this IJN para-balloon corner reflector was in a "Great Marianas Turkey Shoot" AAR.

It was not recognized for what it was because the balloon failed to inflate and the device fell into the ocean.
10/
It was used extensively by the IJN in the Okinawa campaign and was seen by picket destroyers, who termed them "kites" because of their duration.

The CVE's South East of Okinawa reported their use on 12 April 1945.
11/ Image
What is shocking here is that the Boca Raton Radar & RCM facility of the USAAF was not telling Sec. 22, which was supporting the Fighter Commands of 5th & 13th Air Forces, about this Japanese radar decoy.

This was a massive change in the relationship between Sec. 22 & Boca Raton
A direction to Boca Raton to not support US Army Air Forces in combat could only have come from USAAF Headquarters in Washington D.C.

The post-war internal budget wars came early for the USAAF Bomber Mafia.

General Kenny would not be allowed to be CoS USAF...at any cost.
/End

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More from @TrentTelenko

4 Apr
Since COVID-19 has kept the major archives closed or so limited in access they might as well be. This thread is an examination of an on-line source of primary sources here:

Ordnance, Explosives, and Related Items
bulletpicker.com
The bulletpicker.com collection went public in late May, 2016 and has a huge number of ordnance, small arms, and defusing related items.
The library section is the heart of the site and it covers WW2 UK, US, Australian, and technical intelligence by those powers on German, Italian and Japanese ordnance, engineering and small arms.
Read 8 tweets
20 Mar
This tweet thread is the last of 5 that has reviewed & evaluated FEAF's ATIG Report No. 153 Japanese Radar Countermeasures & covers page 3 in the section named the "Actual Operational Use of RCM Equipment By The Japanese Army & Navy - Part B"

1/
Page 3 of that section covers the efforts of the IJAAF "Radar Expeditionary Section" in combat at Okinawa in the period from June thru Aug 1945.

Most radar countermeasures equipment was flown in Mitsubishi Ki-67 Hiryū (飛龍, "Flying Dragon"; Allied reporting name "Peggy")

2/
14. On 20 June 1945 a IJAAS RCM project called "the Radar Expeditionary Section" was sent to Kyushu to combat test a suite of RCM equipment including the TAKI 4, 5, 8, 8, 23, and 40. It was attached to the 60th Fighter Group (Reconnaissance) of the 6th Air Army based at...

3/
Read 20 tweets
20 Mar
This thread is the next tranche, the 4th, of excerpts and evaluations from FEAF's ATIG No. 153 Japanese Radar Countermeasures, "Actual Operational Use of RCM Equipment By The Japanese Army & Navy - Part B"
page 2
1/
I'm going to put the links to the three previous threads at the end, as opposed to the beginning, of this thread as Twitter is only letting me get to 24 tweets before forcing me to post.

Cursed Admins!
2/
Starting at page 2 of "Actual Operational Use of RCM Equipment By The Japanese Army & Navy - Part B"

8. US investigators said the March 1945 Betty 22-Okha attack group trying to sink USS Franklin was the only
airborne combat use of the FT-B radar intercept receivers.

3/
Read 22 tweets
18 Mar
Welcome to the 3rd thread examining the Far Eastern Air Forces report Air Technical Intelligence Group (ATIG) No. 153 Japanese Radar Countermeasures that covered Japanese electronic warfare in WW2. 1/

This was the 1st thread:
The ATIG No. 153 section I'm pulling this summary from is "Actual Operational Use of RCM Equipment By The Japanese Army & Navy - Part B, page 1 of 3"

It is the operational nuts and bolts of how & how often the IJA & IJN used their radio/radar countermeasures kit.
3/
Read 28 tweets
18 Mar
The subject of this twitter thread is US Military airfield engineering in the Pacific War and several documents I uncovered answering a RFI from the Australian War Memorial via a US Army officer I know. 1/
Australian War Memorial requested information on the US Army's 43rd Engineer Battalion and their participation in the Battle of Milne Bay, August through September 1942.

I was pinged by the US officer, who is in Oz right now, to help. 2/
The 43rd Engineer Btn is on wikipedia--

en.wikipedia.org/wiki/43rd_Engi…

According to the wiki the 43rd "was activated at Fort Snelling, Minnesota on 10 February 1941, before being redesignated on 16 March 1943 as the 43rd Engineer General Service Regiment. 3/
Read 25 tweets
15 Mar
@GoodClearTweets @CalumDouglas1 @militaryhistori Another book to go with those three economic tomes is John Stubbington's “Kept in the Dark – The Denial to Bomber Command of Vital Ultra and Other Intelligence During World War II.”

This link is to a review—

speedreaders.info/293-bomber_com…
@GoodClearTweets @CalumDouglas1 @militaryhistori “Kept in the Dark” is -NOT- light reading. There is a lot of organizational ground to cover in documenting the growth of the UK’s wartime intelligence structure supporting the Combined Bomber Offensive. And explaining how it came about that the UK Air Ministry didn’t provide...
@GoodClearTweets @CalumDouglas1 @militaryhistori ...ULTRA intercepts to the U.K. based RAF Fighter, Coastal and especially Bomber Commands.

While at the same time it did so with British military over seas commands and first the American 8th Air Force and later the United States Strategic Air Force in England.
Read 10 tweets

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