History Friday — MacArthur’s Anglo-Australian Radars

Radar was the “Revolution in Military Affairs” in WW2. If you wanted to know the fighting style of a particular military theater in World War 2 (WW2), you have to know the capabilities of the radars the theater had and how the theater was organized to use them. This isn’t just a matter of creating an early warning air defense system, like was used in the Battle of Britain. The far more important and little understood reason is stated in two words — “Operational losses.” The leading killer of aircraft in WW2 was “Operational Losses.” Operational losses are what happen when bad fuel, bad weather, bad parts, bad maintenance and just plain “getting lost” catch up with pilots. Radar as organized & practiced by the Western Allies saved many poor or average pilots that had all of the above happen to them to fight another day and become good pilots. However, when you try and find what radars MacArthur’s South West Pacific Area (SWPA) had in WW2, how and by whom they were used, there is very little in the US Army and US Air Force institutional histories.

The researching of Douglas MacArthur as a “Fighting General” in WW2 means you become used to discovering frustrating dead ends in established narratives. In the case of MacArthur’s radars, it was an exercise in internet searching to gain the understanding that these most important elements of MacArthur’s WW2 fighting style — his Australian and British radars — were designed completely outside the US Military. These radars were either not well documented in the narratives, or if they were, how they were used was classified until as late as the 1990s. Chief among these items from outside the US military were:

1) The Australian Light Weight Air Warning (LW/AW) and Light Weight Ground Control Intercept (LW/GCI) of radars the Royal Australian Air Force (RAAF) and,
2) The British Light Weight (LW) radar, produced in Canada for the US Army Signal Corps as the SCR-602.

Australian Light Weight Air Warning (LW/AW) Mark I Radar Deployed in the SWPA
Australian Light Weight Air Warning (LW/AW) Mark I Radar Deployed in the SWPA

These light weight 1.5 meter band radars were vitally needed in the howling wilderness of the SWPA because the pre-war US 2.7 meter band, 200 mile range, SCR-270 early warning and 1.5 meter band, 30 mile range, SCR-268 searchlight radar designs available to MacArthur weighed in at 60 and 20 tons respectively. In comparison, the late 1941 design, 100 mile range, “tropicalized” Australian LW/AW radar weighed in at four tons and could be moved in three DC-3 transport flights, while the late 1942 design, 30 mile range, British LW radar design (built as the SCR-602) weighed in at 300 lbs (136kg).

All of these radars were used by MacArthur’s US Army Signal Aircraft Warning (SAW) Battalions and RAAF radar detachments in WW2. The war diaries of the SAW battalions, which were taken over by the US Army Air Force (USAAF) from the Signal Corps in 1943, were classified by the sucessor independent USAF until the mid-1980s. While much of the information on the production and use of the “LW/AW” was hidden for 50 years due to Australia’s “Official Secrets Act” sealing of RAAF war records, the LW/AW’s war record in the SWPA was only brought to light in the 1990s by the dogged, unofficial, work of Ed Simmonds — a WW2 Royal Australian Air Force (RAAF) radar Technical Sargent turned history author.

I have mentioned Simmonds’s book “ECHOES OVER THE PACIFIC: An overview of Allied Air Warning Radar in the Pacific from Pearl Harbor to the Philippines Campaign” (Doc Link) on Chicago Boyz before. According to page 17 of Echos, the US Army received the following radars in “Reverse Lend Lease” from the Australian government.

Australian Radars for the US Army:
– 21 LW Mk I Towers and Aerials (Note — 10-15 kW output w/VT90 valve*)
– 83 LW Mk II Towers and Aerials (Note — 43 were 40-50 kW output w/U.S. 100TH type valve)
– 10 LW/GCI Mk I Huts, Towers and Aerials

* “Valve” is Anglo-Australian for vacuum tube.

The on-line Pacific War encyclopedia lists 300 Canadian built SCR-602 as having been deployed in the Pacific.

Using Anglo-Australian Radars
The LW/AW Australian radar was a key element of MacArthur’s “Tri-phibious” (Air-Sea-Land) power projection fighting style throughout both the Buna and Huon Peninsula campaign portions of the fighting in New Guinea. The LW/AW radar could be air landed, transported by landing craft over beaches and often was used in picket boats based on USAAF air sea rescue boats and US Navy Landing Craft Tank (LCT). Many of MacArthur’s early ‘shoe string’ landings in New Guinea were covered by RAAF LW/AW radars clandestinely deployed onto off-shore islands by PBY sea plane or small boat days before amphibious landings. Gen. Whitehead, Kenney’s chief “advanced echelon” Air commander, would not commit his airpower without radar coverage from a LW/AW (page 160 Echos) in the Markham Valley operation. Several of the most advanced versions of the LW/GCI would have been included in the cancelled Operation Olympic landings in 1945!

US Army Air Force Air-Sea Rescue Boat turned Radar Picket with Australian LW/AW
US Army Air Force Air-Sea Rescue Boat turned Radar Picket with Australian LW/AW

“USS Fubar Maru” AKA LCT-389 with Australian LW/AW Radar in Huon Peninsula operations

The SCR-602 changed SWPA radar tactics when it arrived in 1943 as it could be rapidly deployed on the first day of an amphibious landing, but lasted only a few days before the tropical heat destroyed its electronics. Those first few days required only enough warning to alert the anti-aircraft guns of incoming raids, which the SCR-602 did quite well. The pattern of deployment after the SCR-602 arrived was SCR-602 first, the LW/AW in follow-on deployment to fill the gap until the long range SCR-270 could be sited and made operational.

SCR-602 early warning radar derivative AN/TPS-3
SCR-602 early warning radar derivative AN/TPS-3

This light-weight-radar picket tactical style allowed MacArthur to protect his transports from Japanese air strikes in a way that the US Navy would not copy until late in the 1945 Okinawa campaign, under the hammer blows of mass Kamikaze Strikes. And it was a tactic that would have been the cornerstone of the Operation Olympic invasion of Japan.

In early-1944, the Australian LW/AW was showing its age. The Japanese were actively radio jamming and dropping radar decoys (chaff) for the 1.5 meter band radars. For reasons best known to the RAAF senior command, there were no technological improvements in the LW/AW in 1943 incorporating British microwave cavity magnetron technology in anticipation of this. Meanwhile, the US Army Signal Corps had been improving the SCR-602 with other microwave radar technology vacuum tubes it developed for just this event. So when MacArthur moved on to the Philippines, the LW/AW Mark 1 and 2 stayed behind.

A last gasp Australian radar development, the LW/GCI using Anglo-American SCR-602 electronics was used in the Borneo campaign, but missed American service via the good services of the atomic bomb causing the Japanese to surrender prior to invasion.

So ends another journey into “MacArthur Narrative Busting.”

14 thoughts on “History Friday — MacArthur’s Anglo-Australian Radars”

  1. I’d add to “Operational Losses” just accidents. Never will forget the narrative in the story of Louis Zamperini’s B24 – when taking off a loaded B24 on a coral atoll – for the long flight to the target – you could see, through the cracks of the bomb bay doors, the palm trees brushing against the fuselage.

    I am sure there were a lot of accidents from fully loaded bombers – or say P51s full of fuel and external tanks with a bad CG.

    Then there were the B29s.

    A fellow I knew who was a crewman on a B29 (post war) said that the crews hated Gen Curtis LeMay. Upon return from the 14 hour flight from Saipan or Tinian to Japan, if LeMay deemed that too much fuel was remaining on the next mission he’d order that much less fuel loaded on the plane and more bombs.

    That’s why a lot of B29s ditched in the ocean, empty tanks and returning.

    On radar while the British invented it a fascinating story of a little known figure – Alfred Loomis – a successful Wall Street financier who loved science – financed a lot of scientists at his Tuxedo Park Mansion in NY – the atomic bomb, radar (with the British giving him the critical part to improve, Lawrence Livermore Labs (probably wouldn’t have existed without him) –


  2. He was a great man, a very difficult general and insanely brave.

    His staff suffered many casualties and he was famous for wandering around active battlefields as if no bullet could hit him. He was right it seems.

  3. The RADAR aboard the USS Washington was crucial in winning the “second battle of Guadalcanal. Admiral Lee was an expert in the use of RADAR and knew more about it than many of the technicians. An account of the battle is here.

  4. >>Small correction: it’s spelled “magnetron”, with an ‘e’.


  5. Michael – I think you will find Alfred Loomis the most intriguing man – for his influence on science hardly anyone has heard of.

    It was his wealth that enabled him to buy the equipment that the scientists – usually attached to universities – couldn’t afford.

    I think he even attracted Enrico Fermi at one point.

    And he was more than just the financier –

    Magnetron. That’s what I was thinking of.

    The book title I failed to mention was Unbroken – the story of Louis Zamperini.

  6. Bill,

    None of the radars mentioned in Alfred Loomis’s “Tuxedo Park” arrived in the SWPA before mid-to-late 1944.

    The SCR-584 (short for “Set, Complete, Radio #584”) was the first microwave radar developed by the MIT Radiation Laboratory during World War II to reach the SWPA. The SCR-584 gun laying radar played a small part at Biak in New Guinea and were a huge success during Leyte in dealing with Kamikazes.

    The Japanese lost 300(+) planes to US Army anti-aircraft gunfire alone at Leyte from 24 Oct 1944 – thru – Mid-Dec 1944, with half credited to SCR-584 directed 90mm gunfire…gunfire that lacked the proximity fuzes used by US Navy warships.

    The Germans lost roughly that number of planes to _British fighters_ during Oct 1940, in the Battle of Britain.

  7. Trent – I guess in the early part of WW2 radar was still not completely trusted – I just saw from Netflix a documentary on Guadalcanal – one of Robert Ballard’s expeditions – and one thing that stood out for me – that Naval battle that was as costly to us as the Japanese – the Navy commander had radar and didn’t fully trust it – seeing “possible” ships at 12 miles – he ordered his flotilla to get closer – some of these ships were 1/2 mile apart when the battle started – erasing any advantage radar would have given us. Of course the outcome of that battle deprived the Marines of supplies.

    Hearing this reminded me of the incident on the morning of Dec 7 1941, when an Army Lt was told that radar spotted a bunch of planes in the Pacific and he attributed it to a “glitch” – although by that time there was probably little, if anything, that could have been done to change the outcome.

  8. Through most of WWII the RADAR that was used was HF radar. This type of radar uses low frequencies, and valve/tube circuits. It’s not very precise and there are a lot of false targets, reading it is an art-form, but it’s long range. This is what we Brits mean by “inventing RADAR”. This was a very simple system, the Germans had better but they didn’t understand it’s operational significance well enough, so they didn’t use it well enough.

    Later on microwave RADAR was developed from the cavity magnetron, this has a shorter range, but it’s much easier to read and understand. It’s also smaller and can be fitted to aircraft. The cavity magnetrons that were used were invented in Britain but the best Radar system that were built around them came from “Tuxedo Park” in New York. The sizes of microwave “waveguide” we use now are based around the cross-section of the metal bannisters that were ripped from the stairs of buildings in New York to build these early Radar systems.

  9. ” the Navy commander had radar and didn’t fully trust it – seeing “possible” ships at 12 miles ”

    That was the “first battle” and Dan Callaghan, who was a staff officer until this battle, didn’t know about RADAR. The next night Willis Lee, who knew more about it than any naval flag officer, cleaned the Japanese clock in spite of the complete funk of the other battleship, the South Dakota.

    The Japanese, who had won all night battles to that point, never again challenged the US at night.

    The great book about this series of battles is Neptune’s Inferno. The Navy lost more men at Guadalcanal than the Marines.

  10. Are you going to compile Mac myth busting – I think especially the creation and dissolution of task forces?

  11. VXXC,

    My goal right now is to develop both an audience for this column and my writing skills for the research I have been doing.

    A MacArthur myth-busting compilation article for publication, or book, might be a result down the road. It is not a current goal.

    As far as this post is concerned, one of the biggest knocks that the US Naval types have made of MacArthur, even to this day, is that “He was a WW1 General.”

    The point of “MacArthur’s Anglo-Australian Radars” is to demonstrate that he used a uniquely WW2 weapon — Radar — and developed a unique doctrine for that weapon that met the needs of his theater, with less than the best radars to boot.

  12. For those interested in the electrons and wave guides (radar nuts and bolts) of the SCR-602, this comes from the web sites Mobileradar.org, the US Navy Department Library and the Camp Evans museum these links. Note the weight reductions in the SCR-602 design over time and the AN/TPS-3 version:


    This is the development of the SCR-602 radar types drawing from all three sources —

    SCR-602, Type 1 –
    Frequency: 176 MHz, 212 MHz
    Power Output: 100 K.W.
    Pulse Width: 2 µseconds
    Pulse Repetition Rate: 400 Hz
    Range: 40 Miles (Three different sweep velocities create corresponding 10-mile, 40-mile and 100-mile ranges respectively.) Maximum Range: On flat site: 40 to 50 miles at 15,000 to 25,000) feet altitude. Minimum Range on flat site for low flying a/c 10 to 15 mi. Ceiling: About 25,000 feet altitude. Range Accuracy: Range to nearest mile. Azimuth accuracy 2 degrees.
    Vertical Coverage:
    Horizontal Coverage:
    Antenna: Four horizontally polarized Yagi antennas.
    Speed: Continuous at about 6 RPM.
    Beam Width:
    Indicator Type and Quantity: 9 inch PPI, Height A-scope
    Manufacturer: Research Enterprises Limited (Canada)
    Notes: 1,200 pounds; First 25 of manufactured were exact copies of the British LW prototype; last copy of a British radar and the last copy of a long range set (wavelength about one and a half meters) which the Signal Corps produced for the AAF. Equipment rack mounted in two adjoining frame racks. The receiver rack houses power equipment in the bottom, the main PPI and ASV receiver in the central portion, with the PPI power unit and indicator unit at the top. The adjoining transmitter rack continues up in a tapered tower through the tent top to support the rotatable Yagi antenna. The lower part of this rack houses the transmitter, T. and R switching, unit, inductive coupling unit to antenna, and the antenna rotating gear box. Power supply: 6 h.p. gasoline engine drives two 700 watt, 80-volt, 1,000-cycle alternators, and one (1) 500-watt 24-volt d.c. generator. The d.c. generator supplies the alternator fields, blowers, lights and charges batteries. One (1) alternator supplies the transmitter only.

    Documents: Results of SCR-602 Flight Tests 22 April 1943


    SCR 602 Type 2 –

    SCR 602 Type 3 – [US Navy Library says AN/TPS-1 is the SCR-603-T3]

    SCR 602 Type 4 –

    SCR 602 Type 5 –

    SCR 602 Type 6 –
    Notes: Next 250 built after the Type 1

    SCR 602 Type 7 – [Camp Evens.org says the AN/TPS-2 is the SCR-602-T7]
    Manufacturer: General Electric
    Notes: 250 pound parachute-able set

    SCR 602 Type 8 – [US Navy Library says the AN/TPS-3 is the SCR-602-T8]
    Power Output:
    Pulse Width:
    Pulse Repetition Rate:
    Range: 40 Miles
    Vertical Coverage
    Horizontal Coverage:
    Beam Width:
    Indicator Type and Quantity:
    Notes: Signal Corps developed, proved to be the best; receiver, display and high power transmitter in a single unit measuring 42 inches by 20 inches by 20 inches; became AN/TPS 3. Included new IFF Interrogation equipment, built in a separate case.

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