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  • Hiroshima and the Atomic Bomb…Plus 75 Years.

    Posted by Trent Telenko on August 6th, 2020 (All posts by )

    Today’s date, 6 August 2020 marks the 75th Anniversary of the atomic bombing of the Japanese city of Hiroshima. Some where in the neighborhood of 70,000–80,000 people in Hiroshima were killed by the blast and resultant firestorm that reached it’s peak three hours after the detonation.  Japanese military personnel made up 20,000 of the 70,000–80,000 immediate deaths.   This bombing set in motion a train of events including the subsequent atomic bombing of Nagasaki, the Soviet Union’s accelerated invasion of Japanese occupied Manchuria on 9 August 1945 and Emperor Hirohito’s 15 August 1945 broadcast of Japan’s surrender under the terms laid out by the Potsdam Declaration.

    Much has been written on these events and I’ve revisited them here on Chicagoboyz annually from 2011 to 2018.  This year, 2020, I’m going to address a different part of the Atomic attacks.  Namely, how the American military electronically communicated about the Atomic bomb.  How the secrecy and limitations of that communications system meant Admiral Nimitz knew about the Atomic bomb long before General MacArthur. And how General  MacArthur was working to change that for the proposed and cancelled by A-Bomb invasion of Southern Japan

    Figure 1 – This is the mushroom cloud marking the use of the “Little Boy” uranium-235 atomic bomb dropped from the B-29 “Enola Gay.” This photo was taken from the B-29 “Necessary Evil” which was piloted by Captain George W. Marquardt.

     

    AMERICA’S SECRET TALKER

    In World War 2 many of the major powers developed strategic level code & cypher radio electronic communications systems between it’s top level political & military leaders and the various theater commanders.  The German Geheimschreiber (secret writer) is the best known of these systems because British crypt-analysts at Government Code and Cypher School (GC&CS) at Bletchley Park with the the aid of eventually ten Colossus computers.

    Much less well know is the Anglo-American equivalent of the German Geheimschreiber,  The US Army Signal Corps and Bell Telephone Laboratories SIGSALY.  This system was the only form of secret broadcast radio-electronic communications the American and British government trusted to transmit information on the Atomic bomb in the World War II.   It was due in large part to that level of communications security that Admiral Nimitz was informed of the atomic bomb before General MacArthur.  Admiral Nimitz in Hawaii and later Guam was reachable by SIGSALY after his initial courier briefing.  General MacArthur between October 1944 and May 1945 was not, for a number of reasons I’ll get into a little later.

    First, a quick introduction: SIGSALY was a highly secret WW2 digital voice communications system that used a special one-time pad encryption.  There were only 12 station made in all of WW2 and MacArthur’s had two.  The first in Brisbane was sent to Manila.  The 2nd SIGSALY meant for Hollandia was instead placed in a Australian built barge barge in the SWPA “Signal Corps Grand fleet,” a motley collection of small ships and barges with powerful Signal Corps radios.  The barge mounted SIGSALY  was intended for quick sea movement and it was key for MacArthur’s communications at Okinawa and Kyushu during the planned invasion of Japan.

    Figure 2 – This is a SIGSALY digital radio-telephone system screen captured from the Crypto Museum web site.  

    This is how the  Crypto Museum describes SIGSALY.

    SIGSALY Ciphony 1
    Digital voice encryption with OTP

    SIGSALY was a digital speech encryption system, developed by Bell Telephone Laboratories (BTL) 1 in the US in 1941/1942, and built by Western Electric in New York (US) in 1943. The system went into service in April 1943, just two months before the invasion of Italy, and was used until at least 1946.

    .

    SIGSALY was used heavily during WWII, in particular for confidential talks between British Prime Minister Winston Churchill and US President Roosevelt. The system used the highly-secure One-Time Pad (OTP) encryption and is known under various names, including The Green Hornet.

    .

    SIGSALY featured a number of innovative digital communications concepts, including the first transmission of pulse-code modulation (PCM). 2

    .

    SIGSALY was completely built with vacuum tubes (valves). A single system consisted of more than 30 full-height 19″ racks, plus 4 synchronisable turn­tables. It weighted 50,000 kg, consumed 30 kW of power, and had special air conditioning requirements. A single SIGSALY terminal had a price tag of US$ 1 million in 1943. In total, 12 SIGSALY terminals were set up around the world, the first of which was installed at the Pentagon.

    WHY SIGSALY WAS CALLED “THE GREEN HORNET”

    As a vacuum tube technology digital electronic system, SIGSALY was in some ways both far ahead of its time and in others crippled by it. For example, to create it’s “one-time pad” encryption, recordings were made of the heat decay of a vacuum tube — it’s buzz — and pairs of these audio recordings were sent out between various stations.  When a radio-teleconference one station started playing it’s record and the other played their until the signals synchronized on an oscilloscope.  Once a match was locked in the teleconference started.    After it ended, both records were destroyed.  This made the system invulnerable to code cracking with the tools of that time and it would be nearly as hard to break in the 21st century.

    On the other hand, there were some really large limitations which can be sussed out from the following passage from Crypto Museum article.

    SIGSALY provided a full-duplex voice link via narrow-band HF radio channels in the Short Wave (SW) radio bands. Each half of the link used 12 individual data channels, or carriers, through which the data was sent by means of digital 6-level Multiple Frequency-Shift Keying (MFSK).

    .

    The human speech was analysed just 50 times per second (at 20 ms intervals), broken down into its characteristic parts, and then coded and sent across the Atlantic. At the receiving end, the data was decoded and used to reconstruct or synthesize the original human speech again.

    .

    This resulted in a low data rate (comparable to 1500 baud today) but made it very difficult to recognize the person at the other end.

    SIGSALY used short wave/high frequency radio bands to push a low bandwidth digital signal through the Ionosphere.  You had to compute the correct direction, radio antenna critical angle and frequencies at the correct part of the day or night to get the proper distance “skips” for a radio connection. Since SIGSALY used 12 data channels with different H/F carrier frequencies. This required as many antenna’s critical angles to be adjusted for their different channels.  See the figure immediately below –

     

    HF Radio propagation (1).JPG

    Figure 3 – This is a standard model of H/F radio propagation showing critical angles, ionized layers and skip distances.  These ionization layers altitude varies during the course of the day with the energy provided by daylight.  Therefore the critical angles needed to reach a specific receiver location changed over the course of a day/night cycle.  

    There were two other concerns affecting the quality of digital data packets.  H/F bands are naturally static filled and some places on earth are more naturally static filled than others.  Between the data distortion of normal static and the added one time pad static from vacuum tubes, the voice that came out of SIGSALY had the buzz of a hornet.  Given the green of may Army phone handset, the name “Green Hornet” was a natural name given the annoying sound.

    On the upside,  this natural static is affected by sunspot activity.  The more sunspots there are, the more H/F transmissibility was increased in daytime because the solar wind compresses Earth’s magnetic field thus lowering H/F static.

    The issue for the SIGSALY machines generally was that 1943-1945 were in the low sunspot part of an 11-year solar cycle.  The added static from the low sunspot activity degraded digital data packets. This affect was intensified in the two SIGSALY serving in the South West Pacific Area (SWPA) because they were in one of the worse areas for H/F because of the local magnetic field effects.

    Figure 4 – This is a US military Interservice Radio Propagation Laboratory (IRPL) global pattern of Ionospheric interference with high frequency radio communications in World War 2. The larger the number, the more the interference. High frequency (H/F) radio communications from Washington DC, Oakland, Hawaii and, after August 1944, Guam all had to cross or end in “the static blob” of heavy radio interference over the Solomons, Northern Australia, New Guinea and the then Dutch East Indies and now Indonesia to reach either Hollandia in New Guinea or Brisbane, Australia.

    A SIGSALY BARGE FOR A MOBILE WAR
    .
    All things taken together, a SIGSALY was a huge piece of electronic capital equipment requiring a lot of time to set up and be effective.  This simply was not something possible in MacArthur’s theater between October 1944 and May 1945.  The leap to Leyte moved General MacArthur away from a static headquarters for months. Whether SIGSALY could work at Hollandia New Guinea was never tested.  (So we will never know what the “Static Blob” over New Guinea would have done to impinge on SIGSALY.)
    .
    Realizing he needed that SIGSALY capability — if only to connect to the Oakland, CA SIGSALY in order to ask the San Francisco Port of Embarkation about his priority supplies.  General MacArthur ordered his Chief Signals officer Brigadier General Spencer Akin to add a SIGSALY platform to his growing “Seaborne Communications Unit.”  Which was known locally at the time and later in the US Army’s Green Book histories as the “SWPA Signal Corps Grand Fleet.”

    Figure 5 – This is Ocean Lightner Barge av2050 pre-refit as a signals platform. It was one of a class of six Australian barges produced for the Philippines campaign for the US Army Signals Corps.  The SIGSALY carrying barge OL-31 lead an accident prone existence both on the way to the Philippines and after it arrived.

    .
    While the “Seaborne Communications Unit” was effective in the Philippines campaign over all…the same could not be said for the SIGSALY barge OL-31. The following is a e-mail summation of SIGSALY files my research partner Ryan Crierie found at NARA:
    .
    From a lot of the SIGSALY data at Archives II:
     
    The ALGIERS installation was begun on 12 August 1943 and placed into service in October 1943. If we assume it went online on 1 October, that’s 50 days to set up a SIGSALY terminal that was already nicely packed for transport.
     
    Another example was Terminal #9; the OL-31 installation.
     
    May 1944 Arrives in SWPA intended for installation at Hollandia, New Guinea.
     
    7 JUL 1944 – Equipment and personnel arrive at Brisbane, Australia
     
    1 NOV 1944 – Installation onto OL-31 begins.
     
    1 FEB 1945 – OL-31 installation completed. (92 days to complete)
     
    17 FEB 1945 – OL-31 leaves under tow. Hits a coral reef under tow, shaking things up and causing a stop to inspect for damage.
     
    12 APR 1945: Arrives at Hollandia
     
    17 APR 1945: Leaves Hollandia for Manila
     
    10 MAY 1945: Arrives Manila. Due to harbor difficulties it takes 11 days to find a suitable docking site for OL-31.
     
    21 MAY 1945: During the night of 21 May 1945 at the assigned site, the power/Air conditioning system went out of service due to the low tide causing OL31 to settle on the bottom of the river, clogging the circulating system’s intake. OL31 had to be towed to deeper water and the recirculators cleaned out.
     
    23 MAY 1945: OL-31 Terminal #9 turned on for first time in 10 months since it’s arrival in SWPA.
     
    23 JUNE 1945: OL-31 Terminal #9 removed from service.
     
    Meanwhile in Manila…
     
    10 MAY 1945: Construction of quarters at CITY HALL for Terminal 4 is completed.
     
    19 MAY 1945: SIGSALY Terminal #4 equipment arrives.
     
    20 June 1945: SIGSALY Terminal #4 enters service. (32 Days to complete)
     
    So we have the following times of setup for SIGSALY terminals:
     
    50~ days for ALGIERS
    92~ days for OL-31
    32~ days for MANILA

     

    LIVING WITH THE OL-31

    .

    Several members of the 805th Signal Service Company — established by General Marshall to run all 12 SIGSALY world wide — have documented their experience aboard the OL-31 ship and provided an insight into what service aboard this floating terminal of SIGSALY was like. The saga of the OL-31 and this communications flotilla can best be told by two of the men who were there in their own words. They are 805 Signal Service Company Sergeants Bud Brown and Curtis Martin. While overseas experience was a memorable time in any serviceman’s life, their’s had more “SNAFU” (Situation Normal, All Fouled Up) than most with the snake bitten OL-31.  

    .

    Following is a report that Sergeant Bud Brown wrote about his experiences on OL-31.

    .

    “I traveled on Ocean Lighter 31 with several of the Detachment 9 personnel from Manila to Tokyo during August and September 1945. Because the OL’s were not self-propelled, they were towed by three ocean-going tugs, each with a string of two or three OLs. The flotilla was escorted by two destroyer escorts. When we got to the open sea there were always three or four dolphins leading us at the bow of the ship and since the deck was only three or four feet from the water, flying fish easily landed on the deck. Our first stop was at Okinawa where we were moved into Katina Cove to ride out a typhoon that was in the area. On leaving Katina Cove, the Manila rope that connected us to the tug snagged on the bottom and had to be cut off and replaced by a smaller steel cable. From there the ride was rough because steel cable does not give like Manila rope and we felt every wave that hit the tug. As we proceeded, one of the OL’s in another string broke loose. A destroyer escort had to go back and retrieve it and was gone a couple of days before it appeared again towing the OL. Doing a tugs job seemed beneath the dignity of a destroyer. We arrived in Tokyo Bay opposite Yokohama on September 10, 1945, and were overwhelmed by the number and sizes of the U. S. Navy ships in the bay. We didn’t stay long, for a picketboat with a Japanese pilot was added to guide us through the minefields to Tokyo harbor where our trip ended alongside the dock. The Japanese indicated that the OL’s were the first U. S. ships in Tokyo Harbor.”

    Sergeant Curtis Martin describes his experiences onboard OL-31.                

    “Although referred to as a barge, OL 31 had the configuration similar to an oil tanker with superstructure aft. We were towed by a large tug with approximately a mile-long cable. There were three tugs in all with two tugs pulling two OL’s and the other pulling one. Travel was very peaceful with dolphins, flying fish, barracuda, etc. during the day and the phosphorescence moon and stars at night. It was hard to believe that a war was going on. If my memory is correct, there were four other ships in the Seaborne Communications Fleet. These included the transmitter and receiver ships. We had very little contact with the others on these ships. They were very curious about the “Green Hornet” as our signal sounded to them.  

    .        

    “Installation of our equipment on OL 31 was a challenge. Sergeants Durkin, Fruman, and myself, none with any experience in air-conditioning, built all of the ductwork and made the installation. We did have precise installation instructions from the York Corporation and it did work! We probably had one of the very few air-conditioned workplaces and sometimes living quarters in the South Pacific! Our power was furnished by three 50 kW diesel generators. We all had to learn to phase in the engine when switching from one to another. Our destination on leaving Okinawa was Tokyo. Fortunately we arrived after the surrender. The gathering of warships in Tokyo Bay was quite a sight.

    .

    “On July 7, 1944, the equipment and operating personnel arrived at Brisbane, Australia. The installation, which was in a vessel designated the OL-31, started on November 1, 1944, and was completed on February 1st. It left Brisbane on February 17 under orders to be towed to Manila. Somewhere off the northeast coast of Australia in the great Barrier area, the OL-31 was towed across a submerged corral reef causing some damage to the hull and shaking up the equipment considerably, necessitating readjustment and repairs. The vessel was delayed at Port Moresby and Ora Bay, New Guinea, for examination of the damage to the hull. It did not prove to be serious enough to warrant repairs, therefore, it continued north. The OL-31 arrived at Hollandia on April 12, 1944 and left on April 17, continuing to Manila. On May 10, the terminal arrived at Manila. Difficulties were experienced with the harbor authorities and it required 11 days to obtain a suitable site for docking the OL-31 vessel so that it could be placed into service. The site was assigned along the sea wall on the south side of the Pasig River just west of the Jones Bridge. On the night of May 21, the power and air-conditioning system went out of service due to the receding tide that permitted the OL-31 to settle on the bottom of the river. This permitted the circulating system’s intake to take in mud and sludge from the riverbed and clogged up the entire circulating system. This necessitated moving the vessel to deeper water and rehabilitating the circulating system.

    .

    “On May 23, 1945, Terminal 9 on OL-31 was turned up for service for the first time 10 months after its arrival in the theater. It was removed from service at Manila on June 23rd.

    .

    “Terminal 9 is the unit that was sent to the SWPA (Southwest Pacific Area) in May 1944, originally intended for installation at Hollandia, New Guinea. However, it was included in the sea-borne communications plan for SWPA and installed on a small barge referred to as an ocean lighter, which is a small barge type of vessel not capable of self-propulsion. The terminal installation was confined to the hold of the vessel occupying the forward two-thirds with the balance of the space aft devoted to power and air-conditioning equipment. Because of the limited space and particularly head-room, it was necessary to construct a false deck in order to provide sufficient clearance for the equipment bays and this only was possible by stripping the equipment of most of its cabinets and revising such other items so as to reduce the overall dimensions. Considerable modification was necessary in the air-conditioning system, outstanding of which was the Freon condensing and cooling unit which was a constant source of trouble since the installation was completed. It was learned from the Maritime people at Brisbane that the regular condensing and economizer unit normally used with the York air-conditioning system could not be used because of limited space. It would have been necessary to make this installation on deck which would have made the vessel top-heavy and rendered it unseaworthy.  

    .

    “As a substitute for the cooling and economizer unit, a special heat exchanger was built in Sidney, Australia for this installation that was capable of circulating salt water for condensation purposes. This was the basis of the air-conditioning system’s trouble because the Freon circulating coils were not designed for exposure to salt water. This resulted in electrolytic action to the coils and resulted in decomposition of the lines and leaks. The air-conditioning system capacity was 190 pounds. In four months over 1100 pounds of Freon were required to keep the system in operation despite the fact that the modified system only required 60 percent of the Freon as other terminal systems and the space to be air-conditioned was only 50 percent of that of other systems. The conference room for this terminal was only approximately 5ft. by 8 ft. with a 6 ft. ceiling. It was located on the main deck, was not air-conditioned, and was very poorly ventilated.”

    MACARTHUR’S BIG SIGSALY PLANS, NEVER EXECUTED 
    .
    While snake-bit through out it’s career in the Philippines, please note, the OL-31 barge with SIGSALY was to be a key element in the Invasion of Japan.  When stationed at Okinawa and Kyushu, General MacArthur could speak directly with General Marshall in Washington DC and General Spaatz at Guam as to the use of the Atomic bomb in support of the invasion. 
    .
    None of Adm. Nimitz’s on the scene commanders in Operation Olympic — Halsey, Spruance and Turner — could do so with the use atomic bombs for security reasons. 
    .
    No SIGSALY, No Nukes for You!
    .
    Between the OL-31 SIGSALY barge, and his brand new press ship Spindle Eye, General MacArthur would have completely dominated both the press accounts and the atomic bomb decision making bandwidth over the US Navy come November 1945, had Operation Olympic been executed.
    Thankfully for the US Navy, the people of Japan, American invasion troops and Admiral King’s blood pressure, this future was abrogated by Emperor Hirohito’s surrender to the atomic bombings of Hiroshima and Nagasaki.
    .
    -End-
    .

    Sources and Notes: 

    .

    AMERICA’S WORLD WAR II UNBREAKABLE CODE FOR SECRET TELEPHONY
    THE U. S. SIGNAL CORPS’ SIGSALY SYSTEM
    http://www.armysignalocs.com/archived/veteranssalultes/44-35_mehl_bookrvw.html

    BRIGADIER GENERAL SPENCER BALL AKIN CHIEF SIGNAL OFFICER, GHQ, SWPA IN AUSTRALIA DURING WWII
    https://www.ozatwar.com/people/spencerbakin.htm

    J. H. DELLINGER, FELLOW, I.R.E., AND NEWBERN SMITH, SENIOR MEMBER, I.R.E “Developments in Radio Sky-Wave Propagation Research and Applications During the War, ” PROCEEDINGS OF THE I.R.E.-Waves and Electrons Section, Feb. 1948, Pages 258 – 266
    https://tf.nist.gov/general/pdf/2402.pdf

    SEABORNE COMMUNICATION UNIT AND MOBILE COMMUNICATION UNIT IN THE SOUTHWEST PACIFIC AREA DURING WWII
    https://www.ozatwar.com/sigint/seabornecomms.htm

    SIGSALY Ciphony 1
    Digital voice encryption with OTP
    https://www.cryptomuseum.com/crypto/usa/sigsaly/index.htm

    SPSCC-11 17 December 1945
    MEMORANDUM for the Chief, Communications Engineering Branch
    Subject:  Records for the Post-War Organization – Development of Special Conference Systems.
    Found at National Archives II, College Park, MD; RG 111: Records of the Office of the Chief Signal Officer, 1860 –1985;
    Series: SIGSALY Project Files, 1942 – 1948
    ARC ID: 6949922
    HMS/MLR: UD 1029
    Container: 7
    DECLASSIFIED VIA
    NND 891545

     

    Appendix 1 – HISTORY OF THE SIGSALY TERMINALS IN WW2

    TERMINAL NUMBER LOCATION IN SERVICE REMARKS
    1. London* July 1943 Removed from service 31 Oct 45 and returned to U.S.
    2. Washington* March 1943
    3. Algiers Oct 1943 Removed from service April 1944 and returned to U.S.
    4. Brisbane
    Manila
    Nov 1943
    June 1944
    Removed from Brisbane Jan 1944.
    5. Hawaii
    Ft Shafter*
    Dec 1943
    6. Frankfurt June 1945 This terminal first sent to Caserta, Italy, but not installed. Reorganization in theater. Moved it to London where it was held pending invasion of the continent.
    7. Washington Mar 1944 Due to increased load and time differentials a second terminal for Washington was required.
    8. Paris Oct 1944
    9. Barge OL-31 This terminal installed on a ship by SWPA at Brisbane, Australia to facilitate mobility in following the movement of GHQ’s progress north. This terminal was ready for service and first used at Manila, May 1945 and remained in service until Terminal No. 4 was brought up from Brisbane and permanently installed at Manila. From there it was taken to Tokyo and placed in service in Oct 1945 pending the installation of a permanent station there, which is presently in progress. (This permanent station will be Terminal #11, removed from Oakland, Calif).
    10. Guam Mar 45 Installed for the Navy.
    11. Oakland, Calif Oct 44 Removed from service 31 Oct 1945 and shipped to Tokyo for permanent installation there (now in progress)
    12. Berlin Dec 45
    *    These terminals have extension units, making it possible to render SIGSALY service from a designated remote point. The locations are as follows:

    No. 1                    War Cabinet Office London, for the British-Great George Street

    Nos. 2 and 7
    Navy Dept, Munitions Bldg., Wash.          –for the Navy

    No. 5      ”       ”      CINCPAC,Pearl Harbor          –for the Navy

    No. 10    USSTAF HDQ Guam                             –for the Air Forces

     

    13 Responses to “Hiroshima and the Atomic Bomb…Plus 75 Years.”

    1. Mike K Says:

      Interesting and thanks.

      WEB Griffin’s Marine Corps series has a lot about “Magic” and McArthur in Brisbane.

      We were very lucky the atomic bomb worked as the invasion might well have failed. The point system the Army used would probably have resulted in a green invasion army. The senior noncoms and junior officers with high point totals would have been sent home.

    2. Gavin Longmuir Says:

      Mike K: “We were very lucky the atomic bomb worked as the invasion might well have failed.”

      Indeed! The logistic chain across the Pacific Ocean would have presented ongoing difficulties for an opposed landing. And the US had learned during the island hopping approaches to Japan how tenaciously the Japanese would have defended their home islands.

      This would not have changed the eventual outcome of Japan’s defeat. Following a repulsed invasion (or an invasion which established a beachhead at the cost too many US lives), the fall-back would have been effectively a siege of Japan along with continued fire-bombing. The cost in Japanese lives would have been tremendous, as Japan was driven back to the Stone Age. It is also likely that the USSR’s invasion of northern Japan would have continued south into the main Japanese islands — probably with massive indiscriminate slaughter of Japanese civilians.

      The Emperor did his nation a great service by using the atomic bombing as a rationale for surrendering.

    3. MCS Says:

      It was because of one of the previous installments that I read “Last to Die”
      https://www.amazon.com/Last-Die-Defeated-Forgotten-American/dp/0306823381

      I hadn’t even heard of the B-32 before. It has a pretty good account of the period between the A-Bombing and the actual surrender that I also wasn’t aware of. The surrender was not nearly the foregone concussion that is presented now.

      My father was in training to participate in the invasion. Neither he nor I have ever had much doubt that the bombing was the right thing to do.

    4. Leather Helmut Says:

      Interesting. I would have thought polar regions would have
      been worse for radio comm. because of solar flares.

      Was non H/F similarly disrupted? Is there any place to
      get a more detailed explanation of interference patterns?

      The map shows Nov. – Mar. Was the rest
      of the year similar?

      Thanks in advance for any replies.

    5. MCS Says:

      Leather,
      Here are some current links just from a quick search. Hams are probably the people that keep best track of HF since its not used commercially that much. Before satellites, it was the only way for planes to communicate on long hauls over the oceans for example or to make connections to remote locations.
      https://www.hfpropagation.com/
      https://www.qrzcq.com/page/propagation
      http://prop.hfradio.org/
      http://hamwaves.com/propagation/en/index.html
      https://www.youtube.com/watch?v=4EadY6eDKhs
      https://www.youtube.com/watch?v=TBO0IYXF79g
      https://www.youtube.com/watch?v=YgmvPWRYw3I

      Here’s what looks like a discussion covering WWII:
      http://play.fallows.ca/wp/radio/shortwave-radio/ww2-solar-cycle-17-hf-propagation/

    6. Mike K Says:

      On the topic of the invasion of Japan, I have a book on alternate history about the war. It is titled “Rising Sun Victorious.” One chapter is about the 1946 typhoon which would have hit the invasion fleet.

    7. MCS Says:

      Realistically, a lot of things would have affected the invasion like that typhoon that would have increased casualties on our side. None would have changed the outcome. Japan would have been left even more devastated than it was, with many many more civilian casualties.

      We could have simply stood aside and let the Soviets take the whole thing. We could have continued the blockade and let them finish starving for an almost negligible cost in Allied casualties. The invasion was the most costly, least effective course of action open to us. A completely typical government program.

    8. Mike K Says:

      A completely typical government program.

      The typical government program was the B 29, which cost more than the atomic bomb.

      And it didn’t work. The Jet Stream was unknown and high altitude bombing was inaccurate. Curtis LeMay saved everybody’s bacon by throwing out the plan for high altitude bombing and going to low altitude fire bombing. From his Wiki entry:

      In August 1944, LeMay transferred to the China-Burma-India theater and directed first the XX Bomber Command in China and then the XXI Bomber Command in the Pacific. LeMay was later placed in charge of all strategic air operations against the Japanese home islands.[7][8] LeMay soon concluded that the techniques and tactics developed for use in Europe against the Luftwaffe were unsuitable against Japan. His Boeing B-29 Superfortress bombers flying from China were dropping their bombs near their targets only 5% of the time. Operational losses of aircraft and crews were unacceptably high owing to Japanese daylight air defenses and continuing mechanical problems with the B-29. In January 1945, LeMay was transferred from China to relieve Brigadier General Haywood S. Hansell as commander of the XXI Bomber Command in the Marianas.[7][8]

      Major General Curtis LeMay talking with General Joseph W. Stilwell.
      He became convinced that high-altitude precision bombing would be ineffective, given the usually cloudy weather over Japan. Furthermore, bombs dropped from the B-29s at high altitude (above 20,000 feet (6,100 m)) were often blown off of their trajectories by a consistently powerful jet stream over the Japanese home islands, which dramatically reduced the effectiveness of the high-altitude raids. Because Japanese air defenses made daytime bombing below jet stream-affected altitudes too perilous, LeMay finally switched to low-altitude nighttime incendiary attacks on Japanese targets, a tactic senior commanders had been advocating for some time.[7][8] Japanese cities were largely constructed of combustible materials such as wood and paper. Precision high-altitude daylight bombing was ordered to proceed only when weather permitted or when specific critical targets were not vulnerable to area bombing.

    9. Miguel cervantes Says:

      Consider this scenario, truman launches the invasion of the homeland it doesnt go well, he has to step down there was no vice president till 1948, so james byrnes becomes president maybe the weapon is tried again at that point. One assumes the war would still be continuing for the allied powers in the east, with all the consequences that entails.

    10. MCS Says:

      The whole “precision” bombing narrative hasn’t fared very well in the 21st Century. War is the most wasteful government program conceivable. Just about nothing works as well as its inventors/promoters expect it to. It certainly seems plausible that the reason wars seem to happen every 20 years is because that’s how long it takes for a new group of credulous suckers to come to power. Conducting a war for the entire interval is something that hasn’t happened in quite a while, since Napoleon at least.

      Near the end of WWII there was work on bombing using SHORAN. I believe it was used in Europe to bomb the bridges over the Po river and in Japan. With good preparation, it allowed the position of the aircraft to be determined quite accurately. The problem, as you point out, remained the last 5 miles between the plane and the ground. That wasn’t really solved until the advent of first, laser and then GPS guided bombs.

      The SHORAN technology came into its own after the war, enabling the first really accurate, long base line surveys of the U.S. The accuracy was on the order of 1/4 inch over more than 100 miles. It was, of course, also an important advance in navigation once stations were established and receivers became available.

    11. OBloodyHell Says:

      On the 45th anniversary of the Hiroshima, SF author Harlan Ellison expressed the opinion that The Bomb, rather than an immoral weapon for its lack of discrimination between civilian and soldier, was, in fact, the first moral weapon developed since Kings stopped riding into battle at the head of their armies.

      His argument was, I think, seriously meritorious: For the first time in about 500 years, those whose choice it was to START a war, would bear the cost of much of the war.

      And that, he asserted, was why The Bomb has a particularly unique distinction among weaponry invented by humans — once invented, it has not again been used, for (then 45, now) 75 years.

      This is unprecedented in human history.

      As a personal corollary to that, I will argue that, sad though Hiroshima and Nagasaki were, their usage probably saved mankind from a much much worse war.

      Those very graphic images of what the very FIRST and weakest of these managed to do clearly leave an indelible picture on the minds of those “whose choice it was to start a war”. One that cannot be hand-waved off, as might be possible for pictures of tests against Potemkin villages constructed for atom-bomb tests. It put, into the mind’s eyes of the power elite all around, exactly what would happen to THEIR power and privilege, if they chose to go to war with this weapon.

      Would they have held their hands, during the Korean War, when we had a very close brush with a hot war? Would they have held their hands, during the Cuban Missile Crisis, without these images?

      One might hope so, but those images, multiplied by a hundred, a thousand, times… surely made them more reluctant to make that last stupid, fatal step.

    12. Trent Telenko Says:

      >>Interesting. I would have thought polar regions would have
      >>been worse for radio comm. because of solar flares

      This is an “it depends” situation.

      H/F radio has three forms of transmission. Ground wave, Near Vertical incident Skywave and Skywave.

      Skywave is the main advantage of H/F in that it can reach world wide.

      The issue in the polar regions is that when the maximum usable frequency falls below the lowest usable frequency, you get black outs. That is, you cannot get a critical angle reflection past the first atmospheric bounce.

      NVIS is simply shooting signal straight up and having it re-radiate straight down. It gives between 200km and 400 km range. Which is still quite useful in polar regions, but not the thousands of kilometres of a good skywave connection.

      German armored units, and their armored cars in particular, made very extensive use if NVIS H/F in the 1939-1942 blitzkriegs in Poland, Western Europe, the Balkans, Russia and Africa. This is why German Panzer divisions could be more than 100 miles ahead of German infantry formations and both elements stayed well coordinated.

    13. MCS Says:

      OBloodyHell,
      There still seemed to be some that thought it wouldn’t be so bad if we had enough fallout shelters. Luckily, they didn’t get much influence. Probably because of the images.

      The German reliance on HF also meant that they were broadcasting all their plans to Bletchley Park.