There have been literally hundreds of books and thousands of articles on the June 6th 1944 invasion of Normandy. Almost every facet of the invasion has been examined in the last 75 years. Yet for all that, there are simply some subjects related to the Normandy invasion that professional military historians won’t deal with.
There are a lot of reasons for this, but at it’s heart, it is simply the case many, if not most, academic military historians got into history because they didn’t want to do math. When you start talking about bandwidth, frequency, wavelength, quartz crystal radio control, atmospheric transmissiblity, radio ducting, and how all this related to the command, control, communications and intelligence (C3I) systems of the Normandy Invasion. When you bring up all this “Retro-High Technology,” the vast majority run screaming from the subject.
This is a real shame as it has left out the story of how the Allies created a C3I system to control all it’s air and sea forces. Projected this C3I system across the English Channel while destroying/stunning/jamming the German C3I system. And then implanted that C3I system in France. All the while making sure thousands of Allied fighters and anti-aircraft gunners didn’t shoot at each other or down dozens of troop laden transport planes filled with paratroopers or towing gliders, as happened in Operation Husky, the Invasion of Sicily. It simply hasn’t been addressed.
This post is my attempt to fill this gap in the historical record by explaining the problems the Western Allies faced. The Operation’s Neptune and Overlord planning process they used to overcome them with cunning yet simple ideas like invasion stripes, and a broad brush outline of how they executed those plans.
RETRO-HIGH TECH BACKGROUND
World War 2’s “Retro-High Tech” warfare was defined on the ground, in the air and on the sea by the use of electronic signals intelligence (SIGINT) with the addition of RADAR for land or sea based airpower. Both SIGINT and RADAR had to be tied together to an effective radio and wire telecommunications network in order to provide both intelligence services the necessary data for evaluation and the military commanders the processed intelligence to act upon in order to be effective.
The effective use of RADAR required a very rapid gathering, processing, decision making and dissemination of those decisions over a vast geographic area by radio, telegraph and telephone. During World War 2 (WW2) RADAR networks had the addition of first radio direction finding and then “low level” signals intercepts of voice and Morse code in the clear, simple, easy to use, but quickly breakable codes — Organizations doing this were called “Y-Service” by the British — followed eventually by higher level cryptographic code breaking (or “ULTRA”) being added into this network.
This four legged stool of military sensors, communications, intelligence, and decision making by military commanders is normally referred to as Command, Control, Communications and Intelligence or “C3I”. In particular, RADAR played the role of “Keystone Military Technology.” And by “Keystone” I mean an analogy to the biological concept of a “Keystone species” in an ecosystem, not unlike the role of algae in the ocean ecosystem or grass for a prairie ecosystem. This military C3I ecosystem model is far more developed in the 21st century – especially with the arrival of digital electronic computers — but it is simply a conceptual embellishment of this 1940’s “Revolution in Military Affairs.”
RETRO-HIGH TECH LIMITATIONS
The fundamental problem Normandy campaign was the Western Allied powers were going to put more aircraft and ships into their respective air and sea space than could be effectively controlled by the available C3I systems. The quartz crystal control VHF (think television channels 1 thru 13) radios and the meter band radars did not provide enough bandwidth for communications nor precise target definition and altitude for tight two way radio directive control of fighter patrols or surface ship screens. In the age before computer spread sheets and data bases the Western Allied had to control all the emissions for thousands of radios and radars as well as plan on how all these ships and planes were going to shoot move and communicate together without enough electromagnetic spectrum to do so.
To give you an idea as to the scale of the issue, the primary VHF fighter radio for the Allied air forces in the United Kingdom was the SCR-522 or a British radio that the SCR-522 was copied from. (The scale of the USAAF and Lend Lease production was such that American build SCR-522 was the predominant fighter radio in the Normandy invasion.) It was four channel, amplitude modulated (AM), push button, quartz crystal frequency controlled radio that transmitted between 100 Mhz and 156 Mhz. A typical US Army Air Force WW2 fighter squadron set it’s SCR-522 as follows:
Channel A is the frequencies for all planes;
Channel B is the squadron command frequency;
Channel C is the D/F* homing frequency;
Channel D is the D/F* fix frequency”
*D/F means direction finding
There were going to be _171_ Allied fighter squadrons in Operation Neptune. Now see the following passage
from page 8 of USAF historian Richard P. Hallion’s 1994 history “D-Day 1944: Air Power Over the Normandy Beaches and Beyond.”
Air Support on the Beaches
During the June 6 D-Day assault itself, a total of 171 squadrons of British and AAF fighters undertook a variety of tasks in support of the invasion. Fifteen squadrons provided shippingcover, fifty-four provided beach cover, thirty-three undertook bomber escort and offensive fighter sweept thirty-three struck at targets inland from the landing area, and thirty-six provided direct air support to invading forces. The Luftwaffe’s appearance was so minuscule that Allied counterair measures against the few German aircraft that did appear are not worth mentioning.
To give each of those 171 squadrons the standard four frequencies operationally required would call for 564 separate radio channels. Worse, each squadron was between 12 (RAF) and 16 (USAAF) fighters. So you would be looking at between 2052 and 2736 transmitters on those frequencies. If you think digital WiFi congestion of 50 lap tops and tablets at your local Starbucks is bad. That’s nothing compared to the physical impossibility of putting 564 analog radio channels, with ~2300 transmitters, between American broadcast television channel’s 6 and 7.
OPERATION NEPTUNE’S PLANNING AND AGNER ERLANG’S HIGH MATH
In an operation as large as Operation Neptune, planning had to start early. It had to be comprehensive. And it had to include every possible contingency. In modern military terms, it needed a “GO.T.H.” plan built in . [AKA, what you would do when everything else GOes To Hell.] This detailed planning kicked off in January 1944. See Figure 2 below.
This detailed planning included the following issues to be addressed based on the operational experiences of the Operations Torch, Husky, Baytown, Avalanche and Shingle. This list included the following:
This planning process was heavily disrupted, especially in terms of signals and frequency allocation when General Bernard Montgomery took over invasion planning of 21st Army Group and added additional infantry divisions to the initial assault forces. To deal with this change a series of boards, committees and sub-committees were created to deal with the new invasion plan. See figures four and five below for a partial list.
It was the Mutual Interference Sub Committee, Combined Signal Board, Supreme Allied Command that drove the signals plans for Normandy. It did this via a series of practical exercises to determine primary, 2nd and 3rd order harmonic interference patterns for every piece of radar and radio gear in the invasion with priorities on which system gets the best terrain features. See item two in figure six below.
This in turn caused a large number of mathematicians in uniform to start determining frequency allocation via working with a then 26 year old mathematical formulas governing telephone call traffic engineering and queueing theory invented by a Danish telephone engineer by the name of Agner Krarup Erlang. In 1917 Erlang published “Solution of Some Problems in the Theory of Probabilities of Significance in Automatic Telephone Exchanges“, which contained formulas for loss and waiting time, which are now well known in the theory of telephone traffic. Originally published in his native Danish, Erlang’s work was rapidly translated and published in English in the Post Office Electrical Engineers Journal Volume 10 (1917–1918) Pages 189–197. The mathematicians were generally in the uniforms of the RAF and US Army Signal Corps as the pre-war telephone engineering necessary to create Fighter Command and the continent sized American telephone system, respectively, left them with the most practical experts with the Erlang formulas.
What these mathematicians in uniform were doing is known today as Frequency Deconfliction**. It was accomplished in the spring of 1944 with ledger books, lots of skull sweat and endless meetings where officers with stars in a rainbow of different service uniforms often shattered many days or weeks of calculations due to rearrangements of who owned which piece of the radio spectrum.
[** A systematic management procedure to coordinate the use of the electromagnetic spectrum for operations, communications, and intelligence functions. Frequency deconfliction is one element of electromagnetic spectrum management. See also electromagnetic spectrum; electromagnetic spectrum management; electronic warfare. (JP 3-51) (US DoD)]
HOW ALLIED PLANES GOT THEIR INVASION STRIPES
It was in the last of the major meetings of the Combined Signal Board (See item 11 in Figure 6 above) that it was concluded that the thousands of aircraft involved in the invasion would saturate and break down the Allied Mark III IFF (Identification Friend or Foe) system. [Note: The Mark III IFF shared the same frequencies covered by the SCR-522!] This same meeting also approved an alternate visual identification system to replace it – Invasion Stripes.
This visual identification system was pure RAF in origin and it came from bad experience. Namely, it turned out that both the Hawker Typhoon and early production Hawker Tempest Mark Vs had very similar short noses and wing taper to German FW190’s when seem from above and below. Both planes were taking fire from other RAF fighters — mainly Fighter Command Spitfire V’s — intended for the Focke-Wulf Fw 190. Identification bands were added by the RAF to aid identification of these planes in combat. According to the Wikipedia article on the subject:
The order was promulgated on 5 December 1942. At first they were applied by unit ground crews, but they were soon being painted on at the factory. Four 12-inch-wide (300 mm) black stripes separated by three 24-inch (610 mm) white, underwing from the wingroots. From early 1943 the Typhoons also had a yellow, 18-inch-wide (460 mm) stripe on each of the upper wings, centred on the inner cannon. All of these markings were officially abandoned 7 February 1944.
When Air Chief Marshal Sir Trafford Leigh-Mallory, commanding the Allied Expeditionary Air Force approved the invasion stripe scheme. It wasn’t simply a negative control “don’t shoot me” measure. The Allies were reverting to a Western Front WW1 aerial tactic. They were doing standing fighter patrols.
The RAF used standing fighter patrols not only on the WW1 Western front, but also in the Western Desert through 1942, until they had enough radars and VHF band radios to actively control their fighter-interceptors. In the interim period of 1940-1941, the RAF augmented these standing patrols with broadcast plots of German air movements using radar and Y-service intercepts of German Luftwaffe signals so pilots could use the information and their initiative to deal with German raids. This was the same sort of running commentary fighter control system that German night fighters later adopted to deal with RAF Bomber Command jamming limited Luftwaffe radio bandwidth over Germany in 1943.
This standing patrol plus running commentary fighter control system allowed upwards of 7,000 aircraft sorties flying over the Normandy area the day of the invasion and close to 10,000 sorties when the wider RAF operations over France, the English Channel, North Sea and Bay of Biscayne by RAF Coastal Command, RAF Bomber Command, RAF Fighter Command and Allied Expeditionary Air Forces (AEAF) are taken into account.
Words cannot do justice to the numbers and scale of this air effort, so see the following maps:
BOMBER COMMAND’S “SHOCK AND AWE” & FIGHTER COMMAND’S SEAD CAMPAIGN
In May 1944 the Allies, and particularly the RAF Bomber Command’s 100 Group, had the measure and more than the measure of the “murder’s row” of German air defense radars thank to a lot of hard work by Allied Ultra code breaking signals intelligence and the radar intercept operators flying in the planes of RAF 100 Group.
However, while the RAF’s “Window” radar decoys, radar & radio jammers had the measure of German Luftnachrichten Dienat’s (Air Surveillance Service) land based radars. The Germans were passively tracking Bomber Command radio, radar, and yes jamming signals with a separate passive electronic signal tracking organization called the Funkaufklärungsdienst. The Luftwaffe Funkaufklärungsdienst was once part Luftnachrichten Dienat organization and separated from it the year before Normandy. It the used a network of passive ground sensors for direction finding to place night-fighters into the stream of RAF 4-engine bombers. Where the Lichtenstein FuG 220 (Model SN-2) Air Intercept (A.I.) radar — immune to RAF dropped aerial decoys and jamming — let the night-fighters kill bombers at will.
It would not be until July 1944 and the capture of this wrong-way German Ju-88 night-fighter that the secrets of not only the German A.I. radar, but also many of the ways the Funkaufklärungsdienst was passively tracking Bomber Command became known, as smaller versions of the bomber tracking passive sensors were also on the night-fighter. The electronic measure/counter-measure situation was as seen below in Figure 15.
The FuSAn 724/725 “Bernhard/Bernhardine” transmitted in the 30 – 33.3 Mhz VHF radio band below today’s VHF television channel 2. It was was high powered, directional and it’s antenna rotated twice a minute. It was the key communications link between both the ground based Luftnachrichten Dienat & the Funkaufklärungsdienst and the Luftwaffe night-fighter force in the air. Luftwaffe radar/radio operators in the night-fighters could switch between 2 FuSAn 724/725 stations and obtain both a fix and text message air battle update every minute. It also meant they did not have to work two radios to find a jamming free frequency! This set of characteristics very made them extremely difficult to jam as a number of Allied airborne jammers had to orbit the antenna between it and any German night fighters in its up to 400km range. There simply were not enough jammers for the FuSAn 724/725 in France and to cover all the other tasks planned on D-Day. See Figure 1 at the beginning of the article.
The combination of the unsuppressed Funkaufklärungsdienst passive sensor network and the “Bernhard/Bernhardine” night-fighter beacons in France represented a horrible threat to one of the key phases of the Overlord landings. The night time parachute drops of the American 82nd and 101st Airborne divisions and the British 6th Airborne division. The unarmored, slow and heavily laden C-47’s and glider towing British bombers simply were meat on the table for Luftwaffe night-fighters. See Figure 14. below:
To deal with the Luftwaffe night-fighter threat to the airborne drops, three weeks before D-Day the RAF Fighter Command and the AEAF began a systematic campaign to attack German radars in France. It was the first comprehensive Suppression of Enemy Air Defenses (SEAD) campaign in military history. Thanks to the foresight of R.V. Jones, the head of at RAF Scientific Air Intelligence, there was a catalog, complete with photos and map locations, of all German radar installations in Western Europe. And thanks to the assistance of the Air Ministry’s Telecommunications Research Establishment (TRE), the Fighter Command had a special radar hunting kit called ABDULLAH fitted to Hawker Typhoon fighters to assist in the campaign. Unfortunately, as the Greg Goebel’s “Electronics Warfare Against The Axis” web site describes below, sometimes “good ideas” are not practical tools in the face of a competent enemy.
Three weeks before the invasion, Allied bombers and strike aircraft began to attack critical radar stations. Rocket-firing RAF Hawker Typhoon strike fighters proved most effective, but encountered heavy anti-aircraft defenses. The TRE fitted a few Typhoons with a device named “Abdullah” that could home in on radar sites; it was the ancestor of the modern “radar homing and warning (RHAW)” receiver used on “Wild Weasel” type defense suppression aircraft. Abdullah worked fine, but it proved to have a serious drawback. German radar sites that observed Allied aircraft flying straight down the boresight at them immediately put their flak defenses on full alert, and the effect of Abdullah was to simply make the attacks harder. It was set aside, and attack plans were modified so that the Typhoons flew an oblique course toward a radar site and only turned directly on it at the last moment. A better approach to “defense suppression” would need to wait for a later conflict.
R.V. Jones memoir MOST SECRET WAR: British Scientific Intelligence 1939-1945 in his D-Day chapter (43) discusses the AEAF/Fighter Command SEAD effort and what it took to get his radar catalog included in the effort. On page 408 he discusses how well the attacks on German radars went. This is where the “and it went happily ever after” effect of most wartime memoirs comes in. The 12 May 1945 RAF report “REPORT ON AIR OPERATIONS PRIOR TO AND IN SUPPORT OF OPERATION “NEPTUNE” paints a very different story of how things really went.
While R.V. Jones radar catalog humbugged the need to use the radar homing abilities of ABDULLAH. Since the RAF fighter squadrons didn’t need to home on radars they knew the locations of anyway. The straight into them tactic developed with ABDULLAH and the huge German flak response it generated slowed the destruction of German radars to a crawl. The AEAF leaders of the SEAD campaign had to stop and reassess priorities for the final three days before D-Day. See paragraphs 111, 112, & 113 of “REPORT ON AIR OPERATIONS PRIOR TO AND IN SUPPORT OF OPERATION “NEPTUNE” below:
111. On 10th May, 1944, a series of attacks was commenced against the long range aircraft reporting stations and on 13th May, attacks were commenced on the installations used for night fighter control and the control of coastal guns. On 25th May, 42 sites were scheduled for attack. These sites included 106 installations; at D-3, fourteen of these installations were confirmed destroyed.
112. To conserve effort, it was then decided, three days before D-day, to list the twelve most important sites, six chosen by the Naval authorities and six by the air authorities. These twelve sites, containing thirty-nine installations were all attacked in the three days prior to D-day.
113. Up to D-day, 1,668 sorties were flown by aircraft of A.E.A.F. in attacks on Radar installations. Typhoons in low level attacks flew 694 sorties and fired 4,517 x 60-lb. rocket projectiles. Typhoons and Spitfires made 759 dive bombing sorties, dropping 1,258 x 500-lb. bombs, and light and medium bombers dropped 218 tons of bombs. In addition, the sites and equipment were sprayed with many thousands of rounds of cannon and machine gun fire.
In addition to the 12 AEAF targets, more four German military radio transmitting C3I facilities were struck with maximum short range bomb load OBOE radio navigation strikes of 70 to 120(+) RAF Bomber Command Lancaster bombers each with 450 to 600 tons of bomb per target. At an average of 5.75 tons of bombs per Lancaster, these attacks amounted to OBOE ARC LIGHTS**.
[**ARC LIGHT refers to the 1965 to 1973 era use of three plane B-52 formations to drop bombs bombs in the Republic of South Vietnam in support of ground troops. Typical bomb loads were 20 to 27 tons of bombs per B-52.]
Of the sixteen AEAF/Bomber Command C3I targets, eight were absolutely vital to the success of the Overlord landings. The first two were the Luftwaffe “Bernhard/Bernhardine”night-fighter radio navigation beacons covering northern France. One was destroyed and one inoperative on D-Day after RAF attacks.
Targets four through six were radio transmitters struck by Bomber Command. Identified by their unique teletype cipher transmissions, three Geheimschreiber (secret writer) sites from France to the Oberkommando der Wehrmacht (German High Command, OKW) in Berlin were flattened.
This fact was -NOT- in the 12 May 1945 RAF report. It is something I deduced from many other readings and especially watching the following video from the Military History Visualized You Tube channel. This video explains what the German OKW knew and when did they know it on the Normandy landings. When you compare radio sites the Bomber Command struck and the gaps the MHV channel described. They fit hand and glove. See:
On D-Day what did the Germans know?
Military History Visualized
Published on May 28, 2019
Target seven reflected not only the need to protect airborne troops, but also some measure of Bomber Command’s desire for payback for the debacle that was the failed Berlin bombing campaign. The last Bomber Command C3I target was the Funkaufklärungsdienst’s Cherbourg/Urville-Hague headquarters in North Western France. This is how the 12 May 1945 RAF report “REPORT ON AIR OPERATIONS PRIOR TO AND IN SUPPORT OF OPERATION “NEPTUNE” described the attack:
Cherbourg/Urville-Hague. This station is now known to have been the headquarters of the Nazi “Y” Service in North Western France. The attack on this important W/T centre was made on 3rd/ 4th June by 99 aircraft, dropping 570 tons of bombs. The results were remarkable, the centre of a very neat bomb pattern coinciding almost exactly with the centre of the target area. The photographic interpretation report may be quoted verbatim :-
“(a) The station consisted of a line of W/T masts running diagonally across an old fort, and the Headquarters buildings, 150 yards to the south.
(b) Both the masts and the buildings have been demolished; all have received many direct hits. The outline of the only two large blast-wall protected buildings is only just discernible among the craters and the debris.
(c) The target is at the centre of a well-defined concentration of many hundreds of craters. ” The station is completely useless. The site itself is rendered unsuitable for rebuilding the installation, without much effort being expended in levelling and filling-in the craters.”
126. The success of this attack on the German Air Force “Y” Headquarters must have been a major catastrophe for German Intelligence and it may well be that it was an important contributory factor to the lack of enemy air reaction to the assault.
The text in paragraph 126 above was the RAF bragging without giving away the “ULTRA Secret,” because the RAF was very much aware that it had done just that — inflict a catastrophic intelligence disaster — upon the Luftwaffe.
Target eight was the apparent German Wassermann radar complex at Tausenfussler near Cherbourg-Octeville on the tip of the Cotentin Peninsula. And I say apparent for a reason, because the so-called Wassermann was anything but. It was a Luftwaffe technological surprise that was strategic in scope. It was a new radar, in a network of six, that was impossible for the Allied to jam without leaving Great Britain defenseless, because it was a bi-static radar that used the transmission of Fighter Command’s own Chain Home radar chain! It was a Klein Heidelberg – a WW2 bistatic radar system that was decades ahead of its time.
LADY LUCK FAVORS A PREPARED RAF
It cannot be overstated what a stroke of luck befell the RAF in striking the apparent Wassermann at the Tausenfussler location. Had it been operational the night of 5/6 June 1944. The results would have been horrific, as there were 24 available Luftwaffe night fighters that were decoyed by RAF jamming and window well to the east of the Cotentin Peninsula. See Figures 1 above & 20 below.
This is how paragraph 127 of “REPORT ON AIR OPERATIONS PRIOR TO AND IN SUPPORT OF OPERATION “NEPTUNE” described the affect of this decoy operation on the Luftwaffe night-fighter force.
127. On the night of 5/6th June in the opening phases of the assault, the counter measures against such installations as were still active were put into operation. In connection with a diversionary naval force, a formation of specially equipped aircraft flew up and down the coast from Dieppe to the mouth of’ the Somme. The energy was apparently led to believe this to be a major bomber formation, as he reacted with twenty-four fighters which were active approximately three hours hunting the ghost , bomber stream.
Had the Tausenfussler Klein Heidelberg been operational, it’s borrowed Chain Home 50 m wavelength (around 6 MHz) radar signal was so different from the jamming and 1.5 meter wavelength tuned window used in TAXABLE, GLIMMER, plus the bomber stream spoof, that it would have seen right through them. The slow speed of the troop carrier streams compared to RAF Lancaster’s would have betrayed their identity and brought Luftwaffe night-fighters like a school of sharks. Leading German night-fighter pilots could get two to five Lancaster bombers in a single sortie. The slower, unarmored and unarmed transports, many towing gliders, would be easy meat even for novice night-fighter pilots. Easily 50 or more of the 840 IX Troop Carrier Command C-47 could have fallen to the guns of the 24 decoyed Luftwaffe night-fighters. At 24 souls per loaded C-47 or 35 per tow plane plus towed glider, between 1200 and 1750 paratroopers and air crew would have died but for the RAF’s SEAD attack.
And the destruction was not the only stroke of luck the RAF had in it’s last three days of strikes on the German C3I system. The destruction of the Funkaufklärungsdienst’s Cherbourg/Urville-Hague headquarters in North Western France had an additional dividend. As the 10,000 Allied planes across Britain were preparing for D-Day, they were all testing their Mark III IFF systems. The Funkaufklärungsdienst’s intercept operators were listening.
While they Mark III were not to be used over Normandy proper. The systems absolutely were to be used entering RAF Fighter Command controlled air space. As Fighter Command had a very sanguinary reputation of shooting first and only grudgingly answering awkward questions about missing allied air crews when wreckage was found. Every Allied air crew checked their Mark III IFF repeatedly before take off. And as each plane squawked electronic signals, nearby planes squawked replies and so on and so forth. As can be imagined, this raised an incredible electronic racket that could be and was picked up by Funkaufklärungsdienst intercept operators. It was picked up, reported…and not believed.
The following is from ROYAL AIR FORCE HISTORICAL SOCIETY JOURNAL 28, Royal Air Force Historical Society, First published in the UK in 2003 by the Royal Air Force Historical Society.
MORNING DISCUSSION PERIOD
Peter Hearne. I was struck by a comparison between a point raised in Mr Streetly’s paper and a chapter in R V Jones’ book, Most Secret War, regarding the vulnerability of Bomber Command’s aircraft to German night fighters homing on their transmissions. This would possibly have involved IFF and the problem was certainly present in the context of H2S and MONICA. Jones recalls that he had a conversation with a German scientist who said that they were very surprised at how lax Bomber Command’s discipline was, or perhaps how unguarded they were; either way, it seems that the Germans were certainly planning to exploit this weakness.
I wondered whether there was any sort of read-across between our own night fighter’s use of SERRATE and PERFECTOS and our related efforts to protect Bomber Command’s aircraft. In that connection someone has written, (it may have been Dr Price) that the one person who correctly predicted that D-Day was about to happen, was a German radio operator on the listening watch in Holland who detected an enormous amount of tuning pulses from RAF aircraft on the night of 5 June and deduced that the invasion might take place on the following day. Happily, his message was disregarded.
The mass death inflicted on the Funkaufklärungsdienst leadership in France left no one with the technical training and seniority to make the right call with the right information.
If “Luck” is defined as “Opportunity Meeting the Prepared Mind” then the R.V. Jones Air Ministry catalog and the AEAF’s SEAD campaign made the luck of the paratroopers of the 6th, 82nd, 101’s airborne Divisions at Normandy.
PROTECTING THE INVASION FLEET & THE ARRIVAL OF THE RAF’S RADAR SHIELD IN FRANCE
The real C3I issue for the invasion fleet was how to practically see and control the land based airpower protecting it and directing it’s use over the beach head. The Normandy Coast of France was too far away for the land based radar network of Britain to be of practical use. The Allied invasion fleet had to bring it’s own radar, radio and radio intercept capabilities for fighter direction with it. And it had to command naval, air and ground forces simultaneously. And executing those C3I roles is where the centralized command, combined nationality and joint service amphibious warfare culture of the Western Allies in Europe was radically different that the US Navy/US Marine Corps amphibious culture of the Pacific. The UK Royal Navy’s armored carriers simply did not have the internal space for a US Navy style fighter direction system. And even if they did, it was still not anywhere near enough space to control the high hundreds hundreds to high thousands of land based planes the Allies in Western Europe routinely brought to bear from 1943 onward.
There was simply no real way to have a US Navy style AGC amphibious command ship could do both the jobs of fighter direction and landing force high level command. This was due to both frequency bandwidth/interference issues on the AGC and because when this was attempted with the USS Ancon (AGC-4) at the Salerno landings. Luftwaffe signal intelligence used direction finding to isolate it’s location and dispatch specialized anti-ship squadrons to attempt to sink it!
This lesson caused the Allies to separate their defensive air superiority C3I platforms from the Landing force and offensive air power C3I platforms. The defensive role was taken over by a joint RAF/Royal navy ship called a Fighter Director Tender (FDT). These ships were converted landing ship tank (LST) with a full RAF land based fighter sector control center and a 1.5 meter/200 Mhz altitude determining Ground Control Intercept (GCI) radar and a full suite of radio and radar beacons for work with and control of night fighters. There were three of these FDT ship used in Normandy.
The three FDT were equipped with a full RAF Fighter Sector radio and command center set up, two GCI radars plus a suite of meter and microwave band radar beacons. The reason for two GCI radars was simple. The Germans had jammed the 1.5 meter band GCI radars the FDT carried at Anzio in support of Luftwaffe radio guided missile strikes on the Allied fleet there. The second GCI radar on the FDT’s operated on the same 50 Cm frequency of the German Wurtzburg and Wurtzburg-Riese of German air defenses. So if the primary GCI radars’s on the FDT’s were jammed. They would switch to the 50cm sets. This was a less advanced version of the “Hug the enemy’s radio spectrum” game that the Luftwaffe played with the Klein Heidelberg. Come the event, the FDT’s 50cm GCI radar sets were not needed.
The German military leaders who would have made the decision to jam the 1.5 meter band FDT radar sets in Normandy were dead under a dense set of bomb craters at the Funkaufklärungsdienst Cherbourg/Urville-Hague headquarters in North Western France.
ALLIED NIGHT FIGHTER COVERAGE AT NORMANDY
The first night after the landings saw the pay off from the FDT’s. Their extra fighter direction command and control facilities — compared to the US Navy AGC in the Pacific — allowed a dense coverage of 38 twin engine and multiple crew Mosquito and P-61 Black Widow night-fighters over Normandy in June 1944. The radar beacons on the FDT allowed the night-fighters know if they were in the correct orbit locations via their radars “pinging” them without a lot of radio communications. This is compared to only six night fighter orbits at Okinawa by the US Navy during May-June 1945. And, unlike the single engine Hellcat and Corsair night-fighters of the Pacific War. These twin engine night-fighters not only carried the heavy but immensely better SCR-720 A.I. radars to go with their IFF. They had the raw engine power and room to carried their own radar beacons for the FDT to inspect out to the radar horizon without setting off IFF. This “out to the horizon” radar tracking range plus the provision for RAF Y-Service signals intercept teams specializing in direction finding upon and real time translating of Luftwaffe fighter radio traffic on the FDT gave Allied night-fighter a reach across Northern France. See figure 24 below.
It was a good thing that the FDT’s performed so well because Allied plans to project it’s “Ground Radar Shield” upon French shores nearly failed at Omaha Beach.
RAF GROUND RADAR CONVOY PLANS AND THE REALTY OF OMAHA BEACH.
There were extensive plans for the rapid build up of RAF radars very early in the Normandy landings for several reasons. The RAF was simply better at controlling night-fighters. Their radar operators had more combat experience. And they had simply put more thought into how to configure radars on vehicles and move them across a beach. This was reflected in the engineer planning for Neptune with RAF 85 Group GCI.
The reality was when RAF Ground Convoy 15082 landed at the second tide on Omaha Beach. German artillery observers of the 352nd Infantry Division still had commanding sight lines on the beaches with wire communications to heavy artillery. And radars were priority artillery targets. The result was as destructive as it was quick and bloody.
Despite the bloody set back for RAF Ground Convoy 15082 at Omaha Beach, the graft of RAF radar deployments on the French coast took hold. And the following RAF radar units were landed upon the far shore.
AFTER D-DAY — THE U.S. NINTH AIR FORCE COMES INTO ITS OWN
Thus far the C3I story of Normandy has been a British one. This is because, frankly, in all things radar and signals intelligence, British forces had a four year head start. But in that time, there was one USAAF general who learned this new C3I trade from his RAF tutors in North Africa, Sicily and Italy. And on the far Normandy shore, he exceeded the best that his tutors taught him. He was General Elwood Richard Quesada, CB, CBE , he commanded the Ninth Air Force’s IXth Fighter Command. From that post, in Operation Neptune planning, General Quesada was the American flag rank expert in projecting land based air-power through an amphibious fleet to a far shore. And where he exceeded his British tutors was in using radar and radio as an offensive tool to place tactical air-power where ground forces needed them on that far shore.
The key element of IXth Fighter Command was Quesada’s baby, the IXth Tactical Air Command. It was a unique organization that combined all the best technique of RAF C3I with the best of the then brand new American 10cm microwave radars. The keys were the huge Microwave Early Warning radar (MEW) hand built by the British Branch of the MIT Radiation Laboratory in Britain (Later given the Army-Navy designation AN/CPS-1) and the SCR 584 microwave gunfire radars that helped save Anzio from the Luftwaffe, because it’s 10cm wavelength was immune to German meter band jamming and Window decoys. The MEW could control a huge amount of airspace and it’s displays were better than anything the RAF had ever seen. While the SCR-584 could lock on to a target in three dimension and generate fire control solutions that could place anti-aircraft artillery shells within a few dozen feet of a target. Networked together with signals intelligence detachment from the 3rd Radio Squadron Mobile (RSM), it was an air superiority C3I system without match.
It was Quesada’s IXth TAC that saw off the Luftwaffe’s fighter counter attacks in June 1944. Per Martin Bowman’s Osprey book “P-47 THUNDERBOLT VS BF109G/K Europe 1943-45,” at pages pages 39 and 40, there were two mixed BG109/FW190 Luftwaffe fighter Gruppen, JGs 2 and 26, in Normandy. Between them they had 425 BF109 and FW-190 fighters, of which only 250-280 were operational at any one time in the spring of 1944.
In the time immediately after the Normandy landings, the Germans put in 15 more Jagdgruppen into France by June 9, 1944…and lost 170 pilots killed in action plus lost another 350 planes destroyed or damaged on the ground by the time they withdrew at the end of June 1944.
CLOSING OUT THE C3I SECRETS OF D-DAY
It took six years of combat experience and fevered development, five months of intense planning, and seven weeks of intense execution for the air, sea and land based C3I systems of the Normandy of the Allies to make the leap across the English Channel to first wrest first electromagnetic and then aerial supremacy from the Luftwaffe. And now on it’s 75th anniversary, these “C3I Secrets” have finally been told.
SOURCES AND NOTES:
ARMY AIR FORCES HISTORICAL STUDIES: No.36 NINTH AIR FORCE APRIL TO NOVEMBER 1944 AAF HISTORICAL OFFICE· HEADQUARTERS, ARMY AIR FORCES Prepared Historical Office Headquarters Army Air Forces October 1945
Steve Blank’s “Hidden in Plain Sight: The Secret History of Silicon Valley” http://steveblank.com/secret-history
Martin Bowman “P-47 THUNDERBOLT VS BF109G/K Europe 1943-45. Osprey Publishing; 1st edition (August 19, 2008) ISBN-10: 1846033152, ISBN-13: 978-1846033155
F. Dörenberg, BERNHARD INSTALLATION BE-4 AT LA PERNELLE (France, dept. 50) https://www.nonstopsystems.com/radio/hellschreiber-bernhard-Be4.htm
Effectiveness of Third Phase Tactical Air Operations in the European Theater, 5 May 1944 — 8 May 1945
Erlang Calculation – An Introduction
Agner Erlang and the Mathematics of Telecommunication Traffic
Greg Goebel [9.3] GLIMMER & TAXABLE / OPERATION POST MORTEM
Hugh Griffiths and Nicholas Willis “Klein Heidelberg – a WW2 bistatic radar system that was decades ahead of its time” Expanded on-line version of a paper published in IEEE Transactions on Aerospace and Electronic Systems
Richard P. Hallion’s “D-Day 1944: Air Power Over the Normandy Beaches and Beyond.” Air Force History and Museums Program 1994 Air Force History Support Office, 3 Brookley Avenue Box 94, Bolling AFB DC 20032-5000
Horace R. (Red) Macaulay, Chapter XI GROUND CONTROLLED INTERCEPTION RADARS IN OPERATION NEPTUNE/OVERLORD, “THE ALLIED INVASION OF FRANCE” JUNE, 1944. The story of the Fighter Direction Tenders used during the “D-Day” Assault and The Mobile Radar Convoys that Landed on the Beaches. RCAF Radar History at the “The Canadian Radar History Project” web site. www.rquirk.com/cdnradar/cor/chapter11.pdf
Thomas Alexander Hughes, Overlord: General Pete Quesada and the Triumph of Tactical Air Power in World War II, Free Press, October 3, 2002 ISBN-10: 0743247833 ISBN-13: 978-0743247832
John F. Kreis, Air Warfare and Air Base Air Defense 1914-1973 Office of Air Force History United States Air Force Washington. D. C. 1988 ISBN 0-912799-55-2, See the North Africa Chapter for RAF standing patrols.
R.V. Jones MOST SECRET WAR: British Scientific Intelligence 1939-1945 Penguin 6 Aug. 2009
On D-Day what did the Germans know?
Military History Visualized
Published on May 28, 2019
E.W. MacMillan, “Fighter control and aircraft warning in amphibious operations.” United States Army Air Forces School of Applied Tactics Call number N5269.40, Orlando, FL, January 1945. This wartime training lecture has the story of the FDT’s in all the major West European invasions as well as the USS Ancon at Salarno.
Ninth Air Force Invasion Activities April Thru June 1944, N-9469, 17 Feb 1945
Operating Instruction 100-10 Air Ground Communications 15 July 1945 Vth Bomber Command
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October 2, 2015
PATHFINDER CRAIG, “Pathfinder Methods”
Radar No. 6, page 10, 15 Nov 1944, Office of the Air Communications Officer, Headquarters Army Air Forces, Washington.
ROYAL AIR FORCE HISTORICAL SOCIETY JOURNAL 28, MORNING DISCUSSION PERIOD, Page 52 https://www.rafmuseum.org.uk/documents/Research/RAF-Historical-Society-Journals/Journal-28-Seminar-Electronic-%20Warfare.pdf
RAF Radars at Omaha Beach
“REPORT ON AIR OPERATIONS PRIOR TO AND IN SUPPORT OF OPERATION “NEPTUNE” 12 May 1945
Ops. 7 (Records), Air Staff H.Q. A.E.A.F.; Allied Expeditionary Air Force
United States Fleet, Headquarters of the Commander in Chief, Navy Department, Washington, D.C., Radar Bulletin No. 8-A – Aircraft Control Manual, 21 June 1950. (RADEIGHT-A)