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In today’s story, radar has been developed and we venture back to WWII to see the first large-scale use of Electromagnetic Warfare (EW). Electromagnetic spectrum operations (EMSO) has played an important role in military operations since the dawn of the electronics age. Radar historian, Dr. Phil Judkins, University of Leeds, U.K. shares with us the untold stories of EW and EMSO in WWII, starting with the Battle of Britainーthe first time that a battle between two nations was fought entirely in the air. Dr. Judkins then walks us through The Beam Wars and the increasingly accurate use of radio air navigation systems that helped the British defeat the German air power. Finally, we cover the Blitz, a German bombing campaign against the United Kingdom, and show how the advanced radar tactics employed by the British helped to win the Battle and defeat the German’s attacks.
The Evolution of Electromagnetic Spectrum Operations (EMSO)
This podcast will take you on a journey throughout time and around the world to meet the inventors, the battles, and the technology that has not only shaped military operations - how we fight - but also how we live. The History of Crows will cover some of the most important discoveries, battles, and events that shaped what we know today as electromagnetic spectrum operations. Episodes that take you deeper into our history will be added periodically.
Speaker 1 (00:01):
This episode is sponsored by BAE Systems, the global leader in next-generation electronic warfare systems. With more than 60 years of experience and 33,000 people as part of its global defense, aerospace, and security business, BAE Systems electronic warfare systems are found on the most advanced military platforms in the US and around the world. Learn more at baesystems.com/ew.
Speaker 2 (00:35):
Welcome to The History of Crows, a podcast on the evolution of electromagnetic spectrum operations, or EMSO, and the men and women, the Crows who changed the way we conduct military operations and the way we live around the world. The History of Crows will help you navigate the intersection of military history, technology, and scientific discovery through insights and stories from the people and warfighters who know how to fight in the electromagnetic spectrum. We take you through the important discoveries, inventions, battles, and developments that make the Crow motto true, to be the first in and the last out in any military operation today. The History of Crows is brought to you by the Association of Old Crows, or the AOC, an international professional association of people who are experts in electromagnetic warfare and signals intelligence. To learn more about the AOC, please visit www.crows.org. Thank you for listening.
Speaker 2 (02:13):
It was July 1940, a little over a year before the attack on Pearl Harbor. World War II was ravaging Europe. The Holocaust was devastating the world. Hitler's Germany was conquering countries at a rapid pace. It came time for Hitler to focus on the last country that stood in the way of conquering all of Europe, Great Britain, and so the Battle of Britain ensued. This battle and the ones that would follow completely changed the momentum of World War II for the allies. The reason for this, well, it has everything to do with the influence of radar, electronic warfare, and the tactical strategy behind them.
Speaker 2 (02:53):
In today's episode, Beam Wars, we'll hear the story of how electronic warfare was forever cemented into military operations. Radar historian, Dr. Phil Judkins from the University of Leeds of the United Kingdom will walk us through the Battle of Britain from July 1940 to October 1940, The Blitz, and the Beam Wars.
Speaker 2 (03:14):
Prior to Pearl Harbor, the United States didn't have a thorough enough command and control when it came to radar. It was a different story for Britain though. They had been planning and preparing, so when the Battle of Britain began, they took on a never-before-seen battle strategy.
Dr. Phil Judkins (03:30):
The Battle of Britain, fought mainly over Southeast England in 1940, was the first time that a battle between two nations, in this case, Britain and Germany, was fought entirely in the air, the first time that a bomber fleet had faced defenders with radar, fully integrated into and controlling their fighter and AAA defenses, and the first time that both radar jamming and counter radar bombing were employed in an air battle.
Speaker 2 (03:59):
The German attackers, the Luftwaffe, had a clear goal, destroy the British Royal Air Force and clear the way for a seaborne invasion. The two forces faced each other, both ready to employ radar jamming and counter radar bombing. But their preparation for combat couldn't have looked more different.
Dr. Phil Judkins (04:17):
To achieve the same, three German athletes, with bases from Norway to Northern France, deployed almost 2,300 aircraft, 1,260 bombers, and 1,030 fighters, which faced the RAF fighter command of 900 aircraft. However, Germany had very poor operational intelligence. Two [inaudible 00:04:40] missions flown before the war had failed to find clear evidence of radar, while British fighters that in fact, trained with its radar-based early warning system from two years before the war and British codebreakers had begun to break the important German Enigma coding machine.
Speaker 2 (04:58):
The British were ahead of the Germans due to their operational intelligence and smart planning. They had completely developed a system to track incoming German bombers and respond by notifying and distributing fighter aircraft.
Dr. Phil Judkins (05:11):
With data from their long-range early warning radar, Chain Home, RAF ground controllers could track German bombers from their takeoff and give RAF fighters sufficient warning to take off in time to climb to interception heights and be guided into favorable position for interception.
Speaker 2 (05:28):
It didn't matter that the aircraft only had crude metric wavelength radar, which wasn't very useful in detecting German aircraft miles away. RAF pilots didn't even need to spend long hours flying standard patrols, wearing out both the fighter engines and the pilots themselves. With the long-range early warning radar system, pilots were given enough time to respond to an attack and then rely on the often beautifully clear sky to spot their opponents. It was this well-thought-out command and control that gave them an advantage.
Dr. Phil Judkins (06:06):
The British had to conserve their limited resources, particularly of trained pilots. So at first, in June and July, the RAF met German daily attacks. First on ships in the English Channel and then RAF airfields with small numbers of fighters. The main attack on the 13th of August was proceeded by attacks on radar stations and fell on forward RAF fields. Later, attacks struck inland. A German pincer movement to attack both the north of England from Scandinavia and the south from France was defeated by ground control using Chain Home radar, which covered the entire English south and east coasts.
Speaker 2 (06:49):
The Luftwaffe suspected the Royal Air Force had radar, but they didn't know just how integrated it was into British air defenses.
Dr. Phil Judkins (06:57):
The German head of signals and radar, Wolfgang Martini managed to arrange for dive-bombing attacks on some radar stations. The ariel masts proved very resilient to bomb blast and the damaged equipment was substituted by mobile radars trucked in. The Germans continued to hear radar transmissions, for that little damage had been caused, and cease their attacks.
Speaker 2 (07:23):
After ceasing these attacks, the Luftwaffe tried a different approach, but they'd find that the British had thought ahead and implemented something that Germans weren't prepared for.
Dr. Phil Judkins (07:32):
Martini had arranged for powerful jamming transmitters to be placed on high ground in North France. However, long before the war, the British had guessed that an enemy would try to jam their radar, and so built into their radar receivers, several different circuits to minimize the effects of jamming. When the Germans began their jamming campaign, the British operators had switched in their anti-jamming circuits as they've been trained to do, and the jamming had relatively little effect.
Speaker 2 (08:01):
The Royal Air Force's success at countering jamming forced the Germans to change their strategy yet again.
Dr. Phil Judkins (08:07):
The Luftwaffe had followed a sensible strategy of attacking RAF airfields, command centers, and communications, and had that been continued, the outcome for the RAF would have been engraved out. However, following earlier attacks on London, the RAF bombed Berlin. Little damage was done, but it stimulated a strategic switch to the Germans bombing London, particularly after the 3rd of September. This relieved the pressure on the RAF fighter airfields and allowed some respite for the exhausted pilots.
Speaker 2 (08:41):
The German strategy change had little effect on British radar, mostly because Germany's intelligence assessments were consistently unreliable.
Dr. Phil Judkins (08:49):
Fortunately, attacks on Chain Home radar had ceased. But because the attacks on London took the form of massive attacks by hundreds of bombers covering many miles of sky and breadth, height, and depth, the crude Chain Home was sometimes overwhelmed and incapable of giving accurate readings. However, German aircrew who received daily unreliable German intelligence assessments that the RAF strength was almost exhausted, but then found that more RAF fighters were always somehow in position to meet their attacks were becoming disheartened and their losses were mounting. The German dictator, Adolf Hitler concluded that the RAF had not been destroyed and called off his invasion of Britain. The first time he had suffered a defeat.
Speaker 2 (09:40):
The Luftwaffe lost just under 2000 aircraft during the battle and took 4,200 casualties. The RAF lost 1087 fighters and suffered 1900 killed and wounded. While losses were heavy on both sides, the British had two key advantages.
Dr. Phil Judkins (09:57):
RAF airmen shot down over England often rejoined their squadron to fight again, while German aircrew would become prisoners of war. And second, the British had an efficient repair organization, which returned damaged aircraft quickly to battle, while damaged German aircraft often had to ditch in the channel and were lost.
Speaker 2 (10:19):
There was another advantage that made it very clear why the British had the upper hand.
Dr. Phil Judkins (10:23):
While in war, always let the enemy be the best judge. German fighter general, Adolf Galland put it perfectly and succinctly. I quote him, "From the first, the British had an extraordinary advantage, their radar and fighter control network carried to the highest level of technique. We had nothing like it. The fact that the British had anticipated electronic warfare jamming and had incorporated circuitry to defeat it, paid dividends. The fact that the Germans had failed to appreciate the British use of radar, and that their 1939 [inaudible 00:11:03] to uncover its secrets had failed, arguably costs the Luftwaffe the battle.
Speaker 4 (11:13):
At BAE Systems, we're developing full-spectrum, multi-domain electronic warfare capabilities that outpace the threats. Our electronic warfare systems are designed to be open, reprogrammable, and exportable. To deliver on the US Air Force's operational vision of the electromagnetic spectrum, we're committed to delivering electromagnetic spectrum superiority to the warfighter, where it matters most. Learn more at baesystems.com/ew. That's baesystems.com/ew.
Speaker 2 (11:56):
Early in the Battle of Britain, the Germans used an Enigma code to send encrypted classified messages over thousands of miles. The British had made only a few breaks into the code, but with these breaks, they were able to discover the strengths of German aircraft and they planned accordingly. The Luftwaffe had to adapt quickly and they ended up employing a different type of offense.
Dr. Phil Judkins (12:17):
After the daylight and battle faded out in the autumn, as the days grew shorter, the Luftwaffe turned to night battle, which they were well-equipped. Under Martini, the Germans had developed not one, but three different radio navigational beams, which were accurate enough for bombing also. It was here that British breaks into the Enigma code paid significant dividends.
Speaker 2 (12:42):
Two years before World War II, Germany sent aircrew and aircraft to take part in the Spanish Civil War. It was this experience that convinced the German head of signals and radar, Martini that the Luftwaffe needed precise and accurate navigation. The German airline, Lufthansa carried short-range, blind-landing beam approach equipment on their civil aircraft. Beams are radio signals that bounce from tower to tower. With beams, pilots don't need to see where they're flying. They can find their direction solely by listening for the beams. Germany decided that with these beams, they could fly more precisely and carry out strikes. Lufthansa's beam equipment, however, was only for short-range, so the Luftwaffe, they began building more powerful equipment with bigger antenna to lay down radio beams over ranges of 300 miles.
Dr. Phil Judkins (13:32):
The first beam was codenamed Knickebein or Crooked Leg. Powerful transmitters in Germany with huge steerable antennae were used to lay down two radio beams, one for the bomber to follow using his blind landing receiver, and the second being crossing the first to mark the target. When France was occupied by the Germans, a chain of transmitters was quickly set up so that almost the whole of Britain could be covered by these beams.
Speaker 2 (14:04):
After the beams were set, the British discovered something that alerted them to these mysterious signals.
Dr. Phil Judkins (14:09):
RAF scientific intelligence was coordinated by a bright young scientist called R. V. Jones. Papers recovered from crashed German bombers showed him as early as May 1940, that they were radio beacons called Knickebein, and a prisoner confirmed both that Knickebein was a radio beam system and that there was a second beam system called X-Gerät. The British codenamed these beams Headaches. Then in early June, an Enigma decrypt gave a specific Knickebein beam bearing intended to aim for the steel town of Sheffield. Another prisoner was heard to boast that the RAF quote, "Would never find Knickebein." So Jones probed the experts who had investigated crashed German bombers. At first, they saw nothing unusual, though, then they realized the blind landing receiver was much more sensitive than it needed to be for short-range blind landings.
Speaker 2 (15:12):
This information was groundbreaking. So R. V. Jones told Professor Frederick Lindemann, the trusted advisor of Prime Minister Winston Churchill. He invited Jones to brief a meeting of the British war cabinet. Churchill was there and listened as Jones gave clear explanations as to why this information was alarming. Churchill understood the threat and ordered an electronic intelligence flight to find such a beam known to be on the 30 megahertz band.
Dr. Phil Judkins (15:39):
Experts believe that such a beam could not reach Britain due to the curvature of the earth. But Jones use Churchill's name to launch the flight. Using an American Hallicrafters S-27 receiver, signals were detected of a beam which passed over Darby's Rolls Royce factory, the only one making the Merlin engines for all British fighters, a clear and present danger. Hospital diathermy machines were hastily modified to transmit on the beam frequencies. Later, they were superseded by specialized jamming transmitters, codenamed Aspirins. More aircraft were detached to find the Headache beams so that Aspirins near targets could be switched on or mobile jammers moved up. Much later, these aircraft would form the RAF's 109 and then 192 EW squadrons. These countermeasures did not work all the time but did sufficiently well to avoid much damage and many casualties.
Speaker 2 (16:44):
Another German prisoner had let slip that there was a second beam, an X-Gerät beam, so Jones was on the lookout for any mention of it.
Dr. Phil Judkins (16:52):
In early September 1940, an Enigma intercept not only confirmed the beam but also identified the Luftwaffe pathfinder unit, which specialized in its use, Kampfgruppe KG 100 based at Vannes, Northern France. Further enigma intercepts gave details of X-Gerät. It used four beams in the 70 megahertz band, one main beam, which the bomber would follow, and three crossbeams, which allowed a special, accurate clock to be set. This clock precisely controlled the dropping of flares and incendiaries directly over the target, to mark the target for the main force of bombers who had trained with Knickebein, but not the more complex X-Gerät. The British codenamed the new beams Ruffians.
Speaker 2 (17:47):
The Royal Air Force made powerful 70 megahertz jammers against these Ruffians, and they codenamed them Bromides. But radio jammers have to be precise, and these were hastily built and set into position before defense forces were fully trained and ready to use them. The lack of precision ended up causing major damage.
Dr. Phil Judkins (18:12):
The city center of Coventry was flattened because the modulating signal on the 70 megahertz carrier was wrongly measured as 1.5 kilohertz rather than 2 kilohertz. The difference between a whistle and a shriek, and sensitive audio filters in the X-Gerät eliminated the British jamming. A special unit set up in October 1940 to control British ground RAF's RCM, the RAF's 80 Wing gradually gained the upper hand, but it was a new unit with much to learn and this took time.
Speaker 2 (18:48):
Time was running out, so the British tried three more strategies to jam the beam signals and defeat the blitz of German bombers.
Dr. Phil Judkins (18:56):
First, on the 13th, 14th of November, two British bombers directly attacked the Cherbourg X-Gerät transmitter by homing onto its transmissions. Such attacks only rarely hit the tiny target, but it did cause the operators to switch off the beam in haste. Secondly, it was known that the Germans might try to use radio direction finding, DF, on the positions of known British transmitters. For example, the BBC. The British countered this by linking together all the BBC transmitters in such a way that the aircraft DF receivers either could not focus on any individual transmission to obtain a bearing or focused on the wrong one. The same tactic called masking beacons or meacons was extended to all the RAF's medium wave navigational beam teams. So effectively, that one German aircraft completely misled landed in Britain in mistake for France.
Dr. Phil Judkins (19:59):
The third tactic was more basic. Near target cities, sites, codenamed Starfish, was set up in open country with decoys street and factory lighting and the ability to simulate fires and bomb blasts. The aim being that one's attention would be drawn away from their actual aiming point and drop their bombs on the decoy. Starfish proved very successful in some cases, but not in others. For example, east of London at Britain's capital, London, the wide estuary of its river Thames narrows down from the sea to the city center, and at night is expensive water resembles a clear undisguisable arrow pointing to the heart of the city of London. The Luftwaffe blitz of London and other British cities cost 40,000 lives, with many more severely injured.
Speaker 2 (20:57):
The British were then alerted to a third beam, the German Y-Gerät. It had been mentioned in the July 1940 Enigma decrypt under the codename Wotan.
Dr. Phil Judkins (21:06):
The codename gave the clue to that system's operating with a single beam down which the bomber flew. Its distance along the beam being measured by the faintest difference on modulating waveform measured using retransmission to the German ground station. Y-Gerät operated on the 45 megahertz band, which happened to be the British BBC pre-war television frequency. A happy outcome being that the BBC TV transmitter at Alexandra Palace in London became the world's biggest countermeasures transmitter, Domino. This transmitter re-radiated a Y-Gerät signal received elsewhere in the UK and fed to it by a landline. The resulting confusion of signals received and the Boeing aircraft rendering the system unusable and causing the aircrew to doubt that equipment.
Speaker 2 (22:03):
By spring of 1941, all three beams had been discovered, encountered. The Royal Air Force began to dominate British skies with radar-equipped night fighters. The Luftwaffe had no choice but to withdraw and prepare for the German attack on Russia. The Battle of Britain, The Night Blitz, and the Beam Wars were the first major battles where electronic warfare was fully employed. After these battles, military operations were forever different. Implementing electronic warfare was and is an absolute necessity to gain the advantage over your enemy. By the end of 1941, the key players of World War II were established.
Speaker 2 (22:48):
Join us in our next episode. As the story continues with D-Day, and learn how electronic warfare would become the needed undercurrent to win the war. This podcast is brought to you by the Association of Old Crows. Thank you to our episode sponsor, BAE Systems. Learn more at crows.org/podcast. Thanks for listening.