Cold Open

It’s the morning of February 26th, 1935, in the countryside near Daventry, a town in central England.

42-year-old Scottish physicist Robert Watson-Watt rocks from side to side as the van he’s driving bounces along a muddy track. Clinging to the seat beside him is his younger colleague, Skip Wilkins. With a crunch of gears, Robert turns off the road and then brings the vehicle to a skittering stop beside a field.

The cold air hits him as he steps out.

In the middle of the field is a square of four wooden poles, topped with wires stretching between them. Robert has spent the past couple of days putting them up, and he’s still got blisters from digging into the hard, icy ground. But the discomfort will be worth it if this experiment goes to plan.

A month ago, the British military came to Robert with an alarming rumor. Intelligence reports claimed that the German army was developing a “death ray”—a powerful gun that used radio waves to shoot planes out of the sky. Robert quickly dismissed this idea as science fiction, but it got him and his colleague Skip thinking about a different question: whether radio waves could be used not to destroy incoming aircraft, but to detect them. And today, they intend to find out.

Two cables hang limply from the poles. Robert takes one and drags it to the back of the van. Skip does the same with the second.

Robert swings open the rear door. Until recently, this was just a delivery van, but now a radio receiver has been bolted to the floor.

Robert connects the two long cables to the receiver… and then switches on the machine. Then, he sits down on a stool in front of its screen and waits.

He knows that eight miles away, a Royal Air Force pilot is flying a steady circuit at 5,000 feet. If Robert and Skip’s calculations are correct, radio waves from a nearby transmitter will hit the plane, bounce back, and appear as a flicker on their screen.

Lingering just outside, Skip stamps his feet, trying to keep warm in the bitter cold. But Robert is as still as a statue, his eyes never leaving the display.

Suddenly, the screen sparks to life. Robert’s heart lurches. It’s the plane. It has to be. Skip claps him on the shoulder.

They’ve done what seems almost impossible. They’ve pinpointed the position of a plane they can’t even see.

While their experiment is crude, it’s enough to convince the Royal Air Force that this new technology might be useful. But radar, as it comes to be known, will soon prove much more important than anyone expected. It will transform Britain’s defenses and help the country survive an aerial onslaught that will be launched just five years after Robert Watson-Watt’s successful demonstration on February 26th, 1935.

Introduction

From Noiser and Airship, I’m Lindsay Graham, and this is History Daily.

History is made every day. On this podcast—every day—we tell the true stories of the people and events that shaped our world.

Today is February 26th, 1935: The Birth of Radar.

Act One: Within Reason

It’s March 1935 at the Air Ministry in London, England, one week after a team of scientists detected an airplane using radio waves.

Sitting at the head of a conference room, 53-year-old Air Marshal Hugh Dowding frowns as he flips through a dense scientific paper. Dowding is no stranger to advanced technology. He's trained as an artillery officer before transferring to the air force. Still, the document in front of him is difficult to follow, filled with complex equations and unfamiliar terminology.

Across the table from him, three members of the Committee for the Scientific Survey of Air Defence wait patiently, their hands clasped in their laps. The idea of using radio waves to locate objects isn’t new, and Britain isn’t the only country exploring it. But there have long been doubts about whether the theory was workable outside a lab. So, when the committee approached Air Marshal Dowding and proposed using radio waves to detect incoming aircraft, he was skeptical. Still, he recognized that if the scientists could make it work, it had the potential to transform Britain’s defenses. So, he told them to go away and demonstrate that the theory could work in the real world. If they could do that, he said, they could have all the funding they wanted.

Led by Scottish scientist Robert Watson-Watt, these scientists built a simple prototype that successfully tracked a plane by bouncing a radio signal off the aircraft and back to a receiver in a field eight miles away. Now, they’ve returned to London to claim their reward—money for further research into what they call “radio direction finding”, but everyone else will soon call it “radar.”

After finishing the final page of the report, Air Marshal Dowding looks up at the scientists. Then, without a word, he turns the report over, lowers his eyes, and begins reading a second time. The scientists shift uneasily in their chairs. But this time, when Dowding reaches the end, a flicker of a smile creases the corners of his mouth.

He stands up and extends his hand. Congratulating the men on their work, he says that he sees huge potential in this technology. One of the scientists eagerly raises the question of funding. Dowding’s face flushes as he remembers what he promised. But Britain is still feeling the strain of the Great Depression, and budgets across the government are tight. So, Dowding adjusts his earlier offer. The scientists will receive enough money to get a radar system up and running—but it’s not a blank check. If the costs get too high, he’ll have to shut them down.

Over the next year, the scientific committee oversees the construction of a radar station on England’s east coast. To keep costs low, they use existing technology wherever possible. But once that first station is operational, more quickly follow. By 1938, the individual sites are linked together in a single network known as “Chain Home.” What began as a prototype in a field has grown into a web of 100-foot radar towers. And together, they cover most of southern Britain and all the crucial approaches to London.

But even with the world’s first integrated air defense system in place, Air Marshal Dowding still sees room for improvement. Radar can provide up to fifteen minutes’ warning of incoming aircraft, but it can’t tell friend from foe, and scrambling an entire fighter squadron to intercept a lone, off-course pilot would be a costly mistake.

To solve this problem, Dowding establishes a single command post. The data from every radar station in the country feeds into this one place, where information is combined with the latest intelligence reports and sightings phoned in by trained observers along the coast. Only after all this information is assessed do officers determine whether to launch fighters.

It becomes known as the Dowding System—and it’s up and running just in time. Because for years, Nazi leader Adolf Hitler has been expanding the German military, including its air force, the Luftwaffe. And when Hitler orders his troops into Poland in September 1939, Britain is given a stark reminder of just how destructive modern air power can be. The Luftwaffe quickly seizes control of the skies over Poland. Its bombers destroy airfields, bridges, and railway lines. Its fighter planes attack troops caught in the open. And with the Germans enjoying total aerial supremacy, Poland falls in less than a month.

But all of Europe knows that Hitler won’t stop there. Soon, he will turn his attention west. And when he does, Air Marshal Hugh Dowding and scientists like Robert Watson-Watt will find out whether the air defense system they’ve built will be enough to protect Britain from what’s coming.

Act Two: Detect and Defend

It’s June 18th, 1940, at the Air Ministry in London, nine months after the beginning of World War II.

Air Marshal Hugh Dowding checks the time, then rises from his desk and crosses the room to the radio. He switches it on, clasps his hands behind his back, and gazes out at the city street below. In a few moments, Prime Minister Winston Churchill is due to address the nation. Dowding is eager to hear how Churchill will break the grim news that Dowding knows all too well—Britain is losing the war.

Just over a month ago, Germany invaded France and overran the country with stunning speed. After putting up brief resistance, thousands of British and Allied soldiers were evacuated from Dunkirk on the northern coast. That retreat was a stunning feat of logistics under fire. But it didn’t disguise the awful truth. In Europe, Britain is now the last major power fighting to resist the German advance—and only the narrow English Channel protects the country from Adolf Hitler’s armies. And even then, an invasion is expected.

Dowding wonders how the usually bombastic Churchill will address the moment. But as he listens through crackling static, he quickly realizes that Churchill is adopting a more somber tone than usual.

CHURCHILL: …the Battle of France is over. I expect that the Battle of Britain is about to begin. Upon this battle depends the survival of Christian civilization.

Churchill is not shying away from the devastating collapse of France. But he does highlight the resolve of the British people. He insists that Britain will never surrender, and he declares that future generations will remember this as the country’s “finest hour.”

As the commander of Britain’s fighter squadrons, Air Marshal Dowding feels a heavy burden. Military planners expect Hitler to repeat the tactics that proved so successful in Poland and France—wave after wave of aerial attacks, followed by the rapid advance of ground troops. The men and women under Dowding’s command will be Britain’s first line of defense.

And within two weeks of Churchill's speech, the Germans launch the initial phase of their invasion plan. It goes exactly as expected. Luftwaffe pilots fly over the English Channel, determined to gain air superiority by shooting down British planes and bombing British airfields. If the Germans can neutralize the Royal Air Force and control the skies, there’ll be nothing to stop Hitler’s troops crossing the Channel and advancing on London.

But the British have a secret weapon—the Dowding System. Thanks to the web of radar towers that’s been built across the country, Britain has advance notice of German attacks. There’s no need for British pilots to fly blindly up and down the coast, burning precious fuel in the hope they might encounter the enemy. Instead, they only need to take to the skies when the Germans are definitely on their way—and the RAF can fly into battle confident that they know where to find their enemy and in what strength.

This strategy works. Almost nine out of every ten attacks are intercepted. Many German planes are driven back across the Channel. Others don’t return to base at all—in the first two weeks of this Battle of Britain, the RAF claims to have shot down over 150 enemy planes.

But even with that impressive numbers, Dowding still faces criticism. Despite knowing when and where the Germans will attack, he doesn’t want to overcommit his limited resources and risk too many pilots and planes in any one engagement. Some more gung-ho members of the RAF think these cautious tactics may stave off defeat, but they won’t deliver victory. They’d rather use the advantage radar gives them to take the fight to the enemy.

And it’s not just officers in the RAF who oppose Dowding’s approach. Maritime convoys carrying much-needed supplies to Britain are repeatedly targeted by the Luftwaffe, and many ships are sunk. But Dowding refuses to commit more than the bare minimum of resources to protecting these convoys. He believes the pivotal moment of the Battle of Britain is still to come, and he’ll need every pilot and plane he has.

Sure enough, Hitler’s generals will soon launch what they hope will be a knockout blow against the RAF—an overwhelming attack designed to shatter Britain’s defenses and pave the way for an all-out invasion.

Act Three: Dead Eagles

It’s August 13th, 1940, in the skies above southern England, a month after the Battle of Britain began.

Inside the cockpit of a Hawker Hurricane fighter plane, 29-year-old Squadron Leader Sailor Malan stares through the canopy, eyes scanning the pale blue horizon. He sees nothing yet. But over the radio, a calm voice assures him that the enemy is not far ahead.

Only minutes later, the ground-based controller is proven right. A small cluster of black specks comes into view, growing larger by the second.

For the last month, the Luftwaffe has flown dozens of missions over England. And time after time, the result has been the same. Almost every German plane crossing the Channel finds British fighters waiting for them. Frustrated by the lack of progress, Adolf Hitler has now given the go-ahead for “Eagle Day”—an enormous aerial attack designed to overwhelm the British defenses with sheer numbers. But thanks to the early warning radar system, the RAF has a crucial advantage.

But even then, as Malan speeds closer to the enemy, he realizes he’s facing more than 70 German planes. It would be a challenge for his squadron. But Malan is one of the RAF’s best pilots, and he’s a natural at the controls. He lines up behind a German bomber, squeezes his trigger, and then watches it fall away.

It’s a direct hit, but there’s no time to celebrate. The enemy's guns have opened fire. Malan barrel-rolls out of the way, diving then climbing, twisting through the air at hundreds of miles an hour. All around him, engines roar, and bullets fly. There are explosions and near-misses.

But by the time the dogfight is over, the Germans have retreated and lost at least five bombers. Similar scenes play out all across southern England. Hitler hoped that his pilots could deal the RAF a knockout blow on Eagle Day. But it’s the Luftwaffe that's been served the defeat.

After several more weeks of punishing losses, the Germans eventually change their tactics. The Luftwaffe abandons its attempt to destroy the RAF and shifts to bombing British cities instead. These punishing raids become known as the Blitz unleashes terror on the civilian population—but there is also a sign of weakness. The German leadership no longer thinks an invasion of Britain is feasible.

Soon, Prime Minister Winston Churchill will return to the airwaves to pay tribute to the pilots of the RAF, many of whom lost their lives fighting above southern Britain.

CHURCHILL: Never in the field of human conflict was so much owed by so many to so few.

But victory in the Battle of Britain was not earned by the pilots’ bravery alone. It also depended on the new technology that gave the RAF advance warning of incoming enemy planes—an advantage that was only possible thanks to the scientist Robert Watson-Watt and the successful experiment he performed in a field on February 26th, 1935.

Outro

Next on History Daily. February 27th, 1943. More than a thousand Jews are released from Nazi detention after a protest on the streets of Berlin.

From Noiser and Airship, this is History Daily, hosted, edited, and executive produced by me, Lindsay Graham.

Audio editing by Muhammad Shahzaib.

Sound design by Mollie Baack.

Music by Thrumm.

This episode is written and researched by Owen Paul Nicholls.

Edited by Scott Reeves.

Managing producer Emily Burke.

Executive Producers are William Simpson for Airship and Pascal Hughes for Noiser.