0:00:29 > 0:00:32Facing the Nazis across the North Sea
0:00:32 > 0:00:35meant the whole east coast became a fortified line.
0:00:44 > 0:00:46This is a radar transmitter tower,
0:00:46 > 0:00:50a few miles inland from the Lincolnshire coast near Louth.
0:00:53 > 0:00:56The tower here was part of an east-coast early-warning system
0:00:56 > 0:00:58against air attack.
0:00:59 > 0:01:03During wartime, RAF technicians had to climb these masts
0:01:03 > 0:01:06in all weathers and under attack to carry out urgent repairs,
0:01:06 > 0:01:08and now it's my turn.
0:01:12 > 0:01:14OK, don't look down.
0:01:15 > 0:01:17Look straight ahead.
0:01:17 > 0:01:18That's not any better!
0:01:23 > 0:01:27- How high is this, Paul? - Oh, it's just about 50 feet now.
0:01:27 > 0:01:31Might be just 50 feet to you, climbs like 100 to me.
0:01:31 > 0:01:34I've got the RAF watching my back,
0:01:34 > 0:01:38but I can't forget this radar tower was built in 1940.
0:01:38 > 0:01:41I've got it easy compared to the men and women
0:01:41 > 0:01:44who had to clamber up here back then.
0:01:44 > 0:01:46Oh, it's horrible, Paul. I hate it.
0:01:46 > 0:01:50- Hate every minute of it.- Think how much exercise you're getting!
0:01:50 > 0:01:52Oh, my hands are like budgies' claws!
0:01:54 > 0:01:57'During the war, radar technicians had to climb the towers
0:01:57 > 0:02:01'on a daily basis to carry out vital maintenance.'
0:02:01 > 0:02:03Oh, dear. So wrong up here.
0:02:05 > 0:02:06Oh, look at that, will you?
0:02:08 > 0:02:10That's a heck of a thing.
0:02:14 > 0:02:16Right. Finally.
0:02:18 > 0:02:20Finally here.
0:02:20 > 0:02:22That is quite a sensation.
0:02:22 > 0:02:25Exhausted and scared - what a combination.
0:02:27 > 0:02:30And the thing is, when you stand here, this is a nice day -
0:02:30 > 0:02:32it's a sunny day with just a light wind -
0:02:32 > 0:02:36and you can feel the whole thing's gently moving and vibrating.
0:02:39 > 0:02:43Wobbly they may be, but these were war-winning towers.
0:02:44 > 0:02:49In the 1930s, a desperate race was on at Orford Ness.
0:02:50 > 0:02:54Alice is off there to discover more about radar.
0:02:57 > 0:03:02In the First World War, the Germans used zeppelins to bomb Britain.
0:03:02 > 0:03:07In the 1930s, the aerial threat escalated to terrifying new heights,
0:03:07 > 0:03:10as the Nazis assembled a formidable air force,
0:03:10 > 0:03:14whose bombers might win the next war.
0:03:18 > 0:03:22Without a way of detecting incoming enemy planes, we were helpless.
0:03:22 > 0:03:24So, in the mid-1930s,
0:03:24 > 0:03:27an extraordinary scientific struggle started,
0:03:27 > 0:03:30to shield Britain from the bombers.
0:03:30 > 0:03:32On the 12th of February, 1935,
0:03:32 > 0:03:37scientist Robert Watson-Watt sent this memo to the Air Ministry.
0:03:37 > 0:03:40It's been called the birth certificate of radar.
0:03:40 > 0:03:42"I enclose herewith a memorandum
0:03:42 > 0:03:45"on the detection of aircraft by radio methods.
0:03:45 > 0:03:47"It turns out so favourably
0:03:47 > 0:03:51"that I'm still nervous as to whether we've not got a power of ten wrong,
0:03:51 > 0:03:54"but I thought it desirable to send you the memorandum immediately
0:03:54 > 0:03:58"rather than to wait for close re-checking."
0:03:58 > 0:04:01It was this memo that started the race for radar.
0:04:05 > 0:04:09Watson-Watt could barely believe his calculations.
0:04:09 > 0:04:13In theory, by measuring radio waves bouncing off a plane,
0:04:13 > 0:04:18they might be able to detect enemy bombers over 100 miles away,
0:04:18 > 0:04:21day and night, and in any weather.
0:04:21 > 0:04:23It seemed too good to be true,
0:04:23 > 0:04:28so they had to find out if it would really work, and quick.
0:04:30 > 0:04:33On the 26th February, 1935,
0:04:33 > 0:04:35just two weeks after that memo was sent
0:04:35 > 0:04:39about the theoretical detection of planes using radio waves,
0:04:39 > 0:04:42its author was trying it out
0:04:42 > 0:04:46using a real bomber and a BBC radio transmitter.
0:04:46 > 0:04:49Now, some 75 years later,
0:04:49 > 0:04:54we're about to try to re-create that original war-winning experiment.
0:04:57 > 0:05:00The first plane they tried to detect was a Heyford bomber.
0:05:00 > 0:05:02Ours is a bit more modern.
0:05:05 > 0:05:10Radar pioneer Watson-Watt had help from Arnold Wilkins.
0:05:10 > 0:05:15I've got radio boffin Steve Randall to mastermind our experiment.
0:05:15 > 0:05:19The original transmitter they used was a BBC radio mast.
0:05:19 > 0:05:21Technology's moved on, so our signal's
0:05:21 > 0:05:25coming from a television transmitter nearby at Sudbury.
0:05:25 > 0:05:26Steve knows the plan.
0:05:26 > 0:05:29Here's a little example of what we're going to try and do today.
0:05:29 > 0:05:31So this is a model.
0:05:31 > 0:05:35Yeah, it's trying to show how this is going to work.
0:05:35 > 0:05:38Here, we've got the Sudbury TV transmitter.
0:05:38 > 0:05:40It's sending signals out in all directions,
0:05:40 > 0:05:44and we'll try and bounce those signals off of an aircraft.
0:05:44 > 0:05:46And I presume that this is the building we're actually in.
0:05:46 > 0:05:48That's our little hut, yeah.
0:05:48 > 0:05:49And this is the plane -
0:05:49 > 0:05:52rather more glamorous, I have to say, than the one we're using.
0:05:52 > 0:05:55So this is coming in from the sea,
0:05:55 > 0:05:58and you're hoping that we're going to be able to receive
0:05:58 > 0:06:01the reflected waves being bounced off that.
0:06:01 > 0:06:03That's right. What we're going to try and do
0:06:03 > 0:06:06is to get the radio waves to bounce off of the aircraft
0:06:06 > 0:06:08and be received by our receiving station.
0:06:08 > 0:06:12How optimistic are you that we'll pick up the signal from the aircraft?
0:06:12 > 0:06:13Quite optimistic.
0:06:13 > 0:06:15I'm visual with you now.
0:06:15 > 0:06:19'With the plane on its way, like the radar pioneers of the 1930s,
0:06:19 > 0:06:23'we'll watch the signal on an oscilloscope screen.
0:06:23 > 0:06:26'Now it's just showing output from the TV tower.'
0:06:26 > 0:06:27John, can you see him?
0:06:27 > 0:06:31Yes, he's about one-and-a-half, two miles
0:06:31 > 0:06:34more or less straight ahead of us,
0:06:34 > 0:06:36so about 1,500 feet.
0:06:36 > 0:06:39- Oh, yes, I've got him.- Yeah?- Yeah.
0:06:39 > 0:06:41Map position south east.
0:06:41 > 0:06:42Yeah, that looks pretty good, Phil.
0:06:42 > 0:06:45Phil reckons that the plane is about a mile away now,
0:06:45 > 0:06:46so are we seeing anything?
0:06:46 > 0:06:49Yes. Not a huge amount, to be honest.
0:06:49 > 0:06:54We heard the drone of the bomber in the distance,
0:06:54 > 0:06:57and we looked anxiously at our cathode ray tube
0:06:57 > 0:07:01to see whether the expected phenomenon was taking place.
0:07:01 > 0:07:06It's still difficult to see anything on the raw data.
0:07:06 > 0:07:10It wasn't and we became rather concerned.
0:07:10 > 0:07:15'I'm slightly concerned too, as the plane is getting rather close.'
0:07:15 > 0:07:17Is that OUR plane I can hear?
0:07:17 > 0:07:20'Surely we should be seeing some change on the oscilloscope.'
0:07:20 > 0:07:25As the noise of the bomber increased,
0:07:25 > 0:07:31we began to see slight fluctuations in the line on the tube.
0:07:31 > 0:07:35Oh, there's some wider pulses coming through, some wider waves.
0:07:35 > 0:07:41These increased as the bomber got nearer to us.
0:07:41 > 0:07:42We can see these big waves
0:07:42 > 0:07:46coming through on the oscilloscope, very clearly. Look at that.
0:07:46 > 0:07:50When the noise of the bomber was fairly loud
0:07:50 > 0:07:52and it was fairly close to us,
0:07:52 > 0:07:57we were getting quite a marked deflection of this line.
0:07:57 > 0:08:01We then realised that the experiment was successful
0:08:01 > 0:08:04and there was something in our arithmetic
0:08:04 > 0:08:06that we'd done some days previously.
0:08:06 > 0:08:09I can hear him now, he must be really close.
0:08:09 > 0:08:12Yeah, there he is.
0:08:12 > 0:08:13PLANE ENGINE RUMBLES
0:08:17 > 0:08:21It's suddenly gone much wider. The aptitude has increased...
0:08:21 > 0:08:24OSCILLOSCOPE WHINES ..and you can hear it.
0:08:24 > 0:08:25You can really hear it.
0:08:25 > 0:08:29That's fantastic! Amazing concept, that you can use radio waves
0:08:29 > 0:08:33to detect a moving object in the sky.
0:08:33 > 0:08:34It must have been so exciting
0:08:34 > 0:08:38for these scientists in the 1940s... '30s, in fact!
0:08:38 > 0:08:41To see that for the first time, yeah, it must have been.
0:08:43 > 0:08:47The next challenge was to turn waves on a screen
0:08:47 > 0:08:49into a long-range early-warning system,
0:08:49 > 0:08:53to detect enemy aircraft approaching our coast.
0:08:53 > 0:08:58To tackle this daunting task, the engineers moved down the east coast
0:08:58 > 0:09:03to a Victorian manor house at Bawdsey to build the first radar station.
0:09:04 > 0:09:07What went on here was top-secret.
0:09:07 > 0:09:10I'm going to meet two of the people drafted to Bawdsey
0:09:10 > 0:09:13on a clandestine war-time assignment.
0:09:13 > 0:09:15Back then, Gwen Reading and Peggy Haynes
0:09:15 > 0:09:18were two young women sworn to silence,
0:09:18 > 0:09:22because Gwen and Peggy worked on radar.
0:09:28 > 0:09:32The ferry that runs the short distance from Felixstowe to Bawdsey
0:09:32 > 0:09:35transported these raw recruits to an adventure of a lifetime.
0:09:37 > 0:09:39It's a lovely calm day today.
0:09:39 > 0:09:41I don't expect it was always calm making this crossing.
0:09:41 > 0:09:45No, occasionally the ferry couldn't run because it was so rough.
0:09:45 > 0:09:49- So how does it feel coming back to Bawdsey?- Amazing.
0:09:49 > 0:09:52We won't know till we see the manor.
0:09:52 > 0:09:55Well, I think we've got a car waiting for us.
0:09:55 > 0:10:00- Oh, that will be good.- We certainly didn't have that. A bike, maybe.
0:10:12 > 0:10:15I can see our windows from here.
0:10:16 > 0:10:20Gwen and Peggy were part of a secret service -
0:10:20 > 0:10:25radar operators called to the coast to scan the skies.
0:10:25 > 0:10:31I came in April '43. Yes, it was my first posting after Cranwell.
0:10:31 > 0:10:33And if it's not a terribly rude question,
0:10:33 > 0:10:35how old were you when you arrived here?
0:10:35 > 0:10:38- 20.- 20, and how about you, Peggy?
0:10:38 > 0:10:40She was old. I was 19.
0:10:40 > 0:10:43How did you feel when you first arrived here?
0:10:43 > 0:10:45Did you know what you were coming to?
0:10:45 > 0:10:49Well, most people got posted to camps and lived in Nissen huts,
0:10:49 > 0:10:52and when we found we were going to live in the manor house,
0:10:52 > 0:10:54we thought we'd done pretty well, really!
0:10:54 > 0:10:57It must have been quite exciting to be posted here.
0:10:57 > 0:10:58Yes, well, it was for me,
0:10:58 > 0:11:01cos I bullied them to get here
0:11:01 > 0:11:03because my fiance-to-be
0:11:03 > 0:11:07was just up the road, at Dunwich, on another station.
0:11:07 > 0:11:10Did you know what it would involve before you arrived here?
0:11:10 > 0:11:13No, not really, because it was so secret.
0:11:13 > 0:11:15- We had to sign the Secrets Act. - You did?
0:11:15 > 0:11:17We weren't allowed to say anything,
0:11:17 > 0:11:20- and they thought we were all very stuck-up.- Really?
0:11:20 > 0:11:24- Whereas, actually, you just had to keep it secret.- Yes.
0:11:25 > 0:11:28The Germans thought these towers were for radio messages.
0:11:28 > 0:11:34In reality, they were designed to transmit and receive radar signals.
0:11:34 > 0:11:37The technology was perfected at Bawdsey,
0:11:37 > 0:11:40but one site on its own would be useless,
0:11:40 > 0:11:43so the design was replicated along the coast.
0:11:43 > 0:11:45By the start of the war,
0:11:45 > 0:11:49there were 20 so-called Chain Home radar stations,
0:11:49 > 0:11:50but the chain would break
0:11:50 > 0:11:54without operators to interpret the incoming signals.
0:11:54 > 0:11:55That was Gwen's job.
0:11:56 > 0:12:00- So how many people would have been in here?- About eight.
0:12:00 > 0:12:03About eight, and lots of equipment.
0:12:03 > 0:12:06There would be a console across here,
0:12:06 > 0:12:09where people sat and the map where they plotted.
0:12:09 > 0:12:11Get me control, please.
0:12:11 > 0:12:15And if you had 1,900 planes on your screen,
0:12:15 > 0:12:17that was quite an undertaking.
0:12:17 > 0:12:181,900?!
0:12:18 > 0:12:21Yes, but they would be in blocks of 200 here,
0:12:21 > 0:12:24100 there, a single one there.
0:12:24 > 0:12:27Zero, 5,000.
0:12:27 > 0:12:32'Gwen has brought along a photograph taken in this room in 1945.'
0:12:32 > 0:12:34That's lovely. Now, are you in this photo?
0:12:34 > 0:12:37- Yes, that's me. - Wearing the headphones.
0:12:37 > 0:12:38It must have been a job
0:12:38 > 0:12:41which required an enormous amount of concentration.
0:12:41 > 0:12:43It did, it could be very stressful at times.
0:12:43 > 0:12:45If we were very busy,
0:12:45 > 0:12:49we'd try to get someone who was fairly expert on the tube.
0:12:49 > 0:12:53How does it feel coming back to this room that you spent so many hours in?
0:12:53 > 0:12:58Well, it's very strange because those three-and-a-half years
0:12:58 > 0:13:01seem a major part of my long life.
0:13:02 > 0:13:05Without the development of radar
0:13:05 > 0:13:08and the crucial contribution of operators like Gwen and Peggy,
0:13:08 > 0:13:11we wouldn't have won the Battle Of Britain.
0:13:14 > 0:13:16During their years at Bawdsey,
0:13:16 > 0:13:19the women had to keep mum to the wider world
0:13:19 > 0:13:22about what they were up to.
0:13:22 > 0:13:23While you were working here,
0:13:23 > 0:13:27you were very aware that what you were doing was incredibly important,
0:13:27 > 0:13:31but it's not until articles like this appear in the papers after the War
0:13:31 > 0:13:35that most other people must have realised how important radar was.
0:13:35 > 0:13:39I was very pleased that, at last, we could say something about it.
0:13:39 > 0:13:44You found people sending you newspapers, both local and national,
0:13:44 > 0:13:47and in fact the chap I eventually married
0:13:47 > 0:13:52sent me a picture from the Picture Post. He said, "Is that you?"
0:13:52 > 0:13:53THEY LAUGH
0:13:53 > 0:13:55Is that how he found you again?
0:13:55 > 0:13:57No, no, that's another long story.
0:14:03 > 0:14:07It's humbling to think that revolutionary radar experiments
0:14:07 > 0:14:12conducted 70 years ago at this manor house on the coast of Suffolk,
0:14:12 > 0:14:14would touch so many lives.
0:14:14 > 0:14:20We all owe a debt of thanks to people once sworn to secrecy,
0:14:20 > 0:14:23but now happy and proud to tell their stories.