The Device that Won WW2 - The Cavity Magnetron

[@CuriousDroid]

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[@PetraKann]

It was the Soviet army that defeated the Nazis - ask the German historians. It was the Soviet army that liberated the concentration camps in Germany - ask the Jews and other prisoners freed from these evil monstrosities. The terrorist war atrocity nukings of civilian centres in Japan did not end the war. Remember, the Soviet Union lost over 25 million people in WW2. The USA lost less than 400,000 and the UK less than 600,000. There were lots of sacrifices made by many nations but lets not engage in historical revisionism and Hollywood myth.

[@guff9567]

There is no such thing as climate change. Please stick to the science and don't spew PROPAGANDA

[@toxlaximus3297]

ProtonVPN is way better, nordvpn is no good for Arrrrrrrrrrrrrr.

[@graealex]

You switching between talking loudly and then going back to nearly whispering makes it hard to follow the video.

[@knuthamsun6106]

thank goodness that thing helped win the war. It would’ve been horrible if Europe would’ve remainded European. London would still be English. One shudders to imagine the horror

[@michaelpolimer2128]

I started working at Raytheon in 1967 at the old Microwave & Power Tube plant in Waltham Ma. Percy had retired by that time but he still maintained a lab at his home in Newton Ma and would call my boss for parts he needed for experiments. I used to drop them off on my way home. He was an interesting guy. The plant was full of old WW2 & Korean War tube production equipment which we occasionally had to get up and running so we could produce replacment tubes for equipment still in use. It was an "electronics museum". There were some areas which were just as they were in 1945 until Raytheon went out of the microwave tube business in abt 1993. I stayed with Raytheon until I retired in 2010 and could be the "last link" to Percy at Raytheon.

[@vincentsutter1071]

That is a great story. Thanks for sharing.

[@skeeterbodeen8326]

Yeah great addl background, I play guitar and Tubes are still the best organic tone, so sorry the US lost all this special stuff..

[@michaelpolimer2128]

we designed and manufactured microwave tubes; magnetrons, cross field amps, klystrons, TWTs at Microwave & Power Tube in Waltham Ma Raytheon was in the comsumer tube business in the "early days" but that was long over when I got there in 1967. I designed factory test equipment for the Tube Group. There was an attempt to make microwave oven tubes there but that failed because that was a different "culture" from miltary contracts and we couldn't compete with the off shore manufacturers. I will only use tubes in my high power Ham station amplifers, 73 Mike, K1FNX @@skeeterbodeen8326

[@user540000]

I asked Percy about this and he said he never met you

[@michaelpolimer2128]

QSL, it's been a long time and I'm sure his memory isn't what it used to be @@user540000

[@pauljenks4901]

I'm pleased to see Sir Mark Oliphant get a mention. He was the quiet Aussie who always got on with things pushing for more to be done.

[@richardvernon317]

Atom Bombs was one of the other things he was involved in , the man who most likely kicked off the Manhattan project when he sat in on one of the US Uranium Committee meetings and asked, Haven't you guys read the MAUD report???.

[@rickh3714]

Less the Elephant in the room. More of an Oliphant in the Laboratory. Yes, I keep pachyderm puns in! A mammoth tusk indeed.

[@Skipper.17]

Another unrecognised Australian.

[@johnwatters6922]

Not in his home state, South Australia. Knighted in 1959 Sir Mark Oliphant became Governor of SA in 1971 @@Skipper.17

[@paulthomas-hh2kv]

Wish people would listen to interview with Mark Oliphant

[@norlockv]

A part of this story I found enlightening was that the US manufacturing engineers changed their manufacturing from a high precision milling operation to a metal stamping job. They stacked metal disks to build the magnetron instead. This meant they could be built in the thousands by machine operators and assemblers instead of a master machinist.

[@clytle374]

That was the 'magic sauce' for mass production. I've taken apart modern heating type magnetrons and they don't look precision. Would love to know if that is just due to the lack of need for a precise output frequency, or just design improvements.

[@norlockv]

@@clytle374 the magnetron in microwave ovens don’t need a narrow frequency spectrum. They’re not measuring return pulse time, just jostling water molecules.

[@shaider1982]

Yup, I learned that from Bill Hamac's recent video (Engineerinf Guy)

[@David-yo5ws]

@@norlockv They oscillate at the resonant frequency of water. This is what jostles the water molecules. Very sorry, what I read was wrong, so I was wrong. Here is the correct information: Quote: A study of a typical household microwave oven conducted by Michal Soltysiak, Malgorzata Celuch, and Ulrich Erle, and published in IEEE's Microwave Symposium Digest, found that the oven's frequency spectrum contained several broad peaks that spanned from 2.40 to 2.50 GHz. Furthermore, they found that the location, shape, and even the number of broad peaks in the frequency spectrum depended on the orientation of the object that was in the oven being heated. In other words, the exact frequencies present in the electromagnetic waves that fill the oven depend on the details of the food itself. Clearly, the microwaves cannot be tuned in frequency to anything particular if the frequencies change every time you heat a different food. Unquote. And the reason for the frequency, is so the FCC has that classified for microwave ovens. Thanks to the more 'educated' responders in setting me straight. 🤒

[@mytube001]

@@David-yo5ws Nope, that's not what's going on, and not true.

[@iain8837]

I change magnetrons fairly frequently. They are used for producing microwaves inside Semiconductor Ashing machines where silicon wafers are cleaned using a basic O2/N2 microwave plasma. This is usually part of the Dry Etch process. This is however only cleaning. More aggressive etch processes use other gasses and RF generators to produce the plasmas. This microwave plasma is typically pink in colour. It’s actually quite a hard plasma to ignite ( hence when the magnatron isn’t working 100%, it needs replaced.)

[@davidtatum8682]

No clue what you just said but wafers are cool. I eat them sometimes. With cream cheese. Or regular cheese. I like cheese too.

[@manishsakariya4595]

@@davidtatum8682 LOL! Semiconductor wafers is also safe to consume with cheese!

[@davidtatum8682]

@@manishsakariya4595 good to know. I'll try it.

[@pfadiva]

​@@manishsakariya4595but they are really crunchy....

[@variabletalisman9765]

I used to do epitaxial growth on indium phosphide wafers and now I change magnetrons in people's microwaves for a living, among other things. Turns out randos who want their kitchen fixed pay more than fortune 500 companies that require you to hand pour HF for a wet etch process. Go figure.

[@NonEuclideanTacoCannon]

I always love small, solid objects that do something neat with physics just by the way they are shaped.

[@RCAvhstape]

It's kind of Lovecraftian, actually. Lovecraft stories often feature geometric shapes that make people insane by looking at them or which channel energy and open portals to other dimensions.

[@Bialy_1]

Like Wacław Struszyński antena for: "High-frequency direction finding, usually known by its abbreviation HF/DF or nickname huff-duff, is a type of radio direction finder (RDF) introduced in World War II. High frequency (HF) refers to a radio band that can effectively communicate over long distances; for example, between U-boats and their land-based headquarters. HF/DF was primarily used to catch enemy radios while they transmitted, although it was also used to locate friendly aircraft as a navigation aid.(...) Land-based systems were used because there were severe technical problems operating on ships, mainly due to the effects of the superstructure on the wavefront of arriving radio signals. However, these problems were overcome under the technical leadership of the Polish engineer Wacław Struszyński, working at the Admiralty Signal Establishment. As ships were equipped, a complex measurement series was carried out to determine these effects, and cards were supplied to the operators to show the required corrections at various frequencies. By 1942, the availability of cathode ray tubes improved and was no longer a limit on the number of huff-duff sets that could be produced. At the same time, improved sets were introduced that included continuously motor-driven tuning, to scan the likely frequencies and sound an automatic alarm when any transmissions were detected. Operators could then rapidly fine-tune the signal before it disappeared. These sets were installed on convoy escorts, enabling them to get fixes on U-boats transmitting from over the horizon, beyond the range of radar. This allowed hunter-killer ships and aircraft to be dispatched at high speed in the direction of the U-boat, which could be located by radar if still on the surface or ASDIC if submerged." From August 1944, Germany was working on the Kurier system, which would transmit an entire kurzsignale in a burst not longer than 454 milliseconds, too short to be located, or intercepted for decryption, but the system had not become operational by the end of the war.

[@MRblazedBEANS]

It's so cool, stuff like HAARP is jsut a bunch of wires arranged In a certain way that if you put power threw the wires in the right frequency you can heat up the ionosphere

[@David-yo5ws]

And their shape gives them funny 'adopted' names. Like the early curved RADAR structures being called a 'Dish'. And a big rectangular rotating structure was called the 'bedstead'.

[@shable1436]

Circular shapes are the most efficient that's why they are used, they are not solid first, and the amounts of space inside can be magnified by various methods, look into night vision scopes for example

[@gyyv]

I worked with an old WW2 radar tech, many years ago. He told me that when they brought it over, it blew his mind as to what that thing could do. Very interesting fellow to talk to. Passed away some years ago.

[@sojolly]

I worked with a British Engineer that worked on the magnetron. I met him at the end of his career in the 80s. He was proud of what they had accomplished.

[@SunBear69420]

Was he cute?

[@sojolly]

@@retiredbore378 My dad worked for IH and my Granpa Deere they had some interesting breakfast conversations over the years. My dad was part of the team that invented the hillside combine and 2+2 tractor, I don't know if it was just him or a big team. Glad you are enjoying retirement.

[@sojolly]

@@SunBear69420 no

[@hydrolifetech7911]

As he should!

[@MBKill3rCat]

My grandfather worked on the magnetron project during the war. He told us that he dropped the first prototype and broke it lol. His name was John Linsley-Hood.

[@g0fvt]

Thank you for covering this, my late father was involved in the Goonhilly project but had been interested in radio from childhood. I do remember him trying to explain cavity magnetrons to me at a very early age. Little did I know then that I would be later working in a GEC laboratory adjacent to Hirst Research Centre in Wembley. Later on I worked for Racal BCC, I remember sitting in their reception awaiting my interview and picking up a copy of RF Design that included a hobbyist design of an FM television transmitter based on the magnetron from a microwave oven. By modulating the current through the magnetron as though you were attempting to create AM with limited modulation depth it generated an FM signal with many megahertz of deviation. The video has reminded me that I actually own a WW2 Radar test set which I intend to pass on to the Radar Museum at Neatishead, near where I now live. I feel I grew up in the most exciting time for electronics, though I may never use my stock of WW2 807s. My 2 way radio work often took me to Bawdsey, a significant site in our radar history.

[@John_L]

The National Museum of Computing at Bletchley Park would probably be keen to have your spare 807s, as they are widely used in the Colossus rebuild. Might help it to keep running for a few more years. (de G3WGV)

[@dwaynezilla]

I imagine the creators would go something like "Magnetrons!! There's literally a billion of these in use in the future" > "Oh no the war didn't go well?!?" "Oh no it went really well. They are used in the kitchen." > "WHY DO PEOPLE NEED TO RANGE FIND LARGE METAL OBJECTS IN THEIR KITCHEN?!"

[@trukomf1nn162]

I have a Husqvarna microwave oven from 80´s in my kitchen, and still works reliably. Made in U.S.A.

[@cyonemitsu]

Great video! It should be noted that after the war, Yoji Ito, who co-developed a 8 segment 30cm cavity magnetron in Japan back in 1938, and then a 24 segment 10cm cavity magnetron in 1939, was shocked when saw the Birmingham magnetron in a museum in the UK as it had a shocking resemblance to his own design, in a fascinating case of convergent design.

[@williamzk9083]

-The Japanese Yoji Ito and colleagues) (invented a multi-cavity magnetron with circular cavities and narrow slits about 1 year before the British (Randal and Boot) and also developed strapping. They made and operated several 10cm radars by 1942. They started with magnetrons with square cavities and refined the process of understanding. The Germans Sanitas Company had a 2kW 22cm multi-cavity magnetron by 1939. There is a nice paper by "Doering" on German microwave tube development (costs about $25) which has a picture of a German magnetron with circular cavities and narrow slits by the company Lorentz. It was only small device. -The Germans did have a microwave program. One targeted 25cm wavelengths using the LD6 and LD7 disk triode which could produced about 30kW - 50kW pulses. This device could produced coherent pulses for use in Doppler radar. The other targeted 5cm using a tunable split anode magneto of about 1kW. -In 1942 the Germans decided they didn't have the resources to develop microwave radar and that their existing radars were adaquet and so the program was disbanded with many of the engineers and technicians going to the Army. When the British H2S CV64 Magnetron was recovered at the end of 1942 the experts had to be brought back together. LD6 and LD7 development continued because of the 27cm FuMO 231 Euklid fire control radar for the German Navy. The LD6 could produce a 16kW pulse at 9cm so it was competitive with the first generation of British H2S magnetrons but with the advantage of being coherent. .

[@mikekelly5869]

​@williamzk9083 Wow! This response contained more detailed information than the video. Thank you!

[@richardkammerer2814]

Back in 1973, I failed in my attempt to dissuade a manager from heating a tin of soup in a full sized microwave oven. Observing from 10’ away, I saw a most surprising sight - a lovely noise and a nearly unhinged door. Not altogether a peaceful application. Another excellent video, by the way.

[@David-yo5ws]

Well if it was tomato soup, I am sure his face was redder. 😳

[@musicbruv]

Put a tin of tomato sauce in a conventional oven and the same thing will happen.

[@Nighthawke70]

Try a sausage without puncturing the casing. What a mess!

[@abaddon1371]

@@musicbruv Open fire will do it as well. Back in 1992 I saw a guy heat a can of chicken frikassé over a Hexamine solid fuel burner without opening it. Pretty amusing sight though when that thing popped open :D

[@20chocsaday]

Well, it was '73.

[@SeanBZA]

Factoid about that early British research is that they needed to dump all that microwave energy during testing, and did not want to radiate it out. So they buried a lossy coaxial cable into a nearby salt marsh, where the late night testing caused unusual heating of the salt marsh, and a fog bank that was only over the dummy load area.

[@SunBear69420]

Lol you said load

[@vincentsutter1071]

A lossy RF cable is a brilliant way to transfer the RF energy into thermal energy. High power RF attenuators would surely be rare and expensive in those days.

[@SimonHollandfilms]

thats interesting

[@SunBear69420]

@ProfSimonHolland i also found their statement to be interesting.. Especially the part where they said, "Load"... 😄

[@SimonHollandfilms]

@@SunBear69420 quite revealing

[@mikedrop4421]

I love how there is no end to "the ____ that won WWII" video possibilities. They always end up being fascinating. They pretty much let the world's engineers go buck wild for a whole decade.

[@dr4d1s]

It would have been great if it were under different circumstances where we all weren't trying to kill each other. I get what you are saying though. War time usually leads to technological advances.

[@paulmichaelfreedman8334]

That's the only good thing that comes from war. Rapidly accelerated technology development. Right for the wrong reason.

[@PsRohrbaugh]

The relevance is important.

[@slugface322]

Well then, yer simply gonna be ecstatic to see what single handedly won World War Three!

[@finonevado8891]

@@slugface322 we all know it's AI already

[@SimonHollandfilms]

really the brits did not invent the cavity magnetron.. they improved an Ukrainian cavity device and the real work was done in Wembley by GEC who had innovative magnets, a special glue to seal the vacuum chamber and the help of the french, who had discovered a plating method to increase the life of the units.....but i guess i need to make a film about this hidden history. paul is totally correct in saying it won world war 2 . great subject.

[@Andrew-rc3vh]

One of the first books I ever got into reading was a huge book published in the early 50s called Principles of Radar. This was the bible of radar technology from that era. My father used to work in the military designing this kind of thing. It was full of calculus. Fortunately I found a second book in the loft on calculus, so realised I needed to learn that first. I knew what a klystron and a magnetron was at the age of 12!

[@johncasteel1780]

By Merrill Skolnik, perhaps? Maybe not. I think his book was called _The Radar Handbook_.

[@finddeniro]

Fort Bliss ?

[@Andrew-rc3vh]

@@finddeniro Ultra Electronics in London

[@pjb5757]

My great uncle served with 224sqn RAF Coastal Command they were using DMS radar in October 1942. FK242 a lendlease Liberator Mk3a was an aircraft fitted with this radar in a chin fairing it crashed returning home from a mission 30.10.1942. 6 of the 7 crew died including my great uncle. They were not allowed to fly over enemy territory with this radar.

[@therealzilch]

In the sixties, my brother and I played around with war surplus magnetrons. He went on to designing and building electronic control devices. I went on to designing and building musical instruments. Whatever. Fascinating history, physics, and technology. Thanks again from cloudy Vienna, where lunch is always on me if you're in town, Scott

[@philiptownsend4026]

I was a kid in those days too and a bit of a mad professor. I remember we could buy X-ray tubes from advert's in electronics magazines and electronics surplus stores. Soooo dangerous, luckily I wasn't interested in them.

[@SixOhFive]

Do you both have cataracts now?

[@therealzilch]

@@SixOhFive No cataracts, but I do need reading glasses.

[@erichemard7066]

I got my start in tube circuitry at the age of 9 when my dad threw out the old tube tv back in the late 70’s. I was so amazed at the glowing tubes that i didn’t care the screen didn’t work. Fast forward 10 years and I’m a 19 year old guitar player who decided to build his own “champ” clone using spare parts from an old kenwood tube stereo. The amp sounded like crap…but it was a start…by the age of 22, I got a job at a repair shop repairing old Russian tube radios as well as Ham radios. I’m 51 now and still build tube amps. If you are interested in electronics…study tube circuits and everything else in modern electronics will make sense.

[@Scoutter]

The more impressive usage of microwaves is done in a company near me. They build microwave-based Mining equipment to break down ores without the need of chemicals. Needs a lot of power though. Something between 50 kW up to 20 MW depending on the rig. They once said the biggest one they had build was powerful enough to increase the temperature of the water supply line of the city by 80 degrees in 1,5 seconds. So you put cold water in and only like 1 step further you had the same stream but boiling. Thats impressive.

[@nickdanger3802]

developed a few months before Tizard Mission, all they had were a few handmade prototypes. it was left to Bell Labs to redesign for mass production and to MIT Rad Lab to design gear to make use of it

[@Andrew-ep4kw]

I worked in satellite communications in the 90's and an interesting aspect of the klystron tubes is they were tunable. The resonant cavities that sat along side the electron beam had small plungers connected to screw mechanisms. This allowed the plungers to be moved and change the size (and therefore the resonance) of the cavities. We had a procedure to change the tune of a klystron; first we would unlock the tuning mechanism, then change the tuning, then re-lock the mechanism.

[@johncasteel1780]

Another advantage of the klystron is that you can tune the cavities to a single frequency and get LOTS of gain in a narrow frequency OR stagger tune them for increased bandwidth at the cost of gain. Klystrons, however, are not used much in radars today because mechanical tuning does not lend itself to rapid electronic tuning.

[@richardvernon317]

One thing that people don't mention is the Cathode design in the GEC Magnetron wasn't designed by them, it was French!!! One of the French electronics research labs near Paris shared the design of that cathode with GEC in May 1940, just before the Germans Invaded. What it did do was massively extend the running life of the device and allow very high power, especially when GEC discovered that to stop the cathode from burning out, as soon as you had the magnetron run up, you had to turn the heating element off, as a sizable amount of electrons were being thrown back into the Cathode by the magnetic field and they caused it to heat up,

[@SimonHollandfilms]

yes....this is a fascinating story

[@bwarre2884]

That was done by Maurice Ponte. When the Germans invaded France he went to Britain and gave his information. Dutchman Klaas Posthumus who worked for Philips did research and wrote theoretical articles before the war and so helped Randal and Boot of Birmingham University with their thinking.

[@cernejr]

Magnetrons are also used to generate x-rays to treat cancer. The gold standard is klystron, but magnetrons are also widely used due to their smaller size.

[@jamallabarge2665]

I had to go look this up. Magnetrons operated at extra high voltages do generate electrons that generate "breaking radiation".

[@cernejr]

@@jamallabarge2665 As I said, magnetrons are still widely used today, in new treatment machines. Typical energy of the resulting xrays is about 5 MeV.

[@paulmichaelfreedman8334]

@@jamallabarge2665 Was just going to say it would have to make use of bremsstrahlung.

[@MickHealey]

This was a great video, I thoroughly enjoyed it. I worked on Radiotherapy machines for many years. The magnetron is used to generate high power microwave RF (travelling wave) within a tuned linear accelerator (Linac) structure. Note that the RF is used simply to accelerate electrons, so does not generate X-rays directly (at least not on medical Linacs that I know of). Electrons from an electron gun are injected into the linear accelerator at the point where the RF enters the linear accelerating structure. The electrons are initially bunched into packets and "surf ride" the RF wave, accelerating to near light speed, gaining 7x their rest mass in the process. Near the far end of the accelerator, any unused RF is recycled and sent back to the input, or dumped if not required. However, the accelerated electrons continue on their accelerated trajectory. The accelerated electrons then pass through a bending magnet (narrow band energy filter). The bending magnet does not allow electrons that are too low, or too high in energy to pass through. Only those electrons that make it through the bending magnet are at the desired energy for clinical treatment. They then collide with a water cooled tungsten target. These collision cause electrons in the tungsten atoms to jump to higher orbits, then drop back down again, giving off excess energy in the form of a photon in the X-ray spectrum. Final note: You can also have Linac that uses a standing RF wave, rather than a travelling wave.

[@MickHealey]

Great video here for anyone that is interested. I used to work on these machines. kzbin.info/www/bejne/oITKn4qcl6qrZ6M

[@daffidavit]

The "Klystron" was so impressive at the time, even well into the 1950s when the movie "Forbidden Planet" was made. Commander Adams of the spaceship referred to the Klystron monitors so many times in the movie, it was predicted that the device would still be relevant in the future, hundreds of years from when the movie was made. Just an observation.

[@plunder1956]

There are several interesting strands of this story that could be expanded into more detail. The early development in several countries was most interesting. So was the sea-going anti-submarine war with a host of other technological tools & weapons. Then the H2S development path & policy for it's use. Some remember "The Secret War" series, with the battle of the beams etc. I'd love to see more done with these subjects. People I used to travel with every day in the 70s & 80s had been fighting in WW2 in tanks & aircraft. They wanted to read all about the technology that saved Britain when they were young. But most was still secret. I wish they had known then what I know now, but most are long gone.

[@tinto278]

"The Secret War" 😍😍

[@RCAvhstape]

The Secret War is awesome. 1970s documentary featuring a lot of interviewees from both the UK and German side about WWII high tech. I had to go to Daily Motion to find the episodes, I think KZbin takes them down.

[@tinto278]

@@RCAvhstape I've watched all of them. 😁

[@msimon6808]

My dad (Okinawa) gave me Winterbottom's book on the code war not too long after it was published in paperback.

[@kh40yr]

Our first oven was a 1975 Litton Minutemaster. 13 amps. Model 416. The box still holds christmas decorations to this day because they were generous with the cardboard..

[@virt1one]

Great video! I'm a radio enthusiast and I thought I knew most of the history behind the magnetron, but you managed to fill in a few gaps I didn't know I had.

[@williamthethespian]

Always beautifully delivered with thorough understanding. Thank you. 👍

[@jonathanm9436]

Mark Oliphant, an Australian, also discovered tritium and many other things. He went on to contribute valuably to the Manhattan Project, but regretted his involvement and was an avowed pacifist and humanist. He was a close friend of my wife's family in Canberra (where he was pivotal in establishing the Australian National University) and I saw him a number of times at family lunches. He was a guest at our wedding in '97. His life story is fascinating and worth reading about. I'm still in touch with his grandson - we catch up every few months.

[@The-Sea-Dragon-1977]

As a Merchant Navy officer I have spent the majority of my life looking at the output of cavity magnetrons. Now we have solid state radar sets with LCD displays, but to those that understand the technology the magic of a cavity magnetron and a crt display is something.

[@TBrady]

We still use magnetrons and klystrons today on certain ghz communication equipment. One example is the an/trc-170 used by the Marine Corps.

[@David-yo5ws]

In 1980 at the RIMPAC exercise's, our 'old tech' ship was in Pearl Harbor and I got the chance to go on a shakedown of an advanced US satellite ship. In their RADAR room, they had this high tech klystron. I said "What do you do when you want to change the klystron frequency?" The Radio Engineer said "We just turn this switch here. We can change up to 12 frequencies and set it to change every rotation too." I said, "Well we have to pull out the spare one from it's wooden box, swap it out with the operating one. Then we have to get a book out and run it through the coarse tuning by turning a wheel and watching a dial, then fine tuning. That takes us about 10 minutes at best speed." It was a real credit to American advancement. However, on exercise, we had an old low frequency RADAR, that we were not allowed to use, because the Americans could not jam it. So, we snuck in an occasional 1 scan. They would be able to pick-up we used it, but of course we could not 'confirm or deny' it was operating. Fun and games is great in peace time.

[@5400bowen]

This guy is bridging the gap for me between my brother that was an electronics tech for the navy and later at the Naval Electronics Systens Analysis Laboratory assessing for design flaws in naval electronics systems and my basic understanding of electronics principles. I never ran into this type of intermediate knowledge that facilitates understanding of the more advanced stuff, so good job.

[@970357ers]

Never ceases to amaze how much of our modern world was created during/because of WW2.

[@marklewus5468]

yeah, and how much of it is going to be destroyed by the next one…

[@970357ers]

@@marklewus5468You sound like fun!

[@Bomkz]

they say war brings death... the unsung part of war also brings lots of technology research money grants. Because there's no better way to innovate technologies than to simply propose to a prospective government the possibility for a fancier stick and rocks to kill the other with. Albeit something that can be resolved culturally and not hardwired into us. \o/

[@vincentsutter1071]

Then you should be even more amazed by what was developed during the race to space - Gemini, Apollo, etc.

[@harrymills2770]

Nobody notices millions of inventions during peacetime, but they're just as important. Nobody notices all the inventions that weren't created, because the war effort sucked up all the money and resources.

[@philgiglio7922]

The cavity magnetron wasn't the only high tech the Tizzard mission brought to the US...penicillin mold was also brought over and given to Eli Lilly and Smith Kline and French. Within 2 years they had developed methods to grow and purify the drug in bulk...saving many lives MIT wasn't the only radiation lab set up. Georgia Tech set one up as well. It was still operational in 1968 when I started school there.

[@stagggerlee]

I bought my first microwave in 1975, an Amana Radar Range. I still have it in storage. I may have to dig it out and see if it still works. It weighs about 3 times as much as the one i bought last year for the kitchen rework. Cost $425 on sale back then, I don't know how I afforded it. Another great video!

[@David-yo5ws]

The copper in it might be worth about US$80.00 if you were willing to strip it down. But I think if you put a fish tank inside it (don't turn it on 😉) it might make it a great talking point about the ol' Amana.

[@Martindyna]

My Mother bought an Amana Fridge / Freezer about 40 years ago ** from a London department store which is still in use today (she's 98) here in the UK. A Thermador microwave oven came with it free of charge ! It had no turntable but instead had a slowly rotating `stirrer' mounted in the roof I assume to scatter the energy. There was a rudimentary grill IIRC. ** The technician who used to look after it said they no longer last like this one, advising he had to replace a compressor after only 6 years of service recently (this is about 10 years ago). May be due to the new green refridgerants ? or they just decided they were lasting too long.

[@henrysquillante9766]

Amana was the brand name used by Raytheon for the microwave ovens.

[@jesse75]

Does it have one large dial on it ?

[@supertuscans9512]

I saw my first Microwave in 1972 and at tge time it literally seemed like magic. Having said that, most microwaved food still tastes like shit and looks unappetising. One piece of science that is probably simple but I don’t understand how they function are microwaves which also contain electric heating elements for ‘browning’ food as I understand microwaves bounce around when they his a surface and I think these heating elements are made of metal.

[@europhile2658]

At a lecture I heard a different version of those events. One interesting variant was that German submarines mounted a gun that could be used to attack aircraft attacking them, guided by the aircraft's radar. It was a very successful (from their perspective). Also that the limited supply of the magnetrons was taken by "bomber" Harris. This was when the US became involved to make them. Not quite the same story as the "Tizard" mission

[@ianlowery6014]

In 1940 the radar research team at the University of Birmingham produced a working prototype of a cavity magnetron that produced about 400 W. Within a week this had improved to 1 kW, and within the next few months, with the addition of water cooling and many detail changes, this had improved to 10 and then 25 kW. GEC at Wembley then made 12 prototype cavity magnetrons in August 1940, and No 12 was sent to America on the Tizard Mission, where it was shown on 19 September 1940. As the discussion turned to radar, the US Navy representatives began to detail the problems with their short-wavelength systems, complaining that their klystrons could only produce 10 W. With a flourish, "Taffy" Bowen pulled out a magnetron and explained it produced 1000 times that. Britain did not use the device until it was in production. The cavity magnetron was manufactured in the USA. That was AFTER the Tizzard Mission. The lecturer got it completely wrong.

[@riverbender9898]

Part of my work in USAF was tuning kystrons on our transmitters, as needed..

[@DHyre]

A detail you set up but didn’t mention, nor did EngineerGuy: another of the brilliant things that made the cavity magnetron so helpful for the war effort was the design of the circuits that used it. IIRC, while the Germans were struggling trying to squeeze more power out of the klystron, which could be made very stable in frequency, and necessary to synchronize with the matched receiver, but difficult to scale and also make sturdy. Meanwhile, the Allies took a completely different approach: the magnetron was NOT that precise and stable in frequency, which would not have worked with the German approach. Instead, they slaved the receiver frequency to the transmitter frequency, so it was self-compensating, pulse by pulse, with just a circuit change. So now they could use the very powerful and sturdy cavity magnetron :)

[@GrinderCB]

Very interesting video, Paul. Always fun to learn about the components and tech that give us the conveniences we enjoy. Nice shirt, too. Hope the cancer recovery is going well.

[@Kuriente]

My grandfather worked with radio a lot when he was younger as a hobby. In the 1930's, while serving in the Army Artillery Costal Corps, he brought his amateur radio to work to help a pilot communicate with gunners on the ground who were target practicing with a towed glider. Apparently pilots at the time didn't commonly have easy communication with the ground. Fast forward a couple decades and it was his full-time job to work with radar and communication equipment for the Air Force. He and his coworkers knew that microwave antennas could heat things up (similar to the chocolate story in this video) and they would sometimes use the antennas to heat up sandwiches. One of his few regrets in life was not realizing the commercial potential of what they were doing and patenting the microwave oven himself.

[@clintwilde1048]

Even in 1950, German scientists and technicians of the WWII era did not believe that 'Chain Home' was an actual radar. Its frequency, but more importantly its PRF which was 25 cycles, based on 1/2 the Brit AC line freq of 50hz, used to synchronize every transmitter in the system to fire at the same time, made reconnaissance of the era believe they were receiving AC power line interference and not being pinged by a HF radar system. They basically quite doing any ELINT on the mysterious signal and left the Brits Chain Home system in place to provide the vital info the Brits needed throughout the war. One favorite story I have about fine tuning the airborne radar was a MIT tech tinkering with a system and having multiple failures over many months to get it to work properly. A USAAF bomber outfitted with the prototype radar, flying off Boston, the techs got a return on the scope and were cussing the machine as still not working. That is until they confirmed it was working and they were getting a signal off a German sub just off the coast of the US. They had no weapons, so they flew low enough over the sub and one of the techs threw a wrench at the sub. Another true story involves military skepticism of radar guided gun systems. With the system in place in Britain, a Sargent came up with the idea of putting a movie camera on the prototype radar gun mount and have a target aircraft fly a course to in view of the radar guided mount. The gun mount followed the aircraft through every maneuver as the film showed it continually in its cross hairs. When those radar guided mounts came online, not one V1 ever impacted on the ground again, all were shot down. V2's of course, were a different animal flying faster than the speed of sound.

[@supertuscans9512]

The V2’s didn’t follow a flight path in the earth’s atmosphere. They effectively ascended to the edge of the atmossphere and then dropped on their targeted direction from Space.

[@peterblake4837]

In the 70's, I built a spectrometer working in the X and Q bands. I was very surprised to find all the wave guide, phase shifters, attenuators and stuff, o/f copper, gold plated and boxed, readily available on Lyle Street. The only part I had to search for was the klystrons. One of the Marconi labs donated them.

[@bocs69]

My technical teacher in a Hungarian highschool told me that back in his early days he was working with plastic sheet welders which used microwaves as well. That time microwave oven was not even known to us. They used this for heating up coffees in lunch brakes :)

[@DKNguyen3.1415]

I was once told by an 21 year old aviation tech that sometimes you would have to blow on the pitot tube to make the helicopter or airplane think it was flying so you could activate the radar to heat your lunch.

[@t5ruxlee210]

The tunable very low power reflex klystron was the first "semi impractical" radar transmitter at microwave frequencies. Then it became the cw mixer source used to extract an IF signal that the radar set's tube amplifiers could strengthen, detect into video, and present to equipment operators.

[@johnannan2506]

I never mind waiting as long as it takes for the next Curious Droid video to be made. They’re always great stories, well researched, well written and clearly presented for people who know a bit of science. Thank you. Your hard work is very much appreciated.

[@charleskillian9563]

I beg to differ with this presentation's title. To paraphrase an old movie... Men with guts and a bayonet win wars.

[@AnitaJobby]

Welcome back, mate. 👋 Love your channel. 🙏🏻

[@rleconey]

As a child in the mid 60s, a friend showed off the latest Appliance in their kitchen. It was a miraculous device that could cook food in just a few minutes. It was called the Amana Radar Range!

[@MichaelKunz-mt2oo]

Wonderful video, thank you for posting. Not only did Bell Labs copy the magnetron and begin production, within 1 week of receiving that first cavity magnetron, Bell engineers boosted its power about tenfold. Robert Buderi has documented much of this arcane technological history a great book "Radar:The Invention That Changed the World" which is now in paperback.

[@adbayliss]

Thank you - I must admit to being drawn in by the title, but so many old men talk about wartime they were not in. This was fascinating, and how it leads to what I just warmed my dinner in, sublime

[@ThrawnFett123]

I see this guy every few years, he presents impressive informative videos that make me deep dive information I thought I already knew about. 10/10. I look forward to seeing you in like 3 years again mate

[@vipertwenty249]

Way back in the mid 1980's I knew one of the team that had successfully minituarised the cavity magnetron down to a size you could fit into a Swan Vestas matchbox during WW2. This enabled centimetric radar for what was then known as AI - airborne intercept. Bear in mind this was in the days of valve technology, before the semiconductor. His name was Bob Ross, a graduate student at the time of Cambridge University.

[@Seafox0011]

Fascinating how the UK's technological 'Crown Jewels' were bargained for orange juice and nylons (being cynical) - but lead to much of the modern world we now live in. Hard to imagine such gifts being offered effectively 'for free' today. But wars are the mother of necessity in invention when it comes to survival.

[@Reinforce_Zwei]

What rightly angers many Brits is with how much we "gave" to the Americans to ensure victory in the war, we were still demanded to pay back all the war loans while Germany got debts forgiven and even assistance rebuilding to the country it is now. The Americans took advantage and then tried for the next 70+ years to claim they were the sole reason Germany didn't win the war.

[@chumleyk]

@@Reinforce_Zwei Why do you think the Americans took so long to enter the war? it wasn't isolationism, they wanted the rest of the world on its knees so they could come in and take over. A state secret that will be kept classified for centuries.

[@slartybarfastb3648]

In return, the US destroyed the German wolfpacks, ensuring delivery of lend-lease aid, and manufactured useable radar at industrial scale for use by Britain. I'd call that a fair trade.

[@slartybarfastb3648]

@@Reinforce_Zwei The US could have stayed home and sat out the European war instead.

[@Bialy_1]

@@Reinforce_Zwei Brits paid only 10% of the value of Lend-Lease program and finished doing it after 50 years... As a Polish i can say that our inventions that came to Britain and saved British are not even mentioned by British or they are even blatantly reclaimed as British invention. Preaty sure no one knows: about Wacław Struszyński Huff-Duff antena(or its importance)... Or even Marian Rejewski, Jerzy Różycki and Henryk Zygalski work and how they made working copy of Enigma and first devices able to find daily keys for it and how all that know-how ended up in Britain... Any idea who invented hand held mine detectors used by alies in wwII? As an early show of British gratitude Polish soldiers were not even invited to 1945 London victory parade... Poland was sold to stalin and he took all reparations for Poland from Germany and not allowed Poland to be part of Marshall Plan, that btw you were happy to remove from your story as it provided a loot to post war Britain aka would contradict your biased story... Only Polish soldiers were fighting in september 1939 and when Adolf was makind the decision to end himself only Polish and soviet soldiers were fighting in Berlin(and in 1939 soviet soldiers were fighting on axis side...). I am also preatty sure that German logistics was destroyed by Polish Home Army in decisive moment of wwII(German forces about to conquer Moscow) not by British and British ofc repeating the fake "Russian winter" story.

[@markgrissom]

Great show. From El Paso Texas, very appreciative of your efforts resulting in great insights into the past.

[@paulgaskins7713]

12:17 crazy that in 1943 there was ‘little chance’ of the enemy recovering your aircraft from the sea when they are being downed by the dozen and just 80 years later the us has one single aircraft with all our new stuff on it fall into the ocean and we went through the process of getting it before one of our enemies could.

[@simongeard4824]

It's not that recovering a crashed vehicle from the sea was impossible back then - but it's a difficult and time-consuming operation which isn't particularly practical in war-time. A U-boat trying to salvage tech from a crashed bomber is easy prey when another bomber comes along to see what happened to his buddy...

[@simongeard4824]

@@cancermcaids7688 I was assuming the case of a plane which had crashed - shot down by a U-boat, perhaps - but not yet sunken. Yeah, once on the bottom of the ocean, no chance of recovery even in peace-time conditions...

[@stringpicker5468]

Sir Mark Oliphant was Australian and also a leading proponent of the Manhattan Project, playing a major role in convincing the powers that be that such a weapon was possible. Another major contributor to the war effort from Australia was Howard Florey who along with Ernest Chain and Norman Heatley made penicillin into a viable antibiotic, saving thousands of soldiers from death frominfected wounds.

[@williamogilvie6909]

Very good video. When you mentioned Bell Labs, the building shown was the Radiation Lab, or Building 19 at MIT. It was torn down awhile ago. Many researchers at MIT liked having their labs there because they were free to punch big holes in the walls and floors, as necessary.

[@somercet1]

Yes, and home of the Tech Model Railroad Club and the first hackers at MIT.

[@EscarHolmez]

@11:23 is when the photo of Building 19 appears in the video. I took ROTC classes in the building as an MIT undergrad in the late 1970s.

[@joabarrera]

Nice to see the old MIT rad pictures, I was one of the last tenants of the famous E20

[@HweolRidda]

Actually the random phase of magnetrons is a feature. In a sense it tags each pulse with extra information. Some klystron weather radars introduce quasi random phases to emulate this "flaw".

[@ianmangham4570]

King 🤴 klystron 🙏

[@Stoney3K]

Essentially that's the earliest example of spread spectrum transmission, even if that was never the intent.

[@atcengineering]

FM lonlinear modulation.

[@ClarenceCochran-ne7du]

How many former Hard Contact Lens wearers on here? PolyMethylMethAcrylate or PMMA was the plastic used in aircraft windscreens for most of the war. One Ophthalmologist realized that pilots with fragments in their eyes didn't develop eye infections. First Scleral Lenses, that fit over the cornea and sclera were developed and then Corneal Lenses, that floated on top of the cornea were both made of PMMA. Eventually Soft Lenses were developed, but for many years Hard lenses were the go to Contact Lens.

[@mbazzy123]

Great video Paul I always look forward to your new material.

[@FakeRights]

Took 2.5 years for you to post something actually interesting and worth my time.

[@kh40yr]

One of the first luxury use of the Microwave oven in the USA was in passenger trains. Thanks Paul.

[@randal_gibbons]

One of the first microwave ovens used in the home was accurately named the "Radar Range" made by Amana.

[@philipcollura2669]

The Northrup P-61 "Black Widow" night fighter deserves a mention. First flown in 1945, it was the first aircraft designed around a radar installation. Flown in both Europe and the Pacific, a P-71 was credited with the It was credited with the last air - air kill in the Pacific.

[@johncasteel1780]

The airborne intercept radar in the P-61 was the culmination of radar development in WW II. We (the Brits) went from low VHF radar (Chain Home) to X band (10 GHz) AI radar in the P-61 in about 5 years.

[@jimattrill8933]

The microwave radar was used in Beaufighters and Mosquitos long before the P61 was designed. By the time the P61 came along there were no German bombers to shoot down any more. It was not a successful aircraft at all.

[@CosmosNut]

American here, I was taught the proper term is "resonant cavity magnetron"... but then I'm pretty old... I knew one of the Varian designers... same for the klystron...

[@Spitfireseven]

I'm an Englishman raised in United States and this video was just wonderful to watch. The magnetron was so important in so many applications and none of those specific instances can be covered here because the video would be simply to long. One of the amazing facts I can add to the story here is that Boca Raton, Florida back then was a nothing. During world war two it was bulldozed into the coral, palm trees and jungle to build the secret city where the magnetron was industrialized in America. There was nothing here in Florida in the 1940s so it could all be kept secret. To this day you hear little of Boca Raton's beginnings mentioned. The town title means mouth of the rat. It is hardly an attractive sounding moniker. It is now the land of the rich. It was once the secret world of the magnetron and that is amazing.

[@ThePhilosophyOfNature]

Very interesting and very well done, as always, thank You Paul.

[@zedwpd]

The device has made my career possible. I am a Mission Crew Commander Air Battle Manager (and previous AIr Surveillance Officer and Air Weapons Director) on AWACS. The radar can do everything from finding semi submersible boats in counter drug operations to seeing hundred of miles for air targets and even overcome the doppler notch, and so much more. My 9 months of training on ground radar before I was to go through another year of radar training in the air we had a beginning class that looks very much like this video or the history of radar.

[@svonlaven]

Great presentation! Here is a connecting anecdote (disclosure: I am a Raytheon employee). Percy Spencer, credited with the candy-bar inspiration for the microwave oven, is also the Raytheon engineer responsible for the magnetron manufacturing innovation needed by the British. Percy realized that the cavities' flower-petal (or Colt-revolver) pattern could be (as mentioned in another comment) stamped out of sheet metal and the sheets bonded in a stack.

[@SimonHollandfilms]

yes...the colt revolver barrel was used as a machine tool but the sheet metal stamped idea was brilliant

[@alexandermenzies9954]

(Later Sir) Marcus Oliphant (mentioned in the early part of the video) was an Australian (of Scottish extraction) who later became Governor of South Australia. He was soon to be a researcher in the development of the first atomic bomb along with the likes of Oppenheimer in the US.

[@TheSunnyvaleTrailerPark]

Thanks for not copywriting me, I use your videos to help educate students of science and I get excellent results because the people in my study group on Facebook all like the kind manners of the presenter plus his voice is so soothing I swear it helps my study buddies retain information easier. Thank you so much for the work you put in to make these excellent productions, I'm extremely grateful for this kind of work. 🧠🤝✌

[@buddhistsympathizer1136]

I agree - The pace and the tone of the presenter is superb

[@TheSunnyvaleTrailerPark]

@@buddhistsympathizer1136 exactly. My users actually walk away with an education after I present this to them. To be honest this production is so good it should be broadcasted as a TV show like on the BBC or on American, Australian and Canadian TV. 🇦🇺🤝🇺🇸✌

[@philiptownsend4026]

​@@TheSunnyvaleTrailerParkAgreed but this and a small few other channels are too good for today's TV. To thrive there you need to be an idiot.

[@dcus55]

Was friends with a man who’s father brought this device to the US on his lap, and had the opportunity read letters he sent back to his family in Britain at the time.

[@02markcal]

I love how this video ends with the technology used in something we can all relate to and use every day, showing just how much impact it had.

[@randal_gibbons]

One of the early microwave ovens used in the home was accurately named the "Radar Range" made by Amana.

[@alanmcentee9457]

British technicians long knew of the warming effect of microwaves. They often would warm their lunch by leaving it near the magnetrons.

[@MrAvant123]

Worked on military and instrumentation radars for years in the MOD. Saw all sizes of Magnetron from little Decca boat radar mags to massive Long Range air defence mags that had a 2.2Mw pulsed power and were liquid cooled ! Our big radar was given a half hour warm up period, and I was always surprised how you could put a curry in the microwave and zap it straight away.

[@RobbieCec]

The content and production as always are 1st class 🙂

[@Fidd88-mc4sz]

This Tizard mission, and others like it, was literally a war-winning event. All examples of British hydraulic, and electro-hydraulic turrets for the RAF were sent to America in 1940, and these enabled American companies to side-step a lot of the developmental problems the British had encountered with vibration, ammunition feeds and accuracy. The Americans went with fully electric turrets, but much of the initial design work grew out of being able to cull good ideas - and avoid bad ones - in the supplied turrets. This allowed turreted B17's to operate effectively from 1942. Enigma was of course another, as were various items of anti-submarine technology. In time this exchange of technology became reciprocal.

[@edschofield37]

Good stuff. The Germans used radar for their anti-aircraft batteries in France as early as the fall of 1941. For details google the Wurtzberg D. Commandos raided a site in occupied France in Feb 1942 and stole a copy. I think the location was Bruneval. Although a glorious chapter in British commando raids it is little known to war enthusiasts.

[@James_Knott]

There was also the Dieppe raid, where part of the mission was to get info from the German radar site at Pourville, in August 1942. That was conducted largely by Canadians.

[@edschofield37]

@@James_Knott Quite accurate James. The raid only partially succeeded, however. The attacking party of about 10 went up against a blockhouse fortified by machine guns at every window. The raid at Bruneval (Feb 42) alerted the Germans to the need to fortify radar installations near the coast, a fact which the Allies did not consider in planning Dieppe. The Dieppe raid was in planning for too long, had too many objectives in a complicated operational plan hundreds of pages long. I believe the raid at Dieppe was so convoluted as to hide its real purpose, to steal another radar set. The stated official objective, to see if Canadians could directly take a port city for a day, and then give it back simply does not make sense. In any case, radar was top secret so you wouldn't explain to the public why you planned a huge raid to steal a set at the cost of 5,000 Allied soldiers. At least they learned a few things, but in general Dieppe was a disaster. For the most part this cannot be put on Churchill's shoulders, it was Mountbatten that ran that shit-show from start to finish.

[@esporev]

Great video thank you.. love the final line: “for an altogether more peaceful purpose”

[@uku4171]

Watching footage of them experimenting with their old tech is so crazy. Something like an Arduino starter kit would've blown their minds. Just the mosfets inside were beyond their most high-tech capabilities.

[@philiptownsend4026]

It's not right to mock those that came before us. We stand on their shoulders (to borrow a quote from Sir Isaac Newton). In a few years time our present day cutting edge stuff will feel the same... Primitive.

[@jamessutton9323]

For the microwave radar receiver they needed a tunable local oscillator. This requirement led to the development of the reflex klystron called the Sutton tube after Robert Sutton who led the development. The Sutton tube was also vital for the development of microwave radar. It was also included in the Tizard expedition to the USA. There was a further development where they introduced a small amount of gas to ionise and protect the receiver during the powerful transmitter pulse. This was called the Soft Sutton Tube.

[@videolabguy]

I am wondering if the rotating radar antenna systems can be traced to the inventor Logie Baird. He was the famous inventor of mechanical television. He disappeared during the war and was later accused of being a coward in hiding. He claimed that he worked on secret projects and was not able to discuss them due to security issues. The rotating and imaging radar system is so remarkably like his early televisions, there is no doubt in my mind that he was deeply involved in the development effort. Could you possibly delve into this area and give us an update if the info can now be revealed after all these years? Thanks! BTW, nice shirt!

[@James_Knott]

While he may have been hidden away for war work, I doubt there was much connection between his TVs and radar, other than the TV transmitters were "borrowed" for early radar work. His invention was using a spinning disk, with holes in it, to scan an image.

[@RCAvhstape]

@@James_KnottYes, but that bears a fair amount of resemblance to the way older analog radar systems synchronize the antenna, pulsing, and display. So it's a fair question.

[@johnschneider788]

I was fortunate to obtain my 1st Class FCC license and the radar endorsement in 1973 and working at the Ingals Shipbuilding on Spruance destroyers, the parabolic antennae and waveguide were cutting edge technology, I enjoyed the science and the work.

[@zachmiller9175]

I want to know who convinced Doenitz that a 2000lb cow can't stomp on a mole hard enough to kill it...

[@flagmichael]

I knew my father was a radar tech in WW2, but he had a Marine with a .45 assigned to him to ensure the secrets would not fall into enemy hands. At least once a week the Marine would call "Drop!" (or Down, or whatever it was). My father would fall to his knees and the Marine would bring the .45 to the base of his skull. When especially drunk, he related how he had spent about ten minutes in that position as a skirmish raged on the other side of the wall. Anyway, radar was just secret, not _that_ secret, in those days. Declassified documents my brother dug up indicated he was a specialist in ranging radar for shipboard guns. The ship would fire the usual ranging round, but the radar could give much more precise correction information than optical observers could. That meant a crucial time advantage in any engagement: one correction and fire for effect. Why so secret? The radar returns from shells at those ranges required high power at very short wavelengths: that is what magnetrons do.

[@nmccw3245]

I’d say other innovations brought by the Tizard Mission (the design for the proximity VT fuse, details of Frank Whittle's jet engine and the Frisch-Peierls memorandum describing the feasibility of an atomic bomb) were just as important as the cavity magnetron. 🇬🇧👍🏻😁

[@leehotspur9679]

Also penicillin

[@MikeMcNamara_mjmuk]

Another great video. I joined the Royal Navy in 1964 and saw my first magnetron in 1965 and went on to work on various Naval Radars up util 1980. I still have an old broken one in my loft somewhere, must look for it!!

[@andrewremobs9854]

I sometimes think that it's sad that nearly all of humanity's technological leaps come about due to conflict or war of some type.

[@leehotspur9679]

Yes I thought that too What will be coming from Ruzzia, Ukraine war Drones have taken a large leap already

[@holy3979]

It's the power of competition at it's finest and most extreme, trying to do better than someone else when your life is on the line is a massive motivational factor for many developments.

[@ChucksSEADnDEAD]

​@@leehotspur9679 It's sort of the other way around. The commodification of drones and commercial access to parts revolutionized the use of drones in warfare.

[@ravenclaw8975]

A great video and research! You have a gift for taking technical subjects and reducing them into plain language.

[@coniccinoc]

Love the WW2 content! ❤ Thank you

[@curtsmall8596]

Thank you for your quick look at a complicated history. Appreciate the way you were able to bring some coherent history out of all the threads to this. 😊

[@richardconway6425]

Wow! That was interesting ... so many things I didn't know in this story. Paul, do you think you could do a video on the history and development of *torpedoes* ? I have always found them fascinating, but have never entirely understood how they worked, especially ww2 era devices. Thank you!!

[@anthonyjackson280]

My father was a radio/radar technician in the RAF during the later years of, and post WW2. In 1948 or 49 he was bench servicing a night fighter radar system and almost, accidentally invented microwave ovens in a similar incident. He was pulsing the radar unit on the bench when he started to small smoke. He looked around and a tool rack across the workshop had caught fire from the tight beam of the radar unit. I suspect many who worked on them had similar incidents without appreciating the potential of their discoveries.

[@markwilliamson9199]

Sir Mark Oliphant later on became the Governor of South Australia. After he retired I met him in the Naval and Military club dining room, while having dinner there with my Father, who was a member. We are proud of our Australian scientists

[@frankschultz4170]

The radar receiver shown (with the 5" scope) at 15:55 appears to part of the AN APS-13 system, which consists of a half-dozen or so components (antenna, magnetron & modulator, synchronizer, bombing computer, remote scope, etc. Have complete system (including cables) and installation manuals for B-24s, B-25s and I think B-26s. Acquired it in the late '50s when I was a teen a teenager - $75 - a lot of money back then... Also have full documentation (schematics) on microfilm (from Supt. of Documents)... This is the first photo of an actual installation I've ever seen! Great stuff! Would like to know what the unit is to the right of the receiver...

[@JesseP.Watson]

...I'm left wondering if the guys working on the magnetrons were cooking themselves then... which is not ideal.

[@patmanapsal4762]

Bismark had a radar but the radar was fixed facing forward. It could not turn or rotate.

[@Spirit532]

The candy bar story is bogus, because if there was enough energy to melt the candy bar while he was working on/walking near the transmitter, there would most certainly and unavoidably be enough energy to very quickly and quite permanently cook the eyes, *and* make him jump from large area superheating of tissue(not-quite-burns) before the huge thermal mass of the candy bar would allow it to melt. It's probably just the heat of it being in his pocket that did that. This is also mostly why modern home microwave ovens have interlocks and shielding - their primary function is to prevent you from blinding yourself, followed by avoiding subsurface burns, and only in the last priority to avoid radio interference.

[@kwestionariusz1]

You know what newton ring are and why microwave cooker need to rotate🥱 Doubt you know

[@Spirit532]

@@kwestionariusz1 Standing waves have no relation to why this story is bunk.

[@robertmatch6550]

It does not take much energy to melt a candy bar w microwaves. Cadbury egg liquifies in under 5 seconds and can be very hot.

[@coreyandnathanielchartier3749]

Good chance that 'regular' heat radiating from the machine contributed to the melting candy bar. We don't know how close he was to the machine.

[@davidmarkwort9711]

When was the first magnetron invented? Cavity magnetron - Wikipedia In 1910 Hans Gerdien (1877-1951) of the Siemens Corporation invented a magnetron. In 1912, Swiss physicist Heinrich Greinacher was looking for new ways to calculate the electron mass. Need I say more?

[@Nighthawke70]

The major thing why the Tzard mission was undergone was the Brits didn't have the industrial capacity to build the Mags in quantity. When they revealed their little gem, General Electrics reps took one look at it. convened, and came up with an quick solution on the spot: punch press production. Instead of machining each unit in one piece, they would use a punch press to create each layer of the Mag, then assemble and solder seal them together. It took a few months and the skills of MIT's Rad Lab to get it right, but it solved a ton of issues the Brits were having. First it took forever to machine each one, and testing could not be done until it was completely built, and that took a month for each one. If it failed, then all that work was thrown away: there was no real fix when it was fully assembled. Punch press production meant reproducable quality in quantity was feasible, with QA performed with EACH LAYER. This meant if a flaw developed during production, the part was simply discarded, the dies were evaluated for issues. If the die was found bad, it was either redone, or scrapped and a new die put in. This took a handful of hours instead of weeks. GE and Raytheon put this system to good work and Mags started to come off the line by the dozen. Mag production got so good, they were able to supply mission spares to replace bad ones while in-flight.

[@philiptownsend4026]

I think probably the Chinese are doing that kind of production technology work today.

[@Nighthawke70]

@@philiptownsend4026 Back then, numeric control milling and lathe systems were a glimmer in the engineer's eye. It was not until the late 1940's when something barely resembling the turret mills and lathes of today came into being, but didn't sport the precision necessary for magnetrons or nuclear weapon components. But they could reproduce with cost efficiency. The Chinese poached tech from one country or another to get where they are today. Their CNC mills are Pakistani, with German software and controls. The rest is polish and duct tape. The magnetrons are an excellent example of die an tooling to make volumes of components, reliably and quickly. They didn't need high tolerance, but high production numbers. If a die develops a flaw and is picked up, that whole batch was scrapped. Just about the only component in the old style maggies they had to pay attention to was beryllium. Dust from that stuff-instant lung cancer. Modern units don't use as much of that toxic metal back then, but it's smart not to tear one down because of it.