Monday, February 05, 2007

The Cavity Magnetron and Morning Coffee


A long time ago, the world found itself at a dangerous nexus of chaos and change. The chaos was World War II, the change was the rapid increase of discovery and invention to meet the chaos.

One of those inventions saved the lives of thousands by detecting the approaching enemy before they could be seen, and allowed Naval ships like my Dad's, to target the enemy with extreme accuracy. At breakfast today, I used that invention to heat my morning coffee.



Briefcase 'that changed the world'
By Angela Hind
BBC Radio 4's The World in a Briefcase

In the summer of 1940, the war with Germany was at a critical stage. France had recently surrendered and the Luftwaffe was engaged in a concerted bombing campaign against British cities.

The United Kingdom was being cut off from the Continent, and without allies to help her, she would soon be near the limit of her productive capacity - particularly in the all important field of electronics.

On the morning of 29 August, a small team of the country's top scientists and engineers, under the direction of Sir Henry Tizard and in conditions of absolute secrecy, was about to board a converted ocean liner.

With them they carried possibly the most precious cargo of the war - a black japanned metal deed box containing all of Britain's most valuable technological secrets.

They were on their way to America - to give them away.

This high-powered team included representatives from the Army, Navy and Air Force, along with specialists in the new technologies of war.

Earlier that morning, radar expert, Dr Edward "Taffy" Bowen - a vital member of this Tizard Mission and responsible for looking after the metal deed box that was to become known as "Tizard's briefcase" - almost lost it.

When he had arrived at London's Euston station, the Welshman had handed it to a porter while gathering up his remaining luggage, then watched helplessly as the man headed off to find the 0830 boat train to Liverpool without waiting for his customer.

As he struggled to keep the porter in sight above the wartime throngs, Eddie Bowen would not have drawn much attention from the busy Londoners. Only his face would have betrayed his concern.

Short distance

Just five days short of the war's first anniversary, Britain faced one of its most desperate hours.

The Battle of Britain was raging, and bombs were falling nightly on Liverpool. Nazi armies ringed the country from the Norwegian coast down to France; an invasion was expected within weeks.

As Bowen knew, the seemingly ordinary solicitor's deed box - for which he was personally responsible - held the power to change the course of the war.

Inside lay nothing less than all Britain's military secrets. There were blueprints and circuit diagrams for rockets, explosives, superchargers, gyroscopic gunsights, submarine detection devices, self-sealing fuel tanks, and even the germs of ideas that would lead to the jet engine and the atomic bomb.

But the greatest treasure of all was the prototype of a piece of hardware called a cavity magnetron, which had been invented a few months earlier by two scientists in Birmingham.

John Randall and Harry Boot had invented the cavity magnetron almost by accident.

It was a valve that could spit out pulses of microwave radio energy on a wavelength of 10cm. This was unheard of. Nothing like it had been invented before.

The wavelength for the radar system we were using at the start of the war was one-and-a-half metres. The equipment needed was bulky and the signals indistinct.

The cavity magnetron was to be the key that would allow us to develop airborne radar.

Kitchen technology

"It was a massive, massive breakthrough," says Andy Manning from the Radar Museum in Horning.

"It is deemed by many, even now, to be the most important invention that came out of the Second World War".

Professor of military history at the University of Victoria in British Columbia, David Zimmerman, agrees: "The magnetron remains the essential radio tube for shortwave radio signals of all types.

"It not only changed the course of the war by allowing us to develop airborne radar systems, it remains the key piece of technology that lies at the heart of your microwave oven today. The cavity magnetron's invention changed the world."

Because Britain had no money to develop the magnetron on a massive scale, Churchill had agreed that Sir Henry Tizard should offer the magnetron to the Americans in exchange for their financial and industrial help. No strings attached.

It was an extraordinary gesture. By September, the Massachusetts Institute of Technology had set up a secret laboratory; by November, the cavity magnetron was in mass production; and by early 1941, portable airborne radar had been developed and fitted to both American and British planes.

The course of the Second World War was about to be changed. It was, says writer Robert Buderi, possibly the most important development of the 20th Century.

In fact, it was so important a development that the official historian of the Office of Scientific Research and Development, James Phinney Baxter III, wrote: "When the members of the Tizard Mission brought the cavity magnetron to America in 1940, they carried the most valuable cargo ever brought to our shores."


The newest use of this ancient technology is in the US military's ray gun. The blaster shoots an invisible millimeter beam that makes people feel intense, but harmless heat. The 130-degree F. beam is supposed to cause the enemy to drop their weapons and civilians to run away. The millimeter waves penetrate only 1/64th inch of skin, causing discomfort. A common kitchen microwave will penetrate several inches of skin.


The life of Indigo Red is full of adventure. Tune in next time for the Further Adventures of Indigo Red.

3 comments:

indigo rose said...

Perhaps, once again, this will be the answer to winning a war... or at the very least, putting an end to our participation in the Iraqi War. A ray gun that causes intense pain, but no injury. Every parents dream as we send our children off to war.

devildog6771 said...

Had Hitler known that England was so broke after WWI it couldn't afford to upgrade weaponry, it had no nothing left to fight him with if he landed on their shores and its air force was sparse to say the least, the course of events in history may have been different. However, Hitler had not expected England to be such an easy conquest. Had he persued them to their shores he would have defeated them easily. But, he was caught unprepared for that step and refused to go ahead and land on their shores. Our gain, his loss.

Question, I have always said that Germany surrendered at the end of the War; but, the Nazis did not. They subsequently left Germany and concentrated in South America. Presently in America they have done something not able to be done by any of the "white power crowd." They managed to get the Klan, Arian Nation, and others to unite under one front group and named that group something [can't remember the name] that gives the impression of being a Christian based organization.

Do you agree that since WWII they have slowly and methodically continued to reestablish themselves world wide. Also, do you thyink it is possible, as do I, that they could be a silent, behind the scenes, player in the rise of Islamic terrorism? That they could very easily be orchestrating the whole thing and then once things are the way they want them they will step in and take over? Let me clarify one thing here. I don't believe they ever surrendered, the rest is a speculative thought on my part. I realize it is far fetched.

Indigo Red said...

DevilDog,

I'm not one for massive overarching conspiracies, however your conjecture that Germany surrendered and the NAZIs did not is a fact.

Currently is SAmerica there are many German speaking. There are also many towns that for centuries were Spanish speaking, but are now majority Arabic speech. The Germantowns and the Arab towns are often neighbors.

In the Tri-national area Arabs and NAZIs walk across borders at will. If one wants to know which countries are NAZI influenced, one need only look at the military uniform styles and parade march step. American, Canadian, British, French, German, Italian, in short, European anti-NAZI nations march with a relaxed step, wearing neat, but relaxed unifrms. Whereever one finds starched designer uniforms and goose-stepping one will find NAZI influence.

Too bad. THe NAZI German military were sharp dressers. A little known fact of WWII Germany: Karl Lagerfeld, the fashion designer, created the military and Gestapo uniforms and manufactured by Hugo Boss.