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  #1 (permalink)  
Old 01-18-2008, 1:53 AM
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Default Mythbusters episode with magnetrons question.

on one of the mythbusters episodes they were experimenting with microwave ovens. Jaime built a box with 4 magnetrons to microwave a glass of water. but after 30 seconds they found that the water was colder then when the test started.
Jaime said that he thought that 4 magnetrons would heat 4x faster then a single magnetron.

Why did it not work?


EDIT: corrected the spelling just for you that seem to only pay attention to that or feel that you need to point it out.
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Last edited by ybbmadysu; 01-18-2008 at 10:00 PM..
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Old 01-18-2008, 5:59 AM
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because they did it wrong?
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Old 01-18-2008, 6:16 AM
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I'd go out on a limb and say that the beam probably needed to be focused. That particular episode of Mythbusters was on earlier this afternoon. Seeing as I saw it when it first aired in the first or second season, I didn't bother to watch, but I'll check to see if it's on later.
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Old 01-18-2008, 10:05 AM
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Wink Phase?

Quote:
Originally Posted by ybbmadysu
on one of the mithbusters episodes they were experimenting with microwave ovens. Jaime built a box with 4 magnetrons to microwave a glass of water. but after 30 seconds they found that the water was colder then when the test started.
Jaime said that he thought that 4 magnetrons would heat 4x faster then a single magnetron.

Why did it not work?
Hmmm, Were all four of them in phase???????
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Old 01-18-2008, 10:12 AM
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lol I love that show, but sometimes they do stuff that even I question ... and I'm not the smartest cookie in the crayon box if that tells you somethin ...

the last time I saw a tv show try to use a magnetron outside of a microwave it knocked out all their camera gear ... it was hilarious ...
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Old 01-18-2008, 3:42 PM
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On a related note...

Air Force Plots $75 Million Microwave Weapon Push
http://blog.wired.com/defense/2008/0...rce-plots.html
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Old 01-18-2008, 8:38 PM
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Quote:
Originally Posted by pogbobo
lol I love that show, but sometimes they do stuff that even I question ...
Or like when they said you CANT "robin hood an arrow"!!!!

One of my Main hobbies is Archery and I can do that on a weekly basis, with a recurve or compound
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Old 01-18-2008, 9:19 PM
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just fyi its mythbusters not mithbusters
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Old 01-18-2008, 9:58 PM
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thank you to all you that feel you need to correct the spelling error. ignore that and answer the question.
I wrote this post after 2 days of work and no sleep between.

@Shortwavewave(<--see I spelled that correct), got any pics of your split arrow? You should email the show with your pict(s).
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Old 01-18-2008, 10:22 PM
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I save the arrows i split, cant recall ive taken pics but the next time i split one, ill take some pics, then PM you show.
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Old 01-19-2008, 2:38 AM
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OK, after all that here's the answer to your question. The inside of the oven is of such dimensions as to make it a resonant cavity in tune with the waves emitted by the magnetron like a transmitting antenna in tune with the waves it radiates. When resonance occurs the waves are at their strongest, otherwise nothing much happens. Jamie's box was non resonant so the microwaves simply dispersed being unfocused by the sides of the box. He could have had a hundred maggies going and still achieved nothing.

BTW, Adam commented they were humming loudly which told me immediately what was wrong. Everything being out of tune they were drawing excessive current and if the transformers weren't self limiting split core types everything would have gone up in smoke. That's why transmitters have tuned outputs and the antennas tuned likewise, if something fails and goes out of resonance power output components go bye bye in short order.

"and I'm not the smartest cookie in the crayon box if that tells you somethin"

Yeah, it tells me sumpthin', you failed Kindergarten putting cookies in the crayon box there Ralph Wiggam.
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Old 01-19-2008, 2:39 AM
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Quote:
Originally Posted by ybbmadysu
thank you to all you that feel you need to correct the spelling error. ignore that and answer the question.
I wrote this post after 2 days of work and no sleep between.

@Shortwavewave(<--see I spelled that correct), got any pics of your split arrow? You should email the show with your pict(s).
How is it our fault that you wrote it when exhausted? If you expect to be taken seriously as an intelligent poster, make your posts indicative of intelligence. You're doing no one any favors by *****ing about it either, since it will only stir up other inflammatory remarks from others.
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Old 01-19-2008, 2:52 PM
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Quote:
Originally Posted by kb2vxa
OK, after all that here's the answer to your question. The inside of the oven is of such dimensions as to make it a resonant cavity in tune with the waves emitted by the magnetron like a transmitting antenna in tune with the waves it radiates. When resonance occurs the waves are at their strongest, otherwise nothing much happens. Jamie's box was non resonant so the microwaves simply dispersed being unfocused by the sides of the box. He could have had a hundred maggies going and still achieved nothing.

BTW, Adam commented they were humming loudly which told me immediately what was wrong. Everything being out of tune they were drawing excessive current and if the transformers weren't self limiting split core types everything would have gone up in smoke. That's why transmitters have tuned outputs and the antennas tuned likewise, if something fails and goes out of resonance power output components go bye bye in short order.

"and I'm not the smartest cookie in the crayon box if that tells you somethin"

Yeah, it tells me sumpthin', you failed Kindergarten putting cookies in the crayon box there Ralph Wiggam.
Thank You! kb2vxa. Yeah I heard adam say that too, thought it was just normal current draw through the xfrmr's x4.

Austin4wyo, eat me! Again, as I said-thank you to all you that feel you need to correct the spelling error. ignore that and answer the question.
as you said "You're doing no one any favors by *****ing about it either, since it will only stir up other inflammatory remarks from others."
You complain about it, yet you do it?

I thought this was a place to ask questions and learn from those that have knowledge in the subject in question. people like you damage this place.

im done here.
Thank You KB2VXA!
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Old 01-19-2008, 4:06 PM
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Quote:
Originally Posted by ybbmadysu
Thank You! kb2vxa. Yeah I heard adam say that too, thought it was just normal current draw through the xfrmr's x4.

Austin4wyo, STUFF!


Wow...he's a cute kid.

And to point out, in my original reply, I did make a speculation, but since microwaves and such aren't exactly my field of expertise, I was wrong.

Oh well. He'll either get over it or die pissed off, I suppose.

Last edited by Austin4Wyo; 01-19-2008 at 4:17 PM..
 

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