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  #1  
Old 27 November 2010, 03:04 AM
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Cell Phone Use a cell phone to test microwave oven leaks

Comment: To Test whether or not your microwave leaks place your cell phone
into the microwave and shut the door. Call the cell phone number. IF you
can hear it ring your microwave leaks. IF it does not ring it means that
the microwave is sealed tightly and the phone will not ring.
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  #2  
Old 27 November 2010, 03:04 AM
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Cell Phone

Comment: I was recently told about an easy & inexpensive way to check to see if your microwave leaks. You put a cell phone inside & close the door. Now call that cell phone. If you have a proper seal it will not ring. When you take it out it will not even show a missed call because it never received the ignal. BUT... if it does ring you have an improper seal and microwaves are leaking out an could harm your family. I have tried this 3 times and the cell phone did not ring in 2 of the three microwaves tested. The one it did ring in was replaced and when it was tried again it rang yet again. Is this just a rare coincidence that both microwaves leak, could it be the house they're in or is this just a hoax altogether?
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  #3  
Old 27 November 2010, 03:35 AM
Singing in the Drizzle Singing in the Drizzle is offline
 
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Cell phones in the US at least operate from about 800 MHz through 1900 MHz. Microwaves operate around 2.4 MHz - 2.45 MHz. I would guess that there is no reason to block the cell phone range in a microwave. If the material used do, then the signal will not get through if properly sealed. I just do not see a reason why the microwave will have to block a cell phone.

Isn't some of the WLAN (802.11b? channel ?) operating channels in the same range as a microwave oven.
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  #4  
Old 27 November 2010, 08:17 AM
UrbanLegends101 UrbanLegends101 is offline
 
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A microwave oven isn't designed as a perfectly shielded container, either.

A cell phone in a microwave oven isn't a very valid test for several reasons.

First, and perhaps most important, the signal strength of a cell system isn't a controlled value, rather the signal strenth from the cell network isn't uniform, so that signal strength is a variable which clouds the test. Consider a home where one has to find a sweet spot for the cell phone to work. If the cell phone won't work in some rooms in the house, it is likely the cell phone won't work in the microwave oven even with the microwave door open.

Second, while there is certainly a standard for microwave oven leakage:

"shall not exceed 1 milliwatt per square centimeter at any point 5 centimeters or more from the external surface of the oven, measured prior to acquisition by a purchaser, and, thereafter, 5 milliwatts per square centimeter at any such point."

That is actually a quite high RF (radio frequency) power level, in terms of communications devices.

Understand the cell phone is designed as a radio receiving device, therefore it is far more sensitive to RF than the human body. The microwave oven leakage standards are set to protect the body from effects of microwave RF energy in the oven, not totally prevent the escape of any and all radiation from the oven. The shielding is only designed to reduce the RF leakage to the level which is not dangerous.

Contrast this to the much lower level RF signal at which a cell phone will still satisfactorilly operate. The shielding level which is satisfactory to meet the radiation levels for a microwave oven may still permit enough signal for the cell to properly operate.

Any shielded cabinet which has enough loss to prevent a cell phone from operating would reduce the microwave oven radiation to a level far below what is required and would be much overkill, in terms of performance, me thinks.
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  #5  
Old 27 November 2010, 12:53 PM
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Some ovens are at 915 MHz. Plus, I think it's a lot easier just to build the shields so that they block the whole range of microwaves. I don't think they "tune" them to block only a small part of the spectrum.

What I would doubt about this is that the amount of radiation of a cell phone or wireless card is like a tiny LED light compared to the oven's hundreds of watts. So it seems to me it would only be able to tell if your oven is completely useless at blocking that frequency. If it functions at all, I think it should easily block a wireless signal.
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  #6  
Old 27 November 2010, 01:06 PM
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Quote:
Originally Posted by Singing in the Drizzle View Post
Cell phones in the US at least operate from about 800 MHz through 1900 MHz. Microwaves operate around 2.4 MHz - 2.45 MHz.
That's 2.45 GHz, which is 2450 MHz.

Some explanations of the phones that receive inside the oven are saying that the waves are "smaller". That's not right, is it? 800 to 1900 MHz is the frequency so those waves are longer than those at 2450.

Where's Troberg when you need him? I'll bet someone a cold pint of beer he's tried this!
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  #7  
Old 27 November 2010, 01:29 PM
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I don't know about leaks, but I do know that our microwave disrupts the signal from our wireless router. If we are streaming or downloading something, and someone starts the microwave, the download stops until the microwave shuts off, even though the signal strength from the router shows no change. If I understand it correctly, it has something to do with disruption of the electro-magnetic field.
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  #8  
Old 27 November 2010, 01:31 PM
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Quote:
Originally Posted by lynnejanet View Post
... our microwave disrupts the signal from our wireless router.
Have you tried moving the router further away from the oven?
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  #9  
Old 27 November 2010, 10:22 PM
Alchemy Alchemy is offline
 
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A couple thoughts:
  • Microwave oven shielding is probably along the lines of 30-50 decibels of attenuation at 2.45 GHz. The path loss between a cell phone handset and a base station can be as high as 100-200 decibels. If placing a cell phone in the microwave gives identical signal attenuation, it's quite possible the attenuation would still not be high enough to prevent communication with the network.
  • Microwave oven shielding operates primarily as a Faraday cage. Attenuation for a Faraday cage normally increases with frequency up to a point, and then drops off sharply as it reaches the cut-off frequency. Depending on the thickness and conductivity of the shielding, attenuation of 900 MHz might be substantially less than 2.45 GHz.
  • Perhaps most importantly, most microwave doors use a quarter wave choke joint around the door frame to maintain an EMF seal, as it's much simpler and safer than designing an electrically conductive seal. (This is the reason pretty much every microwave oven door is always 3 cm thick.) This joint will prevent 2.45 GHz radiation from leaking out but won't do anything for any other frequency. See for example, Imberg et al., US Patent 3,956,608 (1976).
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  #10  
Old 27 November 2010, 10:41 PM
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Quote:
Originally Posted by ganzfeld View Post
Have you tried moving the router further away from the oven?
They're in adjacent rooms, but there's a brick wall in between. To move the modem, we'd have to move the desktop, and I don't really have anywhere else to put it. Or, I guess I could move the kitchen.

In reality, we don't use the microwave all that much, so it doesn't really interfere.
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  #11  
Old 28 November 2010, 06:44 AM
Singing in the Drizzle Singing in the Drizzle is offline
 
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Lynnejanet, have you tried different channels. I would suggest trying 1 or 11 (the highst channel ?) since one of the two will the farthest away from the interference.
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  #12  
Old 28 June 2011, 04:16 PM
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Cell Phone Test your microwave oven for leaks with a cell phone

Comment: During a safety briefing at work we were told you can test a
microwave for leaks by "putting a cell phone inside a microwave and
calling it from another phone. If it rings it means that the microwave is
leaking. When the briefing was over we went back to our breakroom and
tried it. In both of our microwaves the phone rang. Are they really a
hazard to our health?
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  #13  
Old 28 June 2011, 05:51 PM
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A Turtle Named Mack A Turtle Named Mack is offline
 
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Cell Phone

Did I run the test wrong - I got lightning and a melted cellphone. You were supposed to turn the microwave on, weren't you?
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  #14  
Old 28 June 2011, 05:54 PM
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Not all radiation is treated equally. Just because one type of radiation can escape a microwave doesn't mean all types can and that the radiation is of the same type.
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  #15  
Old 28 June 2011, 09:12 PM
UrbanLegends101 UrbanLegends101 is offline
 
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Quote:
Originally Posted by diddy View Post
Not all radiation is treated equally. Just because one type of radiation can escape a microwave doesn't mean all types can and that the radiation is of the same type.
True, however the radiation from a microwave oven and from the transmit side of a cell phone are both non-ionizing but differ only in power level and frequency.
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