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Groups > sci.physics > #564624 > unrolled thread

Can you call a cell phone in the microwave?

Started bySam Wormley <swormley1@gmail.com>
First post2016-03-22 15:16 -0500
Last post2016-03-29 21:31 -0700
Articles 8 on this page of 28 — 10 participants

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  Can you call a cell phone in the microwave? Sam Wormley <swormley1@gmail.com> - 2016-03-22 15:16 -0500
    Re: Can you call a cell phone in the microwave? jimp@specsol.spam.sux.com - 2016-03-22 20:57 +0000
      Re: Can you call a cell phone in the microwave? isw <isw@witzend.com> - 2016-03-22 21:50 -0700
        Re: Can you call a cell phone in the microwave? john <johnsefton288@gmail.com> - 2016-03-23 07:04 -0700
    Re: Can you call a cell phone in the microwave? Sergio <invalid@invalid.com> - 2016-03-22 16:43 -0500
      Re: Can you call a cell phone in the microwave? Poutnik <poutnik4nntp@gmail.com> - 2016-03-23 05:37 +0100
        Re: Can you call a cell phone in the microwave? Sergio <invalid@invalid.com> - 2016-03-23 11:11 -0500
        Re: Can you call a cell phone in the microwave? isw <isw@witzend.com> - 2016-03-23 21:05 -0700
          Re: Can you call a cell phone in the microwave? jimp@specsol.spam.sux.com - 2016-03-24 06:17 +0000
            Re: Can you call a cell phone in the microwave? benj <none@gmail.com> - 2016-03-24 10:55 -0400
              Re: Can you call a cell phone in the microwave? jimp@specsol.spam.sux.com - 2016-03-24 19:17 +0000
            Re: Can you call a cell phone in the microwave? john <johnsefton288@gmail.com> - 2016-03-24 08:22 -0700
              Re: Can you call a cell phone in the microwave? Sergio <invalid@invalid.com> - 2016-03-24 16:06 -0500
                Re: Can you call a cell phone in the microwave? john <johnsefton288@gmail.com> - 2016-03-25 05:49 -0700
                  Re: Can you call a cell phone in the microwave? benj <none@gmail.com> - 2016-03-25 13:47 -0400
                    Re: Can you call a cell phone in the microwave? Sergio <invalid@invalid.com> - 2016-03-26 21:23 -0500
                      Re: Can you call a cell phone in the microwave? Virgil <VIRGIL@VIRGIL.com> - 2016-03-27 00:13 -0600
                        Re: Can you call a cell phone in the microwave? john <johnsefton288@gmail.com> - 2016-03-27 05:32 -0700
              Re: Can you call a cell phone in the microwave? HVAC <mr.hvac@gmail.com> - 2016-03-25 11:40 -0700
            Re: Can you call a cell phone in the microwave? isw <isw@witzend.com> - 2016-03-24 22:55 -0700
              Re: Can you call a cell phone in the microwave? benj <none@gmail.com> - 2016-03-25 05:18 -0400
                Re: Can you call a cell phone in the microwave? jimp@specsol.spam.sux.com - 2016-03-25 18:11 +0000
                Re: Can you call a cell phone in the microwave? isw <isw@witzend.com> - 2016-03-25 21:39 -0700
                  Re: Can you call a cell phone in the microwave? jimp@specsol.spam.sux.com - 2016-03-26 05:08 +0000
                  Re: Can you call a cell phone in the microwave? benj <none@gmail.com> - 2016-03-26 01:57 -0400
                    Re: Can you call a cell phone in the microwave? jimp@specsol.spam.sux.com - 2016-03-26 17:57 +0000
              Re: Can you call a cell phone in the microwave? jimp@specsol.spam.sux.com - 2016-03-25 18:10 +0000
    Re: Can you call a cell phone in the microwave? James McGinn <jimmcginn9@gmail.com> - 2016-03-29 21:31 -0700

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#565384

Frombenj <none@gmail.com>
Date2016-03-25 05:18 -0400
Message-ID<7o7Jy.81291$LP.47674@fx16.iad>
In reply to#565363
On 03/25/2016 01:55 AM, isw wrote:
> In article <ucdcsc-3tf.ln1@mail.specsol.com>, jimp@specsol.spam.sux.com
> wrote:
>
>> isw <isw@witzend.com> wrote:
>>> In article <nct6bl$1rj$1@dont-email.me>,
>>>   Poutnik <poutnik4nntp@gmail.com> wrote:
>>>
>>>> Dne 22/03/2016 v 22:43 Sergio napsal(a):
>>>>> On 3/22/2016 3:16 PM, Sam Wormley wrote:
>>>>>> Can you call a cell phone in the microwave?
>>>>>>> https://www.youtube.com/watch?v=ot4_jVFXxUU
>>>>>>
>>>>>>> Do cell phones placed in a microwave still receive signals? What is
>>>>>>> the difference between microwave oven radiation and the signals used
>>>>>>> by your phone?
>>>>>>
>>>>>
>>>>> put your cellie in the microwave for 10 min on high.
>>>>>
>>>>> report back here on what happened.
>>>>>
>>>>
>>>> Question is not related to active oven mode.
>>>>
>>>> But as frequency of cell phone signal 900-1800 MHz
>>>> is similar to one of Microwave oven - AFAIK 2400 MHz ,
>>>> attenuation of the Faraday cage of the oven shielding
>>>> should be comparable.
>>>
>>> The metal box should work fine as a shield. The choke-joint door seal,
>>> maybe not. To work properly, it needs to be very close to a quarter-wave
>>> at the desired frequency.
>>>
>>> Isaac
>>
>> A quarter wave at 2.45 GHz is 3 cm.
>>
>> I just looked at my microwave and there is nothing on the door that is
>> anywhere near 3 cm in size.
>
> It's behind the plastic "frame" on the inside of the door. It'll be
> folded into an "L" shape to keep the door from being so thick.
>
> <https://en.wikipedia.org/wiki/Waveguide_flange>
>
> Isaac
>
Microwave doors do not have choke-joints! They simply use the flat thin 
gap between the door face and the oven face as an attenuator. Because 
the gap is much less than a wavelength the waves are evanescent and 
decay rapidly just as the waves through the holes in the mesh you look 
through into the oven. Evanescent attenuation is not resonant and hence 
very insensitive to distance (like door gets old). Microwave ovens have 
switches so that if door is not closed tight (and gap small) it won't 
operate.

-- 

       ___           ___           ___            ___
      /\  \         /\  \         /\__\          /\  \
     /::\  \       /::\  \       /::|  |         \:\  \
    /:/\:\  \     /:/\:\  \     /:|:|  |     ___ /::\__\
   /::\~\:\__\   /::\~\:\  \   /:/|:|  |__  /\  /:/\/__/
  /:/\:\ \:|__| /:/\:\ \:\__\ /:/ |:| /\__\ \:\/:/  /
  \:\~\:\/:/  / \:\~\:\ \/__/ \/__|:|/:/  /  \::/  /
   \:\ \::/  /   \:\ \:\__\       |:/:/  /    \/__/
    \:\/:/  /     \:\ \/__/       |::/  /
     \::/__/       \:\__\         /:/  /
      ~~            \/__/         \/__/

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#565531

Fromjimp@specsol.spam.sux.com
Date2016-03-25 18:11 +0000
Message-ID<ljbgsc-s1t.ln1@mail.specsol.com>
In reply to#565384
benj <none@gmail.com> wrote:
> On 03/25/2016 01:55 AM, isw wrote:
>> In article <ucdcsc-3tf.ln1@mail.specsol.com>, jimp@specsol.spam.sux.com
>> wrote:
>>
>>> isw <isw@witzend.com> wrote:
>>>> In article <nct6bl$1rj$1@dont-email.me>,
>>>>   Poutnik <poutnik4nntp@gmail.com> wrote:
>>>>
>>>>> Dne 22/03/2016 v 22:43 Sergio napsal(a):
>>>>>> On 3/22/2016 3:16 PM, Sam Wormley wrote:
>>>>>>> Can you call a cell phone in the microwave?
>>>>>>>> https://www.youtube.com/watch?v=ot4_jVFXxUU
>>>>>>>
>>>>>>>> Do cell phones placed in a microwave still receive signals? What is
>>>>>>>> the difference between microwave oven radiation and the signals used
>>>>>>>> by your phone?
>>>>>>>
>>>>>>
>>>>>> put your cellie in the microwave for 10 min on high.
>>>>>>
>>>>>> report back here on what happened.
>>>>>>
>>>>>
>>>>> Question is not related to active oven mode.
>>>>>
>>>>> But as frequency of cell phone signal 900-1800 MHz
>>>>> is similar to one of Microwave oven - AFAIK 2400 MHz ,
>>>>> attenuation of the Faraday cage of the oven shielding
>>>>> should be comparable.
>>>>
>>>> The metal box should work fine as a shield. The choke-joint door seal,
>>>> maybe not. To work properly, it needs to be very close to a quarter-wave
>>>> at the desired frequency.
>>>>
>>>> Isaac
>>>
>>> A quarter wave at 2.45 GHz is 3 cm.
>>>
>>> I just looked at my microwave and there is nothing on the door that is
>>> anywhere near 3 cm in size.
>>
>> It's behind the plastic "frame" on the inside of the door. It'll be
>> folded into an "L" shape to keep the door from being so thick.
>>
>> <https://en.wikipedia.org/wiki/Waveguide_flange>
>>
>> Isaac
>>
> Microwave doors do not have choke-joints! They simply use the flat thin 
> gap between the door face and the oven face as an attenuator. Because 
> the gap is much less than a wavelength the waves are evanescent and 
> decay rapidly just as the waves through the holes in the mesh you look 
> through into the oven. Evanescent attenuation is not resonant and hence 
> very insensitive to distance (like door gets old). Microwave ovens have 
> switches so that if door is not closed tight (and gap small) it won't 
> operate.
 
That would describe my oven.


-- 
Jim Pennino

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#565668

Fromisw <isw@witzend.com>
Date2016-03-25 21:39 -0700
Message-ID<isw-62247E.21395725032016@news-roam.garlic.com>
In reply to#565384
In article <7o7Jy.81291$LP.47674@fx16.iad>, benj <none@gmail.com> 
wrote:

> On 03/25/2016 01:55 AM, isw wrote:
> > In article <ucdcsc-3tf.ln1@mail.specsol.com>, jimp@specsol.spam.sux.com
> > wrote:
> >
> >> isw <isw@witzend.com> wrote:
> >>> In article <nct6bl$1rj$1@dont-email.me>,
> >>>   Poutnik <poutnik4nntp@gmail.com> wrote:
> >>>
> >>>> Dne 22/03/2016 v 22:43 Sergio napsal(a):
> >>>>> On 3/22/2016 3:16 PM, Sam Wormley wrote:
> >>>>>> Can you call a cell phone in the microwave?
> >>>>>>> https://www.youtube.com/watch?v=ot4_jVFXxUU
> >>>>>>
> >>>>>>> Do cell phones placed in a microwave still receive signals? What is
> >>>>>>> the difference between microwave oven radiation and the signals used
> >>>>>>> by your phone?
> >>>>>>
> >>>>>
> >>>>> put your cellie in the microwave for 10 min on high.
> >>>>>
> >>>>> report back here on what happened.
> >>>>>
> >>>>
> >>>> Question is not related to active oven mode.
> >>>>
> >>>> But as frequency of cell phone signal 900-1800 MHz
> >>>> is similar to one of Microwave oven - AFAIK 2400 MHz ,
> >>>> attenuation of the Faraday cage of the oven shielding
> >>>> should be comparable.
> >>>
> >>> The metal box should work fine as a shield. The choke-joint door seal,
> >>> maybe not. To work properly, it needs to be very close to a quarter-wave
> >>> at the desired frequency.
> >>>
> >>> Isaac
> >>
> >> A quarter wave at 2.45 GHz is 3 cm.
> >>
> >> I just looked at my microwave and there is nothing on the door that is
> >> anywhere near 3 cm in size.
> >
> > It's behind the plastic "frame" on the inside of the door. It'll be
> > folded into an "L" shape to keep the door from being so thick.
> >
> > <https://en.wikipedia.org/wiki/Waveguide_flange>
> >
> > Isaac
> >
> Microwave doors do not have choke-joints! They simply use the flat thin 
> gap between the door face and the oven face as an attenuator. Because 
> the gap is much less than a wavelength the waves are evanescent and 
> decay rapidly just as the waves through the holes in the mesh you look 
> through into the oven. Evanescent attenuation is not resonant and hence 
> very insensitive to distance (like door gets old). Microwave ovens have 
> switches so that if door is not closed tight (and gap small) it won't 
> operate.

If evanescent wave attenuation works so well, why are the obviously more 
expensive choke joints used almost universally on waveguides?

Isaac

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#565670

Fromjimp@specsol.spam.sux.com
Date2016-03-26 05:08 +0000
Message-ID<s3ihsc-gn3.ln1@mail.specsol.com>
In reply to#565668
isw <isw@witzend.com> wrote:

> If evanescent wave attenuation works so well, why are the obviously more 
> expensive choke joints used almost universally on waveguides?
> 
> Isaac


Maybe because standard waveguide is designed to handle power levels about
6 orders of magnitude greater than microwave ovens.


-- 
Jim Pennino

[toc] | [prev] | [next] | [standalone]

#565685

Frombenj <none@gmail.com>
Date2016-03-26 01:57 -0400
Message-ID<XwpJy.197319$Ia.108033@fx08.iad>
In reply to#565668
On 03/26/2016 12:39 AM, isw wrote:
> In article <7o7Jy.81291$LP.47674@fx16.iad>, benj <none@gmail.com>
> wrote:
>
>> On 03/25/2016 01:55 AM, isw wrote:
>>> In article <ucdcsc-3tf.ln1@mail.specsol.com>, jimp@specsol.spam.sux.com
>>> wrote:
>>>
>>>> isw <isw@witzend.com> wrote:
>>>>> In article <nct6bl$1rj$1@dont-email.me>,
>>>>>    Poutnik <poutnik4nntp@gmail.com> wrote:
>>>>>
>>>>>> Dne 22/03/2016 v 22:43 Sergio napsal(a):
>>>>>>> On 3/22/2016 3:16 PM, Sam Wormley wrote:
>>>>>>>> Can you call a cell phone in the microwave?
>>>>>>>>> https://www.youtube.com/watch?v=ot4_jVFXxUU
>>>>>>>>
>>>>>>>>> Do cell phones placed in a microwave still receive signals? What is
>>>>>>>>> the difference between microwave oven radiation and the signals used
>>>>>>>>> by your phone?
>>>>>>>>
>>>>>>>
>>>>>>> put your cellie in the microwave for 10 min on high.
>>>>>>>
>>>>>>> report back here on what happened.
>>>>>>>
>>>>>>
>>>>>> Question is not related to active oven mode.
>>>>>>
>>>>>> But as frequency of cell phone signal 900-1800 MHz
>>>>>> is similar to one of Microwave oven - AFAIK 2400 MHz ,
>>>>>> attenuation of the Faraday cage of the oven shielding
>>>>>> should be comparable.
>>>>>
>>>>> The metal box should work fine as a shield. The choke-joint door seal,
>>>>> maybe not. To work properly, it needs to be very close to a quarter-wave
>>>>> at the desired frequency.
>>>>>
>>>>> Isaac
>>>>
>>>> A quarter wave at 2.45 GHz is 3 cm.
>>>>
>>>> I just looked at my microwave and there is nothing on the door that is
>>>> anywhere near 3 cm in size.
>>>
>>> It's behind the plastic "frame" on the inside of the door. It'll be
>>> folded into an "L" shape to keep the door from being so thick.
>>>
>>> <https://en.wikipedia.org/wiki/Waveguide_flange>
>>>
>>> Isaac
>>>
>> Microwave doors do not have choke-joints! They simply use the flat thin
>> gap between the door face and the oven face as an attenuator. Because
>> the gap is much less than a wavelength the waves are evanescent and
>> decay rapidly just as the waves through the holes in the mesh you look
>> through into the oven. Evanescent attenuation is not resonant and hence
>> very insensitive to distance (like door gets old). Microwave ovens have
>> switches so that if door is not closed tight (and gap small) it won't
>> operate.
>
> If evanescent wave attenuation works so well, why are the obviously more
> expensive choke joints used almost universally on waveguides?

Because the purpose of the choke in a guide is to allow the energy to go 
DOWN the guide without loss at joints. In a door the purpose of the seal 
is to keep energy from leaking out at dangerous levels. Since the 
microwave has lots of power if a little energy is lost in evanescent 
waves (by definition lossy) it makes no difference. The point is you 
don't want the radiation out where people will have their hands etc. So 
long as the gap is small there is no problem. This is why there is a 
switch on the door that turns off the oven if someone tries to close the 
door on a towel or something that widens the gap. User manual usually 
warns about keeping door gap clean, free of food, or corrosion etc.

-- 

       ___           ___           ___            ___
      /\  \         /\  \         /\__\          /\  \
     /::\  \       /::\  \       /::|  |         \:\  \
    /:/\:\  \     /:/\:\  \     /:|:|  |     ___ /::\__\
   /::\~\:\__\   /::\~\:\  \   /:/|:|  |__  /\  /:/\/__/
  /:/\:\ \:|__| /:/\:\ \:\__\ /:/ |:| /\__\ \:\/:/  /
  \:\~\:\/:/  / \:\~\:\ \/__/ \/__|:|/:/  /  \::/  /
   \:\ \::/  /   \:\ \:\__\       |:/:/  /    \/__/
    \:\/:/  /     \:\ \/__/       |::/  /
     \::/__/       \:\__\         /:/  /
      ~~            \/__/         \/__/

[toc] | [prev] | [next] | [standalone]

#565776

Fromjimp@specsol.spam.sux.com
Date2016-03-26 17:57 +0000
Message-ID<05visc-uua.ln1@mail.specsol.com>
In reply to#565685
benj <none@gmail.com> wrote:
> On 03/26/2016 12:39 AM, isw wrote:

<snip>

>> If evanescent wave attenuation works so well, why are the obviously more
>> expensive choke joints used almost universally on waveguides?
> 
> Because the purpose of the choke in a guide is to allow the energy to go 
> DOWN the guide without loss at joints. In a door the purpose of the seal 
> is to keep energy from leaking out at dangerous levels. Since the 
> microwave has lots of power if a little energy is lost in evanescent 
> waves (by definition lossy) it makes no difference. The point is you 
> don't want the radiation out where people will have their hands etc. So 
> long as the gap is small there is no problem. This is why there is a 
> switch on the door that turns off the oven if someone tries to close the 
> door on a towel or something that widens the gap. User manual usually 
> warns about keeping door gap clean, free of food, or corrosion etc.

Microwave ovens have lots of power compared to cell phones, but that is
about it.

Consumer microwave ovens typically run from about 500 W to 1 kW.

The smallest radar I ever worked on was 5 kW and most where in the
hundreds of kilowatt range with some well over 10 MW.
 
It is in such equipment where standardized, choke jointed waveguide is
used.


-- 
Jim Pennino

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#565530

Fromjimp@specsol.spam.sux.com
Date2016-03-25 18:10 +0000
Message-ID<hhbgsc-s1t.ln1@mail.specsol.com>
In reply to#565363
isw <isw@witzend.com> wrote:
> In article <ucdcsc-3tf.ln1@mail.specsol.com>, jimp@specsol.spam.sux.com 
> wrote:
> 
>> isw <isw@witzend.com> wrote:
>> > In article <nct6bl$1rj$1@dont-email.me>,
>> >  Poutnik <poutnik4nntp@gmail.com> wrote:
>> > 
>> >> Dne 22/03/2016 v 22:43 Sergio napsal(a):
>> >> > On 3/22/2016 3:16 PM, Sam Wormley wrote:
>> >> >> Can you call a cell phone in the microwave?
>> >> >>> https://www.youtube.com/watch?v=ot4_jVFXxUU
>> >> >>
>> >> >>> Do cell phones placed in a microwave still receive signals? What is
>> >> >>> the difference between microwave oven radiation and the signals used
>> >> >>> by your phone?
>> >> >>
>> >> > 
>> >> > put your cellie in the microwave for 10 min on high.
>> >> > 
>> >> > report back here on what happened.
>> >> > 
>> >> 
>> >> Question is not related to active oven mode.
>> >> 
>> >> But as frequency of cell phone signal 900-1800 MHz
>> >> is similar to one of Microwave oven - AFAIK 2400 MHz ,
>> >> attenuation of the Faraday cage of the oven shielding
>> >> should be comparable.
>> > 
>> > The metal box should work fine as a shield. The choke-joint door seal, 
>> > maybe not. To work properly, it needs to be very close to a quarter-wave 
>> > at the desired frequency.
>> > 
>> > Isaac
>> 
>> A quarter wave at 2.45 GHz is 3 cm.
>> 
>> I just looked at my microwave and there is nothing on the door that is
>> anywhere near 3 cm in size.
> 
> It's behind the plastic "frame" on the inside of the door. It'll be 
> folded into an "L" shape to keep the door from being so thick.
>  
> <https://en.wikipedia.org/wiki/Waveguide_flange>
> 
> Isaac

Nope, the dimensions don't allow it.

-- 
Jim Pennino

[toc] | [prev] | [next] | [standalone]

#566588

FromJames McGinn <jimmcginn9@gmail.com>
Date2016-03-29 21:31 -0700
Message-ID<3791050e-1b15-4d6a-9446-ca063634ee7c@googlegroups.com>
In reply to#564624
On Tuesday, March 22, 2016 at 1:16:40 PM UTC-7, Sam Wormley wrote:
> Can you call a cell phone in the microwave?
> > https://www.youtube.com/watch?v=ot4_jVFXxUU
> 
> > Do cell phones placed in a microwave still receive signals? What is
> > the difference between microwave oven radiation and the signals used
> > by your phone?
> 
> 
> 
> 
> -- 
> 

> sci.physics is an unmoderated newsgroup dedicated
> to the discussion of physics, news from the physics
> community, and physics-related social issues.

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