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How to hide from the electromagnetic spectrum/electrical pol

  1. Nov 30, 2014 #1
    Hello.
    I need help!
    is it possible to create a box/cage (ive seen the faraday cage etc) to give one 100% protection from all/some the electromagnetic spectrums - and from electrical pollution?
    "Nothing enters and nothing leaves" style, so it but cut out all that comes outside of it, and blocks anything from inside of it to go out.
    The important part is that it gives 100% protection from extremely low frequency radiowaves/and noise.

    What materials would you use to such a box?
     
  2. jcsd
  3. Nov 30, 2014 #2

    Dale

    Staff: Mentor

    You already mentioned a Faraday cage. That is it.
     
  4. Nov 30, 2014 #3
    it does not protect from extremely low freq noise/sound, just to say ;)
     
  5. Nov 30, 2014 #4

    Dale

    Staff: Mentor

    It does protect from low freq EM waves, as you said "radio waves and noise". If you meant acoustic noise then you should have said so.

    Soundproofing materials are also well known. You would need a Faraday shield for EM and soundproofing for acoustic shielding.
     
  6. Nov 30, 2014 #5

    Drakkith

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    Staff: Mentor

    It's not possible to block 100% of all EM radiation from entering or leaving, but you can get as arbitrarily close as you like, it just gets progressively more difficult the more you want to block out. A sealed box made out of thick metal would probably be the ideal container. What are you trying to shield? Do you need to be able to enter/exit the container regularly? Doors are very difficult to shield, as even a small crack or gap between the door and the door frame, or even dirt buildup between them, will let a great deal of EM radiation in.
     
  7. Nov 30, 2014 #6

    sophiecentaur

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    Gold Member

    It all depends how much money you want to spend. A thick copper box with welded seams and absolutely no holes or gaps will do a pretty good job (>100dB suppression) But in the limit, if you want to get measurement data in or out of your box (and Power supplies) then that gives the EM waves a way in and out. Even an optical link requires a 'hole' somewhere. People spend tens of thousands of pounds on good screened rooms.
     
  8. Nov 30, 2014 #7

    Drakkith

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    Staff: Mentor

    You should see the EMP shielded building my reserve unit works in... ;)
     
  9. Nov 30, 2014 #8
    It is hard to shield static and slowly varying magnetic fields
     
  10. Nov 30, 2014 #9

    nsaspook

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    If you want top performance get ready to spend real money but a tightly sealed metal trashcan can easily give 80 of effective shielding at most RF frequencies.

    Equipment container:
    tipsgraph.jpg

    Shielded room:
    il_series81_chart.gif

    Most of the shielding is from steel/galvanized steel laminate with copper mainly for grounds and beryllium or phosphor bronze contact fingers for doors.
     
    Last edited: Nov 30, 2014
  11. Dec 8, 2014 #10
    And by ''thick metal'' how thick and what metal? No i dont need to enter or exit, does this also give protection from microwave/or extremely low level of noise
     
  12. Dec 8, 2014 #11

    sophiecentaur

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    Gold Member

    The only way you can avoid some 'thing' entering or exiting is to have a battery operated device which records all its results in there. Any wires going in or out (or even holes for optical fibres) are potentially weak points in the screening.
    Before you go any further with this, you need to specify what level of screening you actually need. Only then can you decide if it's feasible or affordable or even a trivial problem. This is an Engineering problem and the numbers count.
    You might find the information in this link of interest.
     
  13. Dec 8, 2014 #12

    Drakkith

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    Staff: Mentor

    I can't tell you how thick since I don't know what you're actually trying to do. You can't block 100% of all electromagnetic interference, so you need to decide how much you want to block. Since I expect that you don't know how much you need to block, it would greatly help if you gave us the details on what you are trying to do.
     
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