How do I make sure that my faraday cage will ensure safety for electronics devices in case of a nuclear warfare?

I don't know if this is a test to ensure it will work, but I've heard it is a decent test to see if it likely won't work. Just put a small radio on and tuned to a very strong FM station in the cage. If there is any actual signal reaching the radio, the cage is flawed and is likely to not work as there are gaps in it or the signal is penetrating the cage somehow. Radio, light, all just electromagnetic radiation, so - if you can possibly see through it, or get a radio signal through it, an EMP wavelenght with be electromagnetic radiation of a different frequency, but IMHO a cage should effectivly protect for all electromagnetic radiation, or I don't see it as likely to work if it takes a good hit from a pulse, and small electronics will risk delicate components being damaged.

I just use a couple galvanized trash cans with lids lined with cardboard. most of the items are in cardboard boxes so I wrap them in aluminum foil just for additional protection and then they go in the can. Would it work, who knows? never mind all the opions about if the cage should be grounded or not. I think not, but there are varying opinions.

Life Enjoyer said:

First problem is that I went on Amazon and found this huge table of specifications unknown to me.

Spoiler: table

What are the main characteristics I should care about?

and the second problem is that I could order anything from Amazon but how do I check the reliability on my own? That those specifications are not a lie.

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Besides the specs listed, which are standardized, you can trust em imo.

Now, i have mission darkness stuff becasue is ws suggested to me by a fellow whose life depended upon operating covertly in denied areas and avoid elint/igint tracking.

The bags i have work, per the normal bubba tests....

stick phone in bag, wait a minute or two, try to call it, if it rings, it failed, if it goes to vm or doesn't ring, good to go..

you can also try small radios, two way radios, etc.,

Good luck

ps..you can also bild your own a metal garbage can, cardboard, metal duct tape....

irv818 said:

The phone test means just about nothing. See here for the reason:

My Ammo Can Faraday Cage Test.

I picked up a NVG case and wanted to test it's effectiveness as a Faraday Cage. (An NVG case is like a U.S. Military Ammo can with foam inside for protecting Night Vision Goggles.) I don’t have an isolated location where I can conduct actual EMP testing without frying the neighbors house and I...

www.survivalistboards.com

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a phone or radio test can tell you at a basic level if the cage is shielding electromagnetic radiation. so a fail on this test certainly tells you there is an issue and for that reason it is worth doing. I'm unaware of any test that can tell you the shielding will protect against a nuclear emp pulse or major solar flair, outside of a very expensive and complicated test lab environment, and still the results are theoretical.

I kind of wonder, since heat from a wood stove, is also electromagnetic radiation - if one could put a thermometer in their cage, at a certain distance from a wood stove, and use that to evaluate effectiveness of shielding electromagnetic radiation. Not that one wavelenth of EMR behaves the same as another, but who knows what it could actually be?

Current clamp - Wikipedia
Supposedly there is a way to simulate a test with one of these. I guess you attach it to something in the cage, and then send an electical pulse to the cage and see if you come up with a reading on the equipment that is supposedly being protected. There are a few other simualtions to do testing, but I've never taken the time to mess with them and not sure I really get how to do them safely. Again, I don't know if the test will prove the cage will work, but it might indicate an issue with the set up if it fails.

irv818 said:

The phone test means just about nothing. See here for the reason:

My Ammo Can Faraday Cage Test.

I picked up a NVG case and wanted to test it's effectiveness as a Faraday Cage. (An NVG case is like a U.S. Military Ammo can with foam inside for protecting Night Vision Goggles.) I don’t have an isolated location where I can conduct actual EMP testing without frying the neighbors house and I...

www.survivalistboards.com

Click to expand...

I am not sure this test is valid. If you are inducing 10s or a hundred milivolts into the receiver of the radio it will pick up a signal however a few hundred millivolts will not damage your electronics. did they use a conducting gasket or copper tape around the edges? The idea here is to attenuate the signal. An ammo can will attenuate the signal especially if you sand off the paint and use an electrical gasket and copper tape around the edges. This will provide about 70 dB of attenuation. 3dB is half. 10 dB is reduction by a factor of 10. If my math is right, that will attenuate the signal by a factor of 10 million.

Still worried, use 2 ammo cans one inside the other.


To build a cage that will not allow any any electrical noise through will need to be thick with multiple layers and is not necessary to protect from EMP. Also EMP's main source of entry is going to be the miles of electrical lines not the few feet of traces on the circuit board. If you put the device in an ammo can then store that in a faraday cage it will likely survive even if a little gets through. If you are still worried drive a ground rod and ground the outer layer. An old microwave oven will also provide attenuation however do not ground it to the outside electrical lines.

EMP destroys devices by inducing high voltage that will kill the IC chips, transistors, inside. By attenuating the signal you reduce the impact. The real question for this test is not did it stop the signal but how much did it attenuate it.

bilmac said:

I play the odds. A perfect cage has a complete metal seal all round, and complete electrical insulation on the inside. A Behrens trash can with maybe a few pieces of metal tape over mini openings like around handles meets the "complete metal shell" standard. A good carefully done lining of soft foam meets the electrical standard. Then the can is in may cellar and grounded. I THINK that is good enough. I have some pretty expensive electronics like night vision in there.

If I thought I lived close to a place that might be a target, I would probably double my protection. A smaller can inside a bigger can, but I live in the middle of nowhere.

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A fariday cage has no requirement for insulation. Ive never seen a full size cage that is ever insulated- and most have been through EMP simulators ( for a first arctic le test). Why does anyone think a sheet foam is going to block an electromagnetic signal, and if it did, why not build the whol box of foam?

I have seen glove boxes that are insulated to prevent accidental shorting as something is probed or adjusted.

it’s just survival fiction. Usually the result of someone developing their on theory on how a faraday cage works. Just like claims that the cages have to be grounded.

ETA- the posted spec, all you care about is EMI attenuaction. It’s rated outside the power spectrial distribution of EMP, but if it’s 40 dB ( blocks 99.99% of energy) at 1 GHz, it’s still going to be effective at 100 MHz.