Faraday Cage

[nfernaays]

I have been kicking around the idea of building a faraday cage. I have always heard you can take a metal trash can, line it with cardboard and this would be a simple faraday cage...After rearranging some gear this weekend i have a spare steel gun cabinet.

Looks like this:



It has a few holes in it for mounting etc. do these need to be filled before lining?

Should i line it with anything other than cardboard?

All suggestions and comments are welcome.

I figure this will be big enough to hold my radio equipment, spare laptop and desktop plus additional electronics with no problem.

 

[spat]

I have been kicking around the idea of building a faraday cage. I have always heard you can take a metal trash can, line it with cardboard and this would be a simple faraday cage...After rearranging some gear this weekend i have a spare steel gun cabinet.

Looks like this:

View attachment 7526

It has a few holes in it for mounting etc. do these need to be filled before lining?

Should i line it with anything other than cardboard?

All suggestions and comments are welcome.

I figure this will be big enough to hold my radio equipment, spare laptop and desktop plus additional electronics with no problem.

More important than filling small mounting holes would be ensuring that the door is electrically bonded to the body, preferably around the entire opening.

Honestly to make an accurate recommendation, you would need to know both the allowable level of radiation for the devices you are protecting, and the level of EMP you are looking to protect them from. In many cases just wrapping them properly in aluminum foil would protect them.

 

[nfernaays]

More important than filling small mounting holes would be ensuring that the door is electrically bonded to the body, preferably around the entire opening.

Any suggestions on how going about this?

 

[spat]

Any suggestions on how going about this?

The commercial version of EMP proofing, is EMI (electro magnetic interference) shielding, in industrial equipment where this is required they use fingers. They are designed to prevent EMP radiation from leaking out and interfering with nearby equipment, and to make equipment resistant to interference from nearby equipment, an EMP is just EMI on steroids.


http://www.orbel.com/emi-rfi-shielding/finger-stock


I don't know what they cost new, it's probably cheaper to get some obsolete router or switch off eBay and cannibalize it. .

 

[Drinkthekoolaid]

I have a steel garbage can totally lined with cardboard on all the inside (including inside the lid). I have items inside wrapped in an insulating layer then aluminum foiled over that and then placed inside my can. With the can lid tightly attached on the can, I wrap the gap where the lid over hangs the edge of the can with an aluminum foil tape to try and seal it better for conducting around the surface.

It is not grounded

Hopefully I never have to find out if it works or not.

 

[Phauxtoe]

I know when I go sailing and we get caught in a thunderstorm we put all the electronics in the oven

I believe that's a faraday cage

 

[Drinkthekoolaid]

I know when I go sailing and we get caught in a thunderstorm we put all the electronics in the oven

I believe that's a faraday cage

Microwaves have same idea too. They have that mesh metal screen in the window

 

[Uzi]

Yes, All holes and cracks must be filled, and not with cardboard.

Don't even waste your time trying to make a safe work. Sure, you might be able to seal the holes, but you'll also need to seal the door too, and very well. On a hinged door, that won't be practical. A good way to test one is by using a walky talky and seeing if it gets a signal through. I wouldn't even bother trying it.

 

[FrankenCub]

Don't you need to have them grounded to give the EMI a path to follow away from what you're trying to protect?

I used to side houses with my uncle and aluminum siding was really good to tell us when a storm was coming in. Long before a storm was on us we could feel a tingle in the siding every so often. As the frequency of the tingling increased we would call it a day and go checking out motorcycles at the shops. Weird experience the first time.

 

[Jackalope]

A microwave as a faraday cage is a myth. Try putting your cell phone is a microwave and then call it, more than likely the cellphone will ring, if you're in a good signal location in the first place. The ring test will prove how porous the microwave is for RF energy The galvanized garbage can with the foil around the top edge works well. Rather than cardboard you can use a heavy duty contractor type garbage bag to line the can. If you're really concerned about EMP, you could place your equipment in a cardboard box, then wrap the box with aluminum foil, then place the foil wrapped box inside another cardboard box, then place that inside a metal garbage can. Multi layer protection is your friend, but it's a pain in the ass to access the equipment, if you need to do so on a regular basis.

 

[Jackalope]

There's no need to electrically ground the can. Think about it, aircraft get hit by lightning all the time, and they're not electrically grounded. Sure, occasionally an aircraft is damaged, but most of the time the charge is dissipated over the skin of the aircraft, the same thing occurs when an automobile is struck.

 

[FrankenCub]

Yeah good point

 

[Marine Cpl]

I'm not trying to be a wise ass but why not get EMP Bags and throw them in an unprotected safe and save yourself the trouble?

EMP Bags - Home

 

[Drinkthekoolaid]

Don't you need to have them grounded to give the EMI a path to follow away from what you're trying to protect?

I used to think it had to be grounded, but after listening to a bunch of YouTube guys (obviously they are smart and must be right) I no longer think you need to ground the faradat cage, and according to what I saw some guys even think it might be detrimental. So who knows....

I have made peace with the route I've chosen to try and make a faraday cage. The honest truth is there isnt a ton of practical research (at least available to the general public) into what would or wouldn't work with certainty to protect from emp waves.

I just hope I never have to find out if my system works or not.


What do you guys have in your faraway cages?

I think in mine I have some hand held 2way radios, a baofeng ham radio, a solar powered emergency AM/FM hand crank radio and charger, an old cell phone, and a think a few other things, maybe a flashlight or something.

Next up on my list is I need to get some solar panel portable chargers and rechargeable batteries and protect them as well.

 

[gun_slinger_boy]

Is there an impending EMP attack that I'm not privy to?

 

[Drinkthekoolaid]

Is there an impending EMP attack that I'm not privy to?

No...and if there was none of us peons would be alerted to it anyway.

Surprise attacks are surprise for a reason

So who knows?

Also the threat of CME (coronal mass ejection) which would have a similar effect. Coincidentally there is actually a large sun spot facing earths direction right now...

 

[Eddie Gunks]

A microwave as a faraday cage is a myth. Try putting your cell phone is a microwave and then call it, more than likely the cellphone will ring, if you're in a good signal location in the first place. The ring test will prove how porous the microwave is for RF energy .

Really? All the microwaves i have tried the cell phone test on worked perfect. No ring. No message. No missed call shown.

Buy a better microwave?


.

 

[spat]

I used to think it had to be grounded, but after listening to a bunch of YouTube guys (obviously they are smart and must be right) I no longer think you need to ground the faradat cage, and according to what I saw some guys even think it might be detrimental. So who knows....

I have made peace with the route I've chosen to try and make a faraday cage. The honest truth is there isnt a ton of practical research (at least available to the general public) into what would or wouldn't work with certainty to protect from emp waves.

I just hope I never have to find out if my system works or not


What do you guys have in your faraway cages?

I think in mine I have some hand held 2way radios, a baofeng ham radio, a solar powered emergency AM/FM hand crank radio and charger, an old cell phone, and a think a few other things, maybe a flashlight or something.

Next up on my list is I need to get some solar panel portable chargers and rechargeable batteries and protect them as well.

What you really want is a solar charger, and a cheap tablet w/ some SD cards full of every bit of information you think you might ever need.

Did you know that all of Wikipedia will fit on an SD card with room to spare ?

I really think that is one thing the prepper community needs is a community maintained "SHTF Archive", that you can download and copy off to a safe place. It should have all the documentation on how to do all the stuff that people won't bother learning till they need it.

Learning a bunch of useful skills is great, but if the whole world changes you have no idea what lll really be useful. Being a decent mechanic is a great skill to have, until the group you end up in has 5. You never know what the future will bring, who knows what skill will end up in demand. Maybe the basket weaver is going to be the guy who can name his price when the community has a dozen mechanics and 2 vehicles, and 1/3 of the people are nurses and doctors.

Learning to shoe a horse is great, but if you don't have any of them now, it's a waste of your time.

 

[Jackalope]

Regarding using a microwave oven as a faraday cage for your electronics, here's a short basic video showing how microwaves don't necessarily block cellular signals: Yeah, SOME microwaves may block SOME cellular signals, but I wouldn't trust precious electronics to a half-assed solution. Microwave ovens may block radio frequency signals at certain frequencies and certain amplitudes, but do you know what amplitude and what frequency the EMP will generate? Here's another article will details that a microwave oven as a faraday cage is effective only at a certain range of frequencies: Microwave Ovens Are NOT Good Faraday Cages I work with RF energy, and the article makes sense, RF energy can be very difficult to block or contain at certain frequencies and amplitudes. You can bet that my electronics equipment isn't sitting in a microwave.

 

[nfernaays]

A microwave as a faraday cage is a myth. Try putting your cell phone is a microwave and then call it, more than likely the cellphone will ring, if you're in a good signal location in the first place. The ring test will prove how porous the microwave is for RF energy The galvanized garbage can with the foil around the top edge works well. Rather than cardboard you can use a heavy duty contractor type garbage bag to line the can. If you're really concerned about EMP, you could place your equipment in a cardboard box, then wrap the box with aluminum foil, then place the foil wrapped box inside another cardboard box, then place that inside a metal garbage can. Multi layer protection is your friend, but it's a pain in the ass to access the equipment, if you need to do so on a regular basis.

Looks like i will go this route, put more emp proof ammo in my old gun locker

 

[spat]

Regarding using a microwave oven as a faraday cage for your electronics, here's a short basic video showing how microwaves don't necessarily block cellular signals: Yeah, SOME microwaves may block SOME cellular signals, but I wouldn't trust precious electronics to a half-assed solution. Microwave ovens may block radio frequency signals at certain frequencies and certain amplitudes, but do you know what amplitude and what frequency the EMP will generate? Here's another article will details that a microwave oven as a faraday cage is effective only at a certain range of frequencies: Microwave Ovens Are NOT Good Faraday Cages I work with RF energy, and the article makes sense, RF energy can be very difficult to block or contain at certain frequencies and amplitudes. You can bet that my electronics equipment isn't sitting in a microwave.

A microwave is designed to be "tight" to 2.4ghz radiation, cause that's what it contains. It will also work for many other frequencies, to varying degrees for the same reason you can drive a nail with a crescent wrench.

As a plan, a microwave is not good, in an emergency (I can't even imagine the circumstances where you would have a minutes notice for an EMP, but whatever...) it's better than nothing.

If I had a minute, and a choice between a roll of AL foil and a microwave to protect my cell phone, I'd take the foil. Really, I'd wrap the sucker a dozen times, then stick it in the microwave, but as a long term plan, no.

For the record, cell frequency depends in carrier, Verizon is in the 700mhz range, others are right around the 2.4ghz the microwave is designed to stop.

As far as holes in your cage, it is a complex interaction between hole size, radiation frequency, and the distance from the hole inside the cage. Suffice to say, smaller holes and more distance are better, you are unlikely to have control over the frequency (which for an EMP will be a very broad band anyway). A faraday cage does not need be airtight, a screen or mesh, if fine enough and conductive enough, and well bonded to the rest of the cage is nearly as good as a solid plate.

 

[gun_slinger_boy]

What about good ol' lead?

 

[FrankenCub]

What you really want is a solar charger, and a cheap tablet w/ some SD cards full of every bit of information you think you might ever need.

Did you know that all of Wikipedia will fit on an SD card with room to spare ?

I really think that is one thing the prepper community needs is a community maintained "SHTF Archive", that you can download and copy off to a safe place. It should have all the documentation on how to do all the stuff that people won't bother learning till they need it.

Learning a bunch of useful skills is great, but if the whole world changes you have no idea what lll really be useful. Being a decent mechanic is a great skill to have, until the group you end up in has 5. You never know what the future will bring, who knows what skill will end up in demand. Maybe the basket weaver is going to be the guy who can name his price when the community has a dozen mechanics and 2 vehicles, and 1/3 of the people are nurses and doctors.

Learning to shoe a horse is great, but if you don't have any of them now, it's a waste of your time.

I wouldn't go cheap with a tablet, which is a good idea to have one, you can have any information you'd ever need on one. Especially great for maps. We've bought at least 15 cheap ones of with many were returned on warranty for replacements, and others just tossed to try another brand. They are made so damn cheesy they aren't worth the time. I would buy a good reputable brand and be done with it. No more cheap ones for me. There is a Chinese one that I do still own, Ainol or something like that. Built like a tank and fairly heavy for it's size. It has been flawless, even better after install of a custom OS. I also have an iPad which has been nothing but problems the past year but I believe that because Apple wants it that way to force you to upgrade after enough OS updates. I may see if I can flash a different OS to it, otherwise it's going in the trash.

 

[gun_slinger_boy]

Ainol tablet. A tragic name indeed.

 

[FrankenCub]

Ainol tablet. A tragic name indeed.

lol yeah right, the Chinese don't seem to realize how their names translate to English. For instance, the receiver I and thousands of other people use in our RC planes is made by a company called Lemon. They are outstanding receivers and priced super, but that name lmao
It's been a great tablet though.

 

[spat]

What about good ol' lead?

Conductivity is the goal, copper or aluminum is better.

 

[spat]

I wouldn't go cheap with a tablet, which is a good idea to have one, you can have any information you'd ever need on one. Especially great for maps. We've bought at least 15 cheap ones of with many were returned on warranty for replacements, and others just tossed to try another brand. They are made so damn cheesy they aren't worth the time. I would buy a good reputable brand and be done with it. No more cheap ones for me. There is a Chinese one that I do still own, Ainol or something like that. Built like a tank and fairly heavy for it's size. It has been flawless, even better after install of a custom OS. I also have an iPad which has been nothing but problems the past year but I believe that because Apple wants it that way to force you to upgrade after enough OS updates. I may see if I can flash a different OS to it, otherwise it's going in the trash.

A cheap tablet you will leave in the box is better than a nice one that will get borrowed. Better would be 2.

If you can put a good one in and leave it alone, then by all means, but this one will never connect to network, let alone the internet, and will not be running apps, so basically documents and video is all it has to handle.

Really a Kindle is ideal for most of the documents, since they have massive battery life and are readable in bright sun, but you may want some other info that they won't display too.

 

[FrankenCub]

A cheap tablet you will leave in the box is better than a nice one that will get borrowed. Better would be 2.

If you can put a good one in and leave it alone, then by all means, but this one will never connect to network, let alone the internet, and will not be running apps, so basically documents and video is all it has to handle.

Really a Kindle is ideal for most of the documents, since they have massive battery life and are readable in bright sun, but you may want some other info that they won't display too.

And most of the time those cheap tablets wont even handle basic functions for more than a few days. Seriously, we've been through a bunch of them. They will turn into bricks. A Kindle would be fine, they have a great track record.