Cheapass Faraday Cage

[Hirudinea]

So I was watching "Jericho" (ok so I have no fucking life, so, so what?) and nobody has any electronics, no radios, tvs, computers, etc... Well anyway I was wondering why nobody put a little radio in a Faraday cage?

I looked up making a faraday cage on the internet web and the best I got was a cardboard box wrapped in mylar, which seems a lot of work, so heres my idea.

Take two aluminum foil containers (the kind you get chinese food in), wrap your electronic goodie in a plastic bag, put in in one container, fold the lips of the bottom container down flat, put the top container on the bottom and fold the lips of the top container over the lips of the bottom (its pretty self explanitory it you have the two containers in front of you.)

This "Faraday cage" is ungrounded, to ground it I'ed take a piece of speaker wire, punch a whole in the lips of the joined containers, attach one end of the speaker wire to the containers ("faraday cage") and the other end to a ground (a cold water pipe or whatever) and when the EMP comes you'll be able to listen to doomsday top 40!

I've tried putting a radio in the container (not grounded) and it will cut out a lot of signal gain, but it STILL got a signal from a strong local AM station, so can you tell me if this POS would work in the real world and what I could do better, for $2 and 5 minutes of work?

[James]

I think I've seen this thread before. But anyways get a 55 galon drum and throw a replacement for all of your electronics in it. (don't forget to put the lid on) When the day comes, you will have your gadgets.

[Hirudinea]

[G]et a 55 galon drum and throw a replacement for all of your electronics in it. (don't forget to put the lid on) When the day comes, you will have your gadgets.

Yes but if I just wanted to store a portable radio/tv, in a bug out bag say, a 55 gallon drum would seem to be a bit of overkill.

Also individual storage containter (@ $.50 a piece) could make it easier to find things than digging through a barrel. By the way how much is a 55 gallon metal drum?

[IAMZERG]

By the way how much is a 55 gallon metal drum?

They are $25 a piece if you know where to look. I still haven't bought one, as I wouldn't have much use for it outside of storing stuff given my current location. I really want to make a charcoal retort with one in the future.

[LibertyOrDeath]

How's the conductivity of those drums? That's something I'd want to check before relying on one for EMP protection. Naturally, you want your container to be made of as highly conductive a material as possible.

[ex tech]

The conductivity isn't really what makes this type of Faraday cage work. In this case it has more to do with the wavelength of the emf you are trying to repel. In the case of a pulse, because the event is so short, the total power you are dealing with is not that great. therefore the one or two millimeter thick steel of the drum should be able to dissipate any energy that gets coupled into the drum. As an alternative, one can also use conductive screen. the only catch is that the holes in the screen must be smaller than half the wavelength of the emf it is intended to repel. so in the case of defense where you don't exactly know what you will be dealing with it would probably be best to use a solid container.

[Positron]

Hirudinea,

Pretty cool post. The reason that your faraday cage isn't working too well, is that you probably have some seams around the cage that are not truly connected together. It might look like it, and you might swear by it, but until all of the edges are soldered a hobbyist usually won't have the truly sealed metal enclosure which is needed to be effective.

The receive sensitivity of the radio you're using is quite high. AM radio stations typically BLAST power out (sometimes hundreds of kilowatts). Only a tiny amount of that signal has to get to the radio's front-end electronics to be detectable.

Fold up a steel window screen and put a radio inside. Solder all of the edges with a $3.00 Radio Shit soldering iron if you have to, and see if you hear any stations then.

There is no need (that I know of) for a human to be inside of the enclosure. I don't think that an atmospherically-propagated EMP can couple enough energy to the human body to cause damage. Semiconductor structures: Yes. Humans: Probably not.

Gotta seal those edges on things that aren't going to be soldered or welded. All mating surfaces must be clean and polished. If you've ever seen high-power RF electronics...all the doors have little brass "fingers" all over them for an electromagnetically-tight seal.

http://en.wikipedia.org/wiki/Faraday_cage

[Hirudinea]

Hirudinea,
Fold up a steel window screen and put a radio inside. Solder all of the edges with a $3.00 Radio Shit soldering iron if you have to, and see if you hear any stations then.

The steel screen idea sounds good, put a cheap radio in the screen cage and the screen cage in a plastic box and then your safe should EMP ever hit (and your cage won't get rusty in the box.

There is no need (that I know of) for a human to be inside of the enclosure.

Unless you think you have CIA implants! ;)

I don't think that an atmospherically-propagated EMP can couple enough energy to the human body to cause damage. Semiconductor structures: Yes. Humans: Probably not.

I believe EMP was 'discovered' when the U.S. explode a hydrogen bomb above the atmosphere over the pacific, it caused disruptions throughout Hiawaii (sp), knocked out power, radio, telephone, etc..., but nobody was hurt in the least, so I guess meat is safe from EMP.

[AustRanger]

i'm researching EMP generators for a project. I found a webpage going into a little depth on faraday cages, it claims:
Many containers are suitable for make-shift Faraday boxes: cake boxes, ammunition containers, metal filing cabinets, etc., etc., can all be used. Despite what you may have read or heard, these boxes do NOT have to be airtight due to the long wave length of EMP; boxes can be made of wire screen or other porous metal.

The only two requirements for protection with a Faraday box are: (1) the equipment inside the box does NOT touch the metal container (plastic, wadded paper, or cardboard can all be used to insulate it from the metal) and (2) the metal shield is continuous without any gaps between pieces or extra-large holes in it.

Grounding a Faraday box is NOT necessary...
the page has a whole lot of other info, check it out here: http://www.aussurvivalist.com/nuclear/empprotection.htm
and for anyone concerned, EMP does not cause harm to the human body.

[Gammaray1981]

Not as yet. What about in a few years? I, for one, want my music player implanted in my mastoid bone, and a titanium replacement for every one of my hand and wrist bones. Not to mention an aerial/microphone setup for completely hands-free phone calls.

Ten, fifteen years time, there'll be enough metal and electronics inside people to make EMP a potential problem. Even now, anyone with a pacemaker is at risk.

This is a GOOD reason for metal-encasing your nuclear bunker.