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Faraday Cage: How to Make on the Cheap
YouTube ^ | 1/6/12 | LDSPrepper

Posted on 05/15/2012 2:04:08 PM PDT by Kartographer

This may well be the best Faraday cage you can make on the cheap and the best Faraday cage at any price. I'm not saying that to brag but I really believe in this design. If you are at all concerned about protecting your electronic equipment from either a man made or solar EMP please consider making a Faraday storage cabinet like this. The cabinet cost me $100, the tape $32 and the aluminum insulation was free. You might be able to make this Faraday cage for less if you stop by construction sites and get left over aluminum insulation and ask for thirteen feet of aluminum duct tape.

(Excerpt) Read more at youtube.com ...


TOPICS: Miscellaneous
KEYWORDS: faradaycage; preparedness; preppers
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Another DIY project.
1 posted on 05/15/2012 2:04:18 PM PDT by Kartographer
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To: appalachian_dweller; OldPossum; DuncanWaring; VirginiaMom; CodeToad; goosie; kalee; ...

Preppers’ PING!


2 posted on 05/15/2012 2:05:48 PM PDT by Kartographer ("We mutually pledge to each other our lives, our fortunes and our sacred honor.")
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To: Godzilla; Quix; backwoods-engineer

PING!


3 posted on 05/15/2012 2:07:49 PM PDT by Kartographer ("We mutually pledge to each other our lives, our fortunes and our sacred honor.")
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To: Kartographer

Thanks, Kartographer.


4 posted on 05/15/2012 2:07:49 PM PDT by unkus (Silence Is Consent)
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To: Kartographer

Been following the emp information here. Pretty well balanced and documented.

http://modernsurvivalonline.com/


5 posted on 05/15/2012 2:08:27 PM PDT by Godzilla (3/7/77)
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To: Kartographer

What you need to place in your Faraday cage is a diesel generator so that, when that EMP goes off, you can sell electricity at whatever price you set.

You’ll be a rich man in a liveless world.


6 posted on 05/15/2012 2:14:18 PM PDT by 353FMG
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To: Kartographer

What you need to place in your Faraday cage is a diesel generator so that, when that EMP goes off, you can sell electricity at whatever price you set.

You’ll be a rich man in a liveless world.


7 posted on 05/15/2012 2:14:18 PM PDT by 353FMG
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To: Kartographer

Just find a junk microwave...


8 posted on 05/15/2012 2:14:43 PM PDT by Thunder90 (Romney barely won in OH with a 12-1 money advantage, he can't beat Obama that way.)
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To: Kartographer; Alamo-Girl; Amityschild; AngieGal; AnimalLover; Ann de IL; aposiopetic; aragorn; ...

Useful prepper stuff about building a useful Faraday cage re EMP pulse hazard etc.

I love y’all.

Please be prayerful . . . walk close to God . . . be safe in His arms in all such matters day by day . . . cue song . . . Day by Day . . .


9 posted on 05/15/2012 2:14:43 PM PDT by Quix (Time is short: INSURE you have believed in your heart & confessed Jesus as Lord Come NtheFlesh)
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To: Kartographer

Why not make a whole body tin foil hat?


10 posted on 05/15/2012 2:15:50 PM PDT by mountainlion (I am voting for Sarah after getting screwed again by the DC Thugs.)
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To: Kartographer

Don’t forget a good Earth ground.


11 posted on 05/15/2012 2:17:09 PM PDT by TonyInOhio ( It is later than you think)
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To: Kartographer

Why bother?

Surely there will be marauding bands of teenagers and sports fans who will come and take your radio from you!


12 posted on 05/15/2012 2:17:09 PM PDT by papertyger ("And how we burned in the camps later, thinking: What would things have been like if..."))
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To: TonyInOhio

And that ground needs to be CLOSE to your cage, or else it will act as an antenna for EMP.

The problem with this setup is, there is really no way to test it. We don’t know if it will work at all.


13 posted on 05/15/2012 2:21:30 PM PDT by MrB (The difference between a Humanist and a Satanist - the latter knows whom he's working for)
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To: Kartographer

BFL


14 posted on 05/15/2012 2:22:33 PM PDT by TEXOKIE
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To: Thunder90
Just find a junk microwave...

Awesome idea!! I'd never even considered that.

15 posted on 05/15/2012 2:22:50 PM PDT by Hodar ( Who needs laws; when this FEELS so right?)
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To: Kartographer

How are you protecting the input power lines?


16 posted on 05/15/2012 2:29:15 PM PDT by InterceptPoint (TIN)
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To: Kartographer

17 posted on 05/15/2012 2:36:30 PM PDT by Bobalu (It is not obama we are fighting, it is the media.)
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To: Kartographer

I don’t think a Faraday Cage is sufficient to stop an EMP.I believe you need a mu-metal cage, to block the magnetic part of the pulse.


18 posted on 05/15/2012 2:37:35 PM PDT by expat2
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To: Kartographer

If your home is already grounded, as it should be per building codes, you can ground your cabinet to it.


19 posted on 05/15/2012 2:37:58 PM PDT by SatinDoll (NO FOREIGN NATIONALS AS OUR PRESIDENT)
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To: Bobalu; Hodar; Thunder90

Use the link at #5 by Godzilla to find out why your suggestions will not work.


20 posted on 05/15/2012 2:40:15 PM PDT by SatinDoll (NO FOREIGN NATIONALS AS OUR PRESIDENT)
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To: MrB

Easy to test.
Place a small am radio within.
Turn radio up loud so you can hear only static.
Make some sparks near the cage and see if the radio picks up the static pops.

Or perhaps place a cellphone within and see if you can
call it.


21 posted on 05/15/2012 2:41:04 PM PDT by Bobalu (It is not obama we are fighting, it is the media.)
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To: papertyger

They’d better be wearing .223 and .30-06 proof Kevlar.


22 posted on 05/15/2012 2:42:00 PM PDT by Dick Bachert
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To: Bobalu; MrB

In the video that exactly what he does to test the cabinet. He places a radio inside and it stops recieving a siginal.


23 posted on 05/15/2012 2:45:00 PM PDT by Kartographer ("We mutually pledge to each other our lives, our fortunes and our sacred honor.")
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To: Kartographer

I’m curious to what would work other than a Farraday cage.

Would being underground, say in a cave, bunker, or fallout shelter protect one’s electronic gear or electrical conductors? If so, how much concrete and earth does one need as protection?

How about a nice, deep cave!


24 posted on 05/15/2012 2:48:45 PM PDT by SatinDoll (NO FOREIGN NATIONALS AS OUR PRESIDENT)
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To: mountainlion; 353FMG

You either prepare and stand on your own beholden to no one or you become dependent on others to provide your basic needs and become thier‘serf’. Me I don’t want to be beholden to anyone for providing what is needed for me and mine. I certainly don’t want to have to kiss some ‘gubberment’ third class bureaucratic to try and coax some help from them, I don’t want some ‘jack booted’ thug herding me in line and telling me where to stand, sit, eat or sleep. And last but not least I don’t want to be herded in with a bunch of ‘zombies’ and have to worry about not only trying to get basic necessities but having to fight to keep what I manage to get.

Now anyone thinking that prepping is foolish ask you what’s easier telling your children and loved ones why you prepared or explaining to them why you didn’t?

But if any provide not for his own, and especially for those of his own house, he has denied the faith, and is worse than an unbeliever. 1 Timothy 5:8

But then someone has to stand on the bridge waiting for FEMA to bring them a bottle of water, an MRE and a warm blank so as to provide the Network Anchors their background ‘Money Shot’. I wonder how that will workout for you?


25 posted on 05/15/2012 2:49:52 PM PDT by Kartographer ("We mutually pledge to each other our lives, our fortunes and our sacred honor.")
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To: Kartographer
You could actually simulate an EMP level pulse by charging a bank of high voltage capacitors and discharging them across a narrow gap. A very high powered single pop version of an old spark gap transmitter. The very short duration spark would have the power of all the caps stored electrons dumped in a microsecond...the amperage would be equal to what powers a small city.

You would want to use capacitors of the sort used to start large motors. A smaller and weaker version of this idea is used to pass huge current pulses through a small 6 turn open air coil that produces such a large magnetic pulse that it can penetrate the skull and induce small currents in the brain. Transcranial Magnetic Stimulation.


26 posted on 05/15/2012 2:56:54 PM PDT by Bobalu (It is not obama we are fighting, it is the media.)
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To: Kartographer

In the event something does happen, won’t those you need to communicate with and through need one also?


27 posted on 05/15/2012 3:12:18 PM PDT by stuartcr ("When silence speaks, it speaks only to those that have already decided what they want to hear.")
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To: expat2

Nah - not required.

A couple of facts for EMP generated by Nuclear devices in the atmosphere. According to an Air Force officer who gave a talk some 30 years ago - you can expect to see something like 30KV/m2 from DC to many Ghz. The pulse will be several nanoseconds in duration.

The officer wasn’t sure ANYTHING would be sufficient to shield against such a pulse.

That being said - from some other things I’ve read/heard - you aren’t going to have any significant effect on a magnetic field. A professor in EE told me about his brother having a contract to create the equivalent to a Faraday cage for Magnetic fields from the Navy. The brother set up an experiment where he created a Mu-metal cage around a detector on the theory that the cage would route the field around the detector. He placed a record player with a bar-magnet 100 feet away. Real nice sine-wave detected inside said cage... so much for Mu Metal..


28 posted on 05/15/2012 3:12:50 PM PDT by fremont_steve
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To: Kartographer
The Faraday cage is featured in the "aliens attack Moscow" movie The Darkest Hour.

I thought it was something the filmmakers just made up themselves.

29 posted on 05/15/2012 3:34:23 PM PDT by x
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To: stuartcr

I was think more to protect my emergency solar power system. than communications, though there are my people involved with and that have formed shtf radio communications groups and most of them have such protection for their radio equipment.


30 posted on 05/15/2012 3:55:14 PM PDT by Kartographer ("We mutually pledge to each other our lives, our fortunes and our sacred honor.")
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To: Kartographer

http://www.faradaycages.com/index2.php?p=Content&id=136&nav=Forensic%20research&nav_grp=Digital%20forensics

http://www.cellular-news.com/story/28121.php

A couple of small Faradays for stopping cell phone transmission. Wrapping in foil works too.

The main thing for nuclear EMP is not to have connections to any power lines or antenna lines- any copper connections at all.

A microwave oven is a super good shield, at about 2 gig or so. You’d want to test it by putting a radio inside and see if it can pick up AM, or FM. Try calling your cell phone.


31 posted on 05/15/2012 4:08:37 PM PDT by DBrow
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To: Kartographer

Thanks, Kartographer. BE PREPARED BUMP!


32 posted on 05/15/2012 4:14:48 PM PDT by PGalt
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To: x

They did make up SOME stuff. A hole in a Farday cage lets in EM radiation, but the size of the hole determines the frequency. A pinhole in a weld will let in only, say, 90 GHz and up while being completely opaque to lower freqs.

A quarter inch hole lets in (iirc) 2.4 GHz MHz and up. To stop older cell phones, a 1/3 inch mesh will stop 1.8 GHz, and 900 MHz is stopped by a little bigger than 1/2 inch. Basically wavelength/20. Quarter inch hardware cloth will stop most cell phones.

Copper window screening works for AM and FM radio and most TV transmitters and cell phones, I worked in a 2x4 cage covered with screen and for “low” freqs it worked just fine. 20 GHZ not so much.

So a chain link fence will protect you maybe from 1000 Hz or so, so the shielded room in the pic is a fantasy.

OTOH, consider the radiotelescope dish at Ariciebo. It’s made of screening, yet is a very good reflector at the freqs the astronomers use. Hmm, wonder if a cell phone works under there?


33 posted on 05/15/2012 4:45:29 PM PDT by DBrow
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To: SatinDoll

Emp is line of sight. Under ground would provide some protection but it depends on the strength of the emp signal


34 posted on 05/15/2012 4:47:57 PM PDT by driftdiver (I could eat it raw, but why do that when I have a fire.)
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To: fremont_steve

If you were to discover a way to shield against a magnetic field you could use that tech to quickly create a magnetic perpetual motion machine.

This means that magnetic shielding is impossible.

Gravity based perpetual motion machines are also impossible because there is no such thing as a gravity shield.

Magnetism and gravity can only be negated by another magnetic or gravity field...at least in a Newtonian universe. :-)


35 posted on 05/15/2012 5:15:16 PM PDT by Bobalu (It is not obama we are fighting, it is the media.)
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To: Kartographer

sfl


36 posted on 05/15/2012 5:21:28 PM PDT by phockthis (http://www.supremelaw.org/fedzone11/index.htm ...)
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To: DBrow
An interesting fact related to all this that is unknown to the non EE types is how an RF choke works. A simple coil of wire can totally stop RF energy and yet allow DC to flow freely.

For instance: If you connect an RF choke across a transmitters antenna feed line it will not hinder the flow of RF in the line. It will however create a low resistance path for dc energy to flow between the feedline conductors. If your transmitter is grounded then the choke across the transmission line means your entire antenna system is directly connected to the ground because the braid of the transmission line is connected to ground. This lets static bleed away to the earth and still the antenna functions normally.

The lower the RF frequency the larger the choke needs to be to block it. The one in the image below is the sort typically used in Ham radio work.

37 posted on 05/15/2012 5:30:16 PM PDT by Bobalu (It is not obama we are fighting, it is the media.)
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To: Kartographer

“solar EMP”

You do not need a faraday cage of any sort for a solar EMP.

The “radio” test fails on dynamic range - an EMP will be much greater in magnitude than can be proven out with a radio in a metal cabinet.

File it under “it might be better than nothing”.


38 posted on 05/15/2012 5:36:52 PM PDT by RFEngineer
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To: Thunder90

“Just find a junk microwave...”

If an EMP is specifically at 2.4 GHz, it will work perfectly.

If it is an actual EMP it won’t work well.


39 posted on 05/15/2012 5:38:56 PM PDT by RFEngineer
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To: TonyInOhio

“Don’t forget a good Earth ground.”

The ground will not affect the environment inside the shielded area, if it’s a true faraday cage, provided you don’t have any other penetrations into the shield.


40 posted on 05/15/2012 5:40:58 PM PDT by RFEngineer
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To: expat2

“I don’t think a Faraday Cage is sufficient to stop an EMP.I believe you need a mu-metal cage, to block the magnetic part of the pulse.”

Steel will do the trick, as it has sufficient permeability.


41 posted on 05/15/2012 5:44:57 PM PDT by RFEngineer
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To: fremont_steve; RFEngineer
A bit of a dichotomy.

You say even mu-metal wouldn't work, but RFEngineer says even steel is good enough to work. One of you is clearly wrong (or both). However, I think that you are probably correct. A high-current pulse with a very short pulse-length is bound to produce a very high magnetic field.

42 posted on 05/15/2012 6:00:52 PM PDT by expat2
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To: RFEngineer

Wouldn’t you say the cage fails if it doesn’t pass the ‘radio’ test? Could you please prove an alternative test.


43 posted on 05/15/2012 6:00:52 PM PDT by Kartographer ("We mutually pledge to each other our lives, our fortunes and our sacred honor.")
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To: fremont_steve

The unclassified EMP states up to 50,000 V/m from about 5kHz to 1GHz

The pulse rise time is about a nanosecond (that’s where the top end 1 GHz comes from)

“The officer wasn’t sure ANYTHING would be sufficient to shield against such a pulse.”

Steel will do it - low frequency permeability ducts magnetic flux around the shield. At higher frequencies it’s conductive enough to suffice.

“The brother set up an experiment where he created a Mu-metal cage around a detector on the theory that the cage would route the field around the detector.”

Not at the very low frequencies, low magnitudes involved in your described test scenario - the low-level magnetic pulse will blow through the shielding because there isn’t enough magnetization energy. This is a big problem for sensitive instruments such as newer electron microscopes.

At even slightly higher frequencies, passive eddy current shielding works very well for magnetic fields (such as 60Hz)


44 posted on 05/15/2012 6:02:04 PM PDT by RFEngineer
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To: SatinDoll

“Would being underground, say in a cave, bunker, or fallout shelter protect one’s electronic gear or electrical conductors?”

No. in “nominal” soil conditions you’d need to be between 100 and 200 ft in depth to be sure you met the MIL SPEC.

However, there are exceptions. For instance, if you are under 200ft of granite, you will not get significant shielding effect, because granite (or dry sand) is very low conductivity and hence, does not significantly dissipate an EMP.


45 posted on 05/15/2012 6:04:46 PM PDT by RFEngineer
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To: Kartographer

“Wouldn’t you say the cage fails if it doesn’t pass the ‘radio’ test? Could you please prove an alternative test.”

That would be true.

To be sure, you’d need multiple tests and many frequencies that could measure across an up to 80dB dynamic range. Not an easy thing to accomplish. Google “MIL-STD-188-125-1” for a lot of detailed information on a test apparatus.

The dynamic range is a key factor.


46 posted on 05/15/2012 6:08:16 PM PDT by RFEngineer
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To: expat2

“One of you is clearly wrong (or both). “

The military usually uses steel for fixed facilities.

“A high-current pulse with a very short pulse-length is bound to produce a very high magnetic field.”

This would create a broad-spectrum pulse with frequency content up to the inverse of the pulse-length.

At low frequencies magnetic fields dominate, at higher frequencies electric fields dominate.

Electric fields at all frequencies can be shielded with foil-thickness shielding. magnetic fields are different. The lower the frequency the more it will penetrate. Think about it...the earths magnetic field goes through the entire earth. you never have to worry about the earths electric field- it never makes it anywhere close to the surface.

The most energetic part of an EMP does not have low frequency components - though the later stage EMP DOES have a geomagnetic component - but it is not highly energetic - so you need a very large collector for it to impact (e.g. power transmission lines, or pipelines).


47 posted on 05/15/2012 6:14:27 PM PDT by RFEngineer
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To: RFEngineer

Then I would use a radio test multiple frequencies on the FM, AM and SW band and then use a couple of cellphones to the GSM and UMTS bands. You could even use a small TV and test UHF and VHF bands. I would say that after such a test you could be fairly sure you were covered.


48 posted on 05/15/2012 6:47:49 PM PDT by Kartographer ("We mutually pledge to each other our lives, our fortunes and our sacred honor.")
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To: RFEngineer

How about just using a multifrequency scanner?


49 posted on 05/15/2012 6:50:22 PM PDT by Kartographer ("We mutually pledge to each other our lives, our fortunes and our sacred honor.")
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To: Kartographer

The problem is both frequency, and dynamic range.

You may think you have a good Faraday cage using receivers but you could fall well short of performance because the signals weren’t strong enough to show your true performance under EMP conditions.

It’s better than nothing - but it’s also a false confidence builder if you get a radio to block a station.

It’s a matter of how sure you want to be. The best inexpensive ad-hoc shield I can think of is the trash can - but use steel wool fragments around the full circumference of the lip and hammer it down solid with a rubber mallet.

No guarantees, but it’s much simpler in its uncertainties than this cabinet thing.


50 posted on 05/15/2012 7:20:31 PM PDT by RFEngineer
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