Best way to build a Faraday shield

Discussion in 'General Survival and Preparedness' started by kansasrebel, Aug 17, 2008.

  1. kansasrebel

    kansasrebel Monkey++

    Electronics is my weakness. I need to know how to build a good Faraday shield for some of my stuff..just in case. Anybody have some ideas?
  2. ghrit

    ghrit Bad company Administrator Founding Member

  3. monkeyman

    monkeyman Monkey+++ Moderator Emeritus Founding Member

    The simplest I have heard is to get a microwave (it dont need to function) and ground it then put the stuff inside. EMPs are energy waves not practicly to difrent from what a microwave produces and the microwave is made to contain the waves within so if there are waves comeing from outside then it blocks them out as well.

    Other than that you could take any metal container thatfully closes, insulate the inside and ground the metal (have also heard the grounding may not be needed but dont recall hearing it can hurt and some say must so may as well), make SURE the items put inside are fully insulated from the metal, put the items inside and close the lid and there you go.

    Screen materials also work so long as the openings in the mesh are smaller than the length of the waves it is protecting against but then you have to determine wave lengths and such, if its solid it should protect from all wave lengths. If the cage/box is open it wont work. If aconductor comes into the cage (say a room built into a farriday cage with antina wires comeing in) then the EMP will be carried in and defeat the cage. So if you keep it simple it IS simple, metal box or can thats grounded with all items inside insulated from the box and closed, if you try to get fancy like building a room for your stuff with visibility and conectivity and such then it get much more complicated.
  4. overbore

    overbore Monkey++

    Since Iran has just placed into orbit a "thing" that could have been an EMP device, if they make or buy one from N Korea, your question is well founded. As to a "newer" vehicle, computer everything, you can get copper wire mesh screen from McMaster Carry Supply, Inc. Make a copper wire cover over the computer and get a grounding strap from Pep Boys to lead the potential off to ground. If this ever gets close to actually happening, gas pumps, banks, credit cards, cell phones etc will be totally "zapped" our Achillies Heel; exactly what our enemies want. Overbore

    ps if you can not find it send me a PM or e-mail
  5. fcb98292

    fcb98292 Monkey++

    Good advise. Any ungrounded box surrounded by metal will do. I use old, large microwave ovens. Heavy and made from thicker metal for shielding. Great for your emergency laptop, power supplies, auto alternators, batteries, electronics and radios.
  6. fcb98292

    fcb98292 Monkey++

    Of course nobody but the military really knows EMP effects on anything electronic, tests run with the military's own EMP simulator indicates that newer vehicles will be toast. Electronics in general will be dead. I do wish there was more information and independent testing on this topic. I have an older pickup loaded for a SHTF event, with no electronics in the beast at all.

    Not sure why more people don't take EMP more seriously, but it would only take one nuke 250 miles over Kansas to wipe out a hundred years of technology. There are also devices other than nukes that create the EMP effect.
  7. padkychas

    padkychas Monkey+++

    You can build a faraday shield out of a 55 gal steel drum with a removable top and a locking ring.
    If you ground the drum to a new ground rod and wire the top to the drum so it is grounded also it will divert the RF energy to ground. also put a few layers of cardboard in the drum to keep anything from contacting the inside of the drum.
    The top needs to be put on the drum with no gap, paint between the top and the drum needs to be removed and a metal gasket made out of a 1-1.5" wide ground strap compressed under the top with the locking ring.

    A microwave will only really block microwave RF frequency around 2-3 gigahertz. to test a microwave for how well it blocks RF put a cell phone (900Mhz to 2Ghz) in one and call it and see if it rings, or a AM (500k-1.3Mhz) and then a FM (84-108Mhz) radio in it with it tuned to a radio station with the volume way up and close the door (do NOT turn ON the microwave, or you will see what EMP will do to the cell phone or radio). If the station still can be picked up it is not blocking the RF, this is cheap way to test a faraday shield/cage/room. this is a way to see if there is a problem with a MRI room in the hospitals, then you call the guys with the real test equipment to find the crack or pin hole in the shield, or bad door seal or bad spot in the floor that you can't see.
    Test the drum with the cell/ radio test above.
    Or you can buy some conductive paint (it looks like copper metal flake and has about .2 ohms per foot) and make a room in the house, with no windows, into a big but not the best faraday shield/room. you will use a lot of the paint few heavy coats and the floor, doors will have to be done as well. the paint and doors ect will have to be grounded to the new ground rod. no unfiltered power can come into the room. lights, AC plugs on the wall, ect.

    Remember the new ground rod and the faraday shield CAN NOT contact the normal house ground or it will not work. EMP will be picked up by the power, ground, neutral /phone/cable lines going into your house and bring the EMP into the house, the long wires act like a big antenna. that is why the faraday shield needs its own isolated ground rod, shorter the wire the better.

  8. QuietOne

    QuietOne Monkey++

    OK, a few corrections.

    Airplanes are hit by lightning all the time. A lightning strike is the closest you'll get to an EMP burst. The reason they don't explode in flight is that the aluminum skin acts as a Faraday cage, diverting the current around the interior structure and allowing the lightning path to continue to ground or another cloud. No ground on an airplane, but the current is diverted.

    Any conductive closed container will act as a Faraday cage. The only reason to worry about small openings is that EMP will contain very short wavelength energy so your container should be as solid as possible. Don't worry about your equipment contacting the inside of the container; unless you mistakenly attach the wiring to the container the EMP will travel around the outside, not go inside. The better the conductivity, the better the shielding, but you do not need heavy gauge metal; copper or aluminum foil works fine. Not sure about what I'm saying? Wrap your cell phone in aluminum foil and try to call it; no signal means no RF can get inside. Sealed ammo cans with a strip of foil over the gasket work OK.
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