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 ...
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.
They’d better be wearing .223 and .30-06 proof Kevlar.
In the video that exactly what he does to test the cabinet. He places a radio inside and it stops recieving a siginal.
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!
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?
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.
In the event something does happen, won’t those you need to communicate with and through need one also?
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..
I thought it was something the filmmakers just made up themselves.
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.
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.
Thanks, Kartographer. BE PREPARED BUMP!
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?
Emp is line of sight. Under ground would provide some protection but it depends on the strength of the emp signal
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. :-)
sfl
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.
“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”.
“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.
“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.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.