Unobtanium
Big Eyed Bug
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What's in your faraday cage?
- Thread starter Unobtanium
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ME :rotflmbo:
just need to cover the windoze with aluminium sheet and the metal box will be complete )-:
Now all ive got to do is protect -
generator
water pump and pressure switch
motorbike
van
and im sorted
Not going to worry about it, as it will be a very different world for survivors of such an event ..................
the grocery where I work had several shopping carts full of aluminum foil marked down to a quarter a roll, so my wife bought a hundred. The checker looked at her funny; my co-worker told her "Jay likes to have tin-foil hat parties at his house". She believed him.... :rotflmbo:
DCFusor
Yellow Jacket
Most preps aren't going to work anyway. Having done TEMPEST work (the military's version of "how can I make this so you can't tell its there via accidental EMI radiation from say, some computer stuff), let me tell you, a tight Faraday cage is very difficult to make - you won't succeed on the first try, and how do you plan to test it? I've got the stuff, but I doubt you do.
The slightest place where two screens overlap but don't perfectly touch, or any joint like that in a metal box == slot antenna. You're toast. We even make EMP weapons that can be tuned for the slot antennas that exist in desktop computer boxes - we can just kill those selectively, or just cel towers, and so forth.
CME's, magnetic storms - really not much worry except the effect on your incoming power - it could fail, and on the way down make some huge voltage spikes reminiscent of a lightning strike on the wires near you. Solution - unplug the delicate stuff. The type of surge suppressor that *might* protect you costs much too much and sometimes fail without warning anyway - and again you have a testing issue.
Nuclear...if you're close enough to an airburst to have serious EMP, you have other issues on top of just that. What will mostly fry is input circuits of things designed for low power - any receiver for example - at least, solid state ones. Tube types tend to live fine, and up till quite recently that's how the Russians handled the issue on their fighter planes - they just continued to use tube type radios. I happen to have collected a lot of WWII and Korean war surplus and have quite the tube collection myself, but not as prep - just because it was a cheap way to buy parts I wanted, and the stuff works pretty well.
Al foil is nearly worthless - the insulating layer of Al2O3 that it always has means you can't make an electrically tight enclosure with it. Tight copper screen or metal with continuous solder joints - that's pretty decent. But then, how to get in there? What they do for doors in screen rooms is pretty "out there" in terms of cost and complexity - silver finger gaskets completely around the door, and a vault type high pressure closure assembly...flex screen at the hinge side and so on - and most of those leak so bad that a 1w signal on the outside is easily picked up by a radio inside.
A cage can seem tight at one frequency, but be an actual antenna with gain at some other. A nuke EMP has pretty much all frequencies in it. CME's etc, not so much, they're easy and usually LF range - and no where near as "loud". The really low frequencies of a magnetic storm (a few cycles/second tops) only really affect super long wire antennas - phone and power cables that are miles long - yet another reason to get off the grid dependency thing.
Sure, you can wrap RFID chips in Al foil, and the 13.56 mhz most of them run off will be stopped well enough to make them not read. That's because there's barely enough RF there to make them work in the first place - a watt maybe, more like milliwatts. This sort of thing might fool someone into thinking they've got an answer for a billion or more watts (Nukes get to trillions). Nope, sorry. Suppose 1% gets through (that's optimistic for a homebrew - 40db or so) So, only 10 million watts gets in...It kind of helps to have a sense of the scales involved.
I fight this every day in the lab. A very high voltage power supply, say 50kv is used to run my fusor. In an arc, depending on where it is, it can produce from 50kw to about 2 billion watts peak EMI. It's enough to fry a desktop computer at 30 feet that isn't connected to anything on the fusor - the mouse wire and others are good enough antennas to bring in enough energy to fry the mobos. So, I put the fusor HV stuff in a faraday cage type setup - cuts it down maybe 1/1000 - still its very bad on things.
Edit - reading the above - that's all from someone with no clue whatever. Ammo boxes make great slot antennas since the top is gasketed and not conductively bonded all around. Foil bags are for anti-static and aren't very conductive at all (only cut radio waves a few percent)...that whole thing is a bad joke. What a shock they might get if those things were tested and they depended on the contents. As they say, there's no do-over.
The slightest place where two screens overlap but don't perfectly touch, or any joint like that in a metal box == slot antenna. You're toast. We even make EMP weapons that can be tuned for the slot antennas that exist in desktop computer boxes - we can just kill those selectively, or just cel towers, and so forth.
CME's, magnetic storms - really not much worry except the effect on your incoming power - it could fail, and on the way down make some huge voltage spikes reminiscent of a lightning strike on the wires near you. Solution - unplug the delicate stuff. The type of surge suppressor that *might* protect you costs much too much and sometimes fail without warning anyway - and again you have a testing issue.
Nuclear...if you're close enough to an airburst to have serious EMP, you have other issues on top of just that. What will mostly fry is input circuits of things designed for low power - any receiver for example - at least, solid state ones. Tube types tend to live fine, and up till quite recently that's how the Russians handled the issue on their fighter planes - they just continued to use tube type radios. I happen to have collected a lot of WWII and Korean war surplus and have quite the tube collection myself, but not as prep - just because it was a cheap way to buy parts I wanted, and the stuff works pretty well.
Al foil is nearly worthless - the insulating layer of Al2O3 that it always has means you can't make an electrically tight enclosure with it. Tight copper screen or metal with continuous solder joints - that's pretty decent. But then, how to get in there? What they do for doors in screen rooms is pretty "out there" in terms of cost and complexity - silver finger gaskets completely around the door, and a vault type high pressure closure assembly...flex screen at the hinge side and so on - and most of those leak so bad that a 1w signal on the outside is easily picked up by a radio inside.
A cage can seem tight at one frequency, but be an actual antenna with gain at some other. A nuke EMP has pretty much all frequencies in it. CME's etc, not so much, they're easy and usually LF range - and no where near as "loud". The really low frequencies of a magnetic storm (a few cycles/second tops) only really affect super long wire antennas - phone and power cables that are miles long - yet another reason to get off the grid dependency thing.
Sure, you can wrap RFID chips in Al foil, and the 13.56 mhz most of them run off will be stopped well enough to make them not read. That's because there's barely enough RF there to make them work in the first place - a watt maybe, more like milliwatts. This sort of thing might fool someone into thinking they've got an answer for a billion or more watts (Nukes get to trillions). Nope, sorry. Suppose 1% gets through (that's optimistic for a homebrew - 40db or so) So, only 10 million watts gets in...It kind of helps to have a sense of the scales involved.
I fight this every day in the lab. A very high voltage power supply, say 50kv is used to run my fusor. In an arc, depending on where it is, it can produce from 50kw to about 2 billion watts peak EMI. It's enough to fry a desktop computer at 30 feet that isn't connected to anything on the fusor - the mouse wire and others are good enough antennas to bring in enough energy to fry the mobos. So, I put the fusor HV stuff in a faraday cage type setup - cuts it down maybe 1/1000 - still its very bad on things.
Edit - reading the above - that's all from someone with no clue whatever. Ammo boxes make great slot antennas since the top is gasketed and not conductively bonded all around. Foil bags are for anti-static and aren't very conductive at all (only cut radio waves a few percent)...that whole thing is a bad joke. What a shock they might get if those things were tested and they depended on the contents. As they say, there's no do-over.
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Seems to me that anyone worrying about EMPs should be thinking about living/survival without an electrical grid at all. Battery powered equipment and solar generators can all fail/break with normal use. If you can't replace them, what are you gonna do?
DCFusor
Yellow Jacket
Right - what's the good of having a radio if there are no transmitters around?
Actually, there will be - there are plenty of hams who take this quite seriously and are ready as can be, they've helped with comm in a lot of emergencies, right up to the present. They even do regular "pretend" emergencies and pull out all their emergency gear and practice and make sure it will work when required.
Heck, not only can that stuff fail with normal use, it can just plain fail while packed away - and I've seen it happen. Batteries goo (even the rechargables) out, corrosion eats PCB tracks...enough rads destroy most semiconductors...plastics age and give of their plasticisers - which means they become too brittle to do their function...you name it.
Generators tend to fail more when you never use them, actually. They need to run some to stay oiled an not internally rusted, along with other issues like the gasoline becoming jello.
But our just-in-time grocery delivery mechanism will be toast almost for certain...they don't even know how to do it by hand anymore. They can't just keep shipping the same stuff the store ordered last time either, nor can they catch up if they suspend shipping for just a few days, there simply aren't the extra trucks and roads to to do the catching up. Basic logistics taught at West Point War College (for other reasons).
The really big EMP worry is nukes. CME's and the like might create power failures that don't last very long, and fry a few computers and phones hooked to landlines. Nothing to see there...move along. We can hope no one insane enough gets a nuke and uses it in EMP mode (which is a high airburst that doesn't do much other damage). None of the minor players in that business could pull it off, just we, the Russians, and probably the Chinese - all fairly sane actors as these things go.
Actually, there will be - there are plenty of hams who take this quite seriously and are ready as can be, they've helped with comm in a lot of emergencies, right up to the present. They even do regular "pretend" emergencies and pull out all their emergency gear and practice and make sure it will work when required.
Heck, not only can that stuff fail with normal use, it can just plain fail while packed away - and I've seen it happen. Batteries goo (even the rechargables) out, corrosion eats PCB tracks...enough rads destroy most semiconductors...plastics age and give of their plasticisers - which means they become too brittle to do their function...you name it.
Generators tend to fail more when you never use them, actually. They need to run some to stay oiled an not internally rusted, along with other issues like the gasoline becoming jello.
But our just-in-time grocery delivery mechanism will be toast almost for certain...they don't even know how to do it by hand anymore. They can't just keep shipping the same stuff the store ordered last time either, nor can they catch up if they suspend shipping for just a few days, there simply aren't the extra trucks and roads to to do the catching up. Basic logistics taught at West Point War College (for other reasons).
The really big EMP worry is nukes. CME's and the like might create power failures that don't last very long, and fry a few computers and phones hooked to landlines. Nothing to see there...move along. We can hope no one insane enough gets a nuke and uses it in EMP mode (which is a high airburst that doesn't do much other damage). None of the minor players in that business could pull it off, just we, the Russians, and probably the Chinese - all fairly sane actors as these things go.
Mark
Predaceous Stink Bug
Being into constructing Vacuum Tube audio equipment, I have capacitors in many Farad ranges. Of course, I don't keep them in cages.
Thank you DCF, youve completely vindicated my approach.
Sometimes 'do nothing' is the right thing to do ........
But for tinfoil hat parties its important to sound like you have it covered (-;
in fact i might even have a tinfoil hat party, :flail:
reckon it could pull in a few of the right kind of idiots for an entertaining evening.
Sometimes 'do nothing' is the right thing to do ........
But for tinfoil hat parties its important to sound like you have it covered (-;
in fact i might even have a tinfoil hat party, :flail:
reckon it could pull in a few of the right kind of idiots for an entertaining evening.
DCFusor
Yellow Jacket
Mark, we're going to have to talk about vacuum tubes at some point. I have several large truckloads and better yet - UTC linear standard iron...designed/made quite a few tube amps myself. Latest was a fully differential, nuvistor inputs, then 12ax7, then 3c33 triodes for output - DC coupled up to the transformer. Came out pretty tube-ilicious. Feedforward comp for the xfrmr, then feedback around the whole loop, some DC coupled inside the loop too. Very nice, very expensive though.
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Just a little bump.
This article describes the effects of EMP and CME and how to build a simple inexpensive Faraday cage.
Most readers of the SurvivalBlog are aware of the potential damage from either a Coronal Mass Ejection (CME) or an Electromagnetic Pulse (EMP) and the impact on everyday electronics. With an EMP, an electromagnetic pulse is generated at high altitudes from a nuclear explosion damaging sensitive electronics. A CME damages electronics in a similar way with the release of a large solar flare from the sun reaches carrying magnetic fluxes and plasma toward earth. These magnetic fluxes interfere with Earth’s magnetic fields and create current surges in power systems and electronics. As of this writing, there is several C and M class flare activity causing some Amateur Radio blackouts on the lower bands. To follow active solar weather visit Spaceweather.com.
survivalblog.com
This article describes the effects of EMP and CME and how to build a simple inexpensive Faraday cage.
Most readers of the SurvivalBlog are aware of the potential damage from either a Coronal Mass Ejection (CME) or an Electromagnetic Pulse (EMP) and the impact on everyday electronics. With an EMP, an electromagnetic pulse is generated at high altitudes from a nuclear explosion damaging sensitive electronics. A CME damages electronics in a similar way with the release of a large solar flare from the sun reaches carrying magnetic fluxes and plasma toward earth. These magnetic fluxes interfere with Earth’s magnetic fields and create current surges in power systems and electronics. As of this writing, there is several C and M class flare activity causing some Amateur Radio blackouts on the lower bands. To follow active solar weather visit Spaceweather.com.
Building a Simple Faraday Cage, by OhioGalt. Faraday Cage Construction.
Building a Simple Faraday Cage, by OhioGalt. Faraday Cage Construction. I prefer the American-made Behrens brand steel trash cans.
survivalblog.com