# Seeking EMP knowledge



## Practical Madman

Does anyone have knowledge of EMP and how to protect from it? My question is does good old dirt give protection? I am digging a bunker, with wood walls and roof. Will put Mylar blankets on the roof, cover with plastic and then 18" of dirt. Bushes planted around it and grass on top will camo it. Will this protect electronic equipment inside from EMP? Are solar panels subject to EMP waves?


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## doc66

Well, the short answer is simple; there is no real knowledge of EMP. 

Many theories abound, but none of them can tell you the real truth. The most recent, and the one I like, is that EMP is like water--depending on where you are in relation to the EMP pluse is what effect it will have on you and your crap. The EMP will roll around hills and those items directly behind the hill will not be effected. Things inside buildings, depending on where they are in the building, what the building is made of and how close it is to the source of the blast may or may not be effected. Any circuits in direct contact with the EMP wave may be effected. It depends on if they are open or closed circuits, grounded or hardened and how far away from the EMP you are. 

There is no good answer. 

Your set up sound reasonable, but I'd have the solar panels taken down should you get early warning and spares just in case. The biggest problem with ANY bunker is the air cleansing and circulation. A friend of mine and others did a 72 hour test of a bunker and found that even though the air system was supposedly set up for twelve people (they had eight) it was not enough to realistically deal with the amount of CO2 being put out. He said that they went just over 48 hours and by the end of that time they were down to shorts and the humidity was so high that water was literally dripping off the ceiling. 

Whatever you plan for, plan for at least twice as many people as advertised and have backups for everything.


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## Canadian

Wrap your ipod in foil? I don't know much about EMP but enough dirt seems to stop anything. Even a nuke.


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## SurvivalNut

Good question.

Here is an article posted on our brother Aussie site.

AusSurvivalist - EMP Protection

I keep some redundant items (radios, commo, batteries, small solar chargers, my radiation monitoring gear) packed in Faraday boxes.

As for solar panels, they are relatively new and I would not trust any single answer without reserve.

I like the answer to stow them inside or to have a smaller back up set inside.

My *totally uneducated guess *is that solar panels would be very susceptible unprotected.


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## Herbalpagan

You can put small thing you wish to save from EMP in an old (unplugged) microwave, as it's a Faraday cage. I hear a lot of people saying they will just store their cell phone in one, but honestly, who ya gonna call if the cell sats are fried? I'd put a small radio in it. I think the shelter has to be surrounded by grounded metal in order to be protected. 
I did a google search on EMP, EMP bombs and general info. I know that electronics made for the military has to be hardened, but not a lot of testing has been done with an actual nuke/EMP such as discribed in recent books. The last tests on that were done in the 60's when electronics were not so sensitive. Though there are several EMP "machines" now for testing, it still doesn't simulate the situation you are looking for.


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## NaeKid

You can visit HowStuffWorks.com's EMP information area for more detailed information regarding EMP

From what I have been able to learn, an EMP (ElectroMagneticPulse) will travel via power lines / TV-Cable / TelephoneLines and *anything *that is within a certain distance of that cable, or, attached to that cable will be fried.

Your vehicle is safe - unless you are driving an electric car and it is plugged in for charging.

A solar panel is safe, unless it is attached to your house and there is power coming into the house as well and you are "pushing" power back into the power-grid. A solar panel attached to your camping trailer that is parked away from any power lines should be safe.


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## The_Blob

here's a BUNCH of stuff...   

from: Utah Shelter Systems - Because Survival Is The Highest Priority

Solar panels may be used to recharge the batteries, but when not in use they should be stored inside the shelter for maximum protection from blast and EMP. They should be placed outside only after all danger of blast &/or EMP has passed. They will be adversely affected by the EMP. If in a remote area, consider putting out a 'sacrificial' panel and purchasing extra solar panels for later. Store these panels wrapped in aluminum foil, for 'EMP' protection, and keep them inside your shelter until use.

Weapons Effects

EMP Effect
Most experts agree that a full scale nuclear attack would be initiated by a high altitude (approximately 200 miles high) nuclear explosion, and that it would most probably be deployed from a satellite. A nuclear bomb detonated at that altitude will not damage living tissue, will not cause significant radiation fallout and is not a health threat to the population. The purpose of this explosion is to damage critical electrical circuitry in our retaliatory defense weapons and our military communications capabilities. This is accomplished by means of the electro magnetic pulse (EMP) associated with the explosion. One such explosion could affect an area of a thousand miles in diameter.

Terrorist nations can deploy EMP weapons from surface to air missiles detonated from a ship in our costal waters. Iran's, Shahab-3 ballistic missile, if armed with a nuclear weapon, would have this capability. North Korea, an ally of Iran, boasts that they already have nuclear weapons with ballistic missiles capable of reaching these heights.

Collectors, such as long runs of cable, house wiring, conduit, large antennas, overhead power and telephone lines, railroad tracks, etc., gather this energy in the form of a strong current and voltage surge. All solid state electronics is vulnerable to this energy surge. The equipment does not have to be attached directly to the collector in order to be damaged. It's possible for a collector to gather in the order of a joule of energy from a one megaton, high altitude explosion. The fact that a small fraction of a joule can cause permanent damage to electronic devices, shows that the EMP threat is a serious one. The damage to equipment could include automobile ignition systems, telephone and radio communications, airline communications, navigational aids, & computers. The power grid throughout the United States would most probably fail. It is estimated that about 95% of our radio stations would immediately loose transmission in an EMP attack.

If a power drop is detected, care should be taken to test telephones, radio stations, and other equipment for loss of function. Many radio stations have alternate power sources, but only about 5% of our radio stations have been hardened against the EMP. If, after checking a battery powered radio, you find that most of the radio stations are not functioning, you should take shelter immediately.

Immediately after the initial EMP explosion, SLBM's and ICBM's would probably be launched against targets in the United States. An ICBM from Russia would reach the center of the continental United States in about 25 minutes. A missile from a submarine could reach us in 8 minutes. However, we are not currently seeing Russian nuclear missile submarines in our coastal waters. The 25 minutes which the power failure alarm will give you could mean the difference between life and death.

If you are asleep, a simple power-drop alarm would awaken you when the power fails. This alarm should be constructed by a certified electrician. Our electrician used a motorcycle horn, a 12 volt battery, a relay switch, and a flasher. The negative line from the battery was connected to the 12 V DC horn. When the 110 V AC currant fails, the relay closes the circuit, which activates the horn. He added a switch to the positive line from the battery to the horn so the horn can be turned off after activation.

Radiation
If the fireball of the weapon touches the ground, the blast is defined as a `ground burst'. In a ground burst, rock, soil, and other material in the area is vaporized and taken into the cloud. This debris is then uniformly fused with fission products and radioactive residues and becomes radioactive itself. It then falls to the ground as `radioactive fallout'. If the fire ball from the explosion does not reach the ground, the blast is said to be an `air burst'. Radiation (except for initial radiation) does not become a factor in an air burst.

Gamma rays from the fallout can easily be attenuated by incorporating a 90 degree turn in the small diameter entrance. Entrances should not exceed 48 inches in diameter and the total length of the vertical and horizontal run should be no less than 25 feet. Approximately 90% of the gamma radiation is directed into the ground from the vertical portion of the entrance. The other 10% is almost entirely attenuated by the horizontal portion of the entrance. We recommend that the horizontal portion of the entrance be about 10 feet long and that it penetrate the shelter body on the side or on the end plate.

The threat of exposure to initial nuclear radiation is confined to a radius of about one and one half miles from ground zero and would prove fatal to any unsheltered individuals. However, in hardened blast and radiation shelters, such as those that are being built by Utah Shelter Systems, people could survive all nuclear weapons effects, including initial radiation, within three quarter mile of ground zero. Shelters which may be within the initial radiation zone, must have at least 8 ft. of dirt cover and the entrances must be configured with the proper shielding and geometry.

Gamma radiation is a great health problem for a two week period. Everyone should stay sheltered in a good fallout shelter for two full weeks. If blast is not a consideration, 4 feet of earth cover is sufficient to shield from gamma radiation. However, the entrances must still each have the 25 feet with both horizontal and vertical runs.

Alpha and Beta radiation can be stopped by a few layers of paper. However , internal to the body, they are a great health hazard. We must be careful to wash the lids of dust before opening canned food, and wash and peel all exposed fruits and vegetables. Water purification, food preparation, and post war survival will be discussed in another section of this web site.

Blast Effect
In the detonation of a one megaton size weapon (which is roughly equivalent to 1 million tons of TNT), the fireball grows to 440 feet in just a fraction of a second. In 10 seconds, the fireball is over a mile wide. At the same time the fireball is forming and growing, a high-pressure wave develops and moves outward in all directions. This wave of air causes a huge increase in air pressure. At one quarter mile from the crater edge, the overpressures are about 200 psi. It is not expected that nuclear weapons with a greater yield than one megaton would be used against the civilian population. We are, therefore, limiting our discussion of blast effects to that yield.

At approximately 4 miles from the epicenter, the winds are 165 mph and the overpressure is approx. 5 psi. Most homes would be destroyed, but it is possible to survive the blast in a basement shelter at that distance. The radiation shielding from the home, however, may have been destroyed in the blast. At 6 and 7 miles from the epicenter, there would be moderate damage to residences and the likelihood of surviving in a basement is greater.

People housed in hardened blast and radiation shelters, such as are built by Utah Shelter Systems, would be expected to survive all NBC weapons effects at ground zero from an air burst (50 psi), and at one quarter mile from the crater edge from a one megaton yield ground burst. At that proximity, an 8 ft. diameter shelter must have at least 8 feet of dirt cover. A 10 foot diameter shelter must have at least 10 feet of dirt cover over head. Each person must have approximately 10 square feet of shelter space for short term survival (up to 2 weeks). Double this space requirement if the shelter is to be used as a permanent residence.

Thermal Effect
Within less than a millionth of a second of the detonation, large amounts of energy in the form of invisible x-rays are absorbed within just a few feet of the atmosphere. This leads to the formation of an extremely hot and luminous mass called the fireball. If we were standing 50 miles away, this fireball would appear to us to be many more times as brilliant as the noon day sun.

You should never look directly at the fireball of a nuclear explosion. Because of the focusing action of the lens of the eye, especially at night when our pupils are open, thermal radiation can cause temporary and even permanent blindness.

The thermal pulse travels at the speed of light and can last for a fraction of a second, up to several seconds. It also generally travels in straight lines, as does light. If there is no warning, you should drop and cover immediately. If you do have warning, you should take cover behind a large structure, or go to a basement or culvert. If unprotected you would receive third degree burns at 6 to 8 miles from the blast; second degree burns at a distance of 8 to 10 miles; and first degree burns at 10 to 12 miles from the blast. Burns would greatly complicate an otherwise survivable situation.

an 11 page document by Dr. Lowell Wood about EMP

http://www.disastershelters.net/pdf/EMP_Wood_Statement_100799.pdf

the 31 page excerpt from the House Committee on Armed Services

"THE REPORT OF THE COMMISSION TO ASSESS THE THREAT TO THE U.S. FROM ELECTROMAGNETIC PULSE ATTACK"

http://www.disastershelters.net/pdf/EMP_Commission_Report_072204.pdf


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## SurvivalNut

All good information here.

One note, some writings suggest grounding ATTRACTS rather than diffuse EMP. 

A farraday box is not a ground, unless you go overboard and wire it. Don't. 

Posted for consideration.


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## Ponce

Do a search in "Popular Mechanics", they even show you how to build a bomb for under $1,000........hummmmmmmmmmm.


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## The_Blob

Ponce said:


> Do a search in "Popular Mechanics", they even show you how to build a bomb for under $1,000........hummmmmmmmmmm.


good luck getting the fissile material, ace


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## JohnB

NaeKid said:


> You can visit HowStuffWorks.com's EMP information area for more detailed information regarding EMP
> 
> From what I have been able to learn, an EMP (ElectroMagneticPulse) will travel via power lines / TV-Cable / TelephoneLines and *anything *that is within a certain distance of that cable, or, attached to that cable will be fried.
> 
> Your vehicle is safe - unless you are driving an electric car and it is plugged in for charging.
> 
> A solar panel is safe, unless it is attached to your house and there is power coming into the house as well and you are "pushing" power back into the power-grid. A solar panel attached to your camping trailer that is parked away from any power lines should be safe.


This is pretty much in line with what I've been able to research. The EMP will pretty much be attracted to the power grid and anything attached to or plugged into it.

Practical Madman: your bunker should be OK as long as you are not plugged into the local power supply.


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## NaeKid

JohnB said:


> This is pretty much in line with what I've been able to research. The EMP will pretty much be attracted to the power grid and anything attached to or plugged into it.
> 
> Practical Madman: your bunker should be OK as long as you are not plugged into the local power supply.


I am in the process of testing power-supply systems right now. I am hoping that within a year I will be able to flip-over from testing to a production-type living. What I hope to do is either build a new house based on 12-volt RV technology or convert an existing house to 12-volt primary if I can't find the right section of land to purchase (hoping to do so prior to this winter).

With the market the way it is - my plans all hinge on the selling of my current house.


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## grizz3000

NaeKid said:


> Your vehicle is safe - unless you are driving an electric car and it is plugged in for charging.
> 
> A solar panel is safe, unless it is attached to your house and there is power coming into the house as well and you are "pushing" power back into the power-grid. A solar panel attached to your camping trailer that is parked away from any power lines should be safe.


A vehicle with Electronic Fuel Injection (EFI) WILL get fried unless you have the frame grounded (i.e. clamped to a grounding rod in the garage or dragging a chain while moving/parked). Most cars prior to ~1975 are not EFI.

Solar panels will most likely get fried since they are essentially one big diode. The batt controller and inverter will mostly get fried too. Don't forget, anything with power connected to it will get fried (i.e. a car connected to a battery, solar panels providing power to batterys, etc)

I think everyone should do research before posting/telling someone information.


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## Turtle

The Pentagon did a study about the effects of a large-scale EMP burst on the U.S. about ten years ago. It cenetered on the fact that a low-yield nuke, detonated at the proper elevation, could use the Earth's atmosphere to conduct the EMP over 66% - 75% of the world's surface. 

Reason we never heard about it? The finding were set to be released on 11 September, 2001.

I'm certain that if you invoke the FOIA, you could get a redacted copy of the findings.


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## Skeeter

Reason we never heard about it? The finding were set to be released on 11 September, 2001.

source?


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## Turtle

Skeeter said:


> Reason we never heard about it? The finding were set to be released on 11 September, 2001.
> 
> source?


Several. But if you pick up a copy of William Forstchen's book, "One Second After" (which is a fine book, by the way), there is a foreword by Newt Gingrich, who I believe was on the investigatory committee, and an afterword by the Navy officer who was in charge of the investigation.


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## HappyPreppers

EMP effects indeed are like WATER! That's a good analogy.

-- Happy Preppers
We believe the happiest people on earth will be those who've prepared when the unthinkable happens.


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## Caribou

I think your design would work well enough for its stated purpose of EMP protection. The Mylar will help quite a bit. 

Personally I would put at least four feet of dirt over myself for added radiation protection. Going as far as you are going this added protection seems reasonable to me. If I lived close enough to a target to need more than four feet of dirt over my head I'd move, but that is just me.

Test your system. Any area where you lose signal on your cell phone should be fine for your electronics. 

Doors and ventilation may well be weaknesses. Wire screens over ventilation should help with bugs and EMP. Any wires or metal pipes that run outside may well act as an antenna and draw the EMP pulse into your bunker.


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## labotomi

Caribou said:


> Test your system. Any area where you lose signal on your cell phone should be fine for your electronics.


That's not a good test. The wavelengths resulting from an EMP are not the same as those used by cellphones.

It's similar to how different frequencies of cordless phones affect their range. Some will travel a very long way but will be blocked by a few walls. Some can perpetrate those few walls but not have nearly the same range as the others.


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## northstarprepper

I was thinking of putting two one inch diameter iron grounding rods on each side of my driveway. Then I would keep each vehicle parked there connected with heavy-duty jumper cables attached to the frame. Do those of you with more knowledge of auto electronics than myself think that would keep the electronics safe in my cars? I am unsure what else to do other than find someone with an all metal storage building that I could store a vehicle in for such an emergency. Any other ideas?


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## Dakine

northstarprepper said:


> I was thinking of putting two one inch diameter iron grounding rods on each side of my driveway. Then I would keep each vehicle parked there connected with heavy-duty jumper cables attached to the frame. Do those of you with more knowledge of auto electronics than myself think that would keep the electronics safe in my cars? I am unsure what else to do other than find someone with an all metal storage building that I could store a vehicle in for such an emergency. Any other ideas?


should they be iron or copper?

and I'm looking forward to a response from Labotomi since he's got some relevant knowledge here!


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## Caribou

labotomi said:


> That's not a good test. The wavelengths resulting from an EMP are not the same as those used by cellphones.
> 
> It's similar to how different frequencies of cordless phones affect their range. Some will travel a very long way but will be blocked by a few walls. Some can perpetrate those few walls but not have nearly the same range as the others.


Labotomi, don't just spank me and send me to my room without dinner! Come up with a better test and educate us all.:2thumb:


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## Tucker

This may be a dumb question but does it matter if it's an EMP from a low level nuc or from the sun?


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## helicopter5472

Tucker said:


> This may be a dumb question but does it matter if it's an EMP from a low level nuc or from the sun?


No question is a dumb question, I don't know the answer and would like to know too....


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## labotomi

Tucker said:


> This may be a dumb question but does it matter if it's an EMP from a low level nuc or from the sun?


Yes, it matters very much.

A solar CME will generate nigh voltages in long power lines and potentially cause damage to power grid components as well as anything plugged in at the time. Components not connected will not be damaged.

An EMP can damage components not connected to the electrical grid if they contain voltage sensitive electronics (diodes, transistors triacs, and other solid state devices).


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## labotomi

Caribou said:


> Labotomi, don't just spank me and send me to my room without dinner! Come up with a better test and educate us all.:2thumb:


There's not a good test that average people can do because of a lack of ability to generate an EMP (even a small one)

Passing the cell signal test could make some over confident that their stuff is protected with setups that are inadequate.

I have a metal barn that blocks enough cell signals for me to lose connection but it's not going to protect anything from an EMP.


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## Tirediron

northstarprepper said:


> I was thinking of putting two one inch diameter iron grounding rods on each side of my driveway. Then I would keep each vehicle parked there connected with heavy-duty jumper cables attached to the frame. Do those of you with more knowledge of auto electronics than myself think that would keep the electronics safe in my cars? I am unsure what else to do other than find someone with an all metal storage building that I could store a vehicle in for such an emergency. Any other ideas?


If by frame you are referring to chassis, it _could_ work, maybe. but the main energy gathering antenna would be the body shell, so the body would need to be grounded at the cable connection point also. 
The body and chassis are connected by small ground straps or wires, some times these are not hi enough capacity or not well enough connected to carry the excess load.

the other problem is that the ground and or the ground rods themselves may become the antenna and make matters worse. dissipative grounding only works if the is a "dump" available. electricity is the flow of electrons, and given the right stimulus they can flow in either direction.

I too would like to see Labotomi's take on this question.


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## black_dog

There is a good book on this called A Nation Forsaken EMP: The escalating threat of an American catastrophe By Michael Maloof He served as senior policy analyst at the Department of Defence. He also served on the Congressional EMP Commission. It tells you everything. Another must have book The Death of Money By James Rickards The coming collapse of the International Monetary System Hope this helps.


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## Caribou

labotomi said:


> There's not a good test that average people can do because of a lack of ability to generate an EMP (even a small one)
> 
> Passing the cell signal test could make some over confident that their stuff is protected with setups that are inadequate.
> 
> I have a metal barn that blocks enough cell signals for me to lose connection but it's not going to protect anything from an EMP.


So, a cell phone and/or transistor radio test won't necessarily tell you that a certain spot is EMP proof but it will tell you that it is EMP resistant. To use your steel building for an example, though you don't trust the building in a worst case scenario, having your electronics inside is better than having them outside?

If you are at ground zero, too bad so sad. If you are further out then perhaps a reset or disconnecting the battery may work. Even further out and your building will provide adequate protection. The more protection you have the closer to ground zero you can be.

You know that if you have cell phone service that you have no EMP protection and that if you lose signal that there is some protection. An imperfect test? Absolutely, but it is the best I am aware of.

I don't like long posts and I rarely read them. I do my best to keep my posts short. I try to fill in the blanks from other posts. I learned a long time ago that we have a lot of really intelligent people here. I trust that you and most others here are able to fill in the blanks from my posts. This, as most subjects here, is worthy of a book. I don't want to read your book and you don't want to read mine but together with everyone here we can get the job done.


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## labotomi

Caribou said:


> So, a cell phone and/or transistor radio test won't necessarily tell you that a certain spot is EMP proof but it will tell you that it is EMP resistant. To use your steel building for an example, though you don't trust the building in a worst case scenario, having your electronics inside is better than having them outside?


Better than nothing, yes. Kind of like having an umbrella as protection in a hurricane.



Caribou said:


> If you are at ground zero, too bad so sad. If you are further out then perhaps a reset or disconnecting the battery may work. Even further out and your building will provide adequate protection. The more protection you have the closer to ground zero you can be.


One interesting fact about a HEMP is that it's magnitude is fairly uniform across the entire affected area because the initiating event happens so far above the earths surface and the density of the air is so low that it allows gamma rays from the blast to travel great distances before interacting with molecules in the atmosphere (which causes the EMP)



Caribou said:


> You know that if you have cell phone service that you have no EMP protection and that if you lose signal that there is some protection. An imperfect test? Absolutely, but it is the best I am aware of.


What it seems you're saying is that cell signals are essentially the same as EMP waves, just at a much lower energy level. There's a lot more differences than that. A 900MHz cordless phone can penetrate walls very well but doesn't have the range to reach my mailbox. A 5.8GHz phone will have longer range but less penetrating power through walls. The only difference is the wavelength of the signals, not the strength. The relative difference in those signals is small. The difference is a cell signal and an EMP is immense, both in wavelength size as well as the strength.


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## labotomi

northstarprepper said:


> I was thinking of putting two one inch diameter iron grounding rods on each side of my driveway. Then I would keep each vehicle parked there connected with heavy-duty jumper cables attached to the frame. Do those of you with more knowledge of auto electronics than myself think that would keep the electronics safe in my cars? I am unsure what else to do other than find someone with an all metal storage building that I could store a vehicle in for such an emergency. Any other ideas?


First, this is only my opinion. Stay away from anyone that says they are certain of the answers. This also only applies to my understanding of the E1 component of an EMP as this is the only component for which a faraday cage is useful.

I don't believe that grounding any faraday cage is beneficial. When looking at the diagrams or description of how a faraday cage works on any reputable site, there is never a ground connection on the drawing or in the description of operation.

People tend to think of an EMP in electrical terms because voltage is always mentioned as causing the damage. I think there's some problems with thinking about it in those terms. First, voltage doesn't cause damage except to voltage sensitive devices such as solid state devices (transistors, diodes, microprocessors, etc.). In just about every other device, current (more specifically heat) is the cause of damage. If current flows through thing that has resistance it will generate heat. The longer if flows the more heat is generated until the built up heat is too much and damage occurs.

With an EMP, there may be a lot of current but the time it is flowing is miniscule. The wave passes at close to the speed of light. Not for enough time for excessive heat to accumulate and cause damage. Think about a lightning rod... They can get hit with 1 Million Volt lightning strikes (actually much more) and with the resistance of the rod and wiring should have massive amounts of current, far in excess of what the rod and wiring are rated for **continuously**. The very small time that the system carries current is why it doesn't have to be much larger.

Back to an EMP, the wave passes in nanoseconds. not enough time for the current to do any damage when the wave passes over the cage quickly. If a ground is added, it makes the "cage" larger and the wave takes longer to completely pass.

That made sense to me when I was typing, but it will probably be confusing to me tomorrow when I read it. Hopefully it'll convey what I was trying to say.


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## helicopter5472

Would these work? I have a bunch of old steel filing cabinets, if I line the insides with foam I think this will work. I have alum. tape for the drawer edges. I have a bunch of radio equipment and test items to attempt to protect.
I also have an old upright freezer which I can store items in too. I guess I would also need to tape between the door and body where the door seals are.
Everything is painted so would you need to grind off the paint where the tape will be placed??


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## readytogo

*I`m no expert on EMP`s*

Some general emphasis of comments fall into either "the world as we know it will come to an end" if there is a high altitude nuclear burst, or the other extreme: "it's not a big deal, nothing much will happen". Since we really have never had a nuclear burst over anything like our current modern infrastructure, no one really knows for sure what would happen, but both extremes are not very believable.


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## Tirediron

labotomi said:


> First, this is only my opinion. Stay away from anyone that says they are certain of the answers. This also only applies to my understanding of the E1 component of an EMP as this is the only component for which a faraday cage is useful.
> 
> I don't believe that grounding any faraday cage is beneficial. When looking at the diagrams or description of how a faraday cage works on any reputable site, there is never a ground connection on the drawing or in the description of operation.
> 
> People tend to think of an EMP in electrical terms because voltage is always mentioned as causing the damage. I think there's some problems with thinking about it in those terms. First, voltage doesn't cause damage except to voltage sensitive devices such as solid state devices (transistors, diodes, microprocessors, etc.). In just about every other device, current (more specifically heat) is the cause of damage. If current flows through thing that has resistance it will generate heat. The longer if flows the more heat is generated until the built up heat is too much and damage occurs.
> 
> With an EMP, there may be a lot of current but the time it is flowing is miniscule. The wave passes at close to the speed of light. Not for enough time for excessive heat to accumulate and cause damage. Think about a lightning rod... They can get hit with 1 Million Volt lightning strikes (actually much more) and with the resistance of the rod and wiring should have massive amounts of current, far in excess of what the rod and wiring are rated for **continuously**. The very small time that the system carries current is why it doesn't have to be much larger.
> 
> Back to an EMP, the wave passes in nanoseconds. not enough time for the current to do any damage when the wave passes over the cage quickly. If a ground is added, it makes the "cage" larger and the wave takes longer to completely pass.
> 
> That made sense to me when I was typing, but it will probably be confusing to me tomorrow when I read it. Hopefully it'll convey what I was trying to say.


 So according to your "model" to ground a vehicle would be detrimental as in effect prolonging the event. and I think I would have to agree with the huge potential theoretically available.


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## Caribou

labotomi said:


> What it seems you're saying is that cell signals are essentially the same as EMP waves, just at a much lower energy level. There's a lot more differences than that.


No, that is not what I am saying. I agree with you about the differences in signal strength and frequency. The cordless phones are good to show your example but as they are useless for testing there is little reason to delve into them further.

Rubbers are not 100% effective, that doesn't mean that that they shouldn't be used. The Troopers in Alaska wear vests tested against pistol cartridges. Most Alaskans own rifles. The vests still have value. What a cell phone, or transistor radio, will tell you is if there is no protection. They will not tell you how much protection there is. We do know that even a little protection will reduce the effect if only a marginal amount. We do know that there is a threshold, that varies from one electronic device to another, beyond which damage is done. If you can reduce the signal strength to below that threshold then you are as effective as reducing all the EMP/CME signal. We know that the force of an EMP is reduced as it passes through the ground. If you put a foot and a half of dirt over your bunker and you loose signal you know you have some protection. If you then add another three feet of dirt on top you have increased your protection.

If I walk into my bunker and lose signal five feet in and then continue to the back of the bunker and get signal three feet from the vent then I know the areas that are definitely unprotected. If my bunker is ten feet long then I know I have more work to do. If my cell lost signal immediately upon entering the bunker and I never found any signal anywhere in the bunker I still wouldn't place sensitive electronics near the door or a vent, why take a chance.

If you are looking for absolutes regarding EMP's I can't help. I find value in knowing where I have some protection V. when I have none.


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## labotomi

Caribou said:


> No, that is not what I am saying. I agree with you about the differences in signal strength and frequency. The cordless phones are good to show your example but as they are useless for testing there is little reason to delve into them further.


They were meant to show that different frequencies have different characteristics. . That is all. I never mentioned anything about using them for testing.



Caribou said:


> We do know that even a little protection will reduce the effect if only a marginal amount.


I don't disagree with this. I disagree with your original statement. 


Caribou said:


> Test your system. Any area where you lose signal on your cell phone should be fine for your electronics.


The electromagnetic radiation spectrum is huge. The difference in the signals is huge. They are related but the characteristics are vastly different










I wouldn't be comfortable in thinking that I was even a little protected because cell signals were blocked.

Referencing your example of bullet proof vests for pistol calibers offering some protection from rifle calibers... So does a tee-shirt.


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## Caribou

labotomi said:


> They were meant to show that different frequencies have different characteristics. . That is all. I never mentioned anything about using them for testing.
> 
> I wouldn't be comfortable in thinking that I was even a little protected because cell signals were blocked.
> 
> Referencing your example of bullet proof vests for pistol calibers offering some protection from rifle calibers... So does a tee-shirt.


I said that it was suitable for your argument and not for testing, so we agree on that point.

Please reread my posts.

Again you misinterpret what I said. I never said that a pistol caliber vest was proof against rifle caliber bullets. What I said was that the fact that it was able to stop pistol caliber rounds had value in itself. Comparing a tee-shirt to a bulletproof vest is a bit of a straw man, don't you think?

This test has been offered up on numerous threads yet I do not remember you speaking out before. If you do not wish to use this test then you have my permission to do as you please. If I have need then I will use this test while understanding its limits. I'll take imperfection over nothing. We just have different opinions on this one.

I believe I have had my say. I see no benefit in our bickering further so I give you the last word.


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## labotomi

Caribou said:


> This test has been offered up on numerous threads yet I do not remember you speaking out before.


I have, more than once. I also think the common belief that microwave oven are good enough cages for EMP protection is false.



Caribou said:


> If you do not wish to use this test then you have my permission to do as you please.


You have my permission to do as you please as well... or to do as you don't please... whatever pleases or doesn't please you. 


Caribou said:


> I believe I have had my say. I see no benefit in our bickering further so I give you the last word.


I'm not sure why you asked me for more information if you didn't want to hear my comments.


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## Geek999

I think this is a subject on which we need to learn to live with uncertainty. 1) Mankind obviously has limited experience with actual, real world, EMPs. 2) Relatively few people have any real expertise. 3) Those people would be hard to recognize vs. some guy full of misinformation on the Internet. 4) Most of us, even presented with valid information would have limited ability to understand and absorb it due to the technical nature of the subject.

So what we are left with is a risk that a TEOTWAWKI event can occur, for which the effects are somewhat known, but not in the detail we would like. How to prepare is expensive (spare electronics in Faraday cages) and might not work, depending on distance, inability to test the Faraday cages, etc.

Getting agitated over this subject is just not worth the mental effort. If you have the money and will to put some electronic devices aside in Faraday cages, by all means do so. If you can prepare to do some tasks without electronic conveniences, do that too. Do the best you can. If your Faraday cage works and mine doesn't, good for you.

By prepping in general, having done nothing special about EMPs, you're going to be ahead of 97% of the population. Given a choice between a) not being prepared for an EMP, or b) not being prepared for an EMP but having a year's supply of food on hand, I'll choose b every time.


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