This statement is commonly known as Clarke's Third Law.
Many people have heard this quotation,
but few people really think about its implications.
Few people think about things such as
the fact that whenever we buy some food item at a supermarket (and
many others are buying the same item), the next time we go to that
same supermarket, they still have about the same supplies that they
had before. There are invisible infrastructures all around us that
are made up of advanced technology. Most of us just take the magic
A nuclear EMP could make the magic go away. I hope it never happens, and I don't think that it is at all inevitable.
It makes no sense, however, to be blind
to the danger. It is both much less likely to happen - and also less
likely to have a catastrophic impact - if, both as a civilization
and as individuals, we are prepared for an attack on our advanced
technology. A nuclear EMP would be a seemingly magical attack upon
our advanced technology, the technological infrastructure upon which
our lives depend.
Protection against the damage of a severe solar storm could be done easily and rather inexpensively by the electrical utilities; however it is not being done, and there is no sign that it will be done. A severe solar storm poses little threat to electronics, but would take down the most important power grids in the world for a period of years. This is a special problem in the United States, and is a severe threat in the eastern United States.
So, more important than preparing for a
nuclear EMP attack is preparing for all of the ramifications of a
severe solar storm which would cause an electrical power outage that
would, in most areas, last for a period of years. Most standby power
systems would continue to function after a severe solar storm, but
supplying the standby power systems with adequate fuel, when the
main power grids are offline for years, could become a very critical
That early-model personal computer
didn't even have a hard drive.
On this page, I'm going to concentrate
on a nuclear EMP attack, but much of this also applies to natural
events such as unusual geomagnetic storms due to extremely large
Consider this Cold War era quotation from a widely-read and highly-respected publication 30 years ago:
First: Another brief note about severe solar storms (and similar natural events), and then I'll get back to nuclear EMP.
Solar storms would primarily affect the power grid, and are not likely to harm things like computers. Also, solar storms would only disrupt communications temporarily, and would not be likely to cause direct harm to communications equipment (except for satellites).
An extremely large solar storm, though,
would induce geomagnetic currents that could destroy a substantial
fraction of the very largest transformers on the power grid
(possibly over much of the world). If this happened, electric power
loss due to a large solar storm would be out for a period of years
and possibly decades. Unlike nuclear EMP, such a solar storm is an
The power grid has only been in place for a tiny fraction of one percent of human history, and a really large solar storm (of the size and duration of the 1859 event) has not happened in that time. There is a general assumption that any solar event that is similar to, or larger than, the 1859 solar superstorm will simply never happen again, although there is no justification for such an assumption - in fact, we know that this assumption is false.
There is a good possibility that such a solar storm will happen in this century.
If it happens in the current situation
without spares for our largest transformers, a large part of the
worldwide power grid (including 70 to 100 percent of the United
States power grid) will be down for years.
There are some companies in the United States that certainly have the capability of moving up from the ability to manufacture medium-sized power grid transformers to the capability of manufacturing even the largest transformers.
So far, that capability has not been
developed. Since such a expansion of manufacturing capability
requires a lot of electrical power, the capability cannot be
developed after an electromagnetic catastrophe. The capability has
to be developed before there is an actual critical need. In the past
year, at least two companies have expressed the intention of getting
back into the large transformer business, but it will take a
considerable length of time to develop this capability fully.
This temporary infrastructure has served us very well, and we now have entrusted our very lives to it. The electric power grid began as a convenience, but has become a necessity for sustaining life through a process that has happened so slowly that most of us have not noticed this transformation.
We do not know how long the current power grid will last; but if it not replaced by a robust permanent infrastructure in time, hundreds of millions of people will die when the electric power grid collapses simultaneously in many countries.
How such a collapse occurs is well
known, and the methods to either prevent it, or to have spare
transformers in place to fairly quickly repair it, are also well
known. Although these preventive measures would not be terribly
expensive, they would take some time to put into place, and those
things have never been done.
Devices such as the SolidGround system
can be installed by local electric companies on all of their large
transformers that are connected to very long lines.
If there is a bright flash in the sky at
the same time that the power goes off, and you've been thinking
about nuclear EMP, your first reaction may be to assume the worst.
It may, however, be just cloud-to-cloud lightning that happened at
the same time that a distant cloud-to-ground lightning strike
knocked out the power. Even if you thought the sky was clear
outside, there may have been a distant thunderstorm, and lightning
bolts sometimes travel remarkably long distances.
There might be some telephone service if
you are very lucky, but anyone that you would call probably won't
know any more than you. The only way that you will get any timely
information will be by listening to broadcasts originating on other
continents using a battery-operated shortwave radio.
Large faraday cages can get extremely complicated. For small portable electronics, though, completely covering the electronic equipment in aluminum foil makes an adequate faraday cage around the equipment.
The foil covering needs to be complete, without any significant gaps. Wrap the device in plastic or put it in an insulated box before wrapping the covered device in foil. (Otherwise, the foil may simply conduct the EMP energy into the device more effectively.)
A single layer of foil may not be
adequate. In order to enclose the equipment in a nested faraday
cage, place the foil-covered device in a plastic bag, such as a
freezer bag, and wrap that bag completely in aluminum foil. If you
really want to protect the equipment against a large EMP, add
another layer of plastic and foil. The layer of plastic need to be
the thickest plastic bags that you can easily find. (They don't need
to be terribly thick, but do try to find some heavy-duty bags.)
I won't bother to explain skin effect here, but you can look it up if you're curious. Don't worry too much about skin effect, though. I only mention it here because many people have the misconception that when it comes to shielding, the thicker the better - and this is definitely not true after a certain thickness is reached.
Layers of shielding separated by
insulation works much better. As a practical matter, though,
wrapping with 2 or 3 layers of foil helps to assure that you
actually have a good shield around the equipment.
The interior of the body of the galvanized metal trash can should be lined with some material to electrically insulate items stored inside the container from the metal exterior.
(Cardboard probably works better than any other inexpensive material for this. Liners such as plastic trash bags may be too thin for this because of the momentary high voltages that could be induced on the exterior during an actual EMP.)
Do not place any insulation at a point
where it would interfere with the electrical connection between the
metal lid and the metal body of the trash can. It would be a good
idea to wrap items placed inside the metal trash can with a layer of
aluminum foil in the "nested faraday cage manner described above.
A common complaint about radios that use
hand-crank power is that the hand cranks are not very sturdy,
however the radios will continue to function by using conventional
battery power (or solar power if it is available.) If you do use the
hand crank on an emergency radio, though, do not treat the hand
crank too roughly. I still recommend keeping plenty of batteries on
Future EMPs may be much larger than the 1962 events. Also, battery technology is evolving and the sensitivity of newer types of batteries to EMP is unknown (although the cylindrical batteries tend to provide a certain amount of shielding just due to the way that they are constructed.). I generally prefer Energizer batteries for cylindrical batteries (AA, AAA, C and D sizes) and Duracell for 9-volt batteries.
The 9-volt batteries contain 6 internal
cells in series. In the Duracell 9-volt batteries, the cells are
spot welded together, whereas most other popular brands use a simple
press-fit interconnect for the cells. The Duracell spot-weld method
generally makes for a much more reliable connection in this type of
This Grundig radio is much less
expensive than the SONY ICF-SW7600GR. You can usually find the
Grundig G8 for around 50 U.S. dollars. In using the Grundig radio
recently, my only complaint was that it seemed to be much more
susceptible to electrical noise than many other shortwave radios.
Electrical noise is always a problem when listening to distant
stations, but, of course, in a post-EMP situation, electrical noise
would cease to be a problem.
The tuning on the S350DL is analog, but
it has a digital readout. Some of the annoying aspects of the tuning
dial in earliest models of this radio have been corrected in current
In a post-EMP situation, or any
situation where the regional electric grid goes down, the situation
will be very different.
In fact, vacuum tube radios actually were damaged in 1962 high-altitude nuclear tests.
Vacuum tube radios also have the disadvantage of requiring much more power than solid-state radios, and electric power will be a rare commodity after a nuclear EMP. Although a vacuum tube radio would have a high likelihood of coming through an EMP event undamaged as long as it was turned off and not connected to an antenna, a modern solid-state shortwave radio kept inside of a nested faraday cage is the best form of insurance for obtaining information after an EMP event.
(Many people don't realize that most
vacuum tube radios still in existence have an early solid-state
device called a selenium rectifier that is quite vulnerable
to EMP damage. Although replacement selenium rectifiers are still
sold for old radios, they are difficult to find, and you would
probably find them to be impossible to get after an EMP attack.)
When it comes to critical small spare items like an emergency radio, it is important to go to some extra trouble to insure the best shielding possible. Simple small nested faraday cages are so simple and inexpensive that you might as well make sure that a few items are very well shielded. When it comes to less critical items, though, such as items that you use frequently, a less-complete electromagnetic shield could easily make the difference between having equipment that survives an EMP and equipment that does not survive.
It is a very common misconception that
certain items must have military-grade shielding and other items are
nothing to worry about at all. Real world electromagnetic
disturbances are much more messy than that.
I believe that a few NOAA emergency transmitters are EMP-protected, but most are not. Repairs to many of these transmitters may be able to be made by military personnel, who can also supply emergency power to them for a while, but that emergency power may not last very long. If you're in the United States, though, it is important to have a NOAA Weather Radio.
These radios really are inexpensive, and whenever the NOAA transmitters are working, they can provide local information that is critically important.
Like your shortwave radio, an emergency
NOAA Weather radio needs to be kept in a nested faraday cage until
you need it. NOAA Weather Radios could be especially important in
the case of a
large solar superstorm, where the
radios would probably continue to work and give information, even
though much of the power grid could be out for years.
LED lights (and, to a lesser extent,
compact fluorescent lights) can be very useful for post-EMP use
because of their efficiency at a time when very little electricity
may be available. Both LED lights and CFL lights, though, are very
sensitive to EMP.
LED lights also can last for a very long
time. I know of one case where a device that I built in 1980 has
some of the older (1970s) type of LED indicator lights that have
been operating continuously for more than 30 years.
These switching transistors, although
they are out of sight, would very likely be damaged by high voltages
picked up by any wiring external the the CFL device itself.
There is an enormous spectrum of
possibilities for an EMP attack.
Large professionally-built faraday cages need to be well-grounded, but for smaller faraday cages, such as you would use to shield a radio or a laptop computer, any wire running to a ground is likely to just function as an antenna, and possibly as a very efficient antenna for gathering EMP. Grounding for EMP is a very specialized area of technology.
In fact, grounding for just about any
application other than simple static discharge or some basic kinds
of electrical safety are also very specialized areas of technology.
Although these underground pipes
probably won't pick up very much of the fast E1 pulse, they can pick
up rather large DC-like currents, and you don't need unexpected
electrical currents coming from what you thought was a ground
A steel enclosure is not a good enough electrical conductor to be called a faraday cage, but it may provide enough electromagnetic shielding to protect its contents.
A related popular myth is that there is
a sharp and well-defined boundary between what is protected from EMP
and what is not.
The level of shielding that is adequate
in any particular case depends upon a great many factors, including
the strength of the EMP, the distance and direction to the weapon
and the electromagnetic sensitivity of the particular equipment that
you are trying to protect. This electromagnetic sensitivity varies
greatly with every electronic device, and the sensitivity changes
rapidly as technologies change.
Within two or three weeks, the military services will likely come to the rescue for many people. If the size of the attack has been very large, though, that period of relief will probably not last very long. An even larger problem for food distribution is that any kind of centrally-directed distribution, no matter how well-intentioned, is highly inefficient.
If you drive into any very large city
with enough food for everyone, no centralized organization has ever
figured out how to devise a mechanism that is anything close to
being as efficient as the marketplace to get the food to everyone.
In any case, most people will soon simply begin to starve to death.
Although most individuals cannot do
anything to protect critical infrastructure computers or to protect
the power to critical central utility water pumps and sewage
systems, some advanced planning can increase the chances that you
will have an adequate supply of food and water.
In most industrialized countries, it is not customary for individuals to keep very much in the way of emergency supplies in their homes. In fact, many people who do keep many emergency supplies are regarded with some suspicion, thought to be "survivalists" or some other strange breed of humans. Disasters are frequent enough, though, that any prudent individual should maintain some basic level of self-sufficiency.
Most people in industrialized countries
see large-scale emergencies happening frequently on television,
while maintaining the irrational and completely unwarranted
assumption that it will never happen to them. It is the people who
do not plan for personal emergencies who ought to be regarded with
suspicion as a strange and irrational breed of human.
The MREs (meals ready to eat) used by military services, especially during emergencies, have to be made on an industrial scale, and they are available for sale to individuals during non-emergency times. The MREs are not the best choice for emergency supplies, though, because of the limited lifetime compared to canned dehydrated and canned freeze-dried food.
Many of these same companies that make MREs also make freeze-dried food in cans, which have a far longer shelf life and a much lower daily relative cost. After any sort of large-scale disaster, these supplies are only going to be available from government agencies, and government agencies will only have a finite supply.
Many basic emergency supplies can be purchased in advance of the emergency from reputable companies that have been making these emergency food supplies for years.
The food that these companies sell
normally has a shelf life of 5 to 25 years or more, depending upon
exactly how it is prepared and packaged. Although I do not want to
get into the process of naming companies, one that I believe to be
one of the best, especially for those who have not thought about the
subject before, is
Although some raw grains have a very
long shelf life and a high calorie density, they do not have an
adequate spectrum of nutrients for long-term use. In any emergency
situation where scarcity of food is a long-term problem, we are
likely to see the return of long-forgotten nutritional diseases such
as scurvy and various kinds of other vitamin deficiencies,
especially of the B vitamins and vitamin D.
After a major EMP attack or a
solar superstorm, electricity for
most of those pumps is going to be unavailable for a very long
period of time. It would be easy for most cities to have a protected
emergency electrical supply in place for critical pumps; but, like
most EMP protection activity, although it is easy and could possibly
save millions of lives, it is not being done.
Although it is the destruction of the very large transformers in the power grid that could keep the power grid from being restored for many years, many much smaller transformers, such as those on utility poles, and spread throughout suburban neighborhoods, are at risk of overheating to the point that they cause fires.
Although the great majority of the
smaller transformers are likely to survive, many of these
transformers are very old, and some of them are likely to severely
Buying prescription medicine out of your
own pocket makes it much easier to stockpile a supply for
emergencies. There is a fairly new web site operated by a physician
that discusses the problem of medicine storage for use during
disasters. See the
Armageddon Medicine site.
If you want to be able to use that electronics equipment after the batteries run down, you will need a personal power source. A simple small electric generator, one that does not depend upon electronics to start or run, is always a good idea.
After an EMP attack, though, fuel for the generator will be a scarce commodity. Solar panels can be used to supply a small amount of electricity indefinitely, especially if you also have some good rechargeable batteries that match the voltage of your solar panel. I don't know how resistant solar cells are to EMP (the solar panel technology is ever-changing), but if you have something like a 50 watt solar panel, you can store it in a nested faraday cage.
Only very rare individuals are going to
be able to have full electric power after an EMP attack, no matter
what advance preparations they might like to make. In a post-pulse
world, though, any amount of reasonably reliable electricity is
going to be a real personal luxury.
Aluminum wire cloth with openings of 0.4 to 0.5 inches will not only supply a certain amount of EMP protection, but can provide some protection against larger hailstones that can cause damage in severe weather.
The wire cloth will block some of the
sunlight, but the right size of wire cloth will block less than 15
to 25 percent of the sunlight. If you are making a new solar panel
system, some consideration should be given to putting the solar
panels inside of a cage made of aluminum wire cloth. This is much
easier to do during the original installation.
For people who own protected
photovoltaic solar cells, a number of DC-powered appliances have
recently become available. Transient protection (capable of reacting
to the fast E1 pulse) must be supplied on the electronic components
of any solar cell system, such as the inputs and outputs of charge
controllers and inverters. Any wire runs of any length should be
The magnetron that generates the heat in a microwave oven would probably survive an EMP just fine. Microwave ovens are heavily shielded, but the sensitive control circuits are outside of the shielding. A few microwave ovens are controlled by a mechanical timer, and these would probably be fully functional after an EMP (assuming that you can occasionally get enough electricity to operate them).
You can still find mechanical-timer-controlled microwave ovens occasionally, although they are getting harder to find every year. I bought one about four years ago at K-Mart for $40 for post-EMP use.
I have recently seen small microwave
ovens with electro-mechanical controls come back onto the market.
Some newer microwave ovens have a chamber that is designed to shield microwaves, but may not effectively shield some lower frequencies. Anything that you are hoping to use as an electromagnetic shield should be tested by putting a radio inside of the shield tuned to a strong FM station. If you can hear the FM station while the radio is inside of the shield, then the shield is not adequate.
There are so many things that can go
wrong with electromagnetic shielding that any shielding that you are
using should be tested first using the FM radio test. (Be sure to
remove the batteries from any equipment before putting it in
permanent storage, though.)
This is true both because of the smaller size of laptop computers and the fact that desktop computers have numerous cables which act as antennas for EMP - and which conduct the pulse directly to the very sensitive electronics inside the computer. Even laptop computers must be well-shielded and without any connections to unprotected wires.
The U.S. military contractors have
developed shielding devices so that laptop computers can continue to
be used during EMP attacks. Devices such as these, however, are not
available on the commercial market.
Don't worry about the fact that this
screen is not a solid material. The size of the tiny ventilation
holes in the mesh of ordinary window screen is irrelevant to EMP
protection. Aluminum screen can make a very effective
electromagnetic shield. Ordinary ferrous (iron-containing) window
screen is not a good material for a faraday cage because it is a
poor electrical conductor.
A partial shield, though, can often reduce electromagnetic signals from the outside by a critical amount. When I was working at a broadcast transmitter site that had an unacceptable level of electromagnetic radiation from the FM broadcast antenna into the area at ground level where the vehicle was commonly parked, I had a carport built with copper screen imbedded into the roof of the carport.
The reduction in electromagnetic radiation beneath the carport was quite dramatic - as actually measured using professional equipment.
Since nuclear EMP comes in from a fairly high angle, it is likely that a similar arrangement, but using aluminum screen, would reduce the EMP substantially, possibly enough to protect vehicles and other large items stored below the shielded structure. In the case of the carport that I had built, I grounded the imbedded screen because I knew that the wire leading to ground would not act as more of an antenna than a ground for the shield. (I also knew that the ground at the bottom of the carport was an extremely well-designed ground.)
Although most small faraday cages should
not be grounded because of the "accidental antenna" problem, if a
carport shield can be well-grounded at all four corners, then a
direct wire going to a ground rod at each corner would probably be a
The components that are most likely to damage ordinary small electronic items are near the FM broadcast band.
Therefore, you can make a rough test of
your shielding effectiveness by tuning a radio to a strong FM
station and see if your shielding silences the radio so that you
can't receive the FM station. You can try the same thing with AM. In
general, the good electrical conductors like copper or aluminum will
be better at shielding the higher frequencies in the FM range, while
steel cases may perform better in the lower-frequency AM band.
If all the computer data is gone, then recovery is going to be many years later than it would be if the data could just be reloaded from optical media.
Computer data runs our modern world. It is a major part of the invisible magic that I mentioned at the top of this page. If you own a small business, that computer data can be especially important. (It is probably not a good idea to use double-sided DVDs, though, since there is the possibility of arcing between layers during electronic attacks. It is best to just use single-sided single-layer media.)
For long-term storage of data, archival
grade CD-R and DVD-R media are available at a reasonable price from
manufacturers such as Verbatim and Memorex. The archival grade media
are much more likely to last for many years or decades, and they
don't cost that much more than standard media. Most stores don't
carry archival grade media, but they aren't that difficult to find,
especially on larger electronics stores on the internet.
There is always the possibility, though,
that you will be near the edge of an area that is affected by an EMP
attack. For this possibility, the combination of ordinary surge
suppressors and ferrite suppression cores could be very valuable.
There is at least one company that makes surge suppressors that look
much like ordinary retail store surge suppressors, that are designed
to be fast enough for nuclear EMP.
The ferrite suppressors on power cords (and inside of many surge protectors) are usually the common type 43 ferrite material, which offers a considerable amount of protection against ordinary transients, but would do only a little to protect against the very fast E1 component of a nuclear EMP. You can buy separate snap-on ferrite suppressors, including snap-on ferrite suppression cores with type 61 ferrite, which will absorb much faster pulses.
The ferrite cores with material 61 don't cost all that much more than the older ferrite, and they should attenuate the spike from a nuclear EMP much better than type 43 material.
If you're in an area where there is a strong EMP, it won't attenuate it enough to do any good at all, but if you're at the edge of the affected area, or just get a nearby lightning strike, or have a lot of ordinary voltage spikes on your power line, these snap-on ferrite cores with material 61 could be extremely valuable. They are sold by companies such as Mouser Electronics.
Look for items such as Fair-Rite part
There is no reason to assume, though, that any EMP attack will be maximally effective - or that you will never be right at the edge of the affected area.
Also, even if an EMP attack never
happens, an endless barrage of small voltage spikes is eating away
at your electronics equipment every day unless you are doing
something to protect against it.
Note: This is a 200-page
report (7 megabytes), and could take a half-hour or more to download
if you are on a slow dial-up connection.
The EMP Commission relied heavily on
data from simulators, and this data does not explain all of the
effects that were actually seen in the 1962 nuclear tests,
especially in the
Soviet EMP tests over Kazakhstan.
Although many vehicles would be rendered inoperative, and it will be a regular "demolition derby" on streets and highways, many (but not all) vehicles that are not running at the time of an EMP will be likely to run after they are started (although there is a very high probability that your car will experience electronic damage outside of the electronic ignition system, and your car may have to be started in an unconventional way.
It is also possible that you may have to
momentarily disconnect the battery so that electronic modules can
recover from an EMP-caused latch-up condition, a situation unique to
EMP.) It may be necessary to have a maintenance manual for your car
so that you, or someone you know, can figure out how to bypass the
damaged modules in your car.
If you have a car parked in a location
where there is a very short and direct connection straight down into
a high-quality ground, then grounding the frame of a car might help,
but I doubt it. In most situations, attempts to ground the frame of
a car are more likely to just make matters worse by providing an
accidental antenna for EMP. The safest way to provide a modest
amount of EMP protection for a car is to keep it parked inside a
For those who want to try, the only authoritative document that I know to be available is one called "EMP Mitigation - Protecting Land Mobile Vehicles from HEMP Threat Environment" which was just published in March, 2011.
To find this document, go to the
Protection Technology Group page,
then click on the Knowledge Base link at the top of the page. Scroll
down on the Knowledge Base page until you get to the article that
you want. The article specifically applies to military vehicles, but
has relevance to commercial vehicles as well. Note that the part of
the referenced article that refers to bonding of "all metallic
structures to a single point ground system" is referring to an
electrical chassis ground on the vehicle, not to an earth ground.
This process was apparently started by a large voltage spike from the fast E1 component of the pulse punching through the insulation on the wiring at a single point.
According to Vladimir M. Loborev, one of the chief scientists who studied this phenomenon,
This should be a warning to anyone who is planning to use any very old vehicle for possible use after an EMP event.
If you have a pre-electronic-ignition era vehicle, it is important that you also have an electrical wiring diagram for the vehicle, and plenty of fuses (and I do mean plenty of fuses) and some critical electrical spare parts. My own personal experience in maintaining a 1959 model RCA high-power television transmitter until the year 2000 tells me that it is very easy for high voltages to punch through old insulation.
Although post-EMP repair of these older
vehicles may be easier than repair of a modern vehicle, it can be
very frustrating, since very old insulation on electrical wiring can
become extremely brittle.
The MOVs are not fast enough to capture the leading edge of the EMP spike, but it takes a lot more energy to punch through enamel insulation than to damage microelectronics, so it is likely that these MOVs would provide adequate protection for the insulation. Small MOVs are readily available from companies such as Radio Shack (part number 276-568).
(It is unlikely that these MOVs would be
fast enough to protect any microelectronics that may be in the
Bentonite is a material that is widely used in drilling industries that can also greatly enhance conductivity between the grounding system and the earth. I have found bentonite to be very effective as a grounding material. For most people, bentonite is easier to obtain and much more practical than the proprietary commercial grounding compounds.
If it is not feasible to bury a ground
rod vertically, a fairly good ground can be made by digging a trench
as long and deep as is feasible, then placing flexible copper tubing
(such as is used in plumbing) in the trench, covering the copper
tubing with bentonite or other grounding compound, covering with
topsoil, then using the above-ground part of the copper tubing for
the ground connection.
(If you think that a water pipe or the
ground wire on an AC outlet is a good ground for EMP, then you
should definitely forget about grounding. Neither of these
connections is close to being an effective EMP ground.)
Although steel can be a good electromagnetic shield for lower-frequency components, I have found it to be considerably inferior to better electrical conductors such as copper and aluminum in actual measurements in intense electromagnetic environments. Steel has different characteristics from better electric conductors such as copper and aluminum, so the best situation if you are using an steel enclosure is to add a layer of copper or aluminum screen or foil as an additional layer of shielding.
(Steel tends to be better at shielding lower frequency components, but aluminum and copper are better at shielding the higher frequency components that are more likely to damage smaller items.)
Actually, there is evidence that the
very best EMP shields would be alternating layers of steel and
aluminum or copper, with an insulating material separating the
layers of metal. (This is how many electromagnetically shielded
buildings are actually constructed.)
It is important to note that most
uninterruptable power supplies on the market are NOT the "true
online" type, and are of very limited usefulness for isolating the
equipment from the power line (even for ordinary voltage spikes).
Most inexpensive uninterruptable power supplies let much of the
voltage spike hit the equipment before switching to internal battery
power after the AC line power has failed.
(Many major UPS manufacturers have been
rather deceptive in the past about whether their UPS units are
actually the true-online double-conversion type, although most
companies are becoming more honest about the architecture of their
UPS units since the difference in actual equipment protection is
Although the principal effects of E3-type events for the individual is total loss of power from the power grid, these events could cause extreme distortions in the AC power waveform for a short amount of time until the grid collapses. This extremely-distorted AC could burn out motors and damage electrical and electronics equipment in a very short amount of time unless measures are taken to isolate the equipment from the power line by using a true online UPS or a ferro-resonant transformer.
Certain types of ferro-resonant
transformers, such as the SOLA CVS series, can isolate equipment
from power line distortions by insuring that the equipment gets
either a pure sine wave or nothing at all. The
SOLA CVS transformers are also
extremely effective at blocking most voltage transients from getting
into equipment, although they won't completely block extremely large
and fast transients such as those from the fast E1 component of a
If you are trying to use either a UPS or
a ferro-resonant transformer to protect any appliance where a motor
is a significant part of the load, you have to select a UPS or ferro-resonant
transformer that has several times the rated load of the appliance.
Although none of the consumer-type surge
protection devices are likely to be completely effective against EMP,
they may be helpful in protecting some types of household
You may want to consider backup data
centers such as
The Polyphaser EMP protection devices
for antenna connections generally use only type N connectors (so you
may need an adapter), and the cost is generally about $125.
Polyphaser does not sell these devices directly to the customer in
small quantities, but they can be purchased through companies such
if you know exactly what model number of
Polyphaser device that you want.
(The aluminum-colored plastic briefcases are useless as an EMP shield unless a considerable amount of additional electromagnetic shielding is added.)
If you are unsure of the electromagnetic integrity of your aluminum briefcase, a layer of electromagnetically shielding metallic spray paint can be added to the exterior of the briefcase. The cans of electromagnetically shielding spray paint tend to be rather expensive, but they can be purchased from companies such as Mouser Electronics.
For maximum effectiveness, there needs to be good electrical contact between the two halves of the briefcase, especially at the hinges and the latches.
A well-shielded briefcase should be able
to completely eliminate reception of an FM radio receiver that is
tuned to a strong FM station and placed inside the briefcase with
the latches secured.
Unfortunately, the information about these events after the initial earthquake and tsunami by the news media in the United States has ranged from horrible to non-existent. Nearly all of the deaths and suffering after the first hour of the tsunami have been due to the absence of electricity and electronic communications.
Just about the only place to get accurate information about the aftermath of the tsunami is from NHK World.
NHK has shown things like what happens
when you try to open the grocery stores after power is restored
after a prolonged outage, and the difficulties of supplying the
grocery stores from the food warehouses when the inventory control
and computerized ordering systems are not working.
Most cell phones are too small to intercept enough EMP to damage them; but the cellular repeaters, which are necessary to the operation of the cellular telephone system, are very vulnerable in a wide range of disaster situations. Unfortunately, the cellular telephone system was not designed with any peer-to-peer (direct cell-phone-to-cell-phone) capability.
This means that if the cellular repeater
stations go down, your cell phone becomes useless.
The only way to make an effective plan is to try to imagine an unpleasant future where you are suddenly thrust back into the middle ages. One thing that an EMP or a severe solar storm won't destroy is the knowledge of how to re-build effectively.
Hopefully, even if we don't get an
robust and permanent infrastructure built in time to prevent a
catastrophe, the rebuilt post-pulse electrical and electronic
infrastructure will be something that is permanent, and that all of
us can finally trust, unlike the very fragile infrastructure that we