What exactly is EMP?
An EMP burst itself is harmless to humans and household pets, kind of like being exposed to a very bright light for a very short time. It's true that a pulse can consist of damaging radiation, but the health risk due to this very short-lived and weak exposure is negligible. |
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The problem with EMP
Any metallic object (think towers, buildings, aircraft, power lines, vehicles, houses, appliances, and computers) subject to a large-enough EMP burst can act like an antenna, bringing destructive voltage pulses to its internal circuitry, especially sensitive micro-electronics. Many modern products previously manufactured as purely mechanical now incorporate microchips, microcomputers, cameras, Bluetooth, and Wi-Fi for monitoring and control, leaving many of these devices vulnerable to the effects of a strong EMP event. The result of a large voltage surge being applied to sensitive micro-electronics can range from the inconvenience of a fried electronic Mickey Mouse watch, to a disabled wide-area communication network. But EMP effects on even small electronic devices can be life-threatening if the device is an implanted pacemaker, for example. Because of the enormous amount of signal strength in these surges, significant electromagnetic pulses can appear in unpredictable power levels, making them very difficult, if not impossible, to control. One point of concern to those aware of the potential of EMP is the effect on our electrical power grid, since in many places it's controlled by computers. |
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The two most significant EMP sources
But even lightning, as powerful as it is, being able to destroy household appliances, your house, or even you, does not produce an electromagnetic pulse at a level that poses a widespread threat. Its destructive properties are mainly high electrical current, extreme heat, and intense light, not to mention the deafening thunder you might hear if you're near such a strike. If we narrowed down a list of EMP sources that could pose a widespread threat, it might include the following:
nuclear detonation pulse generator |
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You will likely never experience a large, man-made EMP
An EMP created deliberately for malicious purposes has a much greater opportunity of affecting the public if the required energy is sufficiently available. But the energy required to produce an effectively destructive pulse is so great, and the accompanyinng equipment so expensive, that it's out of the reach of most would-be perpetrators. One possibility is a military EMP generator (e-bomb, or NNEMP), which typically presents less than a millionth the pulse energy as that of a nuclear source, but has also proven effective for attacking electronics installations, disrupting communication. An incidentally created pulse is generally a side-effect of another, significant event. In the man-made case, that typically translates to a nuclear source, as in a weapon detonation. Known as a nuclear EMP (NEMP), this pulse is large enough to cause widespread damage to vulnerable and exposed electronics. But nuclear weapons are currently only available to a few governments that can afford the extreme cost of researching, developing, and launching such an instrument. Most nuclear detonations must be close enough to the ground to produce noticeable damage. And if a detonation was to occur close enough to ground to produce such damage, chances are that people will be killed by the radiation, and their electronics incinerated, by the resulting heat. However, the geographic area surrounding the deadly radiation and heat zone of such a closely detonated nuclear weapon will most likely be heavily affected by EMP, the size of the area dependent on the terrain and weapon capability. Those still alive in that area of vulnerability will likely experience the loss of device function as a result of the huge pulse. Your device can fail in that case because of direct EMP exposure or because it's simply plugged into the grid, which can deliver the pulse electrically into your home, potentially destroying everything plugged into it. If calculated properly, a nuclear device detonated in the upper atmosphere can produce a high-altitude EMP (HEMP), which can affect an even larger area, due to the interaction between the high-energy free electrons produced by gamma radiation, and the Earth's magnetic field, resulting in a magnification effect of the destructive pulse over that which could have been produced at lower altitudes. Still, the likelihood of such a nuclear scenario is extremely small, especially because there are so many safeguards in place that prevent a nuclear attack from even getting close to American airspace. So, investing a large amount of time and resources into protecting against such an event is left to entities (governments, military, large corporations, etc.) that can afford to develop and maintain the infrastructure. For the rest of us, it's probably best to install some small and inexpensive measures to protect against a smaller, more manageable EMP if we're truly concerned about it. |
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You will rarely experience a solar-caused EMP
Relative strengths of solar flares are classified as follows:
Can a strong, extra-terrestrial EMP originate elsewhere? Yes, of course it can, but that's very unlikely, so the sun remains our largest source for practical EMP concern. |
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How far should you go to protect your equipment from the effects of EMP?
Unfortunately, many point to the US military as an example of the extent of protection that needs to be put in place, in order for their equipment to withstand a specified level of electromagnetic pulse attack, solar or man-made. Our military is charged with the huge responsibility of defending and protecting our government, our infrastructure, and our citizens against attacks, and they do so to the best of their ability with the resources available to them. Comparing their responsibility and resources with those of an individual is unfair at least and nonsense at worst. We cannot hope to provide the level of protection they can, but then, we also don't need to. An EMP originating from a large-enough solar flare can destroy, if not temporarily disable, household electronic devices, such as cell phones, radios, computers, televisions and monitors, home control devices (burglar alarms, cameras, thermostats, etc.), internet access gear, and game consoles. This is because, like a radio antenna, each device has the ability to absorb a bit of that high-energy pulse. By the same radio antenna analogy, the smaller the device, the less its ability to absorb the pulse. Still, they're a little vulnerable. Fortunately, most of these electronic devices can be easily protected from an average solar EMP event by simple shielding using metal containers. Containers that provide effective EMP shielding against an averagely large solar attack include your car, your refrgerator, aircraft, a shipping container, and your house (if it's covered with aluminum siding.) Some household metal containers can also be used as good shields, such as paint cans, metal garbage cans, metal ammo cans, and even a few layers of aluminum foil. You mean you can simply leave your radio in your car during an EMP attack, and it'll be ok afterwards? More than likely, if your vehicle has a metal body (more and more cars these days have fiberglass bodies instead,) your radio can withstand a mild pulse. Wait...cars have computers and other electronic gear controlling them too. Does this mean their metal bodies will protect them against a direct EMP strike? In most cases, yes. As mentioned previously, another concern for EMP is through your electrical system. If a pulse makes its way onto the electrical grid, it can actually fry just about everything in your house that's plugged in. But wait...won't my circuit breakers take care of that surge of current coming into my home? Most likely not, because household circuit breakers are designed to open your circuit during a long-lasting surge, as in milliseconds. But by the time your breakers react to the intense, fast surge of an EMP, most of the energy will get through them, laying waste to your TV, your computer, your fridge, and everything else plugged into the wall. Going completely solar can get you off the grid, but that's expensive, and you'll still be somewhat vulnerable. Ok, but what about a nuclear-generated EMP attack? Well, again, since those are so rare, they're really not worth bothering about, so we'll let the military and the public utilities worry about that extremely unlikely event, and take the chance that we simply will never experience one. |
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About Noji
I'm not a prepper, but I am a member of the Church of Jesus Christ of Latter-day Saints (Mormon), a licensed ham radio operator, and I believe we need to be prepared...within reason. |
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