Sun Unleashes Monster Solar Flare, Strongest in a Decade Since this just happened now might be a good to to evaluate your preps.
Protecting Electronics and Cars from an EMP (Simple, Easy, and Effective)September 6, 2017
by Dr. Arthur Bradley
Perhaps the question that I’m asked most often regarding EMP Attacks is how to protect various types of electronic equipment. The answer is that it depends on what you’re trying to protect. Small items, such as radios, cell phones, LED flashlights, etc. can be stored in homemade Faraday cages. To learn how to build one using aluminum foil, check out my article How to Make Your Own Faraday Cage at Home (Quick, Easy, Effective!).
Some people prefer to build a Faraday cage using ad hoc containers, such as a galvanized garbage can, ammo can, or gun safe. See my video at
https://youtu.be/uYWhTMmv6bs to learn about the importance of properly sealing an ad hoc cage. Note that many people advocate building Faraday cages out of chicken wire. For a clear demonstration of why this isn’t a good idea, see my video at
https://youtu.be/9M6h1U9jgWs. protecting electronics from emp
Perhaps the easiest way to protect small-scale electronics is to store them in EMP bags (aka anti-static bags). There are many types of EMP bags on the market, so it’s definitely a case of buyer beware. I tested a dozen different EMP bags and found that the shielding they offered ranged anywhere from 10 dB (a factor of 3 reduction in electric field strength) to >50 dB (a reduction of 316 in electric field strength). More info about the bags that provided the best protection, as well as how they were tested, is available at
http://disasterpreparer.com/emp-bags. Protecting Generators, Vehicles, and Solar Panels
Protecting larger items, such as generators, solar panels, and vehicles requires a different approach. The easiest way I have found to protect larger electronic items is to cover them with conductive cloth. I tested twenty-five types of EMP cloth and found one that met the following important metrics:
Good shielding protection
Easily sewn
Durable
Safe to handle
Won’t tarnish or rust
Low surface conductivity
Reasonable cost
The cloth is made with nearly invisible stainless-steel fibers and feels like a lightweight denim. It can be sewn by hand or with a sewing machine. The material is durable and safe to handle and doesn’t contain silver or nickel. Also, it has low surface conductivity, meaning that it can be grounded very easily — usually by just allowing it to drape onto the ground or concrete floor. Note that it works even if not grounded—see explanation below about shielding. More info about EMP cloth can be found at
http://disasterpreparer.com/emp-cloth. Conductive cloth and EMP protection
Using EMP cloth is easy. Simply wrap it around (or drape it over) the object to be protected. If it is draped, ideally you want the cloth to touch the ground all the way around the object. That said, even if it doesn’t touch the ground, it will still provide very good protection—see next paragraph for the reason why. Below is a photo of a car cover that I tested that was made from the EMP cloth. Testing showed that it provided between 30 and 40 dB of protection across frequencies from 100 kHz to 1 GHz. Portable generators and solar generation systems (that are not in use) are also easily protected in this same manner.
Testing conductive car cover from 100 kHz to 1 GHz
One question I get asked quite often is how can a car cover placed over a metal car possible work? The answer requires understanding that there are two ways to protect electronics. The first is to fully enclose the object in a conductive housing (aka Faraday cage). When an incident field is present, charge carriers on the surface of the conductor move around to effectively cancel the field that is seen inside.
The second method is more conventional shielding. Placing a conductive barrier in the path of an RF wave causes attenuation due to two mechanisms: reflection and absorption. When you place the conductive cloth over the car, it acts as a shield, causing both reflection and absorption of incoming RF energy. By allowing it to come into contact with the ground, you also create an imperfect Faraday cage, one in which the ground acts as the bottom of the cage—yes, the earth is a modest conductor. To see this yourself, ride down a slide until your hair stands up. Then touch the earth and watch as the charge bleeds off.
Protecting Objects that Remain Plugged In
Some items must remain plugged in all the time. Covering them still provides some protection, but large transients can come in through the corded connections. There are numerous ways to suppress transients that might come in on the wires, including metal oxide varistors (MOVs), transient voltage suppressors (TVSs), and ferrites. Each of these operates on a different principle: MOVs change impedance as voltage increases, TVSs turn on to shunt away excess energy, and ferrites use magnetic fields to resist change in current.
Of the three, ferrites are the easiest to use. Simply clip them around the wire, and they provide immediate transient suppression. Also unlike MOVs and TVSs, they are not damaged by transients. I reviewed several hundred ferrites and selected a handful that provides broadband protection. For more information about ferrites, including saturation and the importance of looping to increase suppression, see
http://disasterpreparer.com/emp-ferrites. More Info about EMP Protection
For more information about protecting against an EMP Attack, see
http://disasterpreparer.com/empsolar-storms or pick up a copy of “Disaster Preparedness for EMP Attacks and Solar Storms”. Finally, if you have questions about any topic related to EMP protection, feel free to send me an email at arthur@disasterpreparer.com.
About the Author
Dr. Arthur Bradley is the bestselling author of the Handbook to Practical Disaster Preparedness for the Family, the Prepper’s Instruction Manual, the Disaster Preparedness Handbook, and Disaster Preparedness for EMP Attacks and Solar Storms. He is also the author of the best-selling post-apocalyptic series, The Survivalist. He provides free disaster preparedness information at
http://disasterpreparer.com.
