Some of you (including me) know of the vulnerability that we face with regards to the risk of ‘natural’ or ‘man-made’ EMP (electromagnetic pulse), which has the potential to destroy our electronic components and electronic infrastructure – and maybe even bring down the grid.
As a precaution, some of you (including me) may stash some particular items in a do-it-yourself Faraday cage for protection from an EMP.
So, I have two questions for you:
1. What specific items do you (or would you) store in a Faraday cage?
2. What is the rationale for each of these items?
An EMP, or electromagnetic pulse, is thought to be a highly unlikely event. And it might be. On the other hand, no one can predict with any certainty one way or the other…if and when we get ‘zapped’ into a pre-high-tech age in which many or most of our ‘survival’ systems stop working (any system which depends upon electronics to keep on functioning).
While the follow-on effects of a devastating EMP event would be horrific, for those who are preparing for such an event – what are the electronic items that you would consider ‘saving’ in a do-it-yourself Faraday cage for life after the EMP?
Here are a few thoughts:
As many of you know, an EMP (electromagnetic pulse) could end life as we know it in approximately one hundredth of a microsecond. Faster than the blink of an eye. While some may argue the likelihood of such an event, lets focus instead on the methods one might consider to protect their electronic equipment in a Faraday cage.
But first, briefly, an EMP in the context of this article is a pulse of considerable electromagnetic energy (with a wide range of frequencies and amplitudes) resulting from a nuclear detonation at (high) altitude in the atmosphere. As the pulse travels away from the burst point at the speed of light, the radiation can be ‘collected’ by metallic and other conductors at a distance. The energy of the radiation can then be converted into strong electric currents and high voltages. With sufficient energy, particularly from the high-frequency components of the EMP, electrical and electronic equipment connected to (or associated with) the collector may suffer severe damage from a strong current and voltage surge.
A protective measure to protect electronic devices from the effects of EMP include the Faraday cage.
(Update) The effectiveness of protection depends on several complicated factors including strength of EMP, your geo location from it, EMP altitude, and the gauge and type of metal you are using, and more… Suffice it to say that any makeshift Faraday Cage is better protection than none.
Build a simple Faraday cage from a small metal garbage can and lid.
The lid must fit snugly over the can. If the lid does not make good metal-to-metal contact, the open area could allow EMP to damage your equipment.
To further protect your equipment, purchase a metal screen about 6 inches wide and as long as the circumference of the can. Fold the metal screen in half, length wise, and then place it around (and fold over) the lip of the garbage can. The lid should then fit snugly against the screen and can, protecting all equipment contained inside the can.
Any metal can act as a Faraday cage. Even an ammo can. However, good metal-to-metal contact is imperative.
Remove all gasket material from the lid. If the can has been painted, make sure to remove the painted area around the lid where it contacts with the can itself (and the inside of the lid) with sand paper, so as to make good metal-to-metal contact.
An electromagnetic pulse (EMP) attack on the American homeland is one of only a few ways that the United States could be defeated by its enemies — terrorist or otherwise. And it is probably the easiest. A single Scud missile, carrying a single capable nuclear weapon, detonated at the appropriate altitude, would interact with the Earth’s atmosphere, producing an electromagnetic pulse radiating down to the surface at the speed of light. Depending on the location and size of the blast, the effect would be to knock out already stressed power grids and other electrical systems across much or even all of the continental United States, for months if not years.
Having said that, it may be prudent to protect some electronic items that may be useful post-collapse. Portable AM/Shortwave Radios. 2-way communication radios. Portable solar battery charger. The list can be as long as your imagination…
Can an old microwave oven be used as a Faraday cage?
YES, to an extent, an old microwave oven may be re-purposed as a Faraday cage against EMP (electro magnetic pulse). In fact, its design is very much similar to a basic Faraday cage. A Faraday cage is an enclosure formed by conducting material or by a mesh of such material. A microwave oven’s very design is to enclose the electro-magnetic radiation of microwaves, and keep them from getting out. The reverse will also be true – they can’t get in.
Think of a Faraday cage as a reflector. A reflector of electro-magnetic waves. It reflects waves on the outside from getting in and waves on the inside from getting out.
A Faraday cage by its very definition does not have to be grounded to reflect or keep out electro-magnetic waves (they normally are not grounded). From inside the cage, it makes no difference if the conductive shell is grounded or not. The inside ‘doesn’t know’ about the outside with regards to electro magnetic radiation.
The effectiveness of the ‘reflection’ properties of a Faraday cage depends upon the wavelength of the electro-magnetic radiation in question, the diameter of the holes in the cage’s conductive material, and the conductivity of the material itself. Aluminum, or even steel window screen is “good enough” to prevent any significant electro-magnetic radiation.
Most purpose built “Faraday cages” that you buy are made out of copper screen instead of solid metal. As long as the holes in the screen are smaller than the wavelength of the frequencies you are trying to protect against, screen works just as well as a solid piece of metal.
An EMP is a broadband, high-intensity, short-duration burst of electromagnetic energy. In the case of a nuclear detonation, the electromagnetic pulse consists of a continuous frequency spectrum. Most of the energy is distributed throughout the lower frequencies between 3 Hz and 30 kHz. However the first effects of nuclear detonation are the very-high-frequency pulses, in the microwave range, and can work their way into Faraday cages if there are cracks, seams, or vents.
The frequency of a microwave oven is 2.45 GHz (gigahertz) and has a wavelength of 4.82 inches. Since the holes of the screen mesh of a microwave oven are small compared to the wavelength of the microwave itself, little radiation can leak out. There are also mesh screens on the sides of the oven cavity, one to protect the oven light while allowing it to shine into the cavity, the other to permit ventilation.
A microwave will indeed protect your electronic gadgets during an EMP, so long as you don’t press ‘START’…
Guest article by NRP;
Preparing and Survival for the most part may be broken down into “Time-Lines”. These concepts have been written about in many articles and seemingly are explained very simply.
My attempt here is to expand on those concepts and to add a few more “Time-Lines” to think about.
1. 3 Nano-Seconds to think
2. 3 Seconds to react
3. 3 Minutes without Air
4. 3 Hours without Shelter
5. 3 Days without Water
6. 3 Weeks without Food
7. 3 Years without Rebuilding
Which specific types of electronic devices may be useful for emergency preparedness?
We sometimes talk about the preparedness basics such as water, water filters, food, food storage, etc.., but this time lets consider the electronic ‘gadgets’ or electronic systems that may be beneficial towards preparedness in one way or another…