Whatever you want to protect must be protected before the EMP. There is no way to run around, gather the equipment and place it all in a Faraday cage. To the best of my recollection, supposedly a nuke set off deliberately to create an EMP would be aimed into an area above the southern US to utilize the magneto sphere to intensify the effect. In doing so, it would be very bad in some areas and not as bad in other areas. Here are a couple of sites about building a Faraday cage. The old thoughts about wrapping your stuff in aluminum foil isn't supposed to be all that reliable. If I had a few minutes notice, I put my stuff in a microwave oven, cut the plug off, and ground the green wire. Try it sometime. Put your cell phone your microwave and close the door, obviously don't turn the microwave on. Now call your phone. If you oven has a good seal, it will not ring.
How to Build a Faraday Cage | eHow.com
Faraday Cage
I have to address this myth head on here. The myth is due to being dated.
First off. For the microwave thing.
Older phones you can apply this type of logic but 1. unplug the microwave, (if you can remove the cable entirely, or better yet ground it, but no do not plug it into the electrical system and expect it to protect against an EMP, the elctrical system will not only act as a giant antenna but it will also probably cause your microwave to arc.
Here is the problem. Microwaves generally emit at 2.450 Ghz approx, they are sheilded for that size and less... not above that.
4G phones operate at higher frequencies than 2.450Ghz so the phone signal will still get through on 4G phones.. older phones often operate at lower frequneces such as 2.1 1.8 and 0.9 Ghz and should be sheilded. Note microwaves are not "perfect" faraday cages, they only offer sheilding, and will dampen the effects of EMP.
But yes they do help, but wrap your devices you want to survive in aluminum foil, between the foil and object wrap it in an insulating material to avoid direct contact between the aluminum and the sheilded object. As you can see if you turn your microwave on with metal inside, the radiowaves are repelled, causing arcs. That is why you don't put metal in the microwave because metal reflects the waves. Powerlines are a bit like this.. but they emit radiowaves, that is why you hear them oscillate with a hum, that is electricity radiating from the lines. It is just the intensity of the pulse that is the issue because it will cause a bottleneck.
BUT the key here is 4G phones operate at higher frequencies than microwaves.... and so the waves are smaller and can travel through the wire mesh..
but note that most nuclear EMP pulses are at the low UHF/VHF range, meaning they are at 1ghz or less and these are the powerful pulses you need to worry about, for electronics. (as opposed to higher frequencies, which are the ones you really need to worry about, but generally only if you see the blast or it snows after the blast or rains. Bear in mind light, and vision operate at a higher frequency that UHF/VHF radiowaves, and xrays at even higher frequencies. Sustained pulses at 30-300mhz are harmful to human health, at sufficient power levels, other frequencies effect other things like insects)Generally speaking these are the guys you need to worry about
http://en.wikipedia.org/wiki/Gamma_ray for health, while UHF/VHF level radiation is a major concern for electornics, although even lower frequencies do some stuff too... if you suspect a nuclear strike at a given location move away from the location and do not look in that direction, it is that whole sodom and gommorah all over again, seek cover at the lowest point possible with thick walls, imo avoid any large structures with multiple stores unless it is a very very very strong structure that will not collapse in a stronger than hurricane force winds.
Also some radio frequencies DO effect human health, and all radiowaves at high enough intensities can cause biological reactions. We have our own magnetic fields also. Generally though EMP's are brief, and not long lasting, hence P. Ionized radiation is what is seen as dangerous to humans, lots of radiowaves are non ionizing. There are safety protocots for exposure times to specific frequencies, most of them arn't pertinent to EMP's, the radiation does kill from nuclear weapons, however this is at much higher frequencies the EMP is the "lower" frequencies, while the lethal radiation is at the higher frequencies.
The lower frequencies travel further at the same power, and can also bounce around more, and travel along the groun, and penetrate into the earth. Different frequencies act differently at different power levels in relation to the environment in which they act.
Most civillian electronics, aside from medicla and industrial devices are just luxury junk anyway. In event of nuclear attack communications devices may not function anyway, however having a good backup device is good, something is better than nothing but you want multiple levels of sheilding. As far as I can tell the aluminum foil with an insultating layer, due to being bonded at the molecular level will offer the most sheilding. That is because the cage is the latice structure of the metal, very very small cage so it sheilds from higher level frequences.
There are equivolents of protection based on thickness of specific material types.
The main point I meant to raise though was that 4G phones operate at a higher frequency level than microwaves so they very well are probably not going to work under the dial yourself test.
