just remember, the Faraday cage can only protect your device from ONE EMP effect, and the microwave oven is just about as good for that as anything
else. All cheap Faraday cages will let in radiation, the cut-off frequency is determined by the holes in the aperture, and even if no holes are in it,
will give just a certain amount of isolation, depending on what kind of material your Faraday cage is made of. A cheap DIY-type Faraday cage will
attenuate the RF component of the signal by about 30dB or 1000x, provided no holes larger than 1/4 wavelength of the highest frequency of the RF
component exist in the box. A properly installed Faraday cage can give you up to 140dB (100000000000000x) isolation, but I doubt many of us can
afford that, and that requires very special techniques.
In other words, an EMP blast, causing a field strength equivalent to that of the Starfish Prime detonation extrapolated to a high-latitude detonation
of around 30kV/m, would be around 3V/m in your home-built Faraday cage, making your equipment fairly safe.
However, that is only part of the equation. Depending on which kind of EMP weapon is used, and your distance from the detonation point, there can be
other effects too, for which a Faraday cage is not going to help. These effects includes the magnetic component, and for nuclear type EMP weapons,
Compton and Gamma radiation.
But it all boils down to one or 2 things. If the whole country is without any communications, what good will your well-protected cell-phone be? I can
understand the case of an HF radio, but any sort of equipment based upon a infrastructure is going to be useless without the infrastructure.
The RF component of an EMP is well-understood, by proxy, to any competent engineer who has had to design equipment for EMC requirements, and that is
what I based my quick calculations upon, but there are a number of different EMP-type devices that are theoretically possible, and have been described
in unclassified documents, but a lot of the data from the nuclear-EMP tests are classified, so one can just extrapolate on it, and derive parameters
from military standards for EMP-proof electronic equipment from those standards. Once, an engineer, who was one one of those who generated the MIL
standard on HIRF and other EMI standards (read EMP), when equipment I designed and had to be tested to those standards, asked me afterwards, "So what,
your equipment passed, but you will be dead, because the limits for these HIRF standards (again read EMP-levels) are lethal to any human being."
Yes, contemplating that, I could see he was correct. Here I was, testing equipment I designed, at a field strength of 120kV/m, if that radiation falls
on you, and you are 1,5m tall, there will be a difference of 180kV between your toes and your head, that is 180 000V, and your mains voltage in
America is 110V!!! (OK, I know I simplify things a LOT now, but that is the effect). Compared to that, the field strength in your average microwave
oven, is only around 1500V/m, and here we were testing almost to 100x that level.
edit on 11/4/2013 by Hellhound604 because: (no reason