I have been thinking about different ways to go about a faraday cage. An EMP is not on the top of my list, but it is still a concern and faraday cage is a rather simple design, so I think I will go for it. And I would hate to invest in radios and other electronic devices and have them useless because I didn't implement a basic device.
Now I am a huge fan of Ammo Cans from the army surplus store. They are inexpensive, seal tight, and are constructed completely from steel. And have thought of using them as a faraday cage and using some form of rubber mats to line the inside. Another thought would be to fabricate my own, I have a welder and could simple weld a cage to my custom design and have a similar approach to an ammo can, but with more work involved, and depending on size and design, cost.
As far as an EMP proof vehicle, I am a little new to that concept and will have to do research, I do know that the vehicle acts as one in it's design to withstand lightening strikes, however the vehicles battery and other electronic components such as the computer could still be at risk, am I right? Now I own a Jeep and I do like the off-road which already has given me a leg up on a BO vehicle or whatever you wish to consider it. I will be designing armor for the underbelly and sides that I would think I could design into a faraday cage that would protect the electronics of the Jeep completely.
I had also considered not worrying about completely EMP proofing my Jeep and simply keeping a spare computer in a faraday cage I would make as stated above. I could pull one from a Junkyard for around $40 or $50, and possibly less if I am frugal and patient.
