> wrap that in aluminium foil, making sure that the ends are folded over and pressed down hard to provide good inter-layer contact I've tried this many times, it's impossible to prevent gaps without welding it shut. Obviously I wasn't testing with an EMP or nuke, but trying to block 2.4GHz WiFi... But that is well within the E1 range the author states. I think the problem with folding is it's too uniform, it's still…
They attenuate signals, they do not block them. The common verbiage is to say "faraday cages block EM radiation", so people naturally assume that it blocks EM radiation. But I learned the hard way while doing compliance testing that no, they do not block EM radiation, they just weaken it (and it's highly frequency dependent on top of that.)