No, it doesn't need to be completely encompassing for the faraday cage effect to work. If you've got a radio 1.5"x3"x5" and you lower it into a faraday cylinder 4" in diameter and 8" tall sitting on a block of insulating material, it will compeltely attenuate the signal. Of coure, that's for radio waves (which tend to travel parallell to the ground, at any reasonable distance from the tower). Next time I can I'll check if you can get a signal by pointing the mouth of the cage around. I suspect that mind control rays would be coming from sattellites--just make sure an opening is pointing up.
Doesn't need to be grounded, either--the faraday effect is served up by the motion of valence electrons already contained in the neutral metal, and a faraday cage retains an overall neutral electrical charge throughout its function. Grounding a faraday cage may tend to decrease its effect, allowing it to draw current from the grounding lug. In the case that the overall charge is not fixed, the boundary conditions no longer negate the EM radiation. So, if ya ground it, it won't work as well.
As for the kissing issue: A fencing mask type deal is one option, but a hoberman sphere type is another. If you had a mesh faraday cage that was three feet larger than you, it would still create a dead zone within it. So long as the mesh size is appropriately small so as to reflect, rathern than transmit, the target wavelength, the entire enclosed volume is meutralized. (In fact, there's a skin depth extending some portion of the mesh size into the volume--if you've got 1/2" chicken wire, you can probably get an understandable signal at 1/4" in, maybe as much as 1/2" in. At 2", though, it's completely attenuated.) Also, a small aperture that isn't facing upwards is fine--so if you do the whole fencing mask or coif method, a hole large enough for the mouth shouldn't permit much unwanted radiation (in addition to making it easier to not die of starvation or of thirst.)
(no subject)
Doesn't need to be grounded, either--the faraday effect is served up by the motion of valence electrons already contained in the neutral metal, and a faraday cage retains an overall neutral electrical charge throughout its function. Grounding a faraday cage may tend to decrease its effect, allowing it to draw current from the grounding lug. In the case that the overall charge is not fixed, the boundary conditions no longer negate the EM radiation. So, if ya ground it, it won't work as well.
As for the kissing issue: A fencing mask type deal is one option, but a hoberman sphere type is another. If you had a mesh faraday cage that was three feet larger than you, it would still create a dead zone within it. So long as the mesh size is appropriately small so as to reflect, rathern than transmit, the target wavelength, the entire enclosed volume is meutralized. (In fact, there's a skin depth extending some portion of the mesh size into the volume--if you've got 1/2" chicken wire, you can probably get an understandable signal at 1/4" in, maybe as much as 1/2" in. At 2", though, it's completely attenuated.) Also, a small aperture that isn't facing upwards is fine--so if you do the whole fencing mask or coif method, a hole large enough for the mouth shouldn't permit much unwanted radiation (in addition to making it easier to not die of starvation or of thirst.)
[/geek]