Reply to post: Re: Wouldn't it be cheaper...

Prisoners' 'innovative' anti-IMSI catcher defence was ... er, tinfoil

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Re: Wouldn't it be cheaper...

"Chicken wire's also probably too big a mesh to block a mobile phone signal, due to the ratio of the holes to the wavelength."

A quick google (which I did before posting my comment) would inform you that the wavelength of a GSM signal is in the order of tens of centimetres.

IIRC, a mesh is an effective Faraday cage if the gauge is in the order of half a wavelength or smaller. Chicken wire has a gauge typically in the order of tens of millimetres, so very roughly 1/10th of the wavelength, and perfectly adequate.

I wonder if the 'phone in the tin' works because the tin, rather than acting as a Faraday cage, is in close enough proximity to the phone's aerial to couple to it via inductance and act as an aerial extension? Admittedly, it's a long enough time since I did any proper physics for this to possibly be complete nonsense, but it feels feasible...

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