[dewayne@warpspeed.com: [Dewayne-Net] New paint blocks out cell phone signals]
----- Forwarded message from Dewayne Hendricks <dewayne@warpspeed.com> -----
On 3/2/06, Eugen Leitl <eugen@leitl.org> wrote:
... Using nanotechnology, particles of copper are inserted into nanotubes, which are ultra-tiny tubes that occur naturally in halloysite clay mined in Utah. Combined with a radio-filtering device that collects phone signals from outside a shielded space, certain transmissions can proceed while others are blocked, the Chicago Tribune reported.
hmm, faraday cage on demand sounds kind of useful. they don't mention the level of attenuation though, and i suspect it's not that great. is anyone else aware of systems that can provide variable rf attenuation on demand?
On Thu, Mar 02, 2006 at 12:58:03PM -0800, coderman wrote:
hmm, faraday cage on demand sounds kind of useful. they don't mention the level of attenuation though, and i suspect it's not that great.
It sounds a bit like snake oil, especially since "nano" was mentioned. I can't imagine this would do anything other than vanilla ferrite paint on metal foil. It is reasonably difficult (and expensive) to shield whole rooms though (I've worked in one). Grounded chickenwire in walls doesn't even begin to approach it.
is anyone else aware of systems that can provide variable rf attenuation on demand?
If it has to be switchable, it has to be active. Sounds improbably expensive and finicky, at least with today's technology. -- Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org ______________________________________________________________ ICBM: 48.07100, 11.36820 http://www.ativel.com 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE [demime 1.01d removed an attachment of type application/pgp-signature which had a name of signature.asc]
On 3/2/06, Eugen Leitl <eugen@leitl.org> wrote:
If it has to be switchable, it has to be active. Sounds improbably expensive and finicky, at least with today's technology.
To my eyes, this looks more like a vanilla Faraday cage with a relay transmitter placed inside, with a hard-link to a relay outside: Combined with a radio-filtering device that collects phone signals from
outside a shielded space, certain transmissions can proceed while others are blocked, the Chicago Tribune reported.
The only reason it's newsworthy is the prefix "nano". -- Ben
participants (3)
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Ben Straub -
coderman -
Eugen Leitl