[time-nuts] GPS through windows

Chris Albertson albertson.chris at gmail.com
Tue Jun 5 16:14:21 UTC 2012


On Mon, Jun 4, 2012 at 11:26 PM, <lists at lazygranch.com> wrote:

> The low-E coatings are known to attenuate WIFI. WIFI is probably a worse
> case than GPS, but the availability of the gear makes experimenting easy. I
> think they are sputtered metal either on the glass or on a thin film
> applied to the glass. Southwall Technology in Palo Alto pioneered or at
> least commercialized the technology.
>
>
They are interference filters.   Layered coating 1/4 wavelength thick that
send some waves back in phase and other out of phase, they reflect heat and
UV be let light go through.   I think it is a tin oxide coating of some
kind.

Sometime they use silver but only on the inside of a double pane window
with the inside filled with inert gas, otherwise the silver tarnishes.
OK, I think they can also over coat the silver with an oxide to keep the
air away from it

I think my windows at home have both.  I can see the 1/4 wave coating
change color with the angle I look at the glass, the silver simply darkens
the glass.   The argon gas between the panes is for insulation.

I assume it is the metallic silver coat the messes with RF signals.   I
think the silver is very common in large buildings.   But with a large
building they make the glass custom to the architect's specifications so no
one can know what is in your building.



Chris Albertson
Redondo Beach, California


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