Re: Mirror as ground plane

On Wed, 27 Nov 2024 14:24:20 -0000 (UTC), Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

legg <legg@nospam.magma.ca> wrote:

 
Anyone had experience using metalization on glass (mirror)
as a ground plane or shield?
 
Any data on conductivity etc?
 
RL
 

>
The best quality second-surface mirrors are coated with silver, followed by
copper plating and a coat of paint.  Those should be pretty good if you can
get wires on them.

A classic way to connect to such things is conductive silver epoxy,
probably to silver-plated copper wire.  Not tin-plated for long-term
use.

.<https://www.masterbond.com/properties/silver-filled-electrically-conductive-adhesives>

As for shielding effectiveness, the key question is the resistance of
a square of the coating, connected only on opposite parallel sides.

Poorer ones have aluminum coatings around 2-3 nm thick and no plating. 

Probably won't work, between high square resistance and oxide layer
preventing reliable connection.

Though people do use metallized Mylar film, with a long bare tinned
copper ground wire in direct contact with the aluminum side, and in a
cable this does work.

Joe Gwinn