[sdiy] Dual ground planes

[megaohm]

On Wed, Aug 4, 2010 at 11:13 AM, Harry Bissell <harrybissell at wowway.com> wrote:
>  For boards mounted parallel to each other (like most right-
> angle mounted boards in modular racks) the ground plane could help a lot.
>

This very interesting. I had been under the impression that to get
effective shielding I would need to fully enclose the pcb in a metal
box/shield. But I guess that is just for specific types of
interference?
Presently, I have been using 3.5mm thick pcb material to mount my pcbs
on (right angle to the panel). I have gotten these made without any
copper because, in small quantities, the price is 1/2 without copper.
So I'm using it more for stability than anything else. But if using
copper on one side will help my future circuits be a little more
immune to interference I'll include it. Note that I haven't observed
any problems yet but my circuits so far have been fairly simple.
  Also, my pcbs are close to one sided. I barely use the top copper so
the ground plane on top of the pcb is pretty much compete.

Would you suggest getting my pcb mount boards with a full side of copper?
If so, would this copper plane be connected to ground at the circuit
pcb, the panel, nowhere, or maybe in only one place? Should it be one
solid plane or is it OK to go nuts with funky artwork as long as it
covers the majority of the area?

I plan on ordering 100 of these mounting boards soon so the price
difference with or without a copper pour becomes less of an issue. If
it saves my ass with some design one day (or even helps a little bit)
I'd consider it a worthwhile expense.

Any advice appreciated.

Thanks,
Phil