Re: gEDA-user: Clearing mask to mount shields

["J.D. Bakker" <jdb@xxxxxxxxxxxx>]

> The board manufacturer allows up to 2500 vias in a board this size. I
> need around 800 for signals, so that should leave me plenty for around
> the edge of the shield box. Any ideas on spacing? I have everything
> from 500 kHz SMPS noise to a 4 GHz local oscillator.

As a reference point, for 2.4GHz ISM stuff I 'stitch' vias every mm 
around the perimeter of critical blocks, with scattered vias in open 
areas so that no via is more than 4mm from any other ground via. This 
is probably overly conservative.

This is probably preaching to the choir, but I usually take hints 
from the dev boards for the parts I'm using, especially if the 
manufacturer claims that the data sheet's Typical Part Specs were 
derived from said dev board.

JDB.
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