"Richard Clark" wrote in message
news
On Thu, 12 Feb 2004 14:57:43 -0500, Mike Coslo wrote:

I'm not sure if this is the right place to ask, but here goes:

Are there any good references to the effects of shielding effectiveness
as related to shield coverage? I want to make a shield for HF
frequencies, and the most convenient method would be to use wire cloth
on one side, with the other 5 sides of the box made of solid aluminum.

- Mike KB3EIA -

Hi Mike,

That is called a Faraday Shield (more or less). You need only
determine the penetration depth of the materials used and the
frequency you want to shield. Handbooks (for RF Engineer) usually
have such tables by material.

Oh, all bets are off if you penetrate the shield for any reason (like
for a wire lead, or a viewing port, or....). The wails of grief and
shock at poor effectiveness are numerous from those who expect a 100%
cure from a 99% solution (-20dB generally isn't all that good).

73's
Richard Clark, KB7QHC

Remember to use "hardware cloth" for the screen. This material is galvanized
steel, and the galvanizing "solders" every crossover point. !/4" mesh is
fine for HF. Your problems will be the penetrations, as Mike described.
Also, you will need to bond the cloth to the aluminum. Soldering would be
best, but that would only work for a copper or tin-plated steel chassis. You
will have to clamp the cloth to the chassis, possibly using lengths of bar
stock with screws every inch or so. Don't forget to polish the aluminum area
that contacts the cloth just before assembly. Get it down to shiny aluminum;
aluminum oxide is an insulator, and you need good conductivity across the
joint.

Ed