"Mike Coslo" wrote in message
...
Ed Price wrote:

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.

Good point and thanks Ed! I was thinking of hardware cloth, and this
would give me a reason not to switch from it.

There will ba an access port in the shield, but I can design a recessed
portion of the shield to keep it continuous.

- Mike KB3EIA


Remember to never rely on the hinge of a port cover to provide a bond path.
Best practice is to use the hinge mechanically only, and have the leaf come
down on a full perimeter of a compressible conductive gasket. Beryllium
copper fingerstock, mating against a strip of copper, is best for high usage
ports. If you don't operate the port very much, you can use a folded-over
length of knitted wire mesh facing onto the hardware cloth. Just remember to
ensure that the gasket is compressed all along its length.

Ed
wb6wsn