On 9/29/13 9:14 PM, Roger (K8RI) on TT wrote:
On 9/29/2013 8:36 PM, Hans Hammarquist wrote:
Yes Jim, the "single point" is not really a single point. In my case
it is a single, conducting panel that has feed-through coax connectors
and surge protections for all other wires coming through the panel. I
plan to use gas discharge for signaling and MOX for power (Done that
before with good result. Yes, it was tested with real lightnings.).
The panel will be connected all around its perimeter to the shield.
Metal window screen works well into the GHz range
For lower frequencies, you need thicker material for good shielding: the
skin depth is bigger.
To be a good shield, it needs to be at least 5 skin depths thick (that
makes the field on the "inside" exp(-5) that of the outside (about 40dB
down)
It'd be a bit more pricey than foil. With foil, I'd use the heavier
stuff. It more effective and not as fragile as the stuff we normally
have in the kitchen.
My shop / ham shack is completely lined with bonded barn metal.
Steel is a good shielding material: the high permeability makes the skin
depth small. It works well for the same reason that winding a choke on
a powdered metal or ferrite core works well.
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