What role does skin effect have in this situation - at 1.8 MHz?
Skin depth isolates the outside and inside, virtually nothing passes through
a conductor wall that is several skin depths thick. This is true for both
the magnetic field and the electric field, and why "shielded loops" are a
misnomer. Look at this link http://www.w8ji.com/skindepth.htm
Current in the center has to be matched by current on the inside of the
closest shield. Current always can get into the center three ways:
1.) The shield can be so thin it doesn't isolate the outside and inside, but
then that would not be a good shield
2.) Current spills over an edge
3.) There is a direct connection to the inside
If we study connectors with an accurate picture of what current has to do
(current, the magnetic field, nor the electric field can NOT go through a
wall several skin depths thick), we can spot potential issues with shield
connections. We don't have to have a connection to the side if there is an
edge to spill over that is right at the same connection spot.
What we do not want is the edge to be inches from the connection point. For
example, a braid overlay on top of foil that has a poor electrical and
pressure connection to the foil is not a good connection point. This is why
LMR400 is problematic when the braid is soldered to a PL-259. The very same
cable is great with a crimp connector, if the cable is clean (not tarnished
or corroded) inside.
73 Tom
All good topband ops know fine whiskey is a daylight beverage.
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Topband Reflector
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