On Tue, 01 Dec 2009 16:42:00 -0800, Richard Clark
wrote:

On Tue, 01 Dec 2009 16:22:08 -0500, Registered User
wrote:

I'm under the impression the current flow
is identical whether metal rods or wire mesh is used in the antenna's
construction.

A discone does not exhibit any quality of shielding, so it wanders off
in that regard.


Maybe I'm confused and can't distinguish between Art's all-band mesh
antennas and his mesh Faraday shields.

I was questioning Art's statement
-quote-
When you feed a time varying current to the mesh it is best to view it
in small parts, say a square in the mesh. The hole is a static field
alongside the applied current flows.
- end quote -

The idea of examining the characteristics of a single square of mesh
seems impractical. The impact of adjacent squares should be accounted
for otherwise the single square is a loop.

Either way I've learned as current varies the fields it produces will
vary. If the fields vary they're not static. Too simplistic? What am I
missing?

The difference between rods, number of rods, thickness of rods, and
mesh all speak to bandwidth. 2, 3, or 4 rods will not be remarkable.
16 rods will closely approximate a cone of sheet metal (as would a
grid of similar spacing). The same can be said of the
rod/rods/mesh/sheet in the upper section approximating a solid disk.

IIUC the current flows around the cone of a discone regardless of
solid, sheet or mesh construction. This appears to be contrary to the
quote above where current flows around each individual hole in the
mesh.

Again, all these "appearances" are a strict function of wavelength to
physical length and spacing relationships.


I've built several discones over the years and understand these
relationships. How well is subject to conjecture hi.