k1drw wrote:
Same thing for Cecil. Just a very, very clear, basic explanation of
the current flow in both pieces of the coax, into the antenna elements
(on the vertical, the antenna 'elements' are the vertical radiator and
the ground radials).

Let's say we have two wires running out to a load.
If we hook a 12 volt battery to those two wires,
DC current flows out to the load through one of
the wires and back to the battery through the
other wire such that the current loop is closed.

With an AC signal, current flows out through one
wire and back through the other for 1/2 cycle.
It then reverses direction in both wires for
the other 1/2 cycle.

Coax is like those two wires. The center conductor
of the coax is one wire and the inside of the
coax braid is the other conductor. When current
is flowing out through the center conductor, it
is flowing back through the braid. 1/2 cycle later
both currents are reversed.

When current is flowing into the vertical antenna
element, an equal amount of current is flowing
out of the radials. 1/2 cycle later, current is
flowing out of the vertical antenna element and
into the radials. Radiation losses from the
antenna and radials make it look like there
might be a 35 ohm resistor attached to the
end of the coax instead of the antenna.
--
73, Cecil http://www.w5dxp.com