[TowerTalk] Radials, lightning ground, RF ground
alwilliams at olywa.net
Wed Nov 23 10:55:20 EST 2005
>----- Original Message ----- > Let me try to help clear the confusion. to
>the best of my understanding.
> 1) RF COUNTERPOISE/GROUND SCREEN. A set of radials or mesh to help an
> antenna (usually a vertical) radiate more efficiently with fewer ground
> losses is an RF counterpoise or ground screen.
The concept of ground losses for vertical antennas seems unclear to me
although I am aware that it has been accepted for many, many years. I refer
only to ground current return and not to currents generated by reflection
from the ground.
It seems to me that it takes two to tango, The radiation from the vertical
member radiates because of the changing current but the changing current in
that lead must be balanced by an equal (but opposite) change in current in
the other lead i.e. ground. If that is true then at all times half of the
transmitter power must be going into the ground (?????).
It then seems to me that improving the ground characteristic with radials,
etc. increases antenna efficiency by allowing the vertical radiator to have
more changing current. At the same time, the ground system has more
current, hence "heating the ground" but that is incidental and not the major
cause for the improvement of radiation.
Thus, improving the ground system doesn't reduce ground losses but actually
heats up the ground more (????????) but at the same time allows the vertical
member to radiate more.
What is wrong with this thinking?
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