In a message dated 3/11/02 10:35:32 AM Eastern Standard Time,
k2av@contesting.com writes:
<< 2) E-plane penetration of the ground and resultant lossy current
immediately below. Solved with moderate DENSE ground screen. The worst
loss is right underneath, so even radials shorter than 1/4 will help.
You're trying to make the ground immediately underneath appear highly
conductive.
>>
Now this is the part that interests me the most. I am certainly going to get
ON4UN's book and study it. Judging from conversations I hear on the air,
this stuff is highly misunderstood and far from settled. Maybe our
discussion can help educate a few folks (myself included). What I don't
understand is:
If the ground screen is not connected to the antenna, what is the mechanism
by which reducing the ground current losses improves your signal? Where
would the ground current be going? Seems to me if it does not go back into
the antenna system, it is heating worms no matter how conductive you make the
earth below the antenna.
Point 3, I understand but on the first bounce you are way beyond the radial
field. And, as you point out, ground clutter may have a substantial impact.
Perhaps the water and salt water verticals benefit from a clear line of sight
as much as from a conductive ground?
And herein lies another source of confusion for my overheated brain. If the
ground is highly conductive, why isn't absorbing energy instead of reflecting
it? Isn't that what conductive means? Low resistance would equal high
current in the ground. Put another way, if I want to reflect light, I use a
mirror, which is highly resistive to light passing through. I could use a
piece of clear glass but I lose a lot of reflection because the glass is
highly conductive. Just another way of looking at it . . .
Radio K4IA
Craig Buck
Fredericksburg, Virginia 22401 USA
FISTS CW CLUB # 6702 CC 788 Diamond #64
QRPARCI # 2550
K1 #470 K2 #2460
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