----- Original Message -----
From: "john" <jb@beaumonts.karoo.co.uk>
> Hi I am thinking of putting up a vertical in my field some 300ft away from
> my inverted vee and thought about drilling down with my homemade rig to a
> good depth to install a deep earth of 28mm copper pipe maybe.
> Lets say I could go down 130ft would this elimnate the need for radials I
> wonder .
Hi, John.
There are three main loss issues that a standard commercial radial field
addresses:
1) losses in the radials as a current sink for the shield connection of the
feed coax. A standard 1/4 wave vertical approaches 35 ohms feedpoint from
above as this loss is eliminated. Radials lower the series ground losses
dramatically by placing the dissipative loss of a lone radial in parallel
with many others like it.
2) Loss from intense E field penetration and heating of ground inside the
eighth wave or so of the radial field next to the bottom of the vertical
radiator. Like microwaving the dirt underneath. The particularly dense
radials in that area act to shield the ground from the field.
3) First bounce loss of below-horizon emission from the vertical due to
dirt's propensity to absorb vertically-polarized RF. Radials provide a
"mirror" close in to return to skywave of some portion of the close in below
horizon radiation.
While some might argue that a 130 ft ground rod might have RF dissipative
losses in the single digits, I would not, and the authors of NEC4 which
treats underground connectors are not generous in this either and would call
it lossy at RF.
Even were the idea lucky in its losses, the ground rod would do nothing at
all for the losses in 2) and 3).
73, Guy.
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