Low-angle Elevation Gain of a 1/4-wave Vertical Monopole
On Fri, 28 Nov 2008 03:53:00 -0800 (PST), Richard Fry
wrote:
Near field analysis is disabled when MININEC-type ground is selected.
...Use some other ground type for near field analysis.
Obviously, near-field analysis was not disabled by/in EZNEC for my
model definition.
How very odd, when this comes as a distinct contradiction with your
explicit:
The near-field analysis of EZNEC for radiation in the horizontal plane
at a point 1 km from a 1/4-wave monopole having two ohms in series
with a Mininec r-f ground, while radiating 1 kW over an earth
conductivity of 8 mS/m is shown as 72 mV/m.
where the question remains at:
where did you get
is shown as 72 mV/m.
from?
It is evident your field quote is NOT from this specific Mininec r-f
ground model of yours above.
As you admit you had near-field analysis available above (you still do
not explain how in the context of a mini-nec ground per your stated
model's characteristics), and you do not describe any radial treatment
(cogent elements of the BL&E paper "Ground Systems as a Factor in
Antenna Efficiency"), and you do describe a 1/4 radiator (not found in
BL&E experimental data), then your call for suggestions on how to fix
your model's failure in the context of BL&E becomes an obscure moving
target. My "suggestion" alters slightly with do it right or discard
it as trash. There aren't really many other alternatives.
Hopefully Roy Lewallen will weigh in, as he has time, to comment on
the methods and results of our two analyses -- although probably Roy
will need more details about your model construction than you have so
far been willing to provide.
More interesting would be his enquiry or explanation into how you
defeated the lock-out for a feature that is a poor method for near
field analysis. I find it more intriguing in how you embrace it in
spite of stated cautions to employ other methods. Yes, this novel
adaptation of Mininec r-f ground to near field solutions bears more
explanation from some source. I cannot imagine that explanation will
improve your model's performance to equal mine however. That is
already well evident.
As for more details, the BL&E paper "Ground Systems as a Factor in
Antenna Efficiency" is the totality of my sources. Those practiced in
the craft of modeling and proficient with its tools will find it
sufficiently informing if they hadn't already proceeded to a
successful implementation from my descriptions in this thread.
73's
Richard Clark, KB7QHC
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