> To me, one of the most frustrating limitations of NEC2-based modeling
> software is its inability to accurately deal with models where
> conductors of different diameters are joined, especially at right
> angles. EZNEC (and probably other programs outside my experience) have
> adjustments for tapered diameter elements, such as those common in
> yagis. But this does not really address connecting a wire capacity hat
> to a large cross-section tower, such as in Gary's 160m vertical.
...
>
>N6RY
_____
The limitation Terry notes is another example why I use modeling for a
"close estimate" rather than "precise replication" of an actual antenna.
In this case, given the scale of the structure relative to conductor
diameters, I figured the error would not be particularly big. My quick test
in EZNEC was to start with a vertical conductor the same as the top hat
wires and progressively make it fatter. The higher inductance with smaller
wires was evident, and no big jumps were noticed in the results.
Gary
K9AY
P.S. I can get away with my less-detailed approach because I tend to work
on relatively simple structures. They are easy to build, measure and adjust.
Greater precision is required for more complex structures, such as long-boom
UHF Yagis.
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