Segmentation question, + Eznec
Jim - NN7K wrote:
Thanks , Roy, and let me try to rephrase #2, with my poor anylitical
mind. IF you feed a dipole , dead center, on a wire that has an ODD
length of segments, how does that compair to a dipole of EVEN segments
(mathamatically)?
In other words we are describeing a DIPOLE (balanced feed), with 6
segments (3+, and 3- at the feedpoint), with a dipole with 7 Wires (
3-1/2 , vs - 3, 1/2 segments, at the same feed
point, or am i tilting at windmills?
Guess the best bet is to make sure Segments ALL odd numbers!
Jim
EZNEC places a source or other object at the center of a segment, as
close as it can to the position you specify. If a wire has an even
number of segments and you specify the wire center (50% of the way from
end 1), the object will be placed at the center of one of the segments
adjacent to the center of wire, a position which is 1/2 segment from the
center of the wire. If the wire has 10 segments, this will result in the
object being placed 5% of the wire length off center. If the wire has
100 segments, it'll be off center by 0.5%. This typically won't have
much effect on the model results, except that you might see a bit of
asymmetry in the pattern and some change in impedance compared to
putting the object in the center of the wire.
The EZNEC manual discusses segmentation at some length.
Roy Lewallen, W7EL
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