On 1/9/2021 3:22 AM, Guy Olinger K2AV wrote:
Hi Rick,
An answer to Rick and some number of others with inquiries off reflector....
Those with EZNEC V5 or V6, including the demo version, can find the help
reference by starting EZNEC (it's identical in V4/5/6). Click on "Help" in
the menu bar on the main window. Click on "Contents". In the User Manual
window, click on "Search" in the Contents-Index-Search tab row. In the "to
find:" space, type in "closely spaced wires" without the quotes. Click on
the "List Topics" button. In the topic list, double click "Closely Spaced
Wires".
Excellent navigation! I found it easily. I will quote the relevant
text from it below:
-------------------------------------------------------------------------
Closely Spaced Wires
When modeling parallel or nearly parallel wires which are closely
spaced, it can be very important to align the segment junctions. That
is, they should be directly across from each other. This is particularly
true if the segment length is greater than the wire spacing. As the
segment length gets shorter compared to the wire spacing, this
requirement becomes less important. When segment junctions are
misaligned but need to be aligned, results can change dramatically as
segmentation is changed.
The easiest way to assure that aligned parallel wires have aligned
segment junctions is to give the wires identical lengths and numbers of
segments. If the wires are staggered or different lengths, break them
into more wires. Make the portions of the wires which are directly
across from each other into separate wires of equal length and number of
segments. An example of this technique is shown below, where the long
wire of a J-pole antenna was broken into two wires. Wire 4 is made the
same length and given the same number of segments as parallel wire 6.
The upper wire is segmented to make its segment length approximately
equal to the segment length on wire 4. (This is a close up view – some
of the long wire, and its number, aren't shown.)
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So I was indeed clueless, but no more. Basically, all I need to do
is align the segments; who knew? Certainly isn't obvious. Now I get
it. Very clear writing by Roy, as usual. The J-pole example is
perfect.
73
Rick N6RK
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