NEC3 doesn't model closely spaced wires well, so it may not work for the
matching system. NEC4 should work.
Another way, which should work with NEC3, is to model the feed assembly
as a transmission line. All you have to do is estimate the
characteristic impedance, which probably isn't too critical. The length
should be the physical length.
73,
Scott K9MA
On 5/19/2019 17:51, jimlux wrote:
On 5/19/19 3:29 PM, Tom Hellem wrote:
Has anyone ever tried to model in EZNEC a C31XR tribander, the one
sold by
JK ?
I would specifically like to know how to model the feed system which
consists of two pieces of aluminum angle that connects the feed
terminals
of the 3 driven elements.
Since they advertise modeled patterns on the website, have you asked
JK for their model files?
I don't know if they're advertising gain in QST, for which they'd have
either model files supplied to ARRL, or measured data.
I didn't see this antenna listed here
http://www.arrl.org/antenna-modeling-files
In general, you should be able to model it as a wire connecting the
appropriate points. Set the wire diameter so that the surface area of
the wire is the same as the mounting bracket's. That way the skin
effect losses work out the same.
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Scott K9MA
k9ma@sdellington.us
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