In preparation for the Stew I'm thinking of setting up a two element
end-fire array aimed at Europe, and possibly another one aimed south.
I've done some reading about these types of arrays and I think I understand
the approach taken by W8JI in his design of the short verticals he uses, as
well as the design of the YCCC short vertical.
Just for kicks I decided to model a short vertical that used matching stubs
made with RG-59.
I'd like to ask for advice on this approach. I would use the array on 160m
only, and the objective is for it to have better RDF than my inverted L, so
even a few dB would be helpful.
I modeled a 6' vertical element in CocoaNEC and designed a matching network
using SimSmith.I have attached the Smith chart of the matching stubs.
In my CocoaNEC model, the feed point impedance does not change much if I
increase the length of the element to 30', and the matching network is not
sensitive to changes in the feed point impedance. I wonder if this
matching network might just be equivalent to matching the coax with no
antenna connected (and if so what that means for the antenna's performance)
Any advice on the antenna, matching network, etc., would be much
appreciated. My next step is to build one and verify that my real world
results for a single element match the model's prediction, and if so, to
subsequently build a second one and connect them with a phasing line to
achieve end-fire directivity over the bottom end of 160m.
Advice much appreciated.
73, Matt NQ6N
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