Hello Joe,
I figured it out. Or found out where to get the answer. Jeff had said that
AutoEZ would do this – so I read over their documentation and I see it is done
using a transmission line and not an inductance. With that knowledge I got a
nice match to 50 ohms with very good SWR. Now if I only knew how accurate the
model is since I can’t seem to model any ‘lump’ caused by the mounting bracket.
I felt good when I entered the manual dimensions and with no changes other than
a very slight change in the driven element length I got excellent results –
comparing almost exactly to the manual values.... but now I’m not so confident
since I don’t have the larger diameter that the bracket represents.
I’m also a bit amazed at how sensitive some of these values are. That too
concerns me a bit. If I change say the first directors length by 1/2” total it
makes a noticeable difference in performance – so that doesn’t bode well since
I’ve not included anything for the bracket.
Any experts out there have a little time that I might talk to them on how to
best do some of these things and feel confident I can make an antenna that will
perform as the model results would suggest? I’m not looking at a test range
here ... I don’t want to “hope” that it does... just want to know it will
work. Or is that asking too much?
Gary
K9RX
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