Ken,
In regard to learning EZNEC, there are a lot of resources to learn the
basics of the software- YouTube, a tutorial built into the software,
etc. But for more advanced use nothing beats this book:
https://www.amazon.com/gp/product/1690175516/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1
by ON5AU. Yes, it is a bit expensive, but on the other hand it is the
size of an ARRL handbook and is for a very narrow market. Take your time
and play with the software. It is well worth your time.
-de John NI0K
Ken Bauer via TowerTalk wrote on 2/5/2020 3:48 PM:
Thank you all for your useful insights. I have a myantennas.com EFHW 8010-2K at over
100’ that has been hard to beat for general coverage. I’ve put several other
antennas up (Trapped vertical, Inv L) and taken them down again as none of them were ever
better than my main antenna per RBN.
It’s poorest band for a match is 30m. I was looking for gain, but it’s not
quite pointed right.
The 30m EDZ would be pointing at Central Africa and New Zealand with a null over Europe. So
I’ll abandon this design for a 30m dipole fed with the ladderline. Feeding with Ladderline
just for the lower loss, there’s still 300’ of LMR400 to the shack.
My other conclusion is that I need to invest the time and training to get EZNEC
running on my Windows 10 / Parallels 14 / Mac to save time in the field -
recommendations on that front appreciated!
Final conclusion is I’m just going to have to get some kinda of modest
rotatable gain antenna, at least for 20. Maybe a moxon or hexbeam.
73,
Ken WC6Y
Ken Bauer WC6Y
I thought this would be easy, but I’ve screwed it up. I’m hoping to
get some insights from this group of antenna experts re the easiest
way to proceed! Perhaps someone could model it for me?
I used the calculator at West Mountain Radio:
http://www.westmountainradio.com/antenna_calculator_zepp.php
Looking for resonance at 10.120mhz. I ordered supplies from Davis RF:
their balanced line / coax center insulator, 14awg solid copperweld
and 16awg 19strand copperweld 450 ohm ladder line. I ordered a Balun
Designs 4:1 current balun.
The WMR calculator recommended a matching stub of ladderline 10’ 2.2”
and each leg of the antenna as 61’ 3.1”.
I thought I would add a half wavelength of ladderline to the stub
thinking that this would present the same impedance present at the
recommended stub length. Figuring a .91% velocity factor, I added
44.22’ to the stub for a total ladder line length of 54’ 5” between
the center insulator and the balun. I temporarily set the antenna legs
lengths at 61’ 5” and wound about 18” of overage back on the antenna
wire leg towards the center insulator on each side.
I hoisted this up to about 70’ , pretty much in the clear, other than
some pine branches at each end. 10’ of RG-213 to my RigExpert AA-55
Zoom dangling at about eye level.
The SWR plot shows a dip at 10.9mhz w SWR of 3.7:1 and a dip at
13.02mhz w SWR of 2.7:1.
Thanks in advance for any insights!
73,
Ken WC6Y
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