[TowerTalk] Insights on 30m EDZ - nowhere near what I thought

[Ken Bauer]

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