[TowerTalk] A Capacitively Fed 102 Degree Vertical for 160Meters

[tedc at nucleus.com]

Jim,
I have to go the tower route due to no trees tall
enough in this area. And I plan on a 120 radial
grouns system.

Ted



------- Original Message -------
>From    : Jim Brown[mailto:jim at audiosystemsgroup.com]
Sent    : 3/22/2015 6:26:21 PM
To      : towertalk at contesting.com
Cc      : 
Subject : RE: Re: [TowerTalk] A Capacitively Fed 102
Degree Vertical for 160Meters

 On Sun,3/22/2015 4:56 PM, tedc at nucleus.com wrote:
> My design is based on the fact that at approximately
> 102 degrees of length a vertical should exhibit a
> feed point impedance of 50 +j100.

I've been using essentially this technique with my
primary 160M vertical 
since 2007. Until this fall, it was 86 ft vertical
with enough top 
loading to bring the feedpoint Z to 50 +jX. Then my
tree guy told me 
that I needed to cut down the tree that held up one
end before it fell 
on my water tank and broke it, so he moved it to a
taller tree that made 
the vertical height 100 ft. The horizontal wire is
now 82 ft.

To broadband it, I made the vertical portion two #10
copper spaced about 
10 inches apart. It measures better than 1.5:1 up to
about 1.9 MHz, and 
still loads well above that. I'm a contester and DX
chaser, work SSB 
only in contests, so that's plenty good enough for
me. :) A tower, of 
course, is a physically larger conductor, so will be
even more broadband 
than my wires. Also, the value of jX when R hits 50
ohms well depend on 
the form factor (all vertical or top loaded), your
radial system, and 
your dirt.

73, Jim K9YC
_______________________________________________



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