Can someonw please enlighten me, what is HPDE?
Thanks 73 Art
Date: Wed, 23 Dec 2009 17:37:46 -0700
From: Art <email@example.com>
Subject: Re: [TowerTalk] Making an 80 meter vertical from Rohn 25
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> > 5. Re: Making an 80 meter vertical from Rohn 25
This is exactly my 80M 1/4 wave vertical. Mine is fed at 15 ft AGL as a
ground plane. The 15 ft attachment point is insulated from the R25. I
use an aluminum tube out the top of the R25 to resonate the ant where I
like it (the CW end of the band). It works extremely well and is easy to
adjust with the Al pipe. Mine has 18 elevated radials. An excellent
If you're feeling ambitious you can use it on 160 as a 1/8 wave. The
feed Z is high on 160. I resolved this issue (first in EZNEC) by
attaching a pair of drooping wires at the top of the R25 where the Al
pipe starts. In my situation these wires are about 25 ft long. The two
wires reduced the feed Z to a point the active antenna coupler was
happy. 160 is similarly extremely effective. I'm working plenty of DX on
According to EZNEC the drooping wires had almost no effect on the
radiation pattern. The two wires are isolated on 80M by homebrew traps
made from toroids resonated by short (about 1 foot) lengths of RG213.
I tune the antenna on 80 as it should be and take what I get on 160.
73 Art K6XT
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