[TowerTalk] 5. Re: Making an 80 meter vertical from Rohn 25

n8de at thepoint.net n8de at thepoint.net
Thu Dec 24 08:10:39 PST 2009


It's HDPE = high density polyethylene

Don
N8DE

Quoting Art <k6xt at arrl.net>:

> Can someonw please enlighten me, what is HPDE?
>
> Thanks 73 Art
>
> Message: 5
> Date: Wed, 23 Dec 2009 17:37:46 -0700
> From: Art <k6xt at arrl.net>
> Subject: Re: [TowerTalk] Making an 80 meter vertical from Rohn 25
> To: towertalk at contesting.com
> Message-ID: <4B32B7DA.8090101 at arrl.net>
> 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
> solution.
>
> 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
> both bands.
>
> 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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