Hi Ron,
A more reliable approach is a tuner in your shack. The extra coax
cable loss from elevated VSWR is insignificant on topband.
How high up the band do you want to go and at what maximum VSWR?
A resonant Rohn 25 160M vertical will be about 124 feet tall for
resonance around 1820 kHz
If for some reason you must install a tuner at the feed point of the
vertical, follow Tree's advice and make it slightly short: 120 feet
of 115 ft if you need to tune for minimum VSWR above 1900 kHz.
Use a small tapped inductor to tune it around the band.
73
Frank
W3LPL
----- Original Message -----
From: "Tree" <tree@kkn.net>
To: "Ron WV4P" <wv4ptn@gmail.com>
Cc: "160" <topband@contesting.com>
Sent: Friday, May 15, 2020 3:18:39 PM
Subject: Re: Topband: 160m Vertical
Slightly shorter makes it easy to use an inductor to make up the
difference. If you make it long - you can do the same with a capacitor -
but it's typically more trouble than the inductor.
Tree N6TR
On Fri, May 15, 2020 at 8:15 AM Ron WV4P <wv4ptn@gmail.com> wrote:
> I have built an insulated base for a 1/4 wave 160 antenna. The antenna
> will be XXX' of Rohn 25. In searching I see people using heights from 115'
> - 130' with a pretty high number around 124'.
> I do not know how I am going to match it yet, I figure I will do my
> research on that once it's up so I can learn while experimenting.... But
> the height has me second guessing. I want it tunable across the band,
> perhaps using a Tornado Tuner like my JK 801's have with a motorized
> inductor ? But the question at hand is do I want the antenna Tall or Short
> ? What is the Method behind the Madness ? :o)
>
> Thanks in advance,
> Ron WV4P
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