Another way to bring a vertical to 50 ohms is with a hairpin coil.
John KK9A
To: towertalk@contesting.com
Subject: Re: [TowerTalk] 160 vertical question (Top Hat)
Date: Sun, 4 Feb 2018 08:48:02 -0800
Jim's suggested tuning method works well for me to cover the entire band. I
short/open 3 series capacitors all the same value and can cover 1800 to 1975
< 1.5:1 swr. I use a transmission line transformer before the caps to match
the 25 ohm resonance.
Now for some propagation to EU from suffering sevens land - Redmond, WA.
It's Unobtainium.
Grant KZ1W
From: Bill via TowerTalk <towertalk@contesting.com>
Date: Sat, 3 Feb 2018 20:20:00 -0500
Planning on putting up a 160 vertical, but of course a 1/4 wave vertical is
out
of the question here in HI since we have a height limitation.
Here's the question: I'm putting up around 50 feet of 3 inch aluminum
tubing
(left over from various antenna takedowns). I plan on putting up on top of
that around another 10 or 15 feet of smaller diameter stinger for a total
height of around 60-65 feet. I obviously need to make up for the lack of
height and I was planning on making a top hat of four wires coming down from
the top of the antenna at around a 45 degree angle. The problem is how long
to
make each of those wires. My guess is around 25 feet based on my past
experience in making Tee-topped 80 meter verticals. However, it is only a
guess and I don't feel like yanking the 3 inch pipe up and down a bunch of
times to get it just right.
I know some trimming will be necessary since this is not an exact science.
I
just need an educated guess for where to start with the length. Any ideas?
Bill K4XS/KH7XS
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