[TowerTalk] Help needed, antenna SWR

[john at kk9a.com]

You can add a hairpin match to raise the impedance to 50 ohms however you
would have to also adjust the vertical length after adding this.

John KK9A


To:	towertalk at contesting.com
Subject:	[TowerTalk] Help needed, antenna SWR
From:	"Gary Smith" <Gary at ka1j.com>
Reply-to:	Gary at ka1j.com
Date:	Mon, 20 Jun 2016 22:58:19 -0400

I did some spring maintenance on my antennas and need advice on how
to get a 1.1 match.

I have a radial plate with somewhere around 50 130' radials. I have 5
wire antennas attached to this and use an Ameritron remote coax
switch to select which antenna to use. There is a sloper for 160,
INV-L for 80 and verticals for 40, 30 and 20. 17 & 24M are obtained
by selecting either the 160 or 80M antennas. No tuner.

I took the Antenna analyzer down to the antennas today and found 80M
is SWR 1.8, 40 is SWR 1.9, 30M is SWR 2.35 to give some values. The
lowest SWR I could get on 30M is 2.35 and the antenna is cut for the
right length for minimum SWR at 10.100 MHz. This gives me the lowest
SWR on the bands.

I would like to get the SWR down as low as 1.1 at my desired
frequencies If I can do so, but I'm not sure of the best way to do
this. I suspect inductance from a coil at the individual feed points
would work after I get the to SWR dip the lowest at the desired
frequency but if this is the solution, what would be a good way to
know do make such coils for each of the antennas?

The antennas are 350 feet away, in the woods & onto a salt marsh and
for me, right now, walking is very difficult to do and I want to make
as few trips as possible.

Suggestions appreciated.

73,

Gary
KA1J