Perhaps the booms are interacting with the antennas. First, try rotating the
antennas to see if that affects the swr. If yes, it is a guy wire or something
else external to the antennas. If not, try turning the 6m in line with the
others. If that doesn’t change anything, its probably a connector or a coax
problem. Are you using an antenna switch on the tower? If so, check swr at the
switch.
Chuck W5PR
Sent from Mail for Windows 10
From: Jeff
Sent: Sunday, April 9, 2017 9:49 AM
To: w5prchuck@gmail.com
Subject: Re: [TowerTalk] Interaction Issues
Yes 90 degrees to. The other beams
Sent from my iPad
On Apr 9, 2017, at 10:41 AM, <w5prchuck@gmail.com> <w5prchuck@gmail.com> wrote:
By: “the 6M in the middle, phased at 90 degrees to the other beams” do you mean
it is mounted pointing 90 degrees off from where the others are pointing?
Chuck W5PR
Sent from Mail for Windows 10
From: Jeffrey Cantor
Sent: Saturday, April 8, 2017 9:07 PM
To: towertalk@Contesting.com
Subject: [TowerTalk] Interaction Issues
I recently had some tower work done. Ihave a Rohn 25 tower up 60 FT. I have
a C-3 and a 6-element Cushcraft 6Mon it. Both antennas were doing fine – SWR
essentially flat on the C-3and around 1.5:1 on the 6M. They were both mounted
on a 9 FT mast,separated by about 6 FT. The job was to replace the 9 FT mast
witha 15 FT lighter mast and to install a new 12/17M WARC Cushcraft antenna.
The new setup had the 12/17M antenna atthe top of the mast; the 6M in the
middle, phased at 90 degrees to the otherbeams - – separated by roughly 6 FT
between it and the lower C-3 and the WARC. After the install, I am noticing a
2.0:1. 2.4:1 SWR on the C-3 on 20M only; 15M & 10M are OK. On the 6M –3.0+
SWR. Do I have an interaction problem betweenthe 6M and C-3? Should the 6M be
at the top of themast? Offset to the others, or not? Jeff/ K1ZN
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