What you have is the magic highly reactive spot on a 135' dipole. It will
create the conditions and difficulty tuning that you describe.
The feedline must be in odd multiple lengths of 1/8-wavelength on the
lowest operating frequency to optimize the impedance presented to the balun
over the frequency range of the antenna
Look at the instructions from this DXE dipole. It describes what you need
to do:
http://static.dxengineering.com/pdf/WA-Multi-Band%20DipolesRev2b.pdf
This is also good:
https://www.dxengineering.com/techarticles/balunsandfeedlinechokes/baluns-ch
oosing-the-correct-balun
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Wes
Attaway (N5WA)
Sent: Monday, August 1, 2016 9:34 AM
To: 'Timothy Holmes' <taholmes160@gmail.com>; ham-antennas@yahoogroups.com;
'Tower Talk' <towertalk@contesting.com>; 'cq-contest@contesting.com'
<CQ-contest@contesting.com>
Subject: Re: [TowerTalk] Flaky dipole
It sounds like a connection is loose somewhere along the line. You probably
need to "wiggle" some things to see if you can cause a reproduction of the
problem.
-------------------
Wes Attaway (N5WA)
(318) 393-3289 - Shreveport, LA
Computer/Cellphone Forensics
AttawayForensics.com
-------------------
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of
Timothy Holmes
Sent: Monday, August 01, 2016 7:34 AM
To: ham-antennas@yahoogroups.com; Tower Talk; cq-contest@contesting.com
Subject: [TowerTalk] Flaky dipole
Hi folks. Sending this to multiple groups to gain expertise.
My primary dipole is acting strange. Its 135 feet of wire up 40 feet. Fed
with ladderline. As I am transmitting I noticevthe swr going from low to
high suddenly for a few seconds and then back. Initially I thought it was
my auto tuner showing damage, butvI put an MFJ manual tuner in place and I
can clearly see it happening on the meter. I dont think it is wind moving
the wire, as it was calm when it was happening. The feed goes from the rig,
through the antenna switch to the tuner, then out the window via a bulkhead
connector and to the 4:1 balun via a 2 foot coax, and then to the
ladderline.
Any ideas on where to look for issues, and or testing methods?
Thanks
TIM
W8TAH
--
Tim Holmes - W8TAH
Sent from my LG Stylo
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