Date: Mon, 01 Aug 2016 12:34:17 +0000
From: Timothy Holmes <taholmes160@gmail.com>
To: ham-antennas@yahoogroups.com, Tower Talk
<towertalk@contesting.com>, "cq-contest@contesting.com"
<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 noticed the swr going from low to
high suddenly for a few seconds and then back. Initially I thought it was
my auto tuner showing damage, but I 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
## has it been doing this since day 1.... or is this just recent ??? If its
just
recently, it may well be the balun. If it has been doing it since day 1, it
may
be the ladderline length. What bandS does it do it on, just one, or all of em?
It may also be something loose, or int..like the coax, any switchs, coax
connectors,
balun, balun connections, ladderline, or ladderline to dipole interface.
## depending on laddeline length, a 4:1 balun might not be optimum. A 1:1
balun can also be used, but this all depends on feedline length, what bands are
used,
like warc etc, and the lowest freq used, length of dipole, etc.
Jim VE7RF
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|