Steve,
When the antenna acts up maybe you can rotate it and see if there seems to be a
connection to physical movement of the antenna. That would point to a bad
connection somewhere. Further tapping can be done by one man at the antenna
with an antenna analyzer connected and in hand. A bad trap connection might
well do this to you.
Jim K1IR
[TowerTalk] TH7 puzzle
from [Steve Lawrence] [Permanent Link][Original]
To: Towertalk <towertalk@contesting.com>
Subject: [TowerTalk] TH7 puzzle
From: Steve Lawrence <SMLX@earthlink.net>
Date: Tue, 13 Sep 2005 19:20:30 -0700
List-post: <mailto:towertalk@contesting.com>
TH7 Puzzle:
I have an FT1000D driving a legal limit amp to a TH7DX. The FT1KD
tuner is left off when driving the amp. Occasionally, the FT's Hi SWR
light will flicker or stay on but only when the amp is off line. The
FT's power setting can be anywhere from the 3 watt minimum to full.
This happens only on 20m, not 15m or 10m and not all of the time. If
I put the amp on, the antenna takes the full legal limit without any
problems. Immediately after that, if I put the amp on standby, the
rig's Hi SWR light no longer reacts and there is no indication of
reflected power.
I can make the light go out when I have the Hi SWR indication and the
amp is off line by switching the FT's tuner in but I'll still see the
same reflected power as if the Hi SWR light is on.
I have connected the FT directly to a dummy load and the Hi SWR light
remains off. Connecting the TH7 directly - no switches, power meters,
coax elbows, no amp in standby - and the light comes on. This is
repeatable. Unless I run the amp and then everything is normal until
some time passes - hours, days or not for some time.
Best guess is that there something going on with the TH7. Loose
hardware? Critters in traps? But why only 20m and why would high
power clear it but not blow it out.
Experiences and thoughts appreciated.
73 - Steve WB6RSE
Jim Idelson K1IR
email k1ir at designet.com
web http://www.k1ir.com
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