John, The the problem was neither VSWR (very low) or Beam Direction
(any direction) even on the ground no signals were apparent except very
very weak ones were heard on ten in any direction. It appeared that a
dummy load was at the end of the feed line. The beam is one the
ground at 10 feet and the insulator cup were changed and the beta rods
installed. Immediately the signals started to come in and the rig came
to life on 10 meters. It appears the cups were acting more like a
resistive element and took out the signals but provided a good load for
VSWR measurements. I installed the beta rods which the manual said are
36 inches long....but no where in the book does it give me the distance
from the Driven Element for the shorting bar on the boom and I looked at
every page....... The manual just refers to it as "L" but does not say
the distance of "L".....Do you have nay idea?.\
Herb, KV4FZ
On 10/28/2015 12:39 PM, john@kk9a.com wrote:
Low SWR is not a bad thing. My homebrew 6el 10m beams have 1.1:1 SWR 28-29
MHz and they work very well. Does the SWR increase outside the 10m band?
Is the antenna pointing the correct direction?
John KK9A
To: towertalk@contesting.com, Yuri <n2tta@yahoo.com>
Subject: [TowerTalk] Strange happening with 10 Meter Beam
From: Herbert Schoenbohm <herbert.schoenbohm@gmail.com>
Date: Wed, 28 Oct 2015 09:30:21 -0400
For the CQ WW I put up a 5 Element HyGain 10 meter beam(LJ-105CA) I double
and triple checked all the element lengths and the VSWR is so low across
the band it really excited me. It also scares me a bit as up in the air
the VSWR is never above 1.3 to 1 from 28.0 to 29.5. The problem is that
signals are very weak on non existent when compared to my 3 element quad
at 80 feet which was the only antenna that worked on ten during the
contest and after.. ( The yagi is one a separate tower at 50 feet)
Here is what I have on it.
New piece of LMR-400 with good connectors fed directly to the insulated
(Hy Gain cup type) director. The beta rods were missing so I use the
direct feed to each director. (OWA type matching idea) I moved the first
director slightly closer to the driven element to obtain the correct match
at 28.4 Mhz Everything looks good but the 10 meter antenna is about as
good as a dummy load.
I have been building yagi's for over 50 years and have never had such a
strange problem. Even a beam with half the driven element missing after a
hurricane could hear something but what I have up can't.
Before I take it down I ask if anyone else had experiences with this
problem. It must be something very simple but I have checked everything I
can think of and still no joy here.
Please let me know
Herb Schoenbohm, KV4FZ
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