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Re: [TowerTalk] Strange happening with 10 Meter Beam

To: Herbert Schoenbohm <herbert.schoenbohm@gmail.com>
Subject: Re: [TowerTalk] Strange happening with 10 Meter Beam
From: Billy Cox <aa4nu@comcast.net>
Date: Wed, 28 Oct 2015 17:39:33 +0000 (UTC)
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Hi Herb,

The "L" data is listed on Table 2 (page 4) in the manual PDF.

It ranges from 13.5" to 28.375 depending on what parameter 
is most important for your performance there.

Hope this helps!

73 de Billy, AA4NU


----- Original Message -----
From: "Herbert Schoenbohm" <herbert.schoenbohm@gmail.com>
To: towertalk@contesting.com
Sent: Wednesday, October 28, 2015 12:11:51 PM
Subject: Re: [TowerTalk] Strange happening with 10 Meter Beam

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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