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Re: [TowerTalk] 160m. Inverted L question (RVZ)

To: Towertalk Reflector <towertalk@contesting.com>
Subject: Re: [TowerTalk] 160m. Inverted L question (RVZ)
From: Bob K6UJ <k6uj@pacbell.net>
Reply-to: Bob K6UJ <k6uj@pacbell.net>
Date: Tue, 15 Jan 2019 18:56:39 +0000 (UTC)
List-post: <mailto:towertalk@contesting.com>
 Detune the tower ?
I am also trying to figure out how to deal with the inverted L coupling to the 
tower.   I tried an L with the vertical wire suspended 3 feet away from the 
tower and it was coupling quite a bit.   I had a horizontal pennant loop for 
receive about 30 feet away from the tower and when I rotated it was affected by 
the tower too.  I lowered the Inverted L so it wasn't influencing the receiving 
loop and it was definitely affected by the tower.  
I am thinking that I need to detune the tower so it is invisible to both the L 
and the receiving loop.  I am researching on how to do this but haven't come up 
with much on how to go about it.  There must be a easy way to do 
this.................   
BobK6UJ 
    On Tuesday, January 15, 2019, 10:01:42 AM PST, Speer, Douglas via TowerTalk 
<towertalk@contesting.com> wrote:  
 
 I read somewhere, and can't remember where, that sloping the vertical segment 
of the "L"  ~15 degrees away from the tower will minimize coupling and loses 
into the tower.  I have a 140 foot inverted L I use on 160m.  It has 60 feet of 
vertical suspended off a Rohn 45g tower with about 3 feet of separation at the 
top.  I sloped it 15 degrees away from the tower in line with but in the 
opposite direction of the 80 foot horizontal segment.  My radial system is very 
minimal with only 16 each, 18 foot radials.  With no science to back it up, I 
think this is working.  I am able to  work anything I can hear on 160m.  

WRT reception, so far this season  working what I hear is not saying much out 
here in North West Texas.  We are simply not hearing what stations a few 
hundred miles in any direction are hearing.  I am using both the inverted L and 
a K9AY loop for receive switching back and forth for best copy and many times 
using both in diversity reception mode.  If it were just me I would say I have 
a receiving antenna issue but other experienced 160 operators in the area are 
experiencing the same thing this season.  I'm baffled.  Sorry to go off on a 
tangent.

Very 73,
Doug, W5WTX
Amarillo, TX 


Message: 1
Date: Tue, 15 Jan 2019 04:38:03 +0000 (UTC)
From: RVZ <rlvz@aol.com>
To: towertalk@contesting.com
Subject: [TowerTalk] 160m. Inverted L question
Message-ID: <369232969.276333.1547527083313@mail.yahoo.com>
Content-Type: text/plain; charset=UTF-8

Guys,

I've got a 160m. Inverted L with the vertical wire spaced 4' from a grounded 
steel tower at the base and 6' at the top.? The radial system isn't perfect but 
it's decent.??Based upon the Inv. L's poor performance, I believe I may have a 
lot of power being coupled to the tower and shorted to ground.? A?couple 
questions:
1) I'd appreciate some guestimates on what percentage of input power may be 
getting shorted to ground?
2) Any guestimate on what percentage of power may be saved if the Vertical wire 
spacing is increased from 4' to 12" from the tower??

Thanks & 73,
Dick- K9OM?
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