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Re: [TowerTalk] Tuning raised radial verticals

To: Rudy Bakalov <r_bakalov@yahoo.com>, Towertalk Reflector <towertalk@contesting.com>
Subject: Re: [TowerTalk] Tuning raised radial verticals
From: Bryon Paul Veal NØAH <bryonveal@msn.com>
Date: Thu, 31 Aug 2017 23:28:36 +0000
List-post: <mailto:towertalk@contesting.com>
this is why I prefer a comtek hybred coupler.....I would suggest you look into 
one.  You will use 75 ohm coax due to velocity factors but any RF feeding back 
due to SWR is burned off in a dummy load. You feed the coupler with 50 ohm coax 
from the shack and from the coupler, in the center of the 4 sqr, 75 ohm coax to 
the verticals. 50 ohm coax  would be too short based upon velocity factors.  
You can see one I built on my qrz.com<http://qrz.com> page.   I recall each 
vertical in this system is exactly like the other and is tuned for the desired 
frequency.  I also wrote substantial reports you can find in towertalk archives 
at www.contesting.com<http://www.contesting.com> under n0ah in 1999, 2000

GL

73 de paul N0AH

DXengineering sells them.

73

paul. N0AH

73

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On August 31, 2017 3:23:32 PM Rudy Bakalov <r_bakalov@yahoo.com> wrote:

I am measuring the impedance at the very base of the vertical with a calibrated 
RigExpert. According to DX Engineering the vertical should be connected without 
any baluns, matching networks...nothing. Furthermore, they are saying that the 
vertical should be resonant 4% of the target array frequency. That is, in my 
case, if I want to tune the array for 3.550 each individual vertical should be 
tuned for 3.413.

Rudy N2WQ
________________________________
From: Bryon Paul Veal NØAH <bryonveal@msn.com>
To: Rudy Bakalov <r_bakalov@yahoo.com>; Towertalk Reflector 
<towertalk@contesting.com>
Sent: Thursday, August 31, 2017, 4:34:40 PM EDT
Subject: Re: [TowerTalk] Tuning raised radial verticals

your seeing changes in the FEEDPOINT impedance using a tuned raised radial,
thus your SWR will move  if yoy mess with them.  Suggest you consider using
UnUns at the feedpoints to match the coax impedence to that of the
verticals.  Also, a Comtek hybred coupler.....

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On August 31, 2017 12:23:04 PM Rudy Bakalov via TowerTalk
<towertalk@contesting.com<mailto:towertalk@contesting.com>> wrote:

> Hi folks,
> I am building my 80m 4SQ. The elements are made of wire attached to 8'
> poles and then raised radials also about 8' above the ground. While tuning
> the verticals we observed an unexpected behavior- shortening the vertical
> wire has almost zero effect on the resonant frequency, while shortening the
> radial does. Is this behavior normal? What is the best approach to tuning
> verticals with a single raised radial?
> 73, Rudy N2WQ

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