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Re: [Antennaware] Fwd: HF Colinear Dipoles

To: "Weinfurtner, Greg" <weinfurt@ohio.edu>
Subject: Re: [Antennaware] Fwd: HF Colinear Dipoles
From: Terry Conboy <n6ry@arrl.net>
Date: Wed, 28 Aug 2019 12:54:27 -0700
List-post: <mailto:antennaware@contesting.com>
Hi Greg,
No secrets here!
Have you considered a double extended Zepp?  If you don’t need an out of phase 
pattern with a broadside null, it’s essentially the same gain as a collinear.
Of course, since the pattern is fairly narrow, you have to have a specific DX 
target in mind, or the gain goes to waste. 

73, Terry N6RY

> On Aug 28, 2019, at 3:25 AM, Weinfurtner, Greg <weinfurt@ohio.edu> wrote:
> 
> I have been eavesdropping on your conversation and would LOVE to be 
> included in any email group that you may have going on. I have room for 
> an 80 meter 2 ele colinear antenna as you are describing and only need 
> 20 some countries on 80 to finish 5BDXCC.
> I have only bought one commercial antenna in my 46 years as a ham and 
> love to experiment with them. Thanks if you include me, for the 
> opportunity to listen in and see what comes up!
> 
> Greg Weinfurtner NS8O  CWT #1496
> 
> 
> 
> On 8/27/2019 9:53 PM, Terry Conboy wrote:
>>> From: Terry Conboy <n6ry@arrl.net>
>>> Subject: Re: [Antennaware] HF Colinear Dipoles
>>> Date: 2019 August 27, at 6:44:24 PM MST
>>> To: Karin Johnson <karinann@tampabay.rr.com>
>>> 
>>> The info in Ch 11 of ON4UN's book is almost all about verticals, so won't 
>>> be of much help.
>>> 
>>> I've attached four EZNEC models of a two element collinear dipole array for 
>>> 20m.
>>> 
>>> Two are just dipoles with separate current sources, one in phase, the other 
>>> 180 degrees out of phase.  This lets you see what the patterns are without 
>>> worrying about the feed system.  You can look at the feed Z of each antenna 
>>> to see what you have to drive.
>>> 
>>> The other two models have coax feed systems.  When in-phase the two 
>>> elements each have about a 100 ohm Z, so you can use two half-wavelength 
>>> (or multiples of 1/2 wl) feedlines and just parallel them at the common 
>>> point.  They can be any impedance, but the losses and bandwidth will be 
>>> best with 75 ohm lines.
>>> 
>>> When out of phase, the elements each have about a 50 ohm Z, so you can use 
>>> 3/4 wavelength 75 ohm lines to transform the impedance to 100 ohms so the 
>>> two can be paralleled for a 50 ohm feed at the common point.  (There are 
>>> many other feed arrangements possible, too.)
>>> 
>>> If you want to switch the patterns in the real world, you'll have to figure 
>>> out how to switch the cable lengths and invert the phase.
>>> 
>>> Let me know if this is what you're looking for.
>>> 
>>> 73, Terry N6RY
>>> 
>>> On Sun, Aug 25, 2019 at 1:57 PM Karin Johnson <karinann@tampabay.rr.com 
>>> <mailto:karinann@tampabay.rr.com>> wrote:
>>> Hello Group:
>>> 
>>> I would like to have a discussion off list about designing a 20 Meter
>>> Colinear dipole array.
>>> 
>>> Right now I am trying some simulations in EZNEC and am referencing the Low
>>> Band DXing
>>> 
>>> Book by ON4UN with regard to the Phasing of the two or multiple antennas.
>>> 
>>> I'm having a bit of difficulty in replicating some the work ON4UN and the
>>> volume authors
>>> 
>>> Did on the understanding of the Array Chapter number 11.
>>> 
>>> 
>>> 
>>> Anyone who has tried building collinear antennas at HF??  I know that Tom
>>> W8JI has
>>> 
>>> Done this on a massive scale and that is not what I am trying to accomplish
>>> here.
>>> 
>>> Just two simple collinear dipoles fed either in phase or out of phase.
>>> 
>>> The EZNEC simulations seem to blow up when the phasing and matching networks
>>> are
>>> 
>>> Applied to the two antennas.
>>> 
>>> 
>>> 
>>> Regards,
>>> 
>>> Karin Anne Johnson  K3UU
>>> 
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