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Re: [TowerTalk] 80 mts four square or yagi?

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Subject: Re: [TowerTalk] 80 mts four square or yagi?
From: Pete Smith N4ZR <n4zr@contesting.com>
Date: Tue, 10 Mar 2015 09:19:55 -0400
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
The *magic* of 1X/2X spacing is that it tends to cancel the second vertical lobe. Depending on your takeoff angle needs, this might not be a good thing, but on the other hand if you can switch to use just the lower antenna you'll find that it emphasizes the same angles that the stack cancels. You might look at 50/100 ft spacing too. HFTA's problems with close spacing begin *much* closer than that - IIRC, <10 ft.

73, Pete N4ZR
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On 3/9/2015 9:11 PM, W0MU Mike Fatchett wrote:
What values did you get using HFTA. HFTA has some issues with very close spaced stacks. The numbers are wrong.

Mike W0MU

On 3/9/2015 7:09 PM, Jorge Diez - CX6VM wrote:
Thanks Jim

Sorry for the delay, just returning from along trip after ARRLDX SSB

Is curious HFTA. It stopped my project for a two stack for 20 mts yagís.
Since many contesters told me to put it at 69/139 ft, HFTA told me that this
is not the best distances.

OK about your document, will read it, but here we don´t have such facilities than in USA to know ho´w the ground conductivity, the terrain data, etc, etc

73,
Jorge


-----Mensaje original-----
De: TowerTalk [mailto:towertalk-bounces@contesting.com] En nombre de Jim
Brown
Enviado el: domingo, 08 de marzo de 2015 02:44 p.m.
Para: towertalk@contesting.com
Asunto: Re: [TowerTalk] 80 mts four square or yagi?

On Sun,3/8/2015 10:06 AM, Jorge Diez CX6VM wrote:
Wish someone have some analysis or field test to compare a 4SQ with
sixty 1/4 WL radials each vertical and a 3 element wire yagi with boom
at 115ft
This is not exactly the answer, but it should help you think about it.
http://k9yc.com/VertOrHorizontal-Slides.pdf

Also, if the land around you is not flat, you also need to study and use
HFTA extensively. It comes on the CD with the ARRL Antenna Book. HFTA tells
only about horizontally polarized antennas, NOT verticals, because they
interact with the earth very differently. The slides tell a big part of that
story.

73, Jim K9YC
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