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Re: Topband: Vertical vs yagi

To: Topband <topband@contesting.com>
Subject: Re: Topband: Vertical vs yagi
From: Don Johnson <n4dj@me.com>
Date: Tue, 14 Feb 2012 17:59:06 -0500
List-post: <topband@contesting.com">mailto:topband@contesting.com>
As far as verticals are concerned, since 2003 I have had great success with a 
Half Square antenna on 80. (descriptions in the ARRL Antenna Book and in ARRL 
Antenna Compendium No. 5)   I have also used one on 40 and have one planned for 
160.
One big advantage is that radials are not necessary as with a "normal" vertical 
and it can be fed directly with coax.  Previously I have used almost full size 
ground mounted verticals (108 to 110 feet) on 160 and several shunt fed towers 
on 80.  Until the 80 meter half square I never had one I thought was a really 
good antenna on 80.  I did think the 160 verticals at 108 to 110 feet were 
pretty good compared to horizontal wires.

On 80 meters the half Square is a very good antenna. It is about 65 feet high 
and beats out dipoles much higher (in the 90 to 100 foot range usually by more 
than 1 S-unit). 
On 40 it is easier to get a horizontal antenna higher than the 35 or 40 feet 
needed for the half square or any ground mounted vertical.  If you can not get 
a horizontal dipole 50 feet or higher then maybe the half square or phased 
verticals is your best choice on 40.   In my case the simple dipole at 50 or 55 
feet equaled or outperformed my half square ( two phased verticals) on 40 so I 
took it down. 

On 80, I can not get a horizontal antenna up 120 to 130 feet, so I go with the 
phased verticals in the half square configuration. Two phased verticals are 
good but four would be better!  I may try a half square reflector when I get 
the time.

On 160, I am planning a "bent" half square. It will be about 2 dB down from a 
full size half square but EZNEC predicts, that at an elevation angle of 15 
degrees and lower, it should have more gain than a 160 dipole at 260 feet!  Of 
course, it can not compare to the Yagi at 260 feet.  That is not much of a 
concern to most of us, because it will not take too long for everyone with a 
160 meter Yagi at 260 feet to work the DX first!   I wonder how many of those 
there really are?

It seems clear that the horizontal dipole or Yagi should be the first choice it 
you can get it up more than a half wave high, roughly 65, 130 and 260 feet 
depending on the band.
I have a few plots of the half square vs horizontal dipoles on my website  
N4DJ.com    On 80 meters the actual on the air comparisons seem to be right in 
line with what EZNEC predicted.  If the  EZNEC 160 meter predictions are only 
half as good as they were on 80, I will be one happy DXer!

All my comments assume that working DX is the goal. 

73,
Don 
N4DJ




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