Topband: Vertical vs yagi

[Don Johnson]

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