160m lives!

[wmhein at aol.com]

>  Can you post to the reflector or to me the details on your phased 160
>  array.  Are you using towers, wires?  Homebrew design or from an
>  article?
>  73, Geoff WA1U


I have been working on a 160m phased vertical array for about two years! 
Finally got it working in the last few days.  I used the array in the CQWW CW
contest, but on the Monday after the contest discovered that two of the four
verticals had their feedlines torn out -- along with 70% of the radials -- by
horses running through the field!

The array consists of 4 towers built with Rohn 45 tower sections (except for
the last 15 feet, which is 2" OD aluminium.  The verticals are insulated at
about 20 foot above ground.  Each vertical has four radials sloping from 20
foot to a little above ground level.  A on-the-shelf Comtek Quadrature Feed
(0, -90, -90, -180 degrees) phasing network is employed.

I designed the array using K6STI's Antenna Optimizer software, optimizing for
a low angle of radiation and for maximum F/B ratio.  The sides of the square
are somewhat larger than the typical quarter-wave spacing typically
recommended, about 165 feet per side.

The computer model says I should get 5.65 dBd of forward gain (main lobe
under 20 degrees), with a F/B ratio of 49.50 dB and a maximum sidelobe of 17
dB.

In actual use over the last couple of days, I am seeing nulls of between 3
and 7 S units depending on the time of day and how close the station lies to
one of the antenna's four axis.  Many signals are only audible when the main
antenna lobe is directed at them.

As far as I know, this is the first computer-optimized amateur Four Square
vertical array.

I am working on a large Beverage system (7 antennas on a "hub and spoke"
installation).  Hope to complete it before Xmas.  I am interested to see how
it compares to the Four Square on RX.

73
Bill AA6TT