Topband: Are concentrated ground radials needed in directions not used?

Tom Cathey
Mon, 1 Apr 2002 21:06:32 -0500

Hi All,

I wonder if someone would be kind enough to guide me through a few questions
before I continue with this new project?....

I've just about completed a new "three in line" 160M vertical array. It
consists of a shunt fed 110' top loaded tower with a vertical wire parasitic
director and reflector 80' in front and behind. Each element has it's own
radial system.

This Rohn 45 tower has a copper wire "cage" running down the legs and tied
to ground.

Based on field strength tuning measurements the elements tune well  and
appear to produce a nice unidirectional pattern.  I believe the soil
conductivity here is fair to slightly below average.

I plan to do a full 120 radials for each element. I'm now currently nearing
about (qty 40)  1/2  wave  (250' long) radials per element. In addition, I
plan a very concentrated ground screen of short radials going out about 40'
or so under each element.  I understand this is an idea used by broadcast


Right now I have a SYMETRICAL pattern of radials in all directions. I want
to add more radials. Since the array is an East/West switchable array ONLY,
what do the radials running north and south contribute to the pattern or
loss reduction?

IE,  am I better off using all the remaining wire to heavily fill in the
long 1/2 wave radial pattern concentration  to the east and west ONLY where
the array beams?

Also, since many of the radials intersect from each element, does it help to
electrically tie these intersections together?

And one last question:  If the array is beaming East, does a great radial
system to the west help improve the front to back ratio?.. IE, if my main
objective is Europe, with the USA as secondary, will f-b suffer if I do not
have as many radials west as I have east to Eu?


Tom, K1JJ