I'm curious to know if the fence would act similar to good
conductivity dirt WRT Beverage performance.
Anecdotal reports over the years (~ 30?) of Beverage antennas over
an existing conductive wire/fence indicates that performance lags
that over moderate earth. The degradation comes from two apparent
modes: 1) the (typically larger) fence picks up noise and couples it
to the Beverage and 2) the the conductive nature of the fence upsets
the velocity factor (wave tilt) resulting in a shorter effective
length with lower signal strengths and broader patterns.
73,
... Joe, W4TV
On 2015-02-03 8:39 AM, Patrick Greenlee wrote:
Chuck, A very good point.
That is the essence of my interest in the effect of having some parallel
grounded conductors (5 strand barbed wire fence with steel posts) a
short (TBD) distance below the beverage antenna. I'm curious to know if
the fence would act similar to good conductivity dirt WRT Beverage
performance.
If not, then what if the antenna wire were mounted above 3 parallel but
horizontally spaced conductors looking for the beginnings of the effect
that would be achieved theoretically with our old friend the infinite
conductive plane over which we mount our verticals? Why 3? Because it
would be easy to put a strand of wire on either side of the top strand
of barbed wire using readily available inexpensive plastic insulating
arms made expressly for adding electric fence wire to a fence built with
T-posts. With a little more fussing I could attach 2 wires either side
of the center wire giving a better approximation of the infinite plane.
One of our experts can maybe tell me if the parallel grounded wires
need to be tied together laterally or if that would matter.
Patrick NJ5G
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|