Hi Brian,
I can see two main problems with doing this. I haven't tried using the
actual fence strand, but I did have a Beverage that ran close along the
top of the fence.
Problem 1.
Being in close proximity to the other fence strands, coupling from them
is significant, compromising the front to back ratio. I found that I
improved the F/B ratio from about 8 dB to about 15 dB by increasing the
spacing between the Beverage wire and the top of the fence, from 300mm
to 1.8m.
Problem 2.
Unless the fence is very high, the top strand is probably quite close to
the ground. The insertion loss of the transmission line formed between
the strand and the ground will be significantly higher, than if the wire
is raised up a couple of metres. This means that currents induced at
the far end of the wire are significantly smaller in magnitude than
currents induced in closer parts of the wire, even thoguh they come from
the same wave. The spatial decorrelation effect of, say, a 300m wire,
is then compromised, and the directivity is reduced. I found that the
common mode inserton loss dropped from 8 dB to 4 dB, when I increased
the height of the wire as described above.
I achieved the height increase (and increased separation from the fence)
by drilling holes in the tops of the fence posts, and inserting bamboo
supports. These have now been in place for nearly a year with no sign
of degradation.
73, Greg, ZL3IX
On 2010-11-03 05:25, Brian Kassel wrote:
> Can the top wire
> of the fence be insulated and used? My 3 acre property shape is very long
> and not very wide, sort of triangular shaped. I don't have enough room to
> run a a wire across the property, only lengthwise, along the fence.
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UR RST IS ... ... ..9 QSB QSB - hw? BK
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