[CQ-Contest] Electric Fence QRN

[Alan C. Zack]

If I remember right from days long time ago working on a farm as a
teenager, that farm animals "learn" after a few shocks to stay away
from an electric fence and you can turn it off.  Can you persuade your
neighbor to turn it off after the animals learn to stay away from it.
Also, no how much someone dares you, DO NOT pee on an active electric
fence.
73

Duane Grotophorst wrote:
> 
> Having been both in farming and ham radio at the same
> some years ago I can attest that electric fences can
> be electrically quiet. When I was still on the farm we
> had miles of the stuff, some of it within 50 ft of my
> antennas, I had very little trouble with noise from
> it. My experience was that it is not the weeds growing
> into the fence and arching that generate the noise,
> including the "weed" burner type of fence charger. It
> is almost always instead a poor connection between
> fence segments, or between the fence charger and its
> ground system/rod.
> 
> Think about a 3-6 KV (@ a few ma) circuit (being
> pulsed for .1 - .8 second durations) coupling to a
> high impedance antenna (the 1000's of feet of fence)
> through a spark gap (the poor connection). That is
> essentially a spark gap transmitter!!! However in the
> case of the weed growing into the fence it would be an
> arc through a relatively low impedance to ground.
> Since the weed stem is resistive and is also a short
> distance to ground it would not generate much, if any
> radio noise, even though the arching was very audible
> when you'd walk by it.
> 
> When I was building electric fence I always used a
> "linemans" splice to connect different wire segments
> using minimum of 8 - 10 turns when joining sections.
> For areas that needed a gateway I always made sure
> that the wire that made up the gate would be pulled
> quite tight when connected to its hook. The bottom
> line that it came down to was making sure that all
> electrical connections were mechanically solid and
> proper. A sloppy job of making the connections didn't
> really hurt the fence's performance all that much for
> keeping the critters in there proper places, but it
> did make a big difference for RFI issues.
> 
> Duane
> N9DG


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                                Alan Zack
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