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Default Finding a Break in an "Invisible Fence" Wire

frank1492 wrote:
Thanks so much Doug! Will relay this info to her.
One quick comment: The Petsafe guy told her she
would need an analog rather than a digital radio. I would
assume that would cover most of the cheapo AM's, no?
Thanks again!
Frank



On Wed, 02 May 2007 12:42:45 GMT, (Doug Miller)
wrote:

In article , frank1492
wrote:
A friend has an invisible fence for her dog. The wire was apparently
severed by someone turning over soil in a rather large area adjacent
to her property.
She claims to have used a portable radio to find the break in
this system before, but she can't remember whether she was using
the AM
or the FM band.


AM, tuned to a staticky place between stations.

In any event, this time she has tried a different
radio (the other one is broken) with no success.


I've observed that some radios work better for this than others. We
have one
radio that's just dandy for locating breaks, and another one that
isn't worth
a hoot. Don't know why.

Fresh batteries make the job a lot easier.

My question is: Can one use a radio to find a break like this?
And if so, how is it done?


Yes. Tune an AM radio between stations, and move it side-to-side
across the
suspected path of the wire, just above the ground. It's best to
start in a
spot where you *know* the exact location of the wire -- like where
it crosses
a driveway, or a sidewalk, where you can see the saw cut that the
installer
made in the concrete or asphalt. Wave the radio back and forth until
you hear
a definite change in the pattern of the static -- that's what you're
searching
for. Then start walking along the path of the wire, continuing to
wave the
radio back and forth.

Sooner or later, you'll come to a spot where the signal fades, and
eventually
disappears completely. Mark that spot.

Now go back to where you started, and in the same manner, follow the
wire
around the yard in the opposite direction. Again, you'll come to a
place where
the signal fades, and eventually disappears completely. Mark that
spot, too.

The break is approximately half-way between the marks.

If not, is there an inexpensive device that
could be used to do it? (She doesn't want to spring for a metal
detector.)


Well, metal detectors aren't all *that* expensive... but the radio
works just
fine.

I really don't need more info, but would like to know a little
more about how invisible fences work. I would assume the wire simply
acts like a transmitting antenna.


Yep, that's all it is.


Right. Actually, the best radio you could use is one of the cheaper ones,
cheaper the better. Or the oldest radio you might have in the house would
likely be sure to not be digital.

Since IIRC this was a dug up garden, there could be a lot more than just one
break in the wire, too. That would account for the "stop" areas mentioned
being really far apart, as in not quite to the garden edges yet. Especially
if a tiller was used. Those wires were probably only buried about 4 inches
deep, so chances of a tiller making spaghetti our of it are good.

If you have to make splices underground, be sure they're watertight. I find
that GE Silicone II works well in a cocoon around the splice.

HTH
Pop`