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Posted by on May 3, 2007, 8:41 am
> 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, spamb...@milmac.com (Doug Miller)
> 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.
Analog rather than digital pretty much because analog radios tend not
to have a "squelch" and you can hear whatever noise there is between
stations, whereas digital radios automatically apply squelch to, well,
squelch the noise (turn off the speaker whenever thewre is no signal).
Dave
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