Another "invisible fence" question

Bob Engelhardt · 2016-03-16T23:42:51+00:00

This particular fence (PetSafe brand, Yardmax model) has 2 modes, one of which is very interesting. It "knows" the inside of the fence from the outside and triggers when the dog goes out and doesn't stop until the dog comes back. Unlike a traditional fence which is simply distance based (if he goes out far enough, it stops). Part of the set up is to test it and reverse the wire ends if it has the inside & outside reversed. I couldn't figure out how it could do this, when I was thinking in radio signal terms. It seemed like the collar would have to have 2 antennas, more than the wave length apart and detect the direction that the signal was traveling. Very improbable, I thought. But now that Win has informed me that it's a _magnetic_ signal, it makes so much sense. The magnetic field a little ways away from the wire is (almost) vertical and "pointing" up on one side and down on the other. So a horizontal loop in the collar will have a voltage induced that is opposite in polarity on the 2 sides. So the collar can know when it's inside and approaching the wire (increasing signal strength), then decreasing as the field direction becomes more parallel to the loop (at the wire), and then increasing in opposite polarity when it's outside. Does this make sense, or is there a approach that's more likely? Thanks, Bob

Mar 16, 2016 24 Replies

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Jasen Betts 9 years ago

So a dog could jump the fence, because during the jump the acellerometer would not know down?

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Adrian Jansen 9 years ago

It would as soon as the dog hit the ground. Not a long time interval to be 'out'.

Regards, Adrian Jansen

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kytoys1 9 years ago

Have the Invisible Fence 800 transformer. Collar activates when dog crosses wire and continues shock for timed interval or shock stops when pet re-ent ers yard. Fields have reversed!!! Exiting yard is painless. Re-entry is mos t unpleasant. What could cause this?

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Jasen Betts 9 years ago

Some joker swapped the wires connecting the loop to the transformer, swap them back

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Cursitor Doom 9 years ago

Maybe someone removed the collar and replaced it upside down? I can't think of anything else.

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