Here's a new one
#1
Here's a new one
...at least to me.
My son has spent the last two weekends installing an invisible fence around the perimeter of his new property. He got it all laid out, tested, trenched in and tested again. Then he put the shocker collar on his dog and took him out to begin training him.
To his surprise, and his dog's pain, they discovered that the cable provider's coax feed had become part of the fence. That means that the run of coax, at least from the edge of the property to the house, acts as a piece of the fence. Approaching that coax shocks the dog in the same way that approaching the actual fence does.
Further investigation revealed that disconnecting the ground connection that the cable company made to the GEC also disconnected the induced connection between the fence and the cable. My son and his other Dad (his FIL) have a theory that the ground bond made the outer wrap of the coax act as an antenna, that the cable company failed to ground the cable at their tower, and that installing that second ground would nullify the antenna.
Further detail is that the invisible fence and the coax cross twice, at right angles and at a greater distance than the fence instructions specify.
My son is ready to call the cable people and ask them to send a tech out to investigate this with him. Any thoughts?
My son has spent the last two weekends installing an invisible fence around the perimeter of his new property. He got it all laid out, tested, trenched in and tested again. Then he put the shocker collar on his dog and took him out to begin training him.
To his surprise, and his dog's pain, they discovered that the cable provider's coax feed had become part of the fence. That means that the run of coax, at least from the edge of the property to the house, acts as a piece of the fence. Approaching that coax shocks the dog in the same way that approaching the actual fence does.
Further investigation revealed that disconnecting the ground connection that the cable company made to the GEC also disconnected the induced connection between the fence and the cable. My son and his other Dad (his FIL) have a theory that the ground bond made the outer wrap of the coax act as an antenna, that the cable company failed to ground the cable at their tower, and that installing that second ground would nullify the antenna.
Further detail is that the invisible fence and the coax cross twice, at right angles and at a greater distance than the fence instructions specify.
My son is ready to call the cable people and ask them to send a tech out to investigate this with him. Any thoughts?
#2
I am wondering if sleeveing either the coax or the fence wire in PVC where they cross would prevent the induction/receiving. OR maybe putting a barrier of wood/non-conductive material between the two cables.
#3
I am wondering if sleeveing either the coax or the fence wire in PVC where they cross would prevent the induction/receiving.
Here's something that just occurred to me: what if the problem originates with the signal from the dog fence getting onto the grounding electrode, and then being transferred to the coax shield when that is connected to the GEC?
#4
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Is the ivisible fence twisted around itself at the point where it leaves the house to the point where you want the invisible fence to begin? Than again, where the fence ends, and returns back to the house? From the point where the wire leaves the house, to the point where the fence both begins and ends, there should be two wires running parallel to each other. those wires have to be twisted around each other in order to cancel the signal and not shock the dog.
#5
From the point where the wire leaves the house, to the point where the fence both begins and ends, there should be two wires running parallel to each other. those wires have to be twisted around each other in order to cancel the signal and not shock the dog.
Yes, the lead out and the return lead are twisted around each other and the field is cancelled out, according to both the testing and the dog's reaction.The problem is that the cable feed - the coax - becomes energized with the fence field iff the coax wrap is bonded to the GEC for the house. The coax takes a different path from the fence leads, so it is easy to see that that is the problem - besides the fact that disconnecting the coax-to-ground bond stops the problem.
Today, my son did these three things, and got these results:
- He drove a new ground rod and grounded the coax on its own. Same result: Fence field on the coax when grounded; not on coax when not grounded;
- He consulted with his neighbor, on the side where the cable enters his property, about his experience and his neighbor's experience with his own professionally installed invisible fence. They discovered that the neighbor has the same problem - but was previously unaware of it - and that each of their fences only energizes their own cable field. If bonded.
- He called the cable company. No response yet.
#7
Puttning the fence power supply on an isolation transformer might help.
The fence came with its own xfmr, of course. It's a wall-wart, and I don't know the output specs, but I can find out.
#8
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An isolation transformer is a two-winding (insulating) transformer with a 1:1 ratio. They are fairly common in shops servicing small appliances and electronics. They isolate the tested equipment from the neutral-ground bond in the service panel.
Unfortunately, I don't think this is your problem, especially since the unit already uses a wallwart for a power supply.
Unfortunately, I don't think this is your problem, especially since the unit already uses a wallwart for a power supply.
#10
It's resolved.
My son installed an isolation block between the coax ground and the house GEC. No more mid-yard shocks, and he's now turned the fence back up to "High."
Thanks for all of the great listening and tips.
Thanks for all of the great listening and tips.
#13
Good to know. Is the isolation block available at most stores or is it a online thing?
#14
No offense, but anyone who wants to use a shock collar on a dog should be required to wear it on their genitalia first ("turned up to high", of course) so they can feel what it's like. They are barbaric and should be outlawed. People use them simply because they are too lazy to properly train the dog. Not to mention they do nothing to keep out the real threats to the dog, such as other dogs/animals and thieves.
#15
No offense, but anyone who wants to use a shock collar on a dog should be required to wear it on their genitalia first ("turned up to high", of course) so they can feel what it's like.
#18
Clarification
I realize that when I posted this:
I didn't explain what the effect of turning the power to the fence up or down is.
For anyone not familiar with an invisible fence, turning the power to it up or down has no effect on the jolt the collar produces. The collar is battery-powered, and it does the same thing any time it's triggered.
Instead, the effect of turning the power up to "High" is to increase the range of the signal from the fence. Our best estimate is that the effective range of this fence can be varied from about 6", on Low, to roughly 8' on High.
No more mid-yard shocks, and he's now turned the fence back up to "High,"
For anyone not familiar with an invisible fence, turning the power to it up or down has no effect on the jolt the collar produces. The collar is battery-powered, and it does the same thing any time it's triggered.
Instead, the effect of turning the power up to "High" is to increase the range of the signal from the fence. Our best estimate is that the effective range of this fence can be varied from about 6", on Low, to roughly 8' on High.