How to Find a Break in an Invisible Dog Fence

Intro: How to Find a Break in an Invisible Dog Fence

Recently I went into my garage to find the invisible dog fence transmitter beeping. After calling the company I was informed that this alarm meant there was a break in the fence, and that I should have them come out as soon as possible - because my dog would surely figure this out in a few days. And hey, for only $100 an hour, they would be happy to help! Long story short, they tried for an hour then told me the yard was too overgrown (half the yard is wooded) and they would have to come back in the fall when everything died back (2 months away). This made me swear that I would do it myself - but after digging up over 100 feet of wire and driving myself crazy for a few days, I had not found the break. Then I found this strategy on the internet (link) that cost me under $20 and worked like a charm. Hopefully this makes it clear for everyone else and saves you some money and frustration. Good luck!

STEP 1: Verify the Break

First thing to do is make sure that you do indeed have a break. There are a few ways to do this. On my unit, two wires run from the transmitter to the perimeter fence. Disconnect these wires from the transmitter and put the ends of a paper clip or small piece of wire into the jacks where the wires had been connected. If the alarm is silenced, the transmitter is working properly and you have a break. Another way to verify that there is a break is to use an ohmmeter and check the resistance on the disconnected wires. If there is no resistance the wires are continuous and there is not a break, meaning you may have a problem with the transmitter itself.

STEP 2: Materials

To start, you'll need to round up a handheld AM radio and a RF choke (Radioshack part number 273-102).

STEP 3: Connect the Choke

Take the two wires that you disconnected from the transmitter and connect them to the leads of the RF choke. Then insert the leads of the choke into the jacks on the transmitter where the wires were originally connected. As I understand it, this allows the transmitter to continue sending a signal to the fence even though it is broken.

STEP 4: Tune In

The fence emits a radio signal that is picked up by a reciever on your dog's collar when it gets in range, causing a warning signal or an electric shock. You should be able to detect this signal in the lower AM range. The signal of my fence was roughly 600 kHz. When tuned to the right frequency, you will hear the signal as you pass the radio over the ground. It may be necessary to turn up the intensity of the signal at the tranmitter, although I didn't have to (there should be a numbered dial somewhere on the transmitter, just remember to turn it back down later so you don't fry fido!)

STEP 5: Find the Break

Walk the perimeter while passing the radio antenna over the ground where you suspect the wire to be. You should be able to pick up a clear, definite signal. The video shows me walking the radio back and forth over the line (in reality the signal was much clearer than it sounds, but you can definitely get the idea). When tuned in perfectly, the signal sounded like a rapid tapping/beeping - when tuned close but not right on, the signal caused the static to get louder as the radio passed over the wire. When you find an area where the signal drops out for a few feet, this is likely to be your break. Go slow and check the whole perimeter before you start digging, I found areas that seemed weak but when I eventually found the break it was pretty obvious.

STEP 6: Dig It

When you've located the area where you suspect the break to be you'll need to expose the wire. I used a 3-pronged hand tiller and dragged it perpendicular to the wire, the invisible fence guys used a pick axe. Use whatever you like but be careful that you don't cut or knick the wire in the process.

STEP 7: Check the Break

Once you've found a break, use the radio to check that you have a strong signal on both lines. I actually had two breaks but didn't know it until I found the first break and realized that one of the ends did not have a signal. I continued to dig in the direction of the dead line and found a second break a few feet away. If you have a strong signal on both ends connect them with a piece of wire, disconnect the choke and reconnect the wires from the fence into the transmitter. If the alarm goes off, congratulations, you've found your break!

STEP 8: Mending the Break

The final step is connecting the broken ends in a way that is weatherproof and secure. I bought these connectors from the local hardware store, time will tell if they are the best ones or not but you want something that is waterproof and suitable for the temperature range in your climate. This type of connector is filled with silicone to seal the twisted wires. Once you're sure the fence is operating correctly, bury the mended wires and you're done! Good luck!

Comments

[gtyler1961]

I use standard crimp connectors inside of a larger diameter tube. Here it is inside a piece of scrap 3/8 tubing. Just make sure to put the tube in place before you start crimping. Once crimped, slide the tube over it and fill with exterior caulk. Sorry, can’t add images

[donens]

The Radio Shack choke listed does not seem to be available, especially in Canada where Radio Shack stores are now The Source. The local Source store doesn't even know what I'm talking about. The other comparable RF choke that would work and common?

[Jebulous]

I was able to find the choke and got a cheapie AM radio on Amazon.

[esteffen]

Thanks worked great for me! I did spend some time trying to find the right frequency. My invisible fence was 1710 not 600.

[countrygrl24]

will not let me download

[gcmillerj]

To JoeysMom, I believe that PetSafe uses a different system and this procedure will not work with that system.
A friend of mine and myself are both very knowledgable in electronics and radio systems. We spent quite an amount of time trying to use the above procedure to find the break in my PetSafe system. It wasn't that we just couldn't find the break, the procedure just didn't work.
I started doing a lot more research on the Internet and believe that the PetSafe device uses a more complex system that does a better job, but requires specialized equipment to troubleshoot it.
I am checking into that now. I'll let you know what I find out.

[DavidU65]

Grateful for information, but .. Another PetSafe Failure.

New (April 2019) PetSafe unit Model 300-1051. RadioShack RF Choke 100 microhenries. No joy on any of the A/B/C frequencies on the unit. Experimented with a known-good 20-foot loop of wire in parallel with the choke, AM radio antenna an inch away. No frequency found on AM radio between 560 -> TOP-LIMIT where level of static had any correlation to proximity to wire loop. No pulsing/beeping nature of static anywhere at all. Perhaps I'm cursed with a local radio station that swamps it, but seems odd that it would swamp all 3 freq. options from the A/B/C selector switch on the uniit.

[huges84]

I have a PetSafe and this worked for me. First make sure you do step 1 to confirm the transmitter is working right. Then when you wire up the choke make sure it's in parallel and has a solid connection. Crank the transmitter to its highest setting. You want an AM radio with an external antenna and you have to be right on top of the wire (inches to the dirt) to get the interference. You can't count on the frequency being 600Hz, you have to play around with the frequency to find the best one.

[borodelostoldos]

Hi! I´m developing a similar circuit for a home made robot-machine and it will help me a lot if I can see how your system is built, Can you upload a picture of the complete electronic circuit?
Thanks!!

[dmaxwell4]

I use these (https://www.amazon.com/UR-3M-Scotchlok-Butt-Connector-Pack/dp/B0076AY7N8) 3M Scotchlok IDC Butt Connector. They automatically make a water tight splice into two unstripped wires.

[AngelaV40]

Step number one just saved me a fortune. I was given a quote to reinstall my whole fence because it is older. I found the problem and the fence is working with no digging required. Thanks!

[CatherineH84]

I can't thank you enough! We just got a second dog and had a break somewhere on our 1/2 acre we have wired - after many downed limbs this spring, we were seriously doubtful of finding the break....so happy we came across this website. Ordered the parts on Amazon for less than $20 and found the break in a very unlikely spot!

[PJMc2]

Before you go through all this, I'd suggest that you double check your transmitter. I have the Radio Fence Pet Safe RF-1010. It started beeping so I was certain that it was a line break. I did all these steps, and spent hours, then simply turned the dial all the way clockwise to 10. For some reason, the sensitivity changed from around 2 to 7.5 on the unit! Below 3, beeping, above 4 it went away! It now works like it did before, and it looks like the problem is solved.

[L8apex]

Glad I read this! Thanks! My kids probably played with the settings. I set the perimeter switch (a/b/c) back to B for under 1300’ wire length and diled it up until it stopped beeping. Tested with collar and it’s working perfectly.

[d1no]

Does anyone know the difference between the old and new pet safe systems? (The frequency maybe?) I have an older system. It looks like the one in this article. Pet safe is telling me I need a new system if I want new collars. The old collars are not available.

[MamaLoca]

Thanks for this Instructable. We found the break and our Beagle is happy to be off the chain.

[cgosh]

Your local AM radio stations may or may not be close on the dial to the frequency the dog fence broadcasts. A cheap-o AM radio might work better than an expensive model (less sensitivity and less adjacent-channel rejection on the cheap model). YMMV so try different radios.

FWIW, the purpose of a choke is to pass DC current (measured in volts, so the fence system thinks a wire is shorted across the terminals) while blocking any AC (the noisy part that shows up in the radio is NOT shorted out, so it continues down the buried wire). You can make one -- it's just a coil of wire. Google it. Perhaps this system uses a constant DC voltage to test for continuity through the buried wire, and an AC signal (the "noise" you hear) to trigger the dog collar. A break would cause the beep that tells you the wire is broken (DC missing in the wire loop) and so you fool the system with the choke so you can test with the AM radio. Simply shorting the wire could diminish the signal to the radio, but I'd obviously try it and see if it's loud enough to do the job.

[KenB91]

FORGET THE CHOKE. You don't need it. Just use a piece of wire in place of the choke and follow the instructions as provided. I plugged both a short piece of wire and the broken perimeter wires into the control box and it sent the 600 mHz frequency out the lines that was detectable by an AM radio tuned to 600. I have just over 1/2 acre inside my perimeter. Maybe the choke is useful for longer runs, but I did not need it.

[DaveH130]

With the RF choke the collar still works. I taped the prongs and used it.

[DaveH130]

With the RF choke the collar still works. I taped the prongs and used it.