Article: Finding a
Break in the Boundary Wire
To locate wire breaks in your loop installation, a wire
break location device called an RF-Choke is available
at Radio Shack (Catalog #273-102C; Figure A). Once you
have this device, follow these procedures:
1. Disconnect power by unplugging the adapter from the
2. Disconnect the boundary loop wires from the wire clips
on the transmitter.
3. Bend the leads of the RF-Choke into the shape of a
4. Gently wrap the boundary loop wire tips around the
RF-Choke leads (one to each side - see figure B).
5. Plug the RF-Choke leads into wire clips on the transmitter.
6. Plug the adapter into the outlet.
7. Set a portable AM radio to AM-60 or AM-600. If a radio
station is at that location, simply turn the radio dial
until you hear static.
8. Set the field width knob high enough to obtain a signal
on the portable radio.
9. Stand outside the structure where the double-twisted
wire exits the building and listen for the pulsating
static on the radio. The signal should be absent until
you reach a single wire on your boundary.
10. Hold the radio chest high and swing the radio over
the wire as you walk around the boundary.
11. If the tone weakens, stop and mark the spot with
a flag or stick. If there is no sound, the wire has a
complete break. If there is a fading or change in pitch,
then a nick in the insulation is present. NOTE: The signal
will be absent when standing on the twisted wire area
because the signal was cancelled.
12. Continue around the remaining boundary and mark each
signal change with a flag or stick.
13. After completing the entire boundary, return to the
marked spots. Examine the wire for 3-4 feet in each direction.
14. Replace the wire using the same gauge wire used in
the original installation and use waterproof splices
to make the connection.
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