Q: TDR says the fault is at 450 meters. Can I start digging there?
A: NO. Maps are old and cables snake. You need "Acoustic-Magnetic Synchronization" pinpointing.
The "Underground Thunder" Method:
• Magnetic Signal: Travels at light speed. Tells receiver: "Pulse fired!"
• Acoustic Signal (The Bang): Travels at sound speed through soil.
• Logic: The receiver measures the time delay between the two. When the delay is ZERO, you are directly over the fault.
Pro Tip: If you hear a "Thud" in the headphones like a muffled drum, you have found the spot. DIG HERE.
Q: The map says the cable follows the road, but the TDR doesn't match. How to find the real path?
A: Never trust an old map. Use the Induction Method to trace the electromagnetic field.
Procedure:
1. Inject Signal: The transmitter injects an audio-frequency signal between core and ground.
2. Trace: Walk with a receiver wand, detecting the radiated field.
3. Null vs Peak: Peak (wand vertical) = loudest over cable. Null (wand horizontal) = silent over center.
Why: If you dig and hit a 110 kV line instead of the dead 10 kV line, it is a fatal mistake. Trace and spray paint first.