Skip to main content

VoD Fundamentals

How Time Domain Reflectometry (TDR) Works — and How to Easily Measure Velocity of Detonation (VoD) with ShotTrack

S
Written by Stefan
Updated this week

Overview

This article explains the basics of Time Domain Reflectometry (TDR) and shows how ShotTrack VoD units make it fast and easy to measure the velocity of detonation (VoD) in blasting applications.

We’ve also included a short instructional video so you can see the process step by step.


Watch the Video

  • How TDR works

  • How to set up your ShotTrack VoD unit

  • How to get fast, accurate VoD measurements


What is Time Domain Reflectometry (TDR)?

TDR is a measurement technique that sends an electrical signal down a coaxial cable and detects the reflections caused by changes in impedance — such as when an explosive detonates and consumes the cable. By precisely measuring the time it takes for the reflection to return, the system can calculate the velocity of the detonation.

This method is highly accurate and widely used in blasting, mining, construction, and explosives testing.


Why Measure Velocity of Detonation (VoD)?

Measuring VoD helps ensure:
✅ Correct explosive performance
✅ Blast optimisation and fragmentation control
✅ Safety and compliance in blasting operations
✅ Improved cost efficiency and reduced waste


Why Use ShotTrack VoD Units?

ShotTrack VoD units are designed for ease of use, accuracy, and reliability:

  • Digital timer chip means no regular calibration needed

  • Simple, fast setup

  • Supports multiple cable types (with a one-time calibration setting)

  • Portable and rugged for field conditions

Did this answer your question?