Time Domain Reflectometry (TDR) Length Calculator

Enter the velocity factor of transmission line and the round trip time of the pulse to get the distance of the reflection i.e TDR Length. This is usually the distance to the fault in a cable.
  • υ (Velocity factor of transmission line)
  • Td (Round trip time)
  • Calculate Reset


  • TDR Length (meters)


c = Velocity of light i.e 108 m/s

υ = Velocity factor of transmission line

Td = Round trip time (RTT) between onset pulse and first reflection



υ = 0.58, Td = 0.18-6

TDR Length = 15.66 m