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Index: WMGBTDR420
Technical Specification
  • Description

    Diagnose faults with TDR-420

    The TDR-420 reflectometer is a handy digital Time Domain Reflectometer (TDR) designed to characterize and locate faults in power and telecommunications cables. The Sonel TDR-420 reflectometer allows to measure the length of the cable and to determine the distance to the damage or impedance change in the range from 4 to 6000 m in cables with metal conductors. The shortest measuring range of 7 meters and the dead zone of 0.6 m allows user to locate a damage in a very short distance from the connection point of the device.

    Product features

    • fault location in power and telecommunication cables
    • two independent cursors to indicate two fault locations and the distance between them
    • fault location in coaxial cables
    • fault location in infrastructure cables
    • detection of breaks, short-circuits, damage caused by moisture and other changes in cable impedance
    • graphic presentation of cable faults with an indication of the distance to the fault on the display


    TDR-420 time-domain reflectometer is designed to detect where faults in metal wires are. This product is designed for:

    • electrical wholesalers and cable dealers,
    • electrical installation companies,
    • maintenance personnel at manufacturing plants,
    • building personnel.

    This device meets the expectations of all those who have to accurately locate a fault and wire end in either power or telecommunications cables.

    Device capabilities

    SONEL reflectometer is distinguished for their long operating range of up to 6,000 m, very low margin of error in measurement (in the order of 1%) and the ability to adjust both the velocity of propagation and the impedance of the cable which is under investigation. By using two cursors there should be no problem with determining both the distance to two faults and the distance between them.

    Easy readout

    The TDR-420 reflectometer is equipped with a readable colour display that, due to its 320 x 240 pixel resolution, allows the fault location to be indicated even more accurately.

    Integrated Help

    In the TDR-420 device a handy help function has been added to facilitate the interpretation of the result obtained during measurement. Thanks to this function, a user can quickly determine the type of anomaly that is present in the cable segment which is being examined, by comparing the displayed reflectogram with typical fault shapes.

    Durable and practical casing

    In response to the customers needs the new TDR-420 model has been designed to operate in difficult environmental conditions. A unique casing with the IP67 ingress protection rating ensures that the device is both waterproof and dustproof. An additional advantage is the elastomer coating of the casing that prevents the device from slipping out of the hands and provides protection if it should be accidently dropped.

  • Technical Specification

    Technical specification

    Parameter Description
    measuring ranges 20, 45, 90, 180, 360, 750, 1500, 3000, 6000, 10000, 20000 [ft] 7 m, 15 m, 30 m, 60 m, 120 m, 250 m, 500 m, 1 km, 2 km, 3 km, 6 km
    accuracy 1% of selected range
    resolution approx. 1% of range
    minimum cable length 4 m
    velocity of propagation within 10…99% or 15…148.5 m/μs
    output impulse 5 Vp-p for an open circuit
    output impedance 25, 50, 75, 100, 125 and 200 Ω
    impulse width 3 ns…3 μs (depending on the range)
    scanning type up to 3 scans/s or a single scan (ONCE mode)
    generated acoustic signal 810 – 1100 Hz
    operating time on a full battery up to 8 hours of continuous scanning
    power supply 4 x alkaline batteries 1.5 V AA type or 4 x NiMH AA rechargeable batteries
    auto-off function 1, 5, 10, 15 minutes or deactivated
    display colour 3.5” LCD TFT, 320 x 240 pixels
    overvoltage protection 400 V DC / 250 V AC
    operating temperature -20...+70°C | -4...+158°F
    storage temperature -30°...+80°C | -22...+176°F
    electromagnetic compatibility standards (EMC) EN 61326-1
    degree of protection / tightness IP67
  • Files

Standard accessories