The Megger TDR900 is an advanced instrument capable of measuring cable lengths and finding distance to an open or a short using Time Domain Reflectometry. It offers exceptional features and a range capability normally associated with far more expensive instruments. The measurement range spans from 15 feet (5 m) to 10,000 feet (3 km) with a minimum resolution of 20 inches (50 cm).

The TDR900 can be used for any cable consisting of at least two insulated metallic elements, one of which may be the sheath or shield of the cable. The Meter has automatic internal matching networks to allow testing of 25Ω, 50Ω, 75Ω, 100Ω, 125Ω, or 150Ω cables. (These correspond to power, telephony, CATV, and LAN cables.)

The Meter can be closely matched to the cable under test using the menu selection keys. The propagation velocity value can be similarly adjusted to match the cable under test; thus ensuring an accurate distance measurement.

The other user adjustable setting is changing the distance measurement units (feet or meters).
The Meter is housed in a rugged ABS enclosure which is dust and weatherproof to IP 42. The unit also comes with a soft carrying case and an alligator clip adapter. It is powered by 4 AA (NEDA 15A or NR 6) batteries, which are stored in a compartment on the back of the Meter. The batteries are held in a carrier for quick and easy replacement.

• Full autoranging for measuring the length of power, telephony, CATV and LAN cables, provides distance to an open or short.
• Extra large, high resolution backlit LCD.
• Automatic output impedance control of 25, 50, 75, 100, 125 or 150 ohms.
• User-friendly menu on screen operation.
• Cable length calibration function.
• Internal library of 39 standard cable types.