The Fisher Labs TW9000-HC Multi-Frequency Underground Utility Locator and Line Tracer System Kit is a rugged, multi-frequency underground utility locating system that employs digital signal processing technology to enable the operator to locate and trace buried utilities quickly and accurately. This system is composed of a transmitter, receiver, conductive connection kit, transmitter rechargeable battery kit, receiver rechargeable battery kit, and a hard carrying case.

The TW9000 Transmitter is a powerful multi-frequency signal generator designed to efficiently energize buried utilities from an above-ground location. This transmitter provides three means of connecting to a utility.

The first method of 'direct connection' is the preferred method in which it is capable of transferring the most power to the utility. The second method of 'coupling clamp' transfers power inductively to an exposed utility conduit when used with a coupling clamp accessory such as the CCLAMP-5-MF (not included). The third method of 'inductive' transfers power through the ground inductively to the utility when no direct connection or coupling clamp access points are available.

Controls are provided for the user to select the tracing frequency of 512 hertz, 8 kilohertz, 33 kilohertz, or 82 kilohertz, adjust both the intermediate and maximum output levels applied to the utility, and to adjust the audio alert volume level. The backlit LCD communicates operating parameters, connection status, and warnings. Powered by a rechargeable 14.4 volt lithium-ion battery, the transmitter features a battery-saving feature to automatically turn off after a specified period of keypress inactivity.

The TW9000 Receiver detects active and passive magnetic fields emitted from buried utilities and sub-surface transmitters or sondes. The user can select from six operating modes, each configured to respond to the magnetic field characteristics inherent in different locating scenarios.

The first operating mode of 'peak and null' is an automated mode for most standard underground utility locating scenarios. The second operating mode of 'wide peak' can be used for lateral lines far away from the connection point or for deeply buried utilities. The third operating mode of 'narrow peak' can be used for congested utilities. The fourth operating mode of 'null' can be used for utilities with low field-shape distortion. The fifth operating mode of 'sonde' can be used with sondes to trace conduit, pipe, and drain locations along with their blockages. The sixth operating mode of 'passive power' can be used for utilities that are energized by AC power currents. This mode does not operate with the transmitter's power source.

Controls allow the operator to select the frequency of 512 hertz, 8 kilohertz, 33 kilohertz, or 82 kilohertz, adjust the gain and volume, and measure both the depth and energizing current of buried utilities. These controls, along with the audio feedback and visual indicators of directional left, right, azimuth, over-target, and signal strength, help to identify and communicate the location, direction, and depth of utilities. The receiver, similar to the transmitter, also has an energy-saving feature to automatically turn off after a specified period of keypress inactivity.