The new Mark IV Receiver employs a high gain, integrated circuit amplifier that is signal-to-noise optimized by three 750 cycle active filter elements. Modern circuit design insures maximum circuit stability even when operated at ambient temperature extremes. The filter attenuates a.c. and d.c. interference. The search coil is contained within the receiver and has low impedance of 2,000 ohms. Although earphones are furnished for operator’s optional use, the loudspeaker offers advantages related to safety, convenience, and comfort. Built-in battery test and signal intensity meter of modern full-face design for ease of observation. Multi-directional depth level gauge for accurate (within 1 inch) depth determination.

The oscillator provided with the set has been designed to use the latest developments in this type of instrumentation. A signal of 750 c.p.s. is generated by using a power transistor switching circuit. This arrangement eliminates troublesome vibrators, buzzers or other moving part elements. The Transistor Oscillator converts low voltage (twelve volts) d.c. to stable audio frequency a.c. directly and hence, by a highly efficient method, the input current to the Oscillator is only 1.7 amperes for a full output of fifteen watts, a conversion efficiency of better than 80%. In order that a maximum of energy can be transferred from the Oscillator to the pipe, the output of the oscillator is provided with taps so that voltages of 2.5. 5, 7.5, 15, 50, and 100 volts are available to match the load. An interrupter is provided to make the signal more easily recognized.

The 45/90 Probe, when used with the Tinker & Rasor Model PD Short Locator, allows for greater accuracy and tracing distances while locating electrical contacts and insulated joints on coated pipelines in corrosion control systems.

Use with all Model PD Receivers by simply plugging the probe jack into the “cleat” receptacle. Follow the same easy operating methods shown in the Model PD Instruction Manual for locating electrical shorts or pipe tracing.

The search coil is located in the tip of the probe head, which allows fast, accurate performance. When the search coil is in a vertical position, a sharp “null” indicates the center of the pipe or cable.

The depth of the pipe or cable can be accurately determined without the usual bending or kneeling. First locate center of the pipe or line “A” by crossing the pipe in a sweeping motion. A “null” (no signal) will mark the center of the pipe. Mark this location “A”, moving 90o from the pipe with bubble centered in 45o angle gauge and holding the probe tip close to the ground until another “null”- “B” is detected. This distance from “B” to “A” less ½ of the outside diameter of the pipe will be the depth of the buried pipe.

The Tinker & Rasor Model PD Short Locator has gained wide acceptance for its usage in locating electrical contacts and insulated joints on buried coated pipelines. The addition of the new Bumper Probe Model BP and vehicle clamp accessories serve to further enhance its operation, because the operator rides in the vehicle. The Bumper Probe is easily mounted on almost any field vehicle with a clamp made especially for this purpose. Twenty-five feet of cable are furnished to reach from the probe to the PD Receiver positioned in the vehicle with the operator.