Schonstedt Locators

It has easy-to-read digital and bar graph displays of signal strength and polarity. Once you have located a target using the audio signal, the digital readout and polarity indications will help you to visually pinpoint the target and, in some instances, even determine its orientation.

When searching an area, set the sensitivity control for mid range, adjust the volume control for a comfortable level and move the locator from side-to-side in a sweeping motion as you walk along. After you have detected a target, hold the locator, vertically and move it back and forth in a "X" pattern. The peak audio and visual indications occur directly over a vertical target, and over both ends of a horizontal target.

This locator has an audio sound indication that goes to depths of 12 feet and it also has a three year warranty.

Designed for one-hand operation, the On/Off Sensitivity and Volume controls are located on the underside of the cover on both locators. This provides easy access, protects the knobs and contributes to their overall ruggedness and dependability.

You can select any one of four sensitivity settings. The GA-72Cd's LCD bar graphs show the selected gain and the battery status. There is a +/- 4 V analog signal available on the GA-72Cd's headset jack, which varies in proportion to the signal strength, that can be connected to your data logger using a standard stereo audio plug.

• Digital readout and expanding bar graph displays of signal strength and polarity
• 4 Sensitivity settings: Low, Medium, High, and Extra High
• Piezoelectric speaker
• Analog output for data logger entry
• 60-Hours operational life (intermittent usage) on 2 lithium 9-volt batteries
• First locator to use Environmentally Friendly and Safe, lithium batteries. The unit is shipped with two 9-volt lithium batteries installed, and a spare set of batteries stored in the case. Lithium batteries provide twice the life of alkalizes, and a 10-year shelf life.
• 4-Segement BATT LCD monitors battery charge
• Lightweight, easy-to-use-design reduces search time
• Modular construction; high performance components
• Patented HeliFlux sensors

As you walk along without encountering any iron or steel items, the receiver's two magnetic-field sensors (A and B) balance out the Earth's magnetic field and the frequency of the audible indication will remain at 40 Hz.

However, as you approach a buried vertical piece of iron pipe, for example, the frequency of the audio indication begins to increase as the strength of the magnetic field becomes stronger as sensor A than at sensor B. When the tip of the receiver is directly over the target, the strength of the magnetic field at sensor A is maximum which causes the frequency of the audio signal to peak.

After you've outlined the target area, reduce the sensitivity level and slowly move the receiver back and forth in an X pattern over the area. You'll be amazed at how quickly the well defined peak of the audio signal will pinpoint the target as you can see in the photo below.

System Description
The MAC-51Bx (the most cost-effective, all purpose locating system on the market) consists of a receiver and a transmitter that simultaneously transmits on two frequencies--571Hz (LF) and 82.5KHz (HF). The receiver has a three position switch that lets you change modes, "on-the-fly", between LO, HI, and MAG, for cable and line tracing with break locating, pinpointing a ferrous metal target, or tracing an energized (82.5 KHz mode) gold vein.

In the LO and HI modes, the receiver's audio signal provides a sharp null when its tip is directly over the target. In the MAG mode (no transmitter required) the audio signal peaks when the receiver's tip is over the target.

You can trace the 571 Hz LF signal conductivity applied to any continuous metal conductor up to 4000 feet. The receiver's on-the-fly mode-changing feature lets you locate a complete break using the LO mode, and then continue on to trace beyond the break in the HI mode, or trace a metal pipe joined with non-conductive gaskets.

Dual-Frequency Cable and Line Tracing Modes
The MAC-51Bx simultaneously transmits 82.5 kHz (HF) and 571 Hz (LF) signals. This feature lets you select and compare received audio signals from both frequencies along with magnetic information without having to return to the transmitter.

Setting the Receiver's Mode switch to HI allows you to trace the 82.5 kHz signal applied to a continuous metal conductor. The HF signal also jumps gaskets between pipe sections, bad telephone cable bonds and small breaks in a cable's sheath.

Induction is achieved by placing the transmitter over the target cable/pipe or by using the optional Inductive Signal Clamp. It's the easiest and quickest way of applying a trace signal that is strong enough for tracing most lines. The trace signal generates an alternating magnetic field around the cable which induces a signal into the receiver's cable sensor. You will hear a steady beeping from the transmitter to indicate the power switch is set to ON, unless the batteries must be replaced. Moving the receiver back and forth as you walk along causes the audio signal to increase in pitch as the receiver is moved to either side of the cable. A sharp null in the audio signal between the two peaks occurs when the receiver's tip is directly over the cable.

With a little practice, selecting the proper gain level to keep the locator's tip directly over the cable will become second nature to you.

Transmitter Conductive Mode
If an exposed section of a target gas or water pipe is accessible, conductive coupling is the most reliable method for applying the trace signal. This mode has to be used to apply both HF an LF frequencies so that you can use all three features on-the-fly. Providing a good electrical contact between the clip and the conductive portion of the target line by removing rust or paint before attaching the clip is very important.

Options
MT-2 Mini-Transmitter (Mole) is used to trace non-metallic pipes, pinpoint obstructions and locate concrete septic tanks. When attached to a plumber's snake, the Mole emits a signal detectable at depths of 18 feet using MAC-51Bx Receiver.