10
Basic Signal Patterns
When the GA-92XTd is positioned directly over a vertical target, the signal strength will peak
(audio signal, digital readout, and bar graph) at either a positive or negative polarity.
The audio signal, digital readout, and bar graph indications also peak over each end of a
horizontal target. One end is positive, the other is negative. This will help you to distinguish
between two vertical pipes or one horizontal pipe. Usually two vertical pipes buried in close
proximity will produce bar graph indications with the same polarity.
Figure 12: Signals from Vertical and Horizontal Targets
After you have detected the presence of a target, hold the locator vertically and slowly move it
back and forth in an "X" pattern while listening to the audio response and observing the bar
graph indicator. For a given gain setting, the number of bars will be greatest when the locator
is directly over a vertical target or the ends of a horizontal target. The "X" pattern, as shown
in Figure 13, is ideal for pinpointing small objects. A 1-1/4 inch PK nail buried up to 10 inches
can be located precisely using this technique.
Figure 13: "X" Pattern provides Precision Locating
If you are looking for a corner marker and detect two or three signals in the same general
vicinity, raise the locator several inches above the ground or decrease the gain setting. Any
signal that disappears when the locator is held higher or when the gain is decreased is likely
coming from a smaller target. The signal from a rusty bolt or other small item (see Figure 14)
