GA-92XTd Magnetic Locator Instruction Manual Schonstedt Instrument Company P: (800) 999 - 8280 100 Edmond Road, Kearneysville, WV 25430 www.schonstedt.com schonstedt.inf@spx.
Table of Contents SECTION I: INTRODUCTION ............................................................................................. 3 SECTION II: OPERATING CONTROLS ON/ Volume .............................................................................................................. 5 OFF .......................................................................................................................... 5 GAIN .....................................................................................
SECTION I: INTRODUCTION The GA-92XTd magnetic locator detects the magnetic field of ferromagnetic objects. It responds to the difference in the magnetic field between two sensors that are spaced approximately 9.5 inches apart. This difference is referred to as the “signal strength” throughout this manual and is represented in the instrument by an audio tone, the display of a bar graph, and a numeric indication.
The GA-92XTd unit can be operated either in the open or closed position and any position in between (see Figure 2). Figure 2: Open and Closed Positions NOTE: In the closed position using non-lithium batteries, a slight signal may be detected in the high gain settings even if no ferrous material is present. This can be avoided by 1) decreasing the gain, 2) operating the unit in the extended position or 3) using a lithium battery.
SECTION II: OPERATING CONTROLS ON / Volume : To turn the unit on, push this button. Upon turn on, the volume defaults to HIGH. Pushing the button a second time changes the volume to MEDIUM. Pushing the button a third time MUTES the volume. Additional pushes of this button cycle the volume through HIGHMEDIUM-MUTE. OFF: To turn the unit off, push this button.
SECTION III: VISUAL AND AUDIBLE INDICATORS Gain Level Indicator: The gain range is indicated by a 4-segment LCD as shown in Figure 4: L (Low), M (Medium), H (High) and XH (Extra High). Upon turn on, the gain defaults to M (Medium). Each press of the UP or DOWN arrow buttons will cause the gain level indicator to change accordingly. Figure 4: Gain Level Indicators Battery Level Indicator: The battery level is indicated by a 4-segment LCD indicator, as shown in Figure 5.
SECTION IV: CONNECTORS AND ACCESSORIES Headphone Jack: The headphone jack is located on the side of the unit near the face of the locator. Headphones are optional and may be purchased from Schonstedt as an accessory. The headphone jack is monaural. Standard stereo headphones may be used, but they will produce sound in only one ear. When the headphones are plugged in, the speaker sound will be muted, but the ON/Volume button still controls the volume of the headphones.
SECTION V: BATTERY REPLACEMENT The GA-92XTd is powered by one 9-volt battery. The battery is located in the handle of the instrument and can be accessed by turning the screw counterclockwise. To remove the battery, tilt the unit so that the handle is pointing down, and the battery will slide out. When replacing the battery, look at the outside of the battery door for the proper battery orientation. As a safety measure, the unit will not turn on if the battery is not inserted correctly.
SECTION VI: OPERATING RECOMMENDATIONS AND APPLICATION NOTES Search Procedure Turn the instrument ON. The gain defaults to Medium (M). Grasp the locator, as illustrated in Figure 10. Since the upper sensor is located near the handle of the instrument (especially if it is being used in the collapsed position), wristwatches may produce unwanted changes in the audio signal and in the meter indication. Therefore, watches should be removed.
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.
is much weaker than the signal from a larger target, such as an 18-inch length of 3/4 inch rebar which can be located at depths up to 8 feet. Figure 14: Decreasing gain Eliminates Unwanted Signals Strongly Magnetized Markers A strongly magnetized marker that is at or near the surface will provide a weaker indication on both sides of the marker, and that could be mistaken for the marker.
Correct Stake Orientation When placing stakes, correct orientation is important. For checking purposes, the orientation of the pin relative to the locator is shown in Figure 16. Check the pin with one orientation. Then rotate the pin 180°. The orientation that gives the largest reading is the one that should be used. This reading should be positive in the Northern Hemisphere and negative in the Southern Hemisphere. An iron pin has two types of magnetization.
The GA-92XTd can also be used to precisely locate the metal handles or reinforcing bars on septic tank covers at depths of up to 4 feet. Figure 19: Signal Patterns Provided by Septic Tank Covers Locating and Tracing Barbed Wire You can often trace barbed wire (from old fence lines) buried just beneath the surface. Even if the wire is only a trail of rust, it can still be detected near the surface. Tip the locator a little lower than usual - but not parallel with the ground.
Searching Areas along a Chain Link Fence Searching in the vicinity of a chain link fence requires a reduced sensitivity setting and some control over the orientation of the locator. As illustrated in Figure 22, position the locator horizontally with its long axis perpendicular to the fence. This insures that the upper sensor is kept away from the fence.
Locating Cast-Iron Pipes As illustrated in Figure 25, cast-iron pipes produce the strongest magnetic signals at their joints. Figure 25: Signal Patterns Provided by Cast-Iron Pipes After an initial sweep search identifies the general direction of the pipe, the steel pipe joints or transition points can be more accurately traced by the following procedure: 1. 2. 3. 4. 5. Set the Sensitivity control to maximum (XH indication). Hold the locator vertically approximately 1 to 1-1/2 feet above the surface.
Locating Ordnance and Weapons The versatile, lightweight, cost-effective GA-92XTd is also designed to aid EOD technicians and law enforcement officers during area search operations. Figure 27: Basic Signal Patterns from Vertical and Horizontal Targets Help to Determine Target Orientation. Figure 28: A 175mm Projectile can be located up to 3 feet deep. Figure 29: An 81mm Mortar can be located up to 10 inches deep. Figure 30: MK81 Low Drag Bombs can be located up to 7 feet deep.
Other Notes 1. A burbling sound indicates the presence of an energized power line. influence the meter indication unless it is associated with a magnetic structure. This will not 2. The instrument will not respond to non-ferrous metals, such as gold, silver, copper, brass and aluminum.
SECTION VII: SPECIFICATIONS (Specifications subject to change without notice) Output: Audio: Signal increases or decreases in frequency with signal strength (gradient field intensity). Audio frequency range: 30 to 4000 Hz. Visual: Expanding bar graph and +/- signs indicates polarity and signal strength. Digital readout shows gradient field intensity expressed in milligauss (mG).
SECTION IX: WARRANTY / SERVICE INFORMATION Limited Warranty: Schonstedt Instrument Company (Schonstedt) warrants each product of its manufacture to be free from defects in material and workmanship subject to the following terms and conditions. The warranty is effective for 7 years* after the shipment by Schonstedt to the original purchaser. Please complete the warranty registration card and send back to Schonstedt Instrument Company.
