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Instruction ManualModel GA-52CxMagnetic LocatorManufactured BySchonstedt Instrument Company100 Edmond RoadKearneysville, WV 25430(304) 725-1050Fax (304) 725-1095Web: www.schonstedt.comE-mail: [email protected] in USAPrefaceThe GA-52Cx Magnetic Locator is a product of over 60 years’ experience in producing the world’sfinest flux-gate magnetometers and magnetic detectors for aerospace, military and civilianapplications. The GA-52Cx incorporates the knowledge obtained from manufacturing under themost rigid quality control standards. The heart of the GA-52Cx is its patented SchonstedtHeliFlux magnetic field sensors. These sensors, acknowledged to be the world’s finest, makepossible the unequaled performance of our locators.February 2017Seattle 425-771-7776 Tacoma 253-922-6087Portland 503-641-3388 Salt Lake City 801-878-9763Las Vegas 702-586-1152 St. George 702-586-1152Boise 208-369-4388www.KukerRanken.com

Table of ContentsSECTION I: OPERATIONIntroduction . 3Turn-On, Volume and Sensitivity Settings . 4Search Procedure . 4SECTION II: APPLICATION NOTESBasic Signal Patterns . 5Strongly Magnetized Markers. 6Locating Manholes, Septic Tanks and Well Casings. 7Locating Objects under Snow or Water . 8Locating and Tracing Barbed Wire . 8Searching Areas along a Chain Link Fence . 9Locating Valve Boxes. 10Locating Cast-Iron Pipes. 10Locating Steel Drums . 11Additional Applications . 12Other Notes . 12SECTION III: MAINTENANCEReplacement of Batteries . 13Troubleshooting Guide . 14SECTION IV: SERVICE INFORMATION. 15SECTION V: SPECIFICATIONS. 15SECTION VI: PARTS DIAGRAM . 16SECTION VII: LIMITED WARRANTY. 17Important NoticeSchonstedt believes the statements contained herein to be accurate and reliable;however their accuracy, reliability or completeness is not guaranteed.Schonstedt's only obligation shall be to repair or replace any instrument proven to bedefective within seven years of purchase. Schonstedt shall not be responsible for anyinjury to persons or property, direct or consequential, arising from the use of anyinstrument.-2-

SECTION I: OPERATIONIntroductionThe GA-52Cx magnetic locator detects the magnetic field of ferromagnetic objects. It respondsto the difference in the magnetic field between two sensors that are spaced approximately 20inches apart. This difference is referred to as the “signal strength” throughout this manual andis represented in the instrument by an audio tone.Figure 1 illustrates an application of the GA-52Cx locator in which it is used to detect an ironmarker used for property line identification. As shown, the magnetic field of the iron marker isstronger at sensor A than it is at sensor B. This creates a signal strength that is larger than zero(which would occur when the field strength is the same at both sensors).The audio response of the GA-52Cx is designed so that the frequency of the audio toneincreases as the detected signal strength increases. As a result, the frequency of the audiooutput is higher than the idling frequency that exists when the signal strength is approximatelyzero.Figure 1: Detecting Magnetic Field of an Iron Marker-3-

Turn-On, Sensitivity and Volume SettingsSet the On-Off/Sensitivity Control to position 2 and adjust the Volume Control until the idlingtone reaches a desired level. The sensitivity of the unit can be increased (to detect smallerobjects at greater depth) or decreased (to detect larger objects at smaller depths) by adjustingthe On-Off/Sensitivity Control. Setting the Sensitivity Control to position 2 provides what isreferred to as the “Normal Operating Range.” Positions 3 to 5 increase the sensitivity; position 1decreases the sensitivity.The locator can be oriented in any direction without producing a significant change in thefrequency of the tone from its idling frequency.When using headphones, the Volume Control has no impact on the output level of the audiosignal.Figure 2: Sensitivity Set for Normal Range (position 2)Search ProcedureTurn the instrument on, set the sensitivity control to position 2(Normal Range), and grasp the locator as illustrated in Figure 3.Because the upper sensor is located near where the locator isusually held, wrist watches may produce unwanted changes inthe tone’s frequency. Remove your wrist watch or hold thelocator in the other hand. Keep the locator away from yourshoes since they may contain magnetic material.To obtain the maximum area of coverage, the locator should beswept from side-to-side. When the locator comes within rangeof an object, you will hear an increase in the frequency of theoutput signal.Figure 3: Searching with the Locator-4-

SECTION II: APPLICATION NOTESBasic Signal PatternsFigure 4: Signals from Vertical and Horizontal TargetsAfter you have detected the presence of a target, hold the locator vertically and slowly move itback and forth in an "X" pattern while listening to the audio response. The audio peak will occurwhen the locator is directly over a vertical target, or it will occur over the ends of a horizontaltarget. The "X" pattern, as shown in Figure 5, is ideal for pinpointing small objects. By using thistechnique, a 1-1/4 inch PK nail buried up to 12 inches can be precisely located.Figure 5: “X” Pattern Provides Precision Locating-5-

If you are looking for a corner marker and detect two or more signals in the same general area,raise the locator several inches above the ground or decrease the gain setting. Any signal thatdisappears when the locator is held higher or the gain is decreased is probably coming from asmaller target. As shown in Figure 6, the signal from a rusty bolt or other small item decreasesfaster with distance than the signal from a larger target, such as an 18-inch length of 3/4 inchrebar that can be located at depths up to 9 feet.Figure 6: Raising the Locator Eliminates Unwanted SignalsStrongly Magnetized MarkersA strongly magnetized marker at ornear the surface may provide locationinformation that is misleading.The heavy line in Figure 7 representsthe variations in tone frequencieswhen the locator is moved over themarker. When moving the instrumentfrom A to B, the frequency of the toneincreases and then decreases suddenlyat B.From just beyond B thefrequency of the tone increasessharply, becomes very high directlyover the marker and decrease justbefore reaching C. From C to D thepattern is the reverse of that from A toB. It is obvious that the locator mustenter the B-C region. Otherwise themarker might be assumed to bebetween A and B, or C and D.Figure 7: Signal Pattern from aStrongly Magnetized MarkerThis phenomenon is explained by the fact that the locator is sensitive to the magnetic fieldcomponents parallel to its long axis. At points B and C the field is perpendicular to the locator sono high frequency is produced at these points.-6-

Locating Manholes, Septic Tanks and Well CasingsThe magnetic field is strongest at the edge of a shallow manhole cover. You can easily trace theedges of covers near the surface. The locating depth for manhole covers ranges up to 10 feet.The great length of a well casing provides a strong field at the surface that makes it easy tolocate casings buried up to 18 feet deep.Figure 8: Locating Manhole CoversFigure 9: Locating Water Well CasingsThe GA-52Cx can be used to precisely locate the metal handles or reinforcing bars on septic tankcovers at depths of up to 4 feet.Figure 10: Signal Pattern Provided by Septic Tank Covers-7-

Locating Objects under Snow or WaterThe locator can be used in flooded areas, but keep the electronic unit out of the water.Snow poses no problem. Thrust the locator into the snow as deep as necessary to locate thetarget.Figure 11: Locating Objects under Snow or WaterLocating and Tracing Barbed WireYou can often trace barbed wire (from old fence lines) buried just beneath the surface. Even ifthe wire is only a trail of rust, it can still be detected near the surface. Tip the locator a littlelower than usual (but not parallel with the ground).First, examine trees for bench marks and bits of embedded barbed wire. Then hold the locatorparallel with the direction of the wire.Figure 12: Tracing Barbed Wire from Old Fence Lines-8-

Searching Areas along a Chain Link FenceSearching in the vicinity of a chain link fence requires a reduced sensitivity setting and somecontrol over the orientation of the locator. As illustrated in Figure 13, position the locatorhorizontally with its long axis perpendicular to the fence. This ensures that the upper sensor iskept away from the fence.Figure 13: Searching in the Vicinity of a Chain Link FencePerform the search by slowly moving the locator forward along the fence while also moving it tothe right and to the left. As you move forward, this technique will allow you to search an areaseveral feet wide. Listen for an abrupt drop in the signal (as shown by the null in Figure 14) thatwill occur when the lower sensor, located 1-5/8 inches from the end of the locator, is directlyover the stake. Any variation in the position of the locator will produce an abrupt rise in thefrequency of the signal.Figure 14: Placement of Locator While Searching Along a Chain Link Fence-9-

Locating Valve BoxesBoth the valve and its casing, when iron, provide strong magnetic fields that make them easy tolocate. Plastic enclosures containing magnets are easily located at depths of 10 feet or more.Figure 15: Locating Valve Boxes and CasingsLocating Cast-Iron PipesAs illustrated in Figure 16, cast-iron pipes produce the strongest magnetic signals at their joints.Figure 16: Signal Patterns Provided by Cast-Iron Pipes- 10 -

After an initial sweep search identifies the general direction of the pipe, the steel pipe joints ortransition points can be more accurately traced by the following procedure:1. Set the sensitivity control to maximum.2. Hold the locator vertically approximately 1 to 1-1/2 feet above the surface.3. Walk without turning or tilting the locator.4. Mark the locations where the maximum signal levels occur.5. Return to an area of maximum signal strength and hold the locator several inches abovethe surface. The sensitivity will probably have to be reduced during this second pass.Four-inch pipes can be located at depths of up to 10 feet.Locating Steel DrumsAs shown in Figure 17, the GA-52Cx’s signal pattern will vary depending on the vertical orhorizontal orientation of the drum and how deep it is buried. A 55 gallon drum can be locatedat depths of up to 10 feet.Figure 17: Signal Patterns Provided by Steel Drums- 11 -