Schonstedt GA-92 XTd User manual

InstructionManual



Model

GA‐92

XTd

™

Magnetic

Locator







Manufactured

By

Schonstedt

Instrument

Company
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100

Edmond

Road,

Kearneysville,

WV

25430

(304)

725‐1050,

Fax

(304)

725‐1095


Web:

www.schonstedt.com

E‐mail:

[e-mail]


Made in

USA





Preface

TheGA‐92XTd™MagneticLocatorisaproductofoversixtyyears’experienceinproducingtheworld’s
finestflux‐gatemagnetometersandmagneticdetectorsforaerospace,militaryandcivilian
applications.TheGA‐92XTd™incorporatestheknowledgeobtainedfrommanufacturingunderthe
mostrigidqualitycontrolstandards.TheheartoftheGA‐92XTd™isitspatentedSchonstedtHeliFlux™
magneticfieldsensors.Thesesensors,acknowledgedtobetheworld’sfinest,makepossiblethe
unequalledperformanceofthelocator.

February2017


2

TableofContents

SECTIONI:INTRODUCTION...................................................................................................................3
SECTIONII:OPERATINGCONTROLS
ON/Volume..............................................................................................................................5
OFF............................................................................................................................................5
GAIN..........................................................................................................................................5
SECTIONIII:VISUALANDAUDIBLEINDICATORS
GainLevel..................................................................................................................................6
BatteryLevel.............................................................................................................................6
SignalStrengthandPolarity......................................................................................................6
SECTIONIV:CONNECTORSANDACCESSORIES
HeadphoneJack.........................................................................................................................7
HeadphoneJackPlug.................................................................................................................7
SECTIONV:BATTERYREPLACEMENT....................................................................................................8
SECTIONVI:OPERATINGRECOMMENDATIONS&APPLICATIONNOTES
SearchProcedure.......................................................................................................................9
BasicSignalPatterns.................................................................................................................10
StronglyMagnetizedMarkers...................................................................................................11
CorrectStakeOrientation.........................................................................................................12
LocatingManholes,SepticTanksandWellCasings..................................................................12
LocatingandTracingBarbedWire............................................................................................13
SearchingAreasalongaChainLinkFence................................................................................14
LocatingValveBoxes.................................................................................................................14
LocatingCast‐IronPipes............................................................................................................15
LocatingSteelDrums................................................................................................................15
LocatingOrdnanceandWeapons.............................................................................................16
OtherNotes..............................................................................................................................17
SECTIONVII:SPECIFICATIONS..............................................................................................................18
SECTIONVIII:TECHNICALSUPPORT.....................................................................................................18
SECTIONIX:WARRANTY/SERVICEINFORMATION...............................................................................19
SECTIONX:PARTSDIAGRAM...............................................................................................................20

ImportantNotice

Schonstedt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bedefective
withinsevenyearsofpurchase.Schonstedtshallnotberesponsibleforanyinjurytopersonsor
property,directorconsequential,arisingfromtheuseofanyinstrument..

3

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.
Inaddition,thepolarityofthesignalstrengthisshownasa+or–signonthedisplay,anddetermines
theside(rightorleft)onwhichthebargraphisdisplayed.Althoughmostobjectscanbelocated
usingtheaudioindicationalone,simultaneoususeoftheaudioandvisualresponseswillprovide
additionalinformationtohelpyoupinpointatargetanddetermineitsorientation.

Figure1illustratesanapplicationoftheGA‐92XTd™locatorinwhichitisusedtodetectaniron
markerusedforpropertylineidentification.Asshown,themagneticfieldoftheironmarkeris
stronger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‐92XTd™isdesignedsothatthefrequencyoftheaudiotoneincreases
asthedetectedsignalstrengthincreases.Asaresult,thefrequencyoftheaudiooutputishigher
thantheidlingfrequency(~30Hz)thatexistswhenthesignalstrengthisapproximatelyzero.The
largersignalstrengthalsocausesthebargraphdisplaytopeakineitherthepositiveorthenegative
direction.


Figure1:DetectingMagneticFieldofanIronMarker


4

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.

TheGA‐92XTd™hasaninternaldetentmechanismtokeeptheunitineitherthefullyextended(open)
orfullyretracted(closed)position.Toextendtheunit,grasptheloopedendofthelocatorandpull
untiltheshaftlocksintoplace.Toreturntheunittotheclosedposition,pushtheloopedendback
intotheshaft.Theunitwilllockintoplace.


5

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HIGH‐MEDIUM‐
MUTE.


OFF:Toturntheunitoff,pushthisbutton.


GAIN():Thesensitivityoftheunitcanbe
increased(todetectsmallerobjectsatgreater
depths)ordecreased(todetectlargerobjectsat
smallerdepths)byadjustingthegainupordown
pushingtheUPorDOWNarrowbuttons.









Figure3:GA‐92XTd™FacePlate

6

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.Whenallfoursegmentsareblack,thevoltagelevelisbetween100%and75%.Asthe
voltagedecreases,thenumberofblacksegmentsdecreases.
Batterylifevarieswithusageandtheambienttemperature.
Coldtemperaturesreducebatterylife.Lowtemperatures
mayresultinonlytwoorthreesegmentsbeingblack.This
couldbetemporary,andallsegmentswillchangetoblackas
thetemperatureincreases.

Figure5:BatteryVoltageStatus
Indicators


SignalStrengthandPolarityIndicator:Thesignalstrength,definedasthedifference(ordeltaΔ)
betweenthemagneticfielddetectedatthetopandbottomsensors,isshownasanumerical
indicationinmG(milligauss)units,isprecededbythepolarityofthesignal(+or‐),andisfollowedby
theΔsymbol(toemphasizethatitrepresentsa“difference”betweenthetwoendsofthesensor
array).

Inaddition,thesignalstrengthisshownina
semi‐circularbargraph,withmorebars
indicatingastrongersignal.Dependingon
polarity,thebargraphwillswitchtothe+
(right)or–(left)side.Thesignalstrengthis
alsoindicatedbythefrequencyoftheaudio
signal;ahigheraudiofrequencyindicatesa
strongersignal.

Figure6showsthevariousvisualindicationsof
signalstrengthandpolarity.




Figure6:SignalStrengthVisualIndications




7

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.








Figure7:Headphones




HeadphoneJackPlug:AHeadphoneJackPlughasbeenincluded
withthisproduct.Itisrecommendedthattheplugremaininserted
intothejackanytimethatheadphonesarenotinuse.Thisaidsin
makingtheinstrumentmorewater‐resistant.


Figure8:HeadphoneJackPlug


8

SECTIONV:BATTERYREPLACEMENT

TheGA‐92XTd™ispoweredbyone9‐voltlithiumbatterythathasashelflifeoftenyears,andit
providestwicetheoperatinglifeofanalkaline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.Youshouldneverhaveto
forcethebatterydoorclosed.Ifthebatterydoesnotseemtobegoinginalltheway,removethe
battery,reverseitsorientationandthenreplaceit.


Figure9:ViewofBatteryDoorandCompartment



9

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.Because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.Keepthe
locatorawayfromyourshoesastheymaycontainmagnetic
material.Toobtainamaximumcoveragearea,sweepthe
locatorfromsidetoside.Whenthelocatorcomeswithinrange
ofanironobject,thesignalstrengthwillpeak,thefrequencyof
theaudiosignalwillpeak,thebargraphwillexpandinthe
positiveornegativedirection,andthedigitalreadoutwillpeak.
ThisisshowninFigure11.
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Figure10:SearchingwiththeLocator
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Figure11:IllustrationofVisualIndicatorswithin
RangeofanIronObject

NOTE:Thenumberofbarsshowninthebargraph,thenumber
displayedinthedigitalreadout,andthefrequencyoftheaudio
signalwillalldependonthesignalstrength,whichisaffectedby
thetypeofironobjectdetected,itsorientation,andthegain
setting.
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10

BasicSignalPatterns
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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.
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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.
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Figure12:SignalsfromVerticalandHorizontalTargets
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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8inchescanbelocatedvery
preciselyusingthistechnique.
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Figure13:"X"PatternprovidesPrecisionLocating
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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