Thebalanceindicator“I-I”regarding thesoil backgroundlightsup on the1st line
attherightside andshowsifthedeviceisbalanced whenthesignalismissing.When
thedeviceisbalanced andtherearenometalobjectswithinthereachoftheantenna,
theindicatorshouldhavetwoequallevelstotherightandtotheleftofthe“ - ”symbol.If
thereisadifferencebetweenthetwolevelsthedeviceshouldbebalanced again,by
pressingthe“CLEARGND”button.Thelevelofthetwocolumnsofthebalanceindicator
showsalsothepowerofthesignalfromthesoil.Thehigherthelevel,thestrongerthe
signalandthustheoperatorcangetorientatedwhichdiscriminationmode touse–when
thesignalisweak(lowindicatorlevel)itisrecommended toworkat“DISCR.1”,whet itis
at averagelevel-“DISCR.2”,andathigh levels(strong signalfromthesoil)-“DISCR.3”
Whenthe“SELECT”buttonispushed atadiscriminationmode andmovementof
thearrow(>)at1st line,thetypeofdiscrimination canbechosen “DISCR.1”,“DISCR.2”
or“DISCR.3”.Ifthediscriminationtypeisnotchanged,afterasecondpushing ofofthe
“SELECT”button,thearrow(>)will positionitselfatthe3dlineand“ggt2”and “ggt3”will
lightup.Bythemthepossiblerangeofsignalsischosenwhenitisbalancedtothesoil
conditions.“ggt2”-at “DISCR.2”,and“ggt3”at“DISCR.3”.
“DISCR.1”isanappropriatemode whenthesoil backgroundisdisparaginglysmall
anddoesnotsignificantlychangethesignal,receivedwhenametalobjectisdetected.
-Whenthesall ismoremineralised,ittransmitsasignal,thatcanincreasesignificantly,
especiallywhentheframeisclosetothegroundsurface.Thehighlymineralised soils,
especiallyiftheyhaveahigh moisturecontent, additionallyincreasethetotalsignalandit
canhavehigh values.Ifthereisanon-ferrousmetalinthistypeofsoil,itwill invertthe
overall signaltomorepositivevalues,thusthesensitivitywill decreasebecauseofthe
soil background.
-Forcaseslikethatthe“DISCR.2”mode isappropriate,wherethe average background
levelsareassumed tobeequaltozeroandeachinstantincreaseofthesignaldetected
fromametalobjectwill besignalised.
Thesensitivityatthismode isgreater,becausethesignalappearsbeforethesoil
backgroundistotallycompensated.Forexampleifthesoil backgroundis“C1=-7”,in
caseofincreasing to -6,-5 thedevicewill makeasignal,whileatanormal
discrimination,thesignalshouldincreaseover0,inorderforasoundsignaltoappear.
Somewhataflawofthismode is,thatitcan giveasignalwhenevenwhena
ferrousmetalisdetected,withitsowncoefficient,morepositivethanthatofsoil.For
exampleifthesignalfromthesoil is -7,and thatofmetalis -3,thedevicewill makea
