Kellyco SOVEREIGN GT User Manual

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Kellyco SOVEREIGN GT User Manual Manual pdf 13 page image

p187.6. Discrimination Control – ContinuedThe Sovereign GT uses the electrical conductivity of the object to determine the type of metal detected,and based upon the Disc control setting, will either ignore or accept the object. The most effective wayto demonstrate this is to consider a number of objects, all of varying conductivity, placed in order ofconductivity on the ground. (see figure 12).Turn the Disc control further clockwise and objects of greater conductivity will be ignored. If the Disccontrol is set to ignore the pull-tab, this will mean that all objects having a similar or lower conductivitythan the pull-tab will be ignored, while objects of higher conductivity will still be accepted (see figure 13).Figure 13 shows some common objects and where the Disc control would have to be set to ignore them.As a general rule, the two objects treasure hunters most commonly wish to ignore are aluminium foil andpull-tabs. As can be seen in Figure 13, both of these objects cover a significant range on the Disccontrol. The conductivities of objects that the user wishes to accept or ignore often overlap, so - setting theDisc control to ignore both foil and pull-tabs will also ignore a large amount of valuable non-ferrous objectsincluding some coins, rings, and other jewellery which have conductivity levels between these junk items.Example: If hunting for thin rings of white gold, with the Disccontrol set to position 4 (see figure 14), some types of aluminiumfoil will also be detected. To avoid old pull tabs, but detect brassbuttons and copper coins, the Disc control would need be sethigher (approximately at number 13).At this setting most fine white gold rings, foil, and some yellowgold rings will also be ignored. With experience, setting the Disccontrol to ignore most unwanted targets (in combination with theNotch control) will become second nature and you will develop apreferred setting for different sites.www.minelab.comFigure 14- Disc controlFigure 12 - Target conductivityFigure 13- Discriminating targets based on conductivitywww.minelab.comp19Figure 15 - Ignoring targets using the Notch controlFigure 16 - Ignoring targets using the Disc and Notch controls7.7. Notch Variable ControlLocated on the centre left of the control panel, the Notch control is used in combination withthe Disc control to discriminate against, or ignore, certain metal objects. As with the Disccontrol, this is continuously variable and features numerous graduations as a guide tosetting the control.The main difference between the Notch and Discrimination controls is that Discriminationsets a continuous band of discrimination, whereas the Notch selects a short segment of discrimination whichcan be moved up or down the scale of conductivity.Note: The Notch control will only be active, if set to a higher or more clockwise level than the Disc control.As the Notch control is turned further clockwise, objects with a conductivity, within the width of its band, willbe ignored. Turning the Notch control to ignore the pull-tab will mean that only non-ferrous objects having asimilar conductivity to the pull-tab will be ignored while all other non-ferrous objects of different conductivityare still accepted.Note, in Figure 15 the ferrous objects are being ignored due to the Disc. setting on zero.When using the Notch and Disc controls in combination, most unwanted objects can be successfully ignored(see Figure 15). Turning the Notch control to ignore the pull-tab and the Disc control to ignore the aluminiumfoil will set up the Sovereign GT to ignore most pull-tabs and aluminium foil while still detecting most valuablenon-ferrous objects (see figure 16).Note: Different pull-tabs may require a slight movement of the Notch setting. Obviously, if the amount ofpull-tabs is not numerous, then you may decide to leave the notch at minimum, which removes the risk ofdiscriminating a valuable object.TIP: It is very important that you recognize the conductivity level of common coins, jewellery and trash targetsso that you know what items will be accepted or rejected at various levels. We recommend that you read andfollow Chapter 9 - Practising the Controls to be familiar with common targets in your area.NOTE: If operating with Threshold, the operator will hear that a target has been discriminated or notched outby the threshold going null (silent) and can determine if it was discriminated or notched by the tone of thereturning threshold ie: if the threshold returns in a deep tone, the object was discriminated and if thethreshold returns in a higher pitch it was notched out.