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Page 4

TDI SL 

Owner’s Manual

the floor. If the instrument fit feels uncomfortable, readjust
clevis/lower rod length with spring clip button and cam-
lock so that search coil can be held near the floor without
stooping over. 

6.

Remove the protective paper from the two black arm cup
foam pads. Carefully align pads on the inside of the elbow
cup, one on each side of the center rod, and press firmly into
place. 

7.

Adjust the elbow cup strap so that it is loose enough for you
to slide your arm in and out without loosening each time
you want to set the detector down. The elbow cup strap pro-
vides extra leverage and control. However, some prefer not
to use it. 

8.

Install the battery pack; see the next section for information
on batteries and charging.

Summary of Contents for TDI SL

Page 1: ...TDI SL White s Electronics Inc Sweet Home Oregon USA Building the World s Finest metal detectors for over 60 years ...

Page 2: ...Principles of Pulse Induction 7 Controls Threshold 9 Power gain 9 Pulse Delay 10 Target Conductivity 11 Ground Balance 12 Frequency 13 TDI In Depth Ground Balancing 14 Audio 14 Pulse Delay 17 Dual field coil 18 Dealing with Noise 20 Specifications 22 Warranty 23 Code of Ethics Back Cover ...

Page 3: ...to one of the adjustment holes in the curved S rod Turn cam lock to secure The second or third adjustment holes are suitable for average sized adults 4 Wind the loop cable around the rod assembly first revolu tion over the top of the rod all the way to the top of the curved S rod about five revolutions Use the black cable retainers one near the loop and one near the top of the curved S rod to hold...

Page 4: ... arm cup foam pads Carefully align pads on the inside of the elbow cup one on each side of the center rod and press firmly into place 7 Adjust the elbow cup strap so that it is loose enough for you to slide your arm in and out without loosening each time you want to set the detector down The elbow cup strap pro vides extra leverage and control However some prefer not to use it 8 Install the batter...

Page 5: ... the cradle and plugged into a wall socket simply drop the NiMH pack into the cradle An LED indicates the sta tus of the charge cycle when the LED turns off the charge cycle is complete and the charger will automatically switch to a trickle mode A typical recharge time of a depleted NiMH pack is 1 2 hours It is normal for NiMH batteries in storage to slowly lose their charge over time be sure to t...

Page 6: ...eve a faint background hum 6 With the coil on the ground no motion increase the Gain until the audio begins to chatter Back off slightly for a rea sonably smooth threshold 7 Optional adjust the Frequency offset to minimize the amount of chatter 8 Using a spot free of targets bob the coil up down and adjust the Ground Balance control to minimize the audio response 9 For most nugget hunting set the ...

Page 7: ... detector the best choice for certain kinds of hunting in bad ground where many VLFs simply won t work There is no traditional discriminator in PI detectors although there is some ability to discern certain types of metals The decay response varies with target conductivity plus other characteristics so that low conductive targets have a fast decay and high conductive targets have a slow decay The ...

Page 8: ...e such as small nuggets jewelry and small iron Target conductivities above the ground balance point produce a nega tive response for which TDI assigns a low tone These targets are generally high conductive such as silver coins relics and large iron The Target Conductivity switch can be used to eliminate either class of targets or to accept them all Care should be used with this feature as it is no...

Page 9: ...e prefer silent search to prevent audio fatigue If you choose to do this increase the threshold to the point where you can hear the threshold tone then slowly back off until it is barely inaudible Reducing the threshold any more than necessary requires stronger target signals to produce an audio response Other controls including Gain Ground Balance and Frequency offset are best adjusted with an au...

Page 10: ...ponential decay Regardless of conductivity the response is strongest at low sample delays and weaker at higher delays However targets of low conductivity or that are thin will decay faster than highly conductive or thick targets See the Principles of Pulse Induction section for more details Smaller gold nuggets fall in the former category so nugget hunters will want the Pulse Delay set as low as p...

Page 11: ...and large gold nuggets are usually high but where the tran sition occurs depends on the composition of the gold alloy Be mindful that searching in low conductivity mode could elimi nate very large nuggets if any happen to be in the area1 The same is true for relics and jewelry Many bullets but tons and most buckles register as high conductors but cuff but tons often respond as low conductors Most ...

Page 12: ...chnique is to start with the GB set intentionally too low say 5 then pump the coil and increase the GB until the high tone begins to transition to a low tone If the Pulse Delay control is changed you will probably need to re adjust the Ground Balance setting In addition if you begin to hear ground noises false signals as you sweep the coil you should check the ground balance There are some cases w...

Page 13: ...her metal detectors being used nearby This interference is recognized by a warbling or repetitive pulsing of the audio threshold and can mask target signals If you are experiencing interference adjust the Frequency control for minimal chatter Adjustments should be done in small steps with a few seconds between each adjustment to see if the TDI settles down If you cannot deal with interference with...

Page 14: ...onductivity which gives TDI some ability to discriminate In rare cases a target might fall so close to the GB point that it gives either no response at all or a double tone response Because ground balance is achieved using a subtraction method there is a slight loss of depth any time ground balance is on Some ground notably neutral beach sand is mild enough that no ground balance is needed In such...

Page 15: ...o response is high for all targets In cases where you have determined that you definitely need only one of the conductivity modes and not the other you will often find that switching to that mode reduces the amount of audio noise chatter and allows you to run a higher gain To better illustrate this let s use a strictly inaccurate but useful dia gram The following is a representation of the audio r...

Page 16: ...g in the Low mode If you primarily want to hunt coins or relics then you will not lose much running in the High mode Be mindful that All is required for ground balancing because that is the only mode that gives you both tones Threshold also has an effect on how much noise gets through to the audio A moderate threshold lets some of the noise through anything in the gray region is suppressed In this...

Page 17: ...t sensitivity can be markedly reduced and weaker targets completely eliminated However Gain can be increased to counter this though the net result is still likely to be less sensitivity than an optimally adjusted threshold Pulse Delay Sampling as close as possible to the end of the transmitted pulse gives the highest sensitivity to all metal targets regardless of their size or conductivity As the ...

Page 18: ...cannot be used Notably wet salt soil such as a saltwater surf zone behaves like a low conductor target and will respond regardless of the Ground Balance setting Increasing the Pulse Delay to about 15 s will eliminate wet salt response However as you move out of the surf zone onto dry sand remember you can reduce the Pulse Delay to maximize sensitivity as dry salt sand does not cause a problem Area...

Page 19: ...weep technique is important with any detector and the DF coil adds a slight twist Round coils tend to have a coni cal pattern of sensitivity as illustrated below As such coverage at maximum depth is less than the size of the coil so it is always recommended that successive sweeps are overlapped by about 50 The DF coil has an additional inner coil which has its own conical detection pattern Since t...

Page 20: ...ctors have wideband receivers they are more prone to noise and interference than narrowband VLF designs There are a few strategies for dealing with noise First TDI has a Frequency Offset control that slightly adjusts the overall pulse rate With the Threshold and Gain turned up to the point of mild chatter make very small incremental adjustments to the Frequency control to minimize the chatter Some...

Page 21: ...I sources If you cannot minimize noise with the Frequency control then turning down the Gain or Threshold is your best bet Excessive chatter will easily mask targets plus results in audio fatigue It is better to trade off sensitivity for smooth audio so you can hear the targets ...

Page 22: ...3 lbs 7 5 DF coil 3 5 lbs 12 DF coil Length 43 48 inches adjustable Batteries 8 AA NiMH alkaline Battery life 5 6 hours typical2 Warranty 2 years transferrable Customer Support Questions concerning your TDI SL There are three ways to contact us Internet http whiteselectronics com support html Phone 1 800 547 6911 US 0044 1463 223456 UK Or mail us White s Electronics White s Electronics 1011 Pleasa...

Page 23: ... Card is filled out and returned to the factory address by your dealer soon after origi nal purchase for the purpose of recording this information and keeping you up to date regarding White s ongoing research development The warranty does not cover damage caused by accident misuse neglect alterations modifications unauthorized service or prolonged expo sure to corrosive compounds including salt Du...

Page 24: ...dispose of any and all trash and litter found 5 Whenever possible return identifiable property to its rightful owner 6 Never destroy historical or archaeological treasures 7 Appreciate and protect natural resources wildlife and property both public and private 8 Act as an ambassador for the hobby be thoughtful considerate and courteous at all times White s metal detectors are proudly designed buil...

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