Whites TDI Pro in Silver Country [including Infinium Comparison]

[Jim Hemmingway]

White's TDI Pro in Silver Country [including Infinium Comparison]

Please click on the attached link to view an updated version of the TDI / Infinium comparison report located in the "Canada" sub-forum here on TNET... thankyou... Jim.

http://www.treasurenet.com/forums/c...ntry-infinium-comparison-february-2011-a.html

 

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[TerryC]

Re: White's TDI Pro in Silver Country [including Infinium Comparison]

Very sorry Jim (H), that I haven't replied till now. Yes, I did buzz out to the "Outback" of AZ. Liked the Rich Hill and Lynx Creek (Prescott) areas so much, I am now an official AZ resident! I like their attitude over there. I have been finding lots (Ok, some exageration ) of gold in AZ. I will be honest, though, nothing under the GB2 or Gmt, YET! Those little buggers have so far eluded me. But my time will come! The law of averages says so! Thanks for the kindly comments on my video(s) but it is clear my experiences don't come CLOSE to yours. You are always a good read. Tnx. TTC

 

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[TerryC]

Re: White's TDI Pro in Silver Country [including Infinium Comparison]

BTW Jim, I see oldestjim posted a reply to you. Would that be THE Jim Straight of "Nuggetshooter's Bible" fame? I have several of his publications. The Nuggetshooter's Bible is next to the computer RIGHT NOW! Man, life is good! TTC

 

[Jim Hemmingway]

Re: White's TDI Pro in Silver Country [including Infinium Comparison]

Hi Terry….

I take it that you are retired and petty much free to do as you please. Same here, but indecision about relocating has kept me in Ontario, at least until I can figure out exactly what my wife would prefer. She still likes to see our children / grandchildren regularly. Arizona is a beautiful state I’d like to see, ditto for California…and soon.

Yes to your question about Jim Straight. He’s enjoyed a highly successful career in the mining and prospecting fields and has been a prolific writer over many years. He recently wrote a review of the Fisher Gold Bug Pro for the Annual Gold & Silver Edition by W&E Treasures, and he has a new book recently released. As a longtime admirer, I was understandably pleased that Jim took a moment to comment here.

As to your Goldbug2, I have a feeling you enjoy the backcountry trips whether or not gold is found with a detector. I’ve got a gold trip coming up and I’d rather find it with a detector. I guess if things don’t work out, I’ll resort to some actual work in the creek to avoid being altogether skunked. Any way you look at it, its gonna be a lot of fun…and get to see some new country…

Jim.

 

[TerryC]

Re: White's TDI Pro in Silver Country [including Infinium Comparison]

Hi Terry….

I take it that you are retired and petty much free to do as you please. Same here, but indecision about relocating has kept me in Ontario, at least until I can figure out exactly what my wife would prefer. She still likes to see our children / grandchildren regularly. Arizona is a beautiful state I’d like to see, ditto for California…and soon.

Yes to your question about Jim Straight. He’s enjoyed a highly successful career in the mining and prospecting fields and has been a prolific writer over many years. He recently wrote a review of the Fisher Gold Bug Pro for the Annual Gold & Silver Edition by W&E Treasures, and he has a new book recently released. As a longtime admirer, I was understandably pleased that Jim took a moment to comment here.

As to your Goldbug2, I have a feeling you enjoy the backcountry trips whether or not gold is found with a detector. I’ve got a gold trip coming up and I’d rather find it with a detector. I guess if things don’t work out, I’ll resort to some actual work in the creek to avoid being altogether skunked. Any way you look at it, its gonna be a lot of fun…and get to see some new country…

Jim.

Yes, Jim, I am retired.... sorta. Had to turn in the uniform (Kennedy Space center) in '07 because of severe back problems... Titanium holding it together. Ah, but I'm straying from the thread so I'll finish the story another day. I truly love getting my hands dirty in the AZ gold fields. Doing ... well... but can only handle 10 buckets of 1/2 inch meshed stuff a day... then about 3 day's rest. More work would kill me. I'm STILL off the thread... so, I'll end it here. Stay thirsty, my friend! TTC

 

[Jim Hemmingway]

Re: White's TDI Pro in Silver Country [including Infinium Comparison]

Terry…thanks for replying and I don’t mind in the least if you’re on a different subject. I visit these forums primarily for the purpose of contacting other hobbyists with similar prospecting interests. I want to hear about their ideas regarding equipment and techniques or what they’ve been doing lately. I sometimes think of the forum as an old-time western saloon where folks drop by to shoot the breeze about various topics of mutual interest…and occasionally draw their sixshooters over disagreements.

**********************************************************************************

I’d like to discuss a few of those TDI Pro “nuances” or features that were mentioned in an earlier post above. That’s in addition to an earlier discussion about VLF target ID readouts on silver ores and their placement on the TDI Pro’s ground balance scale. On that subject we noted that it is not possible to draw a direct correlation between VLF target ID readouts on high conductive silver ores to their GB point on the TDI’s GB scale. Despite silver pieces that may share a similar VLF target ID readout, these pieces may occupy radically different locations on the GB scale due to factors that may include target purity and type of inclusions, size, shape, and structure and whatever other factors come into play.

The TDI Pro has a few other features or nuances that distinguish it for prospecting applications, so lets take a quick look at them...

First, let’s compare how the TDI Pro responds to typical targets encountered while prospecting compared to the Infinium. The Infinium identifies all targets within a conductive range to roughly fringe zinc penny as low conductives producing a hi-lo signal. Hi-lo signals must be dug. Since our silver conductive range only extends to include copper penny range, we check any lo-hi signals in reverse discrimination (iron check). Any targets that dwell within a range bounded by zinc penny to copper penny will reverse their signal from lo-hi to hi-lo or possibly deeper, smaller or spongy targets may lose their signal entirely. These too must be dug to avoid missing any silver…but a portion of high conductive iron also falls into this range. A lo-hi tone in reverse discrimination in a prospecting context means high conductive iron, for example drill rods and bits, nails and spikes etc…and these signals can be ignored. So as we can see, the Infinium tones are based on conductive classification, for lack of a better description, and allow us the option of sticking with zero discrimination tones in high iron junk areas. Infinium’s automated signals permit us to evaluate signals quickly in high iron trash areas typically associated with mining camps. Of course, many elongated iron targets such as drill rods and nails may also respond with a double lo-hi signal along their lengths and these definitely indicate iron. A net result is that we cover more ground over the course of the day. That normally equates with more good finds. For this application Infinium works very effectively… whether by happenstance or by design.

By comparison, the TDI Pro’s low conductive signals as defined in the report only range up to and include roughly mid-pulltab range. Any targets in this range, including low conductive iron, must be dug. Any targets above this range are high conductives, that is to say they can signal in the high conductive tone mode, and these signals can be evaluated to see whether a definitive iron lo-hi-lo tone can be acquired. A result is that Infinium users dig some amount of iron junk above pulltab range that mostly can be identified by TDI Pro’s lo-hi-lo iron tones. On the other hand, one must manually evaluate a good portion of high conductive signals when using the TDI Pro to eliminate digging most high conductive iron in tough rocky substrates…and this is a time consuming practice over a day’s outing. But, the silver lining is that the TDI Pro’s iron tones are definitive…if you get a lo-hi-lo tone it means the target is iron, regardless of whether it falls into screwcap or silver quarter conductive range.

A second attribute or nuance of the TDI Pro, as noted in the report, is that unlike Infinium that signals on all target conductivities, the TDI Pro can eliminate signals from a selected target range on the GB scale. As an example, this means we can search for low conductive gold or silver and eliminate hearing high conductive targets such as nails.

In areas where the trash signals from torn-down buildings become overwhelming for Infinium, the TDI Pro allows one to search exclusively for low conductives. Set the ground balance to GB9, toggle the tone mode switch to low conductives, set the delay set to 10-usec, throw on a small coil to enhance target separation… and hunt away. You would be surprised to learn how effective this technique is for finding silver at reasonably good depths while eliminating most nail signals. Not too shabby for a PI unit over trashy ground I think we can all agree. The best part is that a slow dawdling coil sweep speed provides best depth while allowing one to easily separate out target signals.

A third nuance not mentioned in the report is that many of our high conductive silver pieces will respond with a hi-lo-hi tone, in fact the majority do so. Often enough silver ores will respond with a hi-lo-hi tone without adjusting the GB control from your ground balance setting. Other times we’ll have to adjust the GB control to see if we can acquire it. As with lo-hi-lo iron tones, not all high conductive silver will respond this way, and it appears to be related again to extremely tight ground balance points…. but that’s a guess. That said, this nuance might be of little or no value to gold hunters in most areas where most gold is comparatively quite small and responds pretty much as low conductives. I don’t know if high conductive gold will respond similarly to our high conductive silver because I don’t have any samples to test. I suspect strongly that it will based on sampling various other non-ferrous metals. Rather than speculate in the report, this specific topic was eliminated from the posted version.

Jim.

 

[TerryC]

Re: White's TDI Pro in Silver Country [including Infinium Comparison]

…and occasionally draw their sixshooters over disagreements.

Yeah! And it's a good thing most can't shoot straight or this would be the FORMER FORUM!! TTC

 

[Jim Hemmingway]

Re: White's TDI Pro in Silver Country [including Infinium Comparison]

A question came up about detecting acanthite on a different forum that I thought might as well be addressed here too.

I have no pure acanthite samples, that is to say…acanthite free of native silver… to test specifically. Over 26 years of prospecting here on Ontario’s Precambrian Shield I have not dug one single response from pure acanthite using VLF detectors. Any acanthite samples found have resulted from a detectable presence of native silver associated with acanthite.

Some rockhunters in my area have found acanthite incidental to digging a separate target signal. I have been advised that acanthite on the surface will generate a very mild response to VLF prospecting suitable units with the GB control set to local conditions, but only to a few inches maximum. Similar to other extreme low-level conductive sulfides such as iron pyrite, a VLF detectable response would be predicated on sample size and concentration of the sulfide material. So, while I have no suitable samples to test and be 100% certain of the outcome, it seems to me highly unlikely that a PI unit would respond to this specific sulfide.

Should you locate a suspect rock, you may wish to benchtest it before doing any invasive tests. You will need a suitable full GB range VLF unit for benchtesting, and follow the procedure as outlined in the final section of the Phase Measurement & Magnetic Susceptibility document as per the link below. I have no doubt acanthite in sufficient concentration will respond to this benchtest technique.

If you don’t know where to set your GB control, inquire directly to the manufacturer as to what GB setting is suitable to eliminate positive hotrock response from all “weathered” or oxidized non-conductive iron minerals including maghemite. Otherwise, test various positive hotrocks to determine a suitable GB setting.

http://forum.treasurenet.com/index.php/topic,384948.0.html

As noted in the report, acanthite is normally associated with “wire” silver. Below is a photo…courtesy of Dr. Jim Eckert of northeastern Ontario… that illustrates wire silver with partial acanthite replacement.

​

***********************************************************************************************************************

On a different subject, White’s has just released the new TDI “SL” model as illustrated in the two photos below. Obviously I’ve had no opportunity to evaluate the new unit, but early reports indicate it has a much smoother threshold and significantly enhanced sensitivity to small stuff. DiggerBob has tested the 12” DF stock coil and reports 12 to 14 inches on a nickel, a one grain nugget air tests at about one inch, a 2.5 grain nugget air tests at about three inches.

It uses eight alkaline or NiMH “AA” batteries in a slide-in battery pack that'll last approximately four to five hours of continuous use. The weight has been significantly reduced down to 3.5 lbs while utilizing a smaller MXT size control box. This unit does not have either the "Fine" GB or Volume controls that are included on the TDI Pro. DiggerBob noted that the GB control setting can be a bit touchy over tough ground minerals, for example…it takes only a slight adjustment to take it out of ground balance.

White’s suggested price with stock 12” DF coil = $1299.95 and about $50 less with the smaller 7.5” DF coil…your choice.

 

[arizonaames]

Re: White's TDI Pro in Silver Country [including Infinium Comparison]

Hi, Jim

Bob made a Youtube video of this new addition and the results look to be good.



The depth is a bit less than the standard TDI and TDI Pro but the voltage and amperage is less with the AA batteries in the new unit and one loses a bit of power. However, because of the better designed circuitry it does pick up almost all of the depth loss and does gain sensitivity in that diminished depth loss. With a double vernier pot, one knob for course and the smaller for fine GB, the sensitivity to GB can be overcome. That is a change that Whites could make in the future. I would also like to see the box removed from the shaft for chest mount or belt mount like the TDI box that exists now. The Box used now is the MXT box and shaft for the TDI SL version.

 

[Jim Hemmingway]

Re: White's TDI Pro in Silver Country [including Infinium Comparison]

Hi Jim...thanks a million for posting this excellent video. And we thank DiggerBob for taking time to produce it....I think we can all agree he did a great job.

Well Jim, I like what I saw. The ground balance did appear to be more precise but then too he was over some real tough ground. I don't have any issue with it that I can see from the video, but as you say...a fine GB control would help to resolve any potential problems associated with maintaining proper ground balance.

The sensitivity to small stuff is really something. I see this in conjunction with the improved threshold as a big step forward. I was thinking while watching the video that it would probably have been more meaningful to me if he could have included a threshold comparison between the "SL" and the TDI Pro or TDI models.

A question for you if you don't mind...how did you transplant the video to this thread. I tried right-clicking on the heading at youtube but could only copy a link to it.

Jim.

 

[arizonaames]

Re: White's TDI Pro in Silver Country [including Infinium Comparison]

Hi, Jim H,

Good to see you here. It is getting to the point that one has to walk tip toe on hot coals to post anything anymore without ticking off someone for something. Yes, a fine tune pot of perhaps just 500 ohms would do it whether or not it was a 2 in 1 pot or a separate pot. It would do the job. I have a MXT that I like very much. Seems the jacket for the new TDI SL is the same as the MXT. I do not know about you but my arm gets tired after a few hours hunting with it and I would surely appreciate being able to unscrew the box from the shaft so that I could chest mount it to ease my swinging arm. Whites should offer this option on the sale of a new TDI SL.

Yes, Bob did a great job on the video and so too Reg Sniff who was an asset in designing the new circuitry. Both are to be complimented.
As for the video, I believe one of the moderators set that up for me because all I could do was copy the URL from youtube. Thanks moderator. That will be a help to those that frequent this great forum.....jim

 

[Jim Hemmingway]

Re: White's TDI Pro in Silver Country [including Infinium Comparison]

Jim, don't worry about expressing your views here. Users are naturally going to make comparisons and have different viewpoints. These tend to result in progress if designers and testers are receptive.

I agree with you on the chestmounting, knowing full well how heavy my MXT gets after a few hours with using the 12" stock concentric. I see no reason why they could not have retained the same chest mount configuration of earlier models. There is a separate practical aspect as well. A chest mount is easy to shelter from rain.

If the "AA" batteries last four or five hours...well OK. But if this unit gets less time as has been suggested on the TDI forum, that is an entirely different matter. Possibly White's will address concerns about the new unit, particularly if it becomes apparent that sales are down from expected levels.

Jim.

 

[TerryC]

Re: White's TDI Pro in Silver Country [including Infinium Comparison]

I see the TDI SL's weight has come down to that of the Gold Bug 2, its direct competitor. Whites has always been pretty squeamish about the weight of its products.... try and find an add telling us of the weight of the GMT, for example. It is about a pound heavier than the GB2. Still, the GMT is well balanced, making the weight difference difficult to notice. I don't know what the "SL" weighed before the notice, but since it's built on the same platform as the GMT, it probably was pretty close. TTC

 

[Jim Hemmingway]

Re: White's TDI Pro in Silver Country [including Infinium Comparison]

Hi Terry...you make a good point. My TDI Pro is about five-and-a-half pounds compared to the "SL" at about three-and-a-half pounds = two lb difference...a real plus.

It will be interesting to see how the new unit is received with respect to overall performance. There have been questions about actual battery pack continuous run time, and how the ground balance range compares to the TDI Pro. Comments have been made about "touchy" or over-sensitive ground balancing as well.

Some folks were expecting more in a new unit, but beyond whats mentioned above...I was pleased by what I saw in the video. Reduced weight, smoother threshold, improved sensitivity to small nuggets are the big changes. Beyond that I can't comment on the "SL" until such time as I actually get one in my hands.

Jim.

 

[TerryC]

Re: White's TDI Pro in Silver Country [including Infinium Comparison]

Hi Terry...you make a good point. My TDI Pro is about five-and-a-half pounds compared to the "SL" at about three-and-a-half pounds = two lb difference...a real plus.

It will be interesting to see how the new unit is received with respect to overall performance. There have been questions about actual battery pack continuous run time, and how the ground balance range compares to the TDI Pro. Comments have been made about "touchy" or over-sensitive ground balancing as well.

Some folks were expecting more in a new unit, but beyond whats mentioned above...I was pleased by what I saw in the video. Reduced weight, smoother threshold, improved sensitivity to small nuggets are the big changes. Beyond that I can't comment on the "SL" until such time as I actually get one in my hands.

Jim.

The touchy GB is a simple correction... a few resistors and caps to the IC will be changed and it will smooth out. Hmmm, been about 25/30 years since I did any protoboarding. Do they still use those kinda thingies? My age is showing! Give it the time required to shake out the "goods" and the "bads" and we shall see! Tnx. TTC

 

[Jim Hemmingway]

Re: White's TDI Pro in Silver Country [including Infinium Comparison]

Below is a link to a thread containing a couple of links to two videos just done by Jason at Razorback Coils. These videos demonstrate differences in performance between the new "SL" model and the TDI Pro using a couple of different coils. Enjoy.

This is my last post to this thread for a couple of months. Finally I'm ready to take off prospecting for the entire autumn. Thanks to everyone who participated here...

Jim.

http://z7.invisionfree.com/whitesgoldmaster/index.php?showtopic=347

 

[wltdwiz]

Re: White's TDI Pro in Silver Country [including Infinium Comparison]

ty
that was a well written very thorough & informative report

The White’s TDI Pro in Ontario Silver Country​

Introduction

The pulse induction TDI Pro, manufactured by White’s Electronics, is primarily designed as a gold detector but has proven effective for other pursuits such as relic, beach and even coin hunting. Searching for silver ores with the TDI Pro is a unique application of this detector. The mining areas searched are replete with conductive pyrrhotite hot rocks and iron junk of every type and size imaginable. This report looks closely at the TDI Pro’s ability to search these sites and separate iron from silver.

The TDI Pro has iron handling capabilities that merit discussion. Naturally some comparisons are made to the Garrett Infinium LS and these are included just for the heck of it. Many hobbyists will be interested to learn how these units compare with respect to iron ID / elimination and depth capabilities. Both these units are well suited for silver hunting. Their feature sets permit either to excel over the other in some situations. The TDI Pro is a versatile instrument that proved effective at finding some beautiful silver this past autumn.

The photo below depicts lovely autumn colors in rugged silver country that we’re sure electronic prospectors enjoy and appreciate. Those tailings may look like heck to some folks, but to us they’re an enticing snippet of heaven.

​

Quickview of the TDI Pro

TDI Pro is a solidly constructed unit with user-friendly analogue controls. It is lightweight, better balanced and less fatiguing to use compared to many PI units. Over the normal course of detecting where it is frequently set aside to dig targets, no undue arm fatigue was experienced. The TDI Pro can be hip / chest mounted to further reduce weight.

The TDI Pro comes with two lithium battery packs, a seven hour AC charger, and a “fast charge” three hour full charge auto cigarette lighter plug-in type charger. When the battery dies and needs recharging, the bright battery indicator light turns completely off in about a half-minute. With a full charge the TDI Pro is good for another full day of detecting, or approximately eight hours continuous use.

Gain determines the depth /sens that the detector sees a target at any given combination of ground balance and pulse delay settings. Optimal sensitivity is typically in the 6-8 range for our area. The gain setting affects the unit’s susceptibility to the effects of ground minerals and EMI. Excessive gain may increase instability resulting in excessive chatter and false signals. Set it for the prevailing conditions such that the threshold is reasonably smooth, permitting you to easily hear and identify target signals. The frequency control can mitigate external electromagnetic interference (EMI) to some extent, allowing operation near or under power lines.

Threshold control is best set above the “chatter” level to obtain a consistent “mosquito-like” hum. Reducing the threshold below the chatter zone to “silent” threshold reduces depth / sens especially to smaller or fringe depth targets. If the threshold volume level is excessive, adjust the volume control to reduce it. If using headphones, one may set the volume control to maximum and then adjust the headphones volume level to your preference.

Target Conductivity (Tone Mode) Toggle is activated when the GB Fine control is turned ON. It permits the user to choose whether signals are heard from low conductive targets only, high conductive targets only, or both high and low conductive targets. This feature offers a number of search options in concert with GB control adjustments. This subject is addressed in more detail further into this report.

Pulse Delay adjusts the sample pulse delay from 10-usec to 25-usec between the end of each transmitter pulse and the start of the receiver-sampling period. The 10-usec setting is the most sensitive to all targets including low conductive targets that comprise the vast majority of our silver nuggets and ores. Increasing the pulse delay towards 25-usec generally reduces overall target sensitivity, minimizes ground mineral signals and will suppress low conductive target signals that include signals from small iron bits and low conductive silver.

Ground Balance (Fine & Course) Controls are activated by turning the Fine GB control clockwise to the ON position. With ground balance activated, the target conductivity control and variable audio are also activated. The GB control’s chief function is to compensate for iron minerals in the ground. Most ground in prospecting country will balance between GB8 and GB9 on the coarse GB control.

 The TDI Pro has manual ground balance only. Pump the coil one to six inches above the ground and adjust the coarse control until there is no change in threshold. Over some soils the fine control may be adjusted to fine tune the ground balance, but this is not necessary here. Any adjustment to the pulse delay will require another ground balance procedure if you intend to operate the unit in a ground-balanced condition.

 If ground minerals are not excessive, the ground balance control may be adjusted to achieve some discrimination control. The GB control can be used in conjunction with the target conductivity tone mode toggle to selectively eliminate a GB scale range of signals from detection. Alternately, it may be used to select and hear all iron junk and natural silver signals but arbitrarily assign either a high or low conductive tone to a given portion of the GB scale target range depending on just where the GB control is set.

 If ground minerals are not excessive, the ground balance control may be adjusted to achieve improved depth on a given target GB range. The GB control setting impacts the depth / sens that can be achieved on a given target GB range. Where target GB range lies near or at the operating soil GB setting, reduced detection depths will result. Conversely, if we can search with a GB setting as far as possible from the expected target GB range, a significant depth improvement results for that target range. For example, a high conductive silver specimen has a GB point close to the soil’s ground balance setting, say at GB9. If ground minerals permit searching at GB1, improved detection depth on that target will result.

 Reducing the GB setting increases threshold stability. The GB1 setting is noticeably smoother and quieter to operate than GB9. Over some soils ground balance may not be required. In that case one may operate with fine ground balance control turned OFF, resulting in improved depth and threshold stability. However, operating with GB in the OFF position means that variable audio and target conductivity tone mode are inactivated such that all targets respond with the same tone.

The photo below depicts a handsome half-pound acanthite / native silver specimen located with the TDI Pro. Acanthite is a silver sulfide comprising 87% silver and is often associated with wire silver here. It is quite soft and sectile, blackish and usually with a slight but distinctive deep bluish-black tint in these parts. The native silver you see poking out of the rock runs right through it in veins. This specimen is strictly a low conductive tone mode signal at any GB setting. It will not give a signal in the high conductive tone mode even at GB11…a technique we can use to arbitrarily differentiate high conductive targets from low conductive targets.

​

Target Signals and Ground Balance

(a) Target Signals

The ground balance scale runs from the GB1 position clockwise to the GB11 position. Target conductivity is highest at the GB1 position and decreases as the GB control is adjusted clockwise to the GB11 position. The lowest conductive targets fall into the GB11 category. The signal tone with which a target responds depends on its GB point in relation to where the GB control is set, in concert with the target conductivity tone mode toggle setting.

A low conductive tone mode signal is always strongest at the GB1 position. Depending on a target’s GB point, that low conductive tone signal may disappear or go quiet at some point as we adjust the GB control clockwise. Some targets will continue to give a low conductive tone signal at the maximum setting of GB11. A portion of these targets will only signal in the low conductive tone mode from GB1 up to and including GB11. They will not signal in the high conductive tone mode at GB11. They can only be searched for in either the low conductive or all-conductive tone modes. These are referred to as low conductives in this report.

Low conductive silver occupies a conductivity range up to and mostly including the mid-pulltab range. Low conductive targets, silver and iron junk alike, respond with a low conductive tone only, and must be searched for in either low conductor tone mode or in all-conductor tone mode. Examples of low conductive iron junk include rusty small iron tidbits, flat, thin sheet iron and tin, our plentiful twisted or braided iron wire, small nuts and small nut and bolt combos, small ¼ inch plate, rusted jar lids and so forth.

‘Low conductive’ silver does not imply the silver is somehow second rate. It means that factors such as purity, types of mineral inclusions, size, shape, or structure may be sufficiently dominant to affect where silver exists on the TDI Pro’s GB scale. The specimen illustrated in the photo below exemplifies high purity but very low conductive silver. The low conductivity is almost entirely due to the dominant spongy silver structure.

​

A high conductive tone mode signal is always strongest at the GB11 position. A target may continue to produce a high conductive tone signal as the GB control is adjusted counterclockwise, but in a prospecting context it normally loses its signal at some point along the scale. High conductive targets also signal in the low conductive tone mode anywhere from GB1 up to and including GB11. Any targets that signal in the high conductive tone mode at GB11 are referred to as high conductives in this report. To identify high conductive tone signals, only the high conductive or all-conductive tone modes can be used.

High conductive silver occupies a conductive range from roughly mid-pulltab up to and including copper penny level. Mid-pulltab range is where our silver ores separate into either high or low conductives in response to the TDI Pro. Most mid-pulltab silver here responds as low conductors, but some samples respond as high conductors. Examples of high conductive iron include all manner of nails, drill bits and drill rods, thicker plate iron, tools and implements, iron bar and pipe fragments, 3 ½ inch rail spikes so prevalent at our minesites, milling balls, and so forth.

Massive silver structure is not a prerequisite to attain high conductor status. The copper-colored niccolite in the sample photo below is insufficient to raise the conductivity above nickel level, thus the silver is responsible for increasing the sample’s conductivity. Yet this specimen may very well contain less silver than the low conductive sponge specimen above. As can be seen, both specimens are collectable regardless of conductive measurements on metal detectors.

​

(b) Ground Balance for a Metal Target

Ground balance points do not exist for low conductive metal targets as defined above because they only signal in the low conductive tone mode. For other targets, the ground balance point is the position on the GB control scale where a metal target will have its weakest signal. How do we locate a metal target’s ground balance?

 Using the all-conductor tone mode a silver nugget might signal with a low conductive tone from GB1 clockwise to GB3, and a high conductive tone from GB5 clockwise to GB11. Mixed high and low tones will be heard in a transition zone between GB3 and GB5. GB4 is the null or ground balance point for this nugget. High and low tones will be about equal in volume and duration at the ground balance point.

 Using the low conductor tone mode a good signal is heard from GB1 clockwise to GB3, then gradually weakens and is gone at GB5. In high conductor tone mode the nugget signals at GB11 counterclockwise to GB5, then gradually weakens and is gone at GB3. Again, the transition zone is from GB3 to GB5 and the null or ground balance point is GB4.

TDI Pro & Infinium Depth Comparison

The Infinium with elliptical 10”X 14” mono coil and the TDI Pro with stock 12” dual field coil were compared over a few targets buried in the ground, followed by some air tests presented below. TDI Pro gain was set to the maximum “10” setting. Infinium’s gain is preset, but increasing the threshold improves the depth at which target signals can be heard. The first target is a pre-1981 nickel that Infinium and TDI Pro at GB9 air test at seven and eight inches respectively. Interesting because both units air test a Jefferson nickel at twelve inches or more depending on settings.

Adjusting both units to proper ground balance and a bare threshold, TDI Pro at GB9 gives a modest, repeatable signal on a pre-1981 Canada nickel at ten (10) inches depth. Infinium signals one-way only, but increasing Infinium’s threshold to “6ish” yields a stronger, repeatable signal. If TDI Pro’s ground balance is reduced to GB1, then these units are very close on this target. If soil minerals permit, turning OFF the TDI Pro’s GB control further improves depth.

Lead “nuggets” buried out in the patio were tested. The half-gram to one-pennyweight nuggets were made by hammering some small fishing sinkers together. They respond very poorly to PI units in air tests compared to similar size gold or silver nuggets. Neither Infinium using increased threshold nor the TDI Pro at GB9 will see the half-gram nugget at four (4) inches nor the one-gram nugget at five (5) inches. Infinium signals one-way over a one-pennyweight nugget at five (5) inches every two or three coil sweeps, while TDI Pro does not see this target at all. Now, adjusting the TDI Pro to GB1 results in a modest but repeatable signal over the pennyweight nugget. These units using the coils described are that close in performance on these targets. It would be interesting to see the results if Infinium used a dual field coil and TDI Pro used a 14” mono coil.

Air tests indicate the dual field coil improves sensitivity to small targets compared to a 14” mono elliptical coil. The chart below compares 5” diameter mono and 14” elliptical mono Razorback coils to the stock dual field coil on the TDI Pro. Check out the 0.4 gram nugget results in the chart below. BTW, within the 14” mono data the red-colored numbers highlight improved performance over the dual field coil.

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The next chart presents air depths for both units tested under high residential EMI conditions. Again we see results that indicate improved sensitivity on small nuggets with the dual field coil. The 3 and 5.6 grainers are gold, the 4.5 grainer is solid lead, the half-gram and one-gram nuggets are native silver. Infinium has four sets of results whereby the first number indicates a “sound-off” while the second number indicates a repeatable signal.

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Target depth on high conductive silver decreases as the target GB point approaches the TDI Pro’s operating GB setting. The closer the target GB is to the operating GB, the more significant is the depth loss. The chart below presents data that by design encompasses the full natural silver high conductive range. It does not take into account that high conductive silver ores in the pulltab to mid-screwcap range are more plentiful than those found at higher conductivity levels. The pulltab to mid-screwcap range is more susceptible to depth loss searching with a ground-balanced GB9 setting. BTW, the chart designations T = 4 or T = 6 refer to Infinium’s threshold settings.

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The bar graph below illustrates an air test depth trend with a low pulltab range low conductive silver specimen. The depth loss at a pulse delay of 10-usec from GB1 to GB9 is 5 inches or 24% for this piece. On average the depth loss for samples tested in this specific range is closer to 15% at 10-usec. Regardless whether these air depths accurately reflect buried target depths, the data suggests using as low a GB setting as ground minerals permit to achieve best depth when searching low conductive silver ores and nuggets.

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What About Iron?

High conductive iron and high conductive silver both yield high and low conductive tone signals. To see if anything can be done to separate them by using ground balance and tone mode controls, their respective GB scale signal ranges needed to be identified. Samples were tested in both high and low conductive tone modes by adjusting the GB control until a target signal was ignored while passing the target across the middle of the coil. High (HSEP) and low conductive signal end points (LSEP) were established for all samples tested. What exactly does that mean?

 Take a high conductive silver sample with a HSEP at GB5. This means in high conductive tone mode it will respond from GB11 all the way down to GB5 where the high conductive signal is finally ignored. It will not respond with a high conductive signal at a GB setting lower than GB5.

 That same high conductive silver sample may have a LSEP at GB7 for example. That means in low conductive tone mode it will respond from GB1 all the way up to GB7 where the low conductive signal is finally ignored. It will not respond with a low conductive signal at a GB setting higher than GB7.

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The graphs do not represent relative proportions of various types of iron junk encountered in the field compared to silver finds. For example, if proportionate numbers of nails had been included, the HSEP graph iron numbers at GB4 and GB5 would exceed the graph upper limits by several orders of magnitude. This applies to the LSEP graph for those same nails residing within the GB6 to GB9 range. That said, the results indicate that high conductive iron and high conductive silver occupy a similar range on the TDI Pro ground balance scale.

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(a) Some Observations

In the high conductive tone mode, there is no way to separate silver from iron based on any combination of tone mode and GB control. Moreover, searching strictly in high conductive tone mode eliminates all low conductive signals. The low conductive tone mode with a GB9 setting pretty much eliminates regular nail sizes from detection while capturing all low conductive silver signals. Much of the larger high conductive iron that signals at GB11 in low conductive tone mode can be separated from low conductives by checking signals at GB11 in the high conductive tone mode. Low conductives do not signal in the high conductive tone mode.

The other interesting aspect of the tests was to learn that high conductive iron generates much wider GB spans between HSEP and LSEP overall than does natural silver. Test measurements on 34 high conductive iron samples resulted in an average HSEP to LSEP span of five (5) GB units and that includes a number of smaller nails that pull that average down. The 30 high conductive silver pieces tested have an average GB span of two (2) GB units.

The difference in GB spans can be used as an indicator to distinguish high conductive silver from high conductive iron. It is not a definitive technique because a variety of very compact iron pieces such as drill bits, milling balls, and other nondescript chunky iron also exhibit “tight” GB spans similar to high conductive silver.

(b) Definitive High Conductive Iron Lo-Hi-Lo Tones

Iron lo-hi-lo tones can be used to separate high conductive iron from all silver. This procedure usually involves adjusting the GB control to determine whether a lo-hi-lo tone can be had as we sweep the loop over the target from different directions. The target conductivity tone mode toggle must be set to the “all-conductive” position. GB control adjustment may cause a target to lose considerable depth and go quieter. Try to rotate the GB control slightly off a “quiet” setting but not so far that we lose the ability to discern high and low conductive tones. If we can acquire a lo-hi-lo signal, we know it will be an iron target. The lo-hi-lo tone is a definitive technique to identify iron if it can be had. Perhaps there are other examples such as modern coins with magnetic content that may give a lo-hi-lo tone, but they will not include silver nuggets and ores.

The GB control adjustment technique does not always acquire a lo-hi-lo tone over some iron. Compact high conductive iron such as milling balls, drill bits, and other nondescript iron chunks have very “tight” GB spans. Lo-hi-lo tones are difficult to get without some delicate GB control adjustment, and sometimes they’re impossible to acquire. Elongated iron items like nails, bolts and rods normally present no difficulty obtaining the iron tone.

Part 2 of the report is posted immediately below...

 

[arizonaames]

Re: White's TDI Pro in Silver Country [including Infinium Comparison]

Below is a link to a thread containing a couple of links to two videos just done by Jason at Razorback Coils. These videos demonstrate differences in performance between the new "SL" model and the TDI Pro using a couple of different coils. Enjoy.

This is my last post to this thread for a couple of months. Finally I'm ready to take off prospecting for the entire autumn. Thanks to everyone who participated here...

Jim.

http://z7.invisionfree.com/whitesgoldmaster/index.php?showtopic=347


Thanks Jim H,

This will save some folks that can ill afford it some money......jim

 

[Lanny in AB]

Re: White's TDI Pro in Silver Country [including Infinium Comparison]

Jim--this thread has only gotten better with time! Great job done by you and your other contributors!

All the best, and keep up the great writing,

Lanny

 

[Jim Hemmingway]

Re: White's TDI Pro in Silver Country [including Infinium Comparison]

Howdy Lanny...how the heck are you doing these days?? I hope you've enjoyed your prospecting season as much as I have.

Your comment struck me as insightful Lanny, as I happen to agree that if interested hobbyists will re-read the article they may see more than the first time around. Yes... there is a lot of detail to take in... but a serious prospector or newcomer with an interest in either unit should benefit. As you know, this report is independent of any manufacturer or dealer...allowing for full... but responsible... disclosure of our experience to date with these machines.

Many thanks for commenting again...hey I just returned from a two month highly enjoyable prospecting trip to see your post...not bad timing I guess...all the very best.

Jim.

 

[Lanny in AB]

Re: White's TDI Pro in Silver Country [including Infinium Comparison]

No problem Jim--always great to hear from you. What did you find on your prospecting trip out this summer? Any pictures?

All the best,

Lanny