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Reg

New PI

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Most TDI's sold are done so by new owners who want instant results and don't take time to learn the features or the tricks to maximize the depth.

Ditto... most people want a turn-on and go detector and don't want to take the time to read the manual, nor learn the machine. Speaking for the TDI Pro (which I own one), it isn't a turn-on and go detector. Takes a minute or two to dial it in, but once dialed in, it does an awesome job of finding gold. Although I dig all signals. I'm to the point now where I can tell (about 90% of the time) exactly what I'm going to find before I dig it.

Question for Reg... how come the TDI Pro won't go as deep as a GPX5000 given they are basically the same technology? Is it due to finer circuitry, power usage, or hardware/software programming? What exactly is the magic behind the Minelabs?

FWIW... about a year ago asked a guy (who makes his living prospecting) if he couldn't use his GPX5000, what detector would he be using. His answer with no hesitation was a TDI Pro. Shortly after meeting him, I found one cheap online and bought it. I'm very happy with the product, and later added a GMT to the arsenal as well. When I get a few patches marked and my poke full, I'll upgrade to whatever the latest and greatest is at the time, whether it be a Minelab, Fischer, or Whites. I'm not partial to any manufacturer as long as their products perform. B)

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Help me out here... if you're telling me a GB2 is equivalent to a Whites PI, but not a Minelab PI, then why do many of those who own a Minelab PI, also own a GB2 or other quality VLF machine? :hmmmmm:

I never said it's the equivalent. A 3dwt nugget at 4 inches should sound like a beer can. I'm sure a gold bug will find a 3pwt nugget at 4inches depth. People with mine labs have gold bugs as well to find "fly crap" gold. Gold so small you need tweezers.

Luckylundy said in the detecting game inches are miles...

I'm not trying to be a homer but I have a 4500 and most people I hunt with have the same. Using a

mono coil a 4500 destroys sub gram gold. I have seen tiny nuggets found with it. My first nugget ever

was a .20 gram nugget at 3-4inches with my gp3000 and a mono coil. One of my hunting buddies did some testing with the tdi vs a mine lab . He said the mine lab is far superior to any other PIs out there.

Under 2grand is a good price for a PI detector. But you get what you pay for. I don't enjoy walking over gold.

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Guest Nuggethunting

Hello Reg,

I believe towards the end of the 24K Gold Hunters Club I was doing demo's with the new released GPX4500. During the 24K time, the GPX4000 and GPX4500 were the newer PI's from Minelab.

Just so people know, Reg and I have spent hundreds of hours in various goldfields back in the day testing Minelab vs. other PI's (Eric Foster's, Reg's Mods and other PI's). Reg is a wealth of knowledge when it comes to PI's, whether it's the electronic side or field useage. We both know the advantages and disadvantages of both units.

The Minelab PI's are very capable of finding very small gold also, down to under a grain in size. To find gold this small with a Minelab PI, it's recommended to have a GP or better, but I have found them down to about 0.8 grains with an SD2100. To find nuggets under a grain in size with a Minelab PI, the gold normally has to be flat or dense, very small porous gold doesn't detect well.

We all know on this small gold, a high freq VLF excels if the mineralization isn't too bad. A Fisher Goldbug 2 will find stuff too small for me to even mess with, but I have done it and it's fun to find a dozen or so pieces of gold.

I have used and owned several White's TDI's and they have their place also. They can find the porous gold that the Minelab PI's miss.

In a nutshell, when it comes to selecting the right detector for you, some research is probably needed.

Take care,

Rob Allison

www.nuggethunting.com

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I don't enjoy walking over gold.

We all walk over gold no matter what detector we are using, its just a fact of life.

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He said the mine lab is far superior to any other PIs out there.

So what exactly makes them so superior? I understand the 'nuts and bolts' of PI technology, so don't be afraid to get all technical on me. Anyone here care to elaborate?

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I will try to point out a few things that make the Minelab different from the TDI or the SL. The differences aren't as great as one might think.

First, Listen carefully and you will clearly notice the ML is much more sensitive to its surroundings. The reason is ML is designed to find large gold deep and to do so, they push as much current as possible into the coil and then use maximum sensitivity on the front end to be able to hear the weak signals. This combination has both advantage and disadvantages. The added depth is one of the advantage, but the sensitivity to EMI, whatever the source is noise that affects the detector and is one of the disadvantages.

Usually, when the ML is adjusted to reduce the noise, then the depth generally drops accordingly and the depth difference between the ML and the TDI is reduced accordingly. and can approach the relatively same capabilities.

Very often if not most of the time, you can have a ML being subjected to noise that causes problems in an area where the TDI will function almost quiet as a church mouse. A good example is trying to use them under high voltage power lines. Some of the earlier ML's really struggle and later ones usually need special coils or switch modes to reduce the problem. The TDI with the lesser gain, usually purrs right along with minimal problems. Now, the new SL quiets things a lot more.

For the TDI to compete closer in depth, you have to add extra sensitivity and then you have to add extra filtering and other circuits to minimize noise. The result is a larger pc board and more parts. All of this relates to a higher cost. So, in simple terms the TDI is built on a platform that provides decent depth and can do so, without costing nearly as much money by doing a decent job with less sensitivity. As for coil current, there is a difference there also, but it doesn't translate nearly as much as one might think. ML uses two different pulse lengths to detect different size gold. Whites only uses one pulse length, but it was to provide the best it could of both worlds.

The TDI can do a very decent job of distinguishing much of the iron and even totally ignoring it while generating a signal on gold. Actually, gold less than about 3/8 oz or so can generate one tone while most nails cause a different tone. Using the conductivity switch, the gold tone can be allowed through and the iron signals are simply ignored and cause no response, regardless of their depth and do this with a mono coil.

Now, the first thing someone is going to say is I don't want to ignore large gold. Well, you don't have to and can detect all targets. Another technique is to detect the gold smaller than the 3/8 oz and ignore iron, and then switch to a different mode and detect gold larger than the 3/8 oz and ignore iron again.

Now, I already have a mod in my SL that will alter the gold/iron signals such that gold even over an oz or two will generate a different signal than most iron junk such as nails, bolts, washers, wire, etc. So, by ignoring the other tone, then gold, lead, some aluminum, brass, and a few other non ferrous metals will be detected but much to most of the iron will not be heard.

What will be heard that is a pain is small to medium pieces of tin cans or other very thin ferrous junk. Some small pieces of nails or maybe shoe tacks will be detected as possible good objects. Usually, most of the thin junk is at or near the surface so it is easy to distinguish with the right sweep techniques and coil height. The final result is a lot less junk has to be dug and one can feel relatively confident most small gold will not be ignored. Unfortunately, small gold sitting under iron will not be detected so the design isn't perfect, but no form of discrimination is.

Unfortunately, the techniques that provide this form of discrimination also reduces the depth of the detector to do so. On the up side, a mod I mentioned that helps me detect larger gold as a high tone will also alter this potential depth loss and reduce it considerably.

So, the difference in depth between the ML and the TDI detectors is the result of different concepts aiming at different objectives. ML is aiming at shear depth and trying to push things to the limits. They have been doing this since the SD 2100, which is why the depth difference from the earlier ML's to today's really hasn't changed dramatically on much of the larger gold. Enhancements on the detection of smaller gold and the reduction of noise on the newer units adds potential depth mainly be minimizing the noise potential.

The TDI isn't trying to compete in depth or price. and the two are directly related Instead, it has been refining those features that make it what it is today which is a PI with PI qualities and the ability to ignore many hotrocks while detecting gold at respectable depths and do this while trying to keep the cost down. In the process, the ability to determine iron has been refined also and, in all likely hood, will be advanced even farther in the future.

I am sure if Whites elects to change its mind in the future, a much more expensive detector can be built that is very competitive depth wise. Regardless of what one might think, there is no magic involved. But, at the present, it appears that Whites prefers to target those people who simply can't or don't want to spend above a certain limit. In many cases, this is much more practical for the casual gold hunter who can only go a couple times a years, or can't afford the more expensive units.

In case people haven't noticed, there is a significant difference in base costs between a $1300, a $1600, or a nearly $6000 price tag. One shouldn't expect the lower priced units to perform as well. We don't do it with cars, trucks, or much of anything else, so why expect it with metal detectors?

So, if a person is serious about gold hunting and can readily afford the more expensive detector, then, that is the way to go if they so desire. However, if a person is on a tight budget, wants a worry free warranty one gets with a new detector or may only hunt when times permits, then the TDI or SL can seem quite practical.

Reg

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If these forums are for sharing and informing fellow members...why is a simple and news worthy post from Reg so agitating???

The newest version of the TDI is finally getting to be what many people want...a realitvely low cost and easy to swing PI detector that can be used for gold, on the beach or in the parks.

Reg has been involved in much of the early development...if anyone knows what this machine can do he is among the few.

It amazes me that Reg keeps trying to help when so many people wallow in the mud rather than picking up his pearls.

Again, REG, I thank you for the many pearls you have thrown...

fred

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If these forums are for sharing and informing fellow members...why is a simple and news worthy post from Reg so agitating???

The newest version of the TDI is finally getting to be what many people want...a realitvely low cost and easy to swing PI detector that can be used for gold, on the beach or in the parks.

Reg has been involved in much of the early development...if anyone knows what this machine can do he is among the few.

It amazes me that Reg keeps trying to help when so many people wallow in the mud rather than picking up his pearls.

Again, REG, I thank you for the many pearls you have thrown...

fred

Well said Fred!

Reg

You patience and willingness to share knowlege

still amazes me!!

Herb

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Hi Fred,

Thanks for the kind words. I am getting cranky in my old age and have a tendency to pop off too much, so I need to ignore some people, but it can be fun at times.

Anyway, I wanted to expand a little more on the differences between the ML and the TDI.

The ML has a menu which allows a wide variety of selections for the owner. Once learned, such a concept really expands the ability of the detector to handle different conditions. Now, what people don't know is for every action, there is a reaction, meaning nothing is free and perfect. So, if all of the modes are tested thoroughly, there will most likely be some glitch that is hidden. Many times finding it can be difficult.

As much as it is disliked, some of the glitches have been posted on an OZ forum to enlighten owners. Unfortunately, instead of welcoming the info, many people attack. It is much like a protective mother attacking someone who said something less desirable about her child. This is sad and actually hurts progress in my opinion. When a glitch is found, the company can try to duplicate it and find a solution, but if no one brings it out, it can be a problem for a long time.

What most people don't know is it is not possible to predict all that can happen. Worse yet, when something finally surfaces a long period of time may have passed and a lot of other changes may have been made. What this can mean is the problem might have started out small but ended up big only because people with big egos don't want people to pick on their favorite child.

This is why when I stumble into something on the TDI, I will do my best to get the info out, so people know all the hidden warts. Quite often I will post something about a technique or a setting that can have a negative impact and cause a depth loss so people know what to expect and possibly avoid the issue and right away, some mentally challenged person has to jump on it in the attack mode rather than accept the info from a positive standpoint.

I used to provide similar info when I ran into something on the ML, but the attacks really came in full force. Since I don't use a ML or use one often, I figured people don't want to know so I simply keep info to myself. It is better and easier than reading all the stupid things people would say.

Yes, all detectors have warts and anomalies, with many hidden. Gold can be missed because of these anomalies and in many cases, quite easily. Knowing such information allows the operator to avoid those that have a negative impact, or allow the operator to make adjustments that minimize the problem. Usually, this means one has to search an area again to be thorough.

In the simplest terms, it is easier than people think to walk over gold and not know it is happening.

The TDI is a simplified design that has its warts. Knowing them and how to adjust the detector such that less gold is missed, takes knowledge of the detector and knowing why the limitations or warts occur and how to minimize the effects.

Let me go back to something I mentioned in a previous post about the SL and try to explain the good, bad, and ugly about a potential mod. Keep in mind the SL wasn't even on the market when I was doing this mod. Anyway, I stumbled into a simple change that would enhance small gold signals. My calculations came up with a value that worked like a charm. (BTW, this little mod is what enhanced the SL small gold detection ability). However, altering that value had its merits also, right along with some strange side effects. In simple terms, too much of what appears to be a good thing, may be good in one aspect but not in another.

So, I made the mod change and pushed the limit. This had a negative impact on the delay and how it works at the very minimal settings. To a novice, this would be a disaster. Even for me, it can be a problem if I forget. Now, on the plus side, at certain other settings. the ability to detect certain targets such as gold in the 1/4 oz to maybe 2 oz range could possibly be detected maybe 30% deeper while being able to ignore most iron junk.

Better yet, relic hunters would love the fact that the changes to the response of some items was altered sufficiently that the operator did not have to struggle with setting their detector to accept minie balls and ignore nails. This target separation was dramatically expanded, which in simple terms meant it was both easier to separate the good from the junk and gain depth at the same time.

Now, the way to handle this simple mod can't be done as the detector is designed today if it is to be done right. The minimum delay would have to be limited at the least. This means more controls which aren't practical, so going to software and some display screen would be the practical solution. Then there would be the programming, etc. The result would be a more versatile detector with a heftier price tag.

The point I am trying to get across is many ideas are being noted and may show up in future designs that are more sophisticated. That means a more expensive detector though and a lot of evaluation and thought has to be put into such a venture to see if it is really practical. Since nothing is free, the man hours could be extensive to perfect and add additional features. Add the additional cost of increased parts and complexity and the result could easily double or triple the cost. When that happens, it has to be determined if such a change is cost effective. Is there that big of a market for higher priced detectors? Most likely not here in the US, but world wide, it might be practical. Then there is the competition and it is always possible more companies will jump into this high priced zone, thus reducing marked share for any one company, which can impact predictions.

So, once again, a company would have to make decisions as to whether it is practical or not to take on such a venture. Keeping it simple assures that marked niche and perfecting that market niche can quite often be more profitable. In the case of the SL, this is a win win. Both the company and the customer wins. Few things go down in price today. So, from a budget standpoint, the SL can be quite appealing, especially if it has enhanced features that make its use smooth and simple.

So, to take the long winded post here and simplify it, Whites could make the TDI better and go deeper, but at what cost???? Or they could do what they did and do something unique in today's market, make something less expensive with enhanced features with reasonable and decent depth.

Reg

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Reg,

As a fairly new detectorist I really appreciate all of the info you have provided. I am also a recording engineer, and it is amazing in the various audio forums I participate in how many Fan Boys of certain products dig-in their heels defending their favorite software or hardware manufacturers. We use these forums to share and learn from each others experiences, and it always amazes me how some allow their egos to close their minds when valuable information is presented. Everyone cannot afford, or justify, spending $ 5000.00+ for a piece of equipment when their level of participation in this hobby makes it impractable. Why the Fan Boys cannot understand this is beyond me.

I own a GMT and I'm very happy with it so far. Would I like to own a ML in addition to my GMT? Sure! And when my level of interest grows maybe some day I will decide to make the jump, but for now I am a Happy GMT owner!

Thanks again Reg for this valuable information!

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For the TDI to compete closer in depth, you have to add extra sensitivity and then you have to add extra filtering and other circuits to minimize noise. The result is a larger pc board and more parts. All of this relates to a higher cost. So, in simple terms the TDI is built on a platform that provides decent depth and can do so, without costing nearly as much money by doing a decent job with less sensitivity. As for coil current, there is a difference there also, but it doesn't translate nearly as much as one might think. ML uses two different pulse lengths to detect different size gold. Whites only uses one pulse length, but it was to provide the best it could of both worlds.

Thanks Reg... that answers my question. As stated previously, me thinks I'll use the tools I have now (TDI Pro, GMT, which appear to be more than sufficient for my current needs) to establish several producing patches and fill my poke, then bring in the heavy artillery to do a thorough clean up.

I have another question which I'll pose in another thread.

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I've never met Reg in person, but I can tell you from experience how helpful he has been to me personally with tips for my Whites TDI.

I have learned by reading other posts on this, and other forums, that he has a "great deal" of experience with many machines, and has always been willing to share his knowledge freely.

His posts have always been very informative, and to my knowledge has never "bashed" any other machine.

To be sure, he is welcome at my campfire anytime.

Patrick.....

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Hi All

To those who don't know Reg he is one of the most knowledgeable on detectors, coils and settings I know :wubu: . Rob I had over 3 dwt in the bag you couldn't hear about double your guestimate :huh: . That was rubbing them on your coil :yikes: . There is one solution to the invisible nuggets, just wack em with a hammer then the minelabs will hear them :puke: . Now all you have to do is find em :*&$*(: . Makes one wonder what what you walk over :spinnin: ??

Happy Huntin John B.

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reg has always gone out of his way to answer any questions i had and is a valuable asset to this and any other metal detecting forum but every time he comes on here to help some idiot kicks him in the sack...i guess that just proves that the world is full of stupid people that are constantly striving to sabotage themselves ...in the future some of us would appreciate it if they sabotaged themselves and not the forum because most of the more intelligent people on these forums really value reg's expertise

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Hi Reg, I remember that day well at the 24K and I was not able to hear those nuggets, must have been someone else. I was fairly new at that time and was running a 3500. I Was very surprised at not being able to hear them for the size they were.

The things you learn along the way! Thanks everyone!

Bunk

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We all walk over gold no matter what detector we are using, its just a fact of life.

I understand we walk all walk over gold. I'm just saying I hate doing it. I spend 60 bucks on gas and 20 on supplies every time I go detecting. So i want the best if im going to spend so much time on my hobby.I'm by no means a "great gold detector" but I have found some little patches. I know a minelab gives be the best chance to find the gold I'm walking over. I know people can't always afford a mine lab hell I cant lol. When I was in the market for a detector I was looking at a tdi. I was told to save and buy a used GP mine lab. Best advice I ever had. I love my GP. Finds tiny gold,and deep gold. It my wife's now. I know that whites has decent PI detectors but mine lab is the best clearly. If whites where the best I would use a whites. I seen what a ML can find and it's nuts!

Ps my first detector was a gmt had it for a year and never found gold. But I was very new and had no idea what I was doing.

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Guest Nuggethunting

Hey John B.,

You're probably correct on the weight. I just remember about 5-7 pieces, maybe more for probably 3+ Dwt in weight and not being able to hear them. I know over the years you found several other pieces, one was a big chunk of iron type ore with some gold on it from the "You Know Mine" area. I remember placing the small Coiltek Joey Mono on the Minelab PI (I believe GP3000 or 3500) and not being able to hear it.

Never doubted what I couldn't hear, but the flip side of that coin is what I have heard in Greaterville (I'm sure you would agree). :wubu: Thanks to the pointy fingers.

Take care,

Rob Allison

www.nuggethunting.com

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Hi Bunk,

Sorry I got you mixed up with someone else. I would only spend a few days a year at the 24K club and met a lot of people each time. I was never good at remembering names and associating them with faces. For some reason your name stuck in my mind as the person who said he could hear those odd nuggets. Sorry about the mix-up.

Hey John B.

Boy, you have no idea the distance traveled in new ideas because of the nuggets you sent. So, once again, I want to thank you.

BTW, I still have the truly invisible 1 oz nugget you sent along with the two smaller ones. I just don't know where I put it since I can't see it, but I know it is here.

Reg

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Help me out here... if you're telling me a GB2 is equivalent to a Whites PI, but not a Minelab PI, then why do many of those who own a Minelab PI, also own a GB2 or other quality VLF machine? :hmmmmm:

As backup mostly....

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Everyone should have a backup....I love my GP3500 and my backup GPX4000!!!!

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Hi Reg and All

Yeah Reg I'm glad they went to a good use :D . I remember Doc's first encounter with one he thought they were fake or :wah: ?? I found a whopper invisible nugget not too long ago :thumbsupanim !! I'll be darned I can't find it either :lol: !!

Happy Huntin John B.

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Hi Wyndham,

Yes, the coils are waterproof, but the control box isn't so one has to be very careful even to the point that the coil is not lifted in the air so any water in the shaft might go back to the control box. Saltwater and electronics parts don't mix.

Reg

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Well ... I haven't been on this forum for awhile ... looks like we need some moderation and consideration between a couple of folks on this thread. Come on guys NOBODY knows and has experience with all things in the detection world. We all have our own personal experiences ... successful and not so successful! may I suggest that we all have opinions and beliefs about certain things and leave the personalities out of it. Just a thought for this saturday morning when i should be out prospecting instead of commenting on the forum! :) :) :)

Hand shakes all around, campfire stories and a few beers could settle this whole thing! :)

Mike F

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