New Whites PI

[Rattlesnake Jim]

Hi Jim,

Great info - thanks!

Hey JW, if Bruce Candy said "gold machines are tuned to never eliminate gold, not to eliminate everything but gold" then he really screwed up with the SD/GP units.

I do not mind a unit calling an iron object all that much as compared to a machine calling a piece of gold iron. And the SD/GP units call gold iron a lot. It is not that the units improperly identify iron that makes the disc on them so useless, it is that I've seen so many pieces of gold called iron.

If my GPX was right 100% of the time on gold and only 50% of the time on iron the disc feature would actually be useful. But I've seen enough gold called iron now that the disc on my GPX-4000 stays at zero.

Dan Judd spent some time with an X-Terra 70 at Moore Creek checking peoples dig piles. He found several nuggets that people had dug up and walked away from. The nuggets tend to read good and then turn to an iron reading when you get closer. I've tested nuggets and found this to be true. Now I should clarify that at Moore creek most of these would be more properly called specimens and are about half gold and half rock, and that no doubt is a factor.

Lesson of course is that if you've already dug it up, use you eyes, not the disc!

So Reg, here is my easier challenge. The goal as far as I am concerned is to have an machine that comes as close as possible to always calling gold correctly. And then calling as much iron as possible iron. As long as I am sure I'm not going to leave nuggets in the ground, and reduction at all of iron dug is a plus. Any iron id system that calls significant numbers of nugget iron is totally useless, at least for me!

Steve Herschbach

Hey Steve,

here's an option. Carry and use a Fisher FX3 fierro probe in conjunction with your metal detector. It only detects objects of iron or steel (magnetic items) since it is a magnetometer and not a conventional metal detector. I understand it gets good depth also. When an object is detected with your regular detector, lay your detector aside and us the FX3 to pinpoint your target. If the FX3 picks it up it's iron, if not; then dig.

Just a thought!

RSJ

[Steve Herschbach]

Hi Jim,

I actually tried it at Ganes Creek!

I discovered that a Minelab hits iron and steel far deeper than the FX-3. These wand type mags are very much tuned to a long vertical item, like a rebar, buried in the ground. They have little sensitivity to flat items or small surface trash. So on the vast majority of the most troublesome junk it really did not help much.

Combining a mag with a detector may have promise but I think the mag would need to be built specifically for the task.

I've tried carry a VLF detector around a couple times to check targets also. Talk about just one too many things to be toting around! But it does pretty much solve the small surface trash problem.

Steve Herschbach

[Reg]

Hi Jim,

Unfortunately, the FX 3 doesn't do that well on the thin ferrous metal or small ferrous metal junk. Unless I have a bad one, I can say it isn't worth it to try to carry the FX 3. I didn't try it on the larger stuff except to make sure it worked but concentrated on how well it would do on the stuff I have problems with with my PI.

Reg

[Reg]

Hi Steve,

The GS 5 isn't that far off from what you want. The trick is to know how to read what the detector is telling you and how to adjust it to tell you what you want. Jim French and another owner have done a good job of learning the unit and can basically do that

Eric Foster has discussed a couple of key issues that sort of explain the difficulty involved. In a recent post on this thread, he discussed a nugget that fits in the "hole" will still generate a signal because of the secondary signals involved.

By this I mean, as a coil passes over a target, there really are more than one type of signal. At the edge, the signal can be opposite of what you hear when the coil is directly over the object. This depends on the object, the distance from the coil, etc.

As an example, you can pass over a silver coin with the coil close to the object and you will get a positive signal at the edge, a strong negative response directly over the coin and another positive as it passes past the edge on the other side with the unit properly ground balanced.

Now, raise the coil a little and the two outer signals disappear. So, it is easy to tell many signals.

This multiple response occurs with most objects including gold, so the signals one deals with are not a simple response if the ground balanced is advanced enough.

The signals are not linear and do respond differently when the coil is quite close or farther away from the object also, so the problem does get a little complex.

Now, on my PI, I have widened the ground balance adjustment to the point I can adjust it over its entire range so I can set it at points to cause different objects to switch signals from a typical positive response to a negative one. At or near ground balance, many iron objects will change. Well before that, silver and copper objects switch from positive to negative responses.

Gold, on the other hand, will switch when it wants to. Most smaller stuff will not switch, but from about 1/4 oz up, it will generally change from a positive signal to a negative signal somewhere around the GB point. Now, this is generally true for solid gold. Specimen type may change or it may not, depending upon the gold makeup in the rock, the mass involved and how it is connected within the host rock. So, there is no set technique that can be used to assure something is gold except at a particular setting. That is near my tin ID setting.

Even then, the tin ID feature I plan on testing requires I raise the coil a little to assure a more accurate read of the object. Larger gold will generate a strong negative response but the real small stuff, maybe a gram or so will or can generate a weak positive signal. Raise the coil a little and the small gold becomes a null signal while tin type trash is a nice strong response. Small pieces of thin metal, small tacks, and other small ferrous objects generally react with a nice strong positive indication. Much of the larger iron will generate a double blip type signal which is easy to recognize.

Gold or other non ferrous item such as lead, will generate a negative response that is generally quite smooth. So, telling non ferrous objects becomes somewhat easy to do, especially if the operator uses the GB control to generate the double blip on typical larger iron junk.

Again, all of this takes a little practice to obtain the greatest accuracy.

Now, I hope to try a different approach in the near future I hope will work. If it does, then the accuracy should improve.

Will it be fooled? Of course, but not often.

I have a couple of ideas but I need to see if what I have in mind is covered by a patent. I think my idea is ok, but I need to check some more.

Reg

[Eric Foster]

Hi Steve,

For the type of searching you do, would a long probe be a useful accessory? The first GS5's had a small probe clipped to the side as a pinpointing aid, but this was dropped in later versions. What I am thinking of though, is a long probe,say 30in, which can be used in less accessible places instead of a conventional coil. I have one here that I made about 10 years back for a different detector, but one could quite easily make such a probe for the GS5 type machine. Most of the shaft would be handle, but sensors can be made that have quite a respectable detection range. For example. I would expect to be able to detect a US nickel at 6 - 8in, maybe more. The outer diameter of the one I have is 1in and it is made of 1/10in thick fibreglass tube, fully waterproof and immensely strong. All the facilities on the detector are still fully functional including the all important ground balance, for mineralised areas.

Probes are strange things, some detectorists can't do without them, and others never use them. However, there is no getting away from the fact that for searching between rocks and in dense undergrowth, they are very useful. The one described above can even double as a walking stick.

Eric.

[kcoulson]

Eric,

that probe sounds like a hell of good idea.

Lots of places that you cannot put a coil into- like large crevices or between boulders and such

Ken

[wyndham]

Eric, that would be great for walking in shallow streams if the water didn't throw off the probe too much.

Would the it be arranged (coil & probe) or (either coil or probe)?

I must be hung up on the notion of the RX signal being a problmatic area in MD'er. It seems from my inexperienced POV that iron has a greater afinity to create a magnetic field but if it were possible, it would also seem that each metal or alloy would have it's own signature compared to iron and maybe show itself unique..

The second part is the audio response. There again my lack of knowledge may led me to stumble here ,but I know that if I take my music system that has 16 channels and mix them down to one, there will be a muddier sound it I don't leave room in each channel for the unique sound in that channel to exist without overlapping in the next channel before I mix down.

Is is reasonable to consider a housing with several rx coil windings ,each for a "channel". More of a parralell approach as opposed to serial.

Pardon the off track nature of my post but we have covered a lot of ground in this thread. Thamks Wyndham

[Eagle Spirit]

Hi,

I have been following along and learning some new things. The mention of probes for tight places has brought up a question that I have about a detector I saw advertised, the Facon MD 20. I see that they have a handle that can be added. Has anyone used one of these for probing between rocks? What kind of depth does the Falcon have? Any thoughts on this detector?

Thanks!

[Steve Herschbach]

Hi Eric,

Such a probe is absolutely needed, and in fact I was just looking at the Coiltek probes. They make one that is about 30 long. Would it not work on your units?

It is useful for more than just checking in dug holes. I was hunting some bedrock recently, and the smallest coils for the Minelab units I know of are the Joey coil and the 8" mono. But the fact is some types of bedrock have deep crevices and pockets that these coils cannot get in for being too large. Nuggets do like getting into deep holes and crevices and after that last hunt I decided I needed a probe to poke down in those holes. I'm certain there are nuggets I'm missing in those pockets.

And Eagle Spirit, I have a Falcon. It will hit pinheads and is great for scanning quartz for enclosed gold. But the range even on a large nugget is no more than an inch and on small stuff even less. Still, for tiny gold in certain types of bedrock it is a great cervicing toll.

Steve H

Hi Steve,

For the type of searching you do, would a long probe be a useful accessory? The first GS5's had a small probe clipped to the side as a pinpointing aid, but this was dropped in later versions. What I am thinking of though, is a long probe,say 30in, which can be used in less accessible places instead of a conventional coil. I have one here that I made about 10 years back for a different detector, but one could quite easily make such a probe for the GS5 type machine. Most of the shaft would be handle, but sensors can be made that have quite a respectable detection range. For example. I would expect to be able to detect a US nickel at 6 - 8in, maybe more. The outer diameter of the one I have is 1in and it is made of 1/10in thick fibreglass tube, fully waterproof and immensely strong. All the facilities on the detector are still fully functional including the all important ground balance, for mineralised areas.

Probes are strange things, some detectorists can't do without them, and others never use them. However, there is no getting away from the fact that for searching between rocks and in dense undergrowth, they are very useful. The one described above can even double as a walking stick.

Eric.

[montana]

Reg. The 8" coil is apparently the optimum coil for gold in the .1 or .2 gram range. A 5x9 elliptical is good for even tinier gold but the eliptical shape seems to cause it to be a little less stable in hot ground and more sensitive to hot rocks. The elip shape doesn't seem to be a problem with larger coils. I don't think that going any smaller than 5x9 or 8" round would work well at all on a PI. People ask me often why their PI won't pick up the tiny gold that I find on a regular basis. I usually know the answer to that before I even ask them what size coil they are using. Although a larger coil will sometimes pick up a surprisingly tiny nugget ,it usually happens when the nugget is very shallow and almost touches the EDGE of the coil and often won't pick it up on the center at all. A very small coil has a much more concentrated feild . On a nugget over 1 gram , the larger and more dispersed feild of say a 14" coil has no problems. Many people worry about losing depth by using a smaller coil, but if the gold is very small you will actually gain depth and in some cases a lot of depth by going as small as possible. In fact the larger coil will flat ignore tiny nuggets that give a very good strong response on the 8" coil. The difference is even more pronounced on porous or spongey gold . So, in certain cases it can be said that the 8" goes deeper than a 16" coil. This is one of the things that make it so hard to answer the question we all too often hear" How deep will it go?". I showed you a bottle of tiny nuggets in the 1/2 GRAIN size and smaller that I have detected with a GPX4000. When I'm really on my game I can pick up on these. I could get them with the GP3500 also at times but the signal was a little weaker to almost non-existant. I believe the better interference handling of the GPX4000 has a lot to do with hearing them easier and the signal is just more recognizable. Lack of coverage is the biggest drawback to using a small coil, but I don't usually use it on wide open spaces. I use it more for hunting small washes and terrain with large rocks, or trashy areas. It's much easier for me to pinpoint small targets with a small coil and I can work through trash much more quickly than with a large coil. I believe a novice is much better off with a small coil for this reason too. Someone who has struggled for months trying to find his first nugget would also be thrilled to death to pick out a .2 gram nugget which outnumber larger nuggets by a huge factor inmany places. He may have swung over several of them and just couldn't hear them. The one drawback to the small coils is that if you stick with it all the time you will eventually miss the large very deep nugget that is just beyond it's capabilities. There is a trade off !!! You probably know all this and it is probably all there in your notebook or your memory banks, but I know there is a lot of confusion about coils amongst detectorists and especially novices. These are my thoughts on it and some may differ with me, but I find more than my share of tiny nuggets and I credit the little coil for that. Just to be on the safe side I will almost always try a 14" round coil anyplace I've found small shallow nuggets . ----Bob

[Eric Foster]

Hi Eric,

Such a probe is absolutely needed, and in fact I was just looking at the Coiltek probes. They make one that is about 30 long. Would it not work on your units?

Steve H

Hi Steve,

I know the Coiltek probe well - I designed the sensor. The ferrite core used in that one is 2.75in long, but to get the ranges I was thinking of you would need to have a core around 6in long. It's like a bar magnet, the longer it is, the further the magnetic field extends. The Coiltek probe was designed for the SD's and would probably work OK on the GS5, although maybe not optimally. I still have some wound cores and will give it a try and see what ranges I get.

Eric.

[Reg]

Hi Montana,

If you see Jim French, let him know I expect to be at Rich Hill no later than Friday afternoon but will probably get in earlier. It all depends on when I am able to leave.

Now, your evaluation of small coils is in line with what I find with the GS 5. However, on the GS 5, I also find the narrow elliptical do not iron ID as well. They are plenty sensitive enough, but one can't distinguish metals as well. At least I can't.

Now, when I tried an 8" round coil, I was really surprised as to the depth capabilities of this coil on the typical size gold that is usually found. Needless to say, I am impressed with its ability. The only limitation I can see is the ground coverage per sweep.

Most people using ML's indicate they get more depth with a mono than with a DD. Now, I really haven't found this to be the case with the GS 5 and similar detectors. In some cases, I have done better with the DD's because it is generally quieter. The limitation I see with a DD is the rather narrow zone of detection down the center of the coil. This zone does appear to balloon out deeper into the ground but doesn't cover the entire coil surface like the mono.

On the plus side, the DD does have a tendency to give a nice sharp signal on the GS 5 to smaller gold. At least, the coils I have used and built do seem to work well for the small stuff. As an example, the "invisible nuggets can be detected almost the length of a DD. On a mono coil, the signal is mainly confined to near the coil windings. The signal is so weak to begin with, it is almost not audible in or near the center. This can get confusing to a novice who detects a very small nugget and may think the loudest signal is when it is centered on the coil when the loudest signal may be when the nugget is at the edge.

One of the other benefits of a smaller coil such as the 8" is the fact one can normally get the coil closer to the ground. This is very important when hunting the small stuff that doesn't generate a strong signal to begin with. Getting the coil an inch or more closer may mean the difference between detecting a small nugget and not detecting it.

This is where simple testing can show what is happening and can show the advantages and disadvantages of each coil. Unfortunately, in some cases, terrain and noise environment can alter the tests. So, in some areas, a mono may work best and in others, the DD may excel. At least, that is what I have found using my PI's.

Reg

[FlakMagnet]

Montana,

your last post is absolutely spot on.

It mirrors my experience exactly and I wholeheartedly recommend that

people read what you've said closely.

They will find gold just using the information

from that post alone.

Flak

[Steve Herschbach]

Hi,

Yeah, I also agree with Montana. Small coil sizes are underutilized, especially by owners of PI units. I would still like to see even smaller coils/probes just for getting into pockets and wide crevices. But it is true with PI units that making coils smaller will not in and of itself get you smaller gold like with VLF units. Getting closer to the gold will.

The Coiltek probes are really too small. Does anyone have one of the old 3" probes they would part with? I'd be interested in buying one.

Steve Herschbach

[seeker]

I like the 8" round I did use it a little this summer and as you say these coils are site specific. For most of my purposes the 14E does a magnificent job, finding small bits that amazed me. As a rule I really don't care for Ellipticals and would avoid buying one, but buy the same size round as they seem to be a deeper seeking coil and that may be the way the field is introduced or shape of the field as it is swept along. Monos seem to be the coil of choice right now for the 4000 and that comes back to the adjustability of this unit. The 14E I already had and did not get much use out of it on the 3000 or 3500 but it was my primary coil and is now looking pretty ragged but will get the Epoxy treatment on the outside... Enjoying the posts, not too technical, but just the right amount of information for the lay person to make use of ...... Good Hunting Geo

[nuggethunting]

Hello Reg,

Give me a call on my cellular when you arrive on the Hill. I'm going to be camped on the claims from Friday morning to Sunday afternoon. I'm bringing some of those copper specimens that you asked about and will also have a Coiltek probe if you want to see how it will work on your detector.

Cell - 602-909-9008

Talk with you later,

Rob Allison

[montana]

Geo. It's hard to beat the 14E for an every day coil in most places in the U.S. Whether you use a narrow eliptical like the first Nugget Finders or the broader design now used by both Nugget Finder and Coiltec. I believe that Minelab has a 15" E also which would be in the same category. It is such a versatile size and shape with good sensitivity to small gold and very good depth on all sizes of gold. The 8" round just gives a better signal on the the very smallest nuggets and gets into tighter places. I think the worst mistake a beginner can make is to start out with a 20" or 18" round coil, and I've seen this happen often. In his enthusiasm to go deep and find a huge nugget which he is sure are all over the place if you go deep enough, he may be doing a bit of overkill. What usually happens is that he finds himself in a trashy place and the coil is over 3 or 4 targets at once. Nothing is more confusing and frustrating than trying to pinpoint just one of these targets with a 20" coil and would make an old hand want to pull out his hair. For this reason I always recommend either the 8" round or a 14" E as their first mono coil. Both are very easy to pinpoint with and won't wear out his arm which is not accustomed to swinging a detector for hours on end. The 14"E eliminates the quandry of what coil to use in most cases. It will cover most bases and for that reason it is by far the best selling coil size in the U.S.. With all that being said, there are places that the 8" coil is the way to go. It has been a constant in my coil box dating back to when I first tried one on my SD 2000. That was when I realized that the PIs were more than capable of responding to very small gold. It made a totally different machine out of the old SD2000 which had previously sat in the closet when I was beeping the bedrock for small gold. After seeing the results with the 8" coil on it, my Gold Bug then became the closet queen.----Bob

[Eagle Spirit]

I have been looking for a probe and I found the DetectorPro Uniprobe site and wanted to ask if anyone has tried that probe. I see on the site that Rob and Steve are both listed as dealers. What kind of depth would you have with the Uniprobe? Finding a probe to get between some rocks and in crevices would be a bonus.

Here is a link, http://www.detectorpro.com/uniprobes.htm

[Steve Herschbach]

Hi Eagle Spirit,

The Uniprobe is easily the best probe I have used. It will hit coin size targets at 4-5 inches. It has poor sensitivity to smaller gold, however, and I've not tested mine to see where the cutoff point might be. I use the one built into the headphone. I tried the Pocket version, but since I always tend to use headphones I could not hear it well so upgraded to the headphone version.

The nice thing is it works with most detectors, although the SD/GP units pump out so much power it is very noisy used next to them when they are on. I usually turn the Minelab off to quiet it down. Great for poking around in holes looking for junk that often ends up just off to the side of the hole. I'll be digging a hole to China having just missed a spike as they often read a few inches off each end.

I'll check one out on some nuggets but I'm doubtful it will do very well on them. It is tuned more for coin detecting. I suspect a probe plugged into the Minelab will do better. I have a Coiltek probe now so will do an official comparison soon.

Steve H

I have been looking for a probe and I found the DetectorPro Uniprobe site and wanted to ask if anyone has tried that probe. I see on the site that Rob and Steve are both listed as dealers. What kind of depth would you have with the Uniprobe? Finding a probe to get between some rocks and in crevices would be a bonus.

Here is a link, http://www.detectorpro.com/uniprobes.htm

[Ridge Runner]

If you go to White's detector site you will see the picture of the MXT and DFX with the words saying Fall Is The Time To Go For The Gold.I'd think that we all knew that.The big question is will White's have their new gold detector on the market before fall and winter is over with?

I do believe we won't see it until they( White's ) are sure they have a winner.Being a big user of their coin machines over the years I've never seen one detector that didn't meet up to what they said it would do when it hit the market.

If they want to out do Minelab they could add a digging arm on it.

The thing with this post it's not at 20 thousand so I just couldn't let it die.

Chuck Anders

[Reg]

Hi Chuck,

I was happy to see this tread hit 10,000 and now it is on its way to 20,000. Hopefully, that will not take too long. That isn't bad for a thread discussing a detector that isn't on the market yet.

Chuck, I can certainly understand Whites wanting to get it right the first time. The problem is, the development of the ideal design is an ongoing thing. So, the question is, just where does one stop and take the unit into production.

As an example, a couple of months ago, the GS 5 I was working on did quite well, depth wise and I thought we had about reached the max. With those mods, the GS 5 was a vast improvement over the original. Well, that wasn't true and now with a couple of new unique mods, the overall sensitivity, especially to small gold has increased quite a bit.

One does have to keep in mind that my experimenting is with a GS 5 and not the Whites unit so my testing doesn't necessarily reflect what is going on at Whites. They could be doing something totally different as far as I know.

Getting back to my personal design modifications, my recent testing and comparing GS 5's at Rich Hill recently indicates my latest mods have added as much as 2" or more to the depth capability on a buried 1 gram nugget and this is over a previously modified GS 5 which already had improvements that were obvious. This additional depth capability was obvious even with the gain or what is called the Range control reduced significantly when compared to the other detector. I had the control only at about 1/4 of maximum. I am not sure just what could be the case with the control at or near maximum. At maximum I would have had to alter my hunting techniques which I preferred to not do. I found I liked the overall way the GS 5 operated with the gain reduced, and it matched my hunting technique, so I left it that way even during testing.

Now, on a little different note, my thin metal trash ID didn't work quite as well on the GS 5 and needed a mod I was reluctant to do without the owners approval, so it couldn't separate the smallest gold from the tin. Any larger nugget maybe a couple of grams or bigger could easily be distinguished from tin. I could tell the smaller ones by raising the coil some and this allowed me to determine the vast majority of the junk with little effort. So, it did work but not like I would have liked.

I know the fundamental design works and could work better because the same design was built into a low powered unit and it worked as expected when I tested it at Octave. I could easily distinguish tin junk from gold even as small as a gram or less without having to raise the coil. In fact, testing a 6 grain nugget also responded like I expected so I could easily separate this small of a nugget from tin junk.

As far as the size of tin junk that could be eliminated, I found anything larger than a dime or so could be determined. So, little of this type of trash was a problem on the low powered unit without having to do anything but a quick test.

Now, I need to fine tune the GS 5 iron ID to match the low powered unit.

As for future mods to the GS 5, I have one coming back to me so I can mess with my own unit shortly. That way, I don't have to worry about doing something the owner might not like. When working on other people's units, I am conservative. On my own, anything goes.

Reg

[fredm]

So,Reg;

Where has Dave and the PD gone to??? All these machines to choose from, if they would materialize.....i think you are gonna get to 12,000...lots of interest in this wandering thread. How did you do down RH way?

Fred

[Reg]

Hi Fred,

I didn't find anything at Rich Hill but that was ok. I did manage to get some time in testing some of the latest changes I have come up with. Right now, the GS 5 I tested was nothing like the original.

I did manage to have the 4wd go out on my vehicle and that kept me from the Saturday morning pushes and tied up the better part of two days of my vacation getting it fixed. So, my hunting time was limited. As they say, stuff happens.

As for the PD, my latest conversation with Dave was he was waiting for the faceplate for his Nemesis. So, hopefully by now, that problem has been taken care of. I do have to get back with him to see what the forecast is as to when one can expect to see them. Hopefully, it won't be much longer.

As for the Whites, I wish I had some knowledge of just when they will introduce it but I don't. My guess is it will not be that long before there is some news and at least, maybe, some of the prototypes will be seen publicly, At least, that is the rumor on another forum. Lets hope it is true. This will mean, more will be on the way shortly.

On a different note, with all the fires out your way, I hope everything is ok where you are at.

Reg

[dave wiseman]

Reg,what are your insights into what type of discrimination on the new P.I.,or if it will have any at all.Perhaps a Iron I.D. more advanced than my GMT?...........Dave

[Reg]

Hi Dave,

Since the Whites unit is based upon the GS 5 design, I would expect the same basic iron ID features as the GS 5. Is this design perfect? Nope, but it does work for many larger and thicker iron objects. The problem of trying to identify tin can type junk is still difficult with the initial GS 5 design. Using some generic analysis does work and that is what some GS 5 owners use. I have had some say they can identify most iron junk but it took them a while to be able to do this.

So, it is my guess and people have to remember that this is just a guess on my part, the new Whites will be quite similar in its abilities as the present GS 5 and, as such will do a decent job on some ferrous items but have difficulties with others. The others will include thin flat metal such as pieces of tin cans or similar metals.

Not having used the GMT and not having used my GM4 that much, I can't say which is best (the GMT or the GS 5) with any accuracy. Personally, I have never found any iron ID to be foolproof, but I have heard from some Whites owners their GMT's are about foolproof once a person fully learns it.

Now, trying to determine iron is not that easy even for a VLF as many people find when they use one for coin hunting. It is even far more difficult on a PI. The reason is, certain ferrous trash can simulate a coin or other non-ferrous item quite well and simply fools the detector. The reason is because the ferrous object contains both conductive and magnetic properties, both of which can have an effect

So, some people think that what is needed is a form of magnetometer built in to help with the determination. Since a magnetometer doesn't respond to gold but does detect ferrous items, one would think this is the ideal solution. Well, unfortunately it isn't. The reasonably priced magnetometers out there do not respond well to tin can type junk either, so they don't do much of a job of helping on this type of trash. They do better on thicker metal but that is what the GS 5 does a good job on also.

I have tried both my own magnetometer design and the Fisher FX3 (with my own design being superior) and neither did that well in the tin can type junk.On should also keep in mind that certain rocks will also cause a response depending upon the amount of iron oxides in the rock. My original idea was to use the magnetometer for detecting meteorites. The idea sounded good at the time, but the flaws became noticeable quickly.

Now, having said all of that, it is also my guess that any iron ID unit that is considered accurate will also fail at times. If the gold is in a rock matrix that has sufficient magnetite, I would expect this type of specimen to be rejected as iron at times. It will depend upon the amount of oxides as to just how it does respond, but it could respond as a piece of ferrous junk. If a gold nugget is sitting near a rock having sufficient magnetite, the same problem could exist. This is one of the big problems with any VLF. Unless the operator knows their detector well, they could easily ignore a decent size nugget if it is sitting close to a piece of magnetite or is a specimen having a lot of magnetite in the host rock.

So, this iron ID thing is much more complicated that one might realize. That is why I have tried to explain some of the difficulties in this post. There is more that can be said and tricks that can be done, but it would take a whole lot more space. So, people should not expect perfection because they are not going to get it.

BTW, this post just gave me another idea to try. Thanks.

Reg