Steve Herschbach

I certainly do not discount Dave and now with Carl Moreland on board I tend to have faith in what might happen with First Texas eventually. It is no secret that they have been working on multi frequency and pulse induction machines for years and that something should hit the market in the not too distant future. http://www.detectorprospector.com/forum/topic/555-new-fisher-pulse-induction-multi-frequency-detectors/ I do worry the bean counters call the shots at First Texas more than the engineers however. I believe they would rather back $300 detectors than invest large sums into expensive high end machines that they view as niche products.

That quote was from 2009 Rick. First Texas is a company chasing mass market sales. Follow the patents if you are looking for which companies are investing in developing new cutting edge technologies.

Ray, I made the 10K thing up to illustrate the point of such a detector being desirable. I have no idea when or if such a detector will appear, or what it will cost. On the other hand if I could get my hands on a PI that discriminated to full depth for 10K I estimate I could pay for it with gold found in less than two weeks at several locations I know of.

I had a recent scare running my truck battery dead while charging stuff. A portable rechargeable jump starter is a good idea. In my case I now have a new deep cycle battery with solar panel that I toss in the truck to use as a charging station and emergency backup.

Very nice - my kind of work! Being lazy and cheap (I prefer to think efficient and frugal) I got an Ace Knee Brace with Dual Side Stabilizers for $15 It is neoprene so it is stretchable and the whole thing is velcro covered so it is very versatile in how the three straps can be wrapped. Actually looks pretty neat and easy to change battery without completely removing. Now that I have used it for some time I am happy enough with it that it is probably all I will use. If you want a pod cover, the pod cover for the Minelab X-Terra series will work just fine but then so will a plastic sandwich bag. I do not cover the pod myself except for using a screen protector but this is what the X-Terra cover looks like when fitted on the GPZ 7000.

It is all a matter of degree. A little bit of salt will produce a little bit of an issue. Simply raising the coil could solve that or reducing the gain or the threshold, etc. More salt will have more effect to overcome. Moisture is the big thing with salt soil. If wet you can really have big problems. The same ground when bone dry may have minimal issues. Chris is spot on though but again it is a spectrum of issues and solutions. If the salt response can be dealt with while not having to reduce the threshold that would be preferable. But what if the operator simply cannot tolerate or differentiate a nugget signal from the salt signal? Then compensating with methods that in theory reduce sensitivity is the answer. We can go in circles like this: A. "I am driving my car too fast on a winding road and am afraid I am going to crash. Should I reduce my throttle setting?" B. "Well of course, you do not want to crash and burn!" A. "Yes, but if I reduce my throttle setting, won't I lose speed? I do not want to give up performance." You have multiple settings on your detector that must be used like salt, pepper, and other seasonings in the stew. The goal is to minimise the ground signal while enhancing the nugget signal. You are looking for the combination that most makes the nugget stand out TO YOUR EAR. Some people like myself can listen to constant noise as a sort of threshold of its own and pick out a target signal. Others would argue that getting the quietest, smoothest threshold possible is paramount. I rebel at the concept of a certain setting for everyone because I do not think we are all the same in how we hear and how our brains process sounds. The smartest thing to do is spend time experimenting in the field in real conditions with found targets or test targets to find what works best for you.

Well, we finally know what it is that Minelab was working on, and ZVT is not half sine technology. Rumor (sorry Chris) has it a new White's hybrid may be seen by year end? (Edit - note this post was in 2015) We will see. Can you imagine having a PI that discriminated like a VLF? How much is something like that worth to people? Another 10K detector? I would be first in line.

1. The GPX can scrub the ground usually with no problem. The settings used on a GPX to deal with salt ground depend on the amount of salt in the ground and how wet it is. 2. The GPZ can normally scrub the ground with no problem. JPs suggestion was a solution to a potential problem as described at my post at http://www.detectorprospector.com/forum/topic/970-minelab-gpz-7000-a-super-vlf-saturable-soil-tips/ 3. The potential ways for alleviating saturable ground and salt issues are outlined at my post, but there appears to be no "solution" for running the GPZ on salt ground. It is problematic, and if the salt ground is bad enough it may be unworkable with the GPZ. Milder salt ground can be dealt with, but the machine will probably be noisy. It all depends on how much salt is in the ground and how wet it is, plus how much iron mineralization exists. This is a range of issues, not a single problem with a single solution.

That is so weird. I just spent over an hour typing up a post on this subject at http://www.detectorprospector.com/forum/topic/970-minelab-gpz-7000-a-super-vlf-saturable-soil-tips/ and after I post it I come up for air and see this! I agree the benefit is not as much as I would have hoped Chris. The point is not that raising the coil eliminates the problem and I suppose if everyone has a GPX 5000 sitting around that is an alternative. The point is simply what can you do if faced with the situation to possibly help alleviate it? A dedicated salt mode is the easy preferred solution, but that also comes at a cost as my other post mentions. In my case I prefer some noise to total elimination of the salt signal but I think we can all agree being able to choose what level of salt rejection works best for each of us via a "Salt Reject" control would be preferable. For now if you have a GPZ 7000 and run into saturable ground or salt ground you can employ these tips as best you can, use a different detector, or just go somewhere else. Be fun to have you run your salt mode quiet GPX 5000 against my moaning groaning GPZ to see what is better on found targets.

This is not a technical paper by a technical genius. My smarts tend to be in the practical application of metal detector technology in the field. I am less concerned by the theory at work under the hood than the actual detecting characteristics revealed in actual use. I would very much welcome smarter people than I pointing out any obvious technical inaccuracies below! It has been clearly stated that the GPZ 7000 is not a pulse induction metal detector. Yet it sounds and acts deceptively like previous Minelab pulse induction models, just enough to get people into trouble. I think it is people who are expert with Minelab pulse induction detectors that are having a harder time adjusting to the GPZ 7000. My background comes far more from the VLF side of things. VLF is a misnomer, because it means Very Low Frequency, and was originally nothing more than a subset of induction balance or transmit/receive (TR) detectors. From http://www.vlf.it/frequency/bands.html ULF ultralow frequency 300Hz to 3000Hz VLF very low frequency 3kHz to 30kHz LF low frequency 30kHz to 300kHz Thus it can be seen that the White's GMT at 48 kHz and Fisher Gold Bug 2 at 71 kHz are actually LF (Low Frequency ) detectors, not VLF detectors. And a White's V3i running in 2.5 kHz single frequency mode is running in the ULF range. But these days VLF has become a more generic term referring to induction balance detectors in general. I used to always think in terms of Induction Balance and Pulse Induction as the two different methods used for inducing currents into the ground by modern metal detectors. But things are getting more complicated. Most single frequency induction balance detectors use phase shift for ground balance and discrimination, whereas Minelab BBS and FBS multi frequency detectors rely on time constants, blurring the line between time domain pulse induction and frequency domain induction balance. Minelab is addressing that by now referring to all non-pulse induction detectors as Continuous Wave or CW detectors. Pulse induction detectors have a transmit period, and a non-transmit (zero transmit) period. From http://www.minelab.com/__files/f/254716/KBA 24-1 Basics of the GPZ 7000 Technology Zero Voltage Transmission (ZVT).pdf "CW means Continuous Wave and includes all technologies that do not have zero transmit periods (almost all technologies other than PI)." The GPZ 7000 is most definitely not a pulse induction detector in that the detector is always transmitting into the ground. But where a PI measures the time constant of items from the point where the transmit period ends the GPZ measures from the instant where the transmitted field polarity reverses. Again, like with the BBS and FBS detectors Minelab is mixing continuous wave transmission with time domain processing. OK, blah, blah, blah in layman's terms and no doubt not entirely accurate from a technical standpoint. But close enough for me to have an epiphany recently while running the GPZ 7000. It acts like a super VLF detector more than a pulse induction detector. The ground responses, hot rock responses, salt responses, and gold responses are not that different than what I might expect from a mid-frequency VLF detector albeit one that is much, much more powerful. Everything in metal detecting tends to be a trade off or come at a cost. The Minelab SD/GP/GPX series of pulse induction machines were a progression with later models designed to handle salt ground and hot rocks that earlier models could not handle. The problem is when you tune out a salt signal you tune out weak gold signals. When you tune out certain hot rocks, you tune out certain types of gold signals. Savvy operators always knew that by running in older "Normal" modes they would have to deal with more noise and possibly dig more hot rocks but they could also find gold that more aggressive timings missed. When I run the GPZ 7000 from a purely operational standpoint it acts and feels like a super VLF and basically that is what it is, with a transmission mode that leaves the ground with less ground signal to deal with than that generated by a high power pulse, employing an advanced coil design, and advanced ground balancing algorithms to deal with ground mineralization while still deriving the extra power and sensitivity inherent in continuous wave detectors. I am curious where Bruce Candy's head was when he came up with the ZVT concept, but it appears to me to derive more from the BBS and FBS line of thinking than being something related to the PI machines. The point of all this? Forget about how your PI acts and works and if anything treat the GPZ more like a Super VLF than a pulse induction detector. Certain old VLF tricks work with the GPZ. The main one being - get that coil off the ground!! Saturable Soils Again from http://www.minelab.com/__files/f/254716/KBA 24-1 Basics of the GPZ 7000 Technology Zero Voltage Transmission (ZVT).pdf "The GPZ 7000 coil must be symmetrical about the left‑right axis because ZVT transmitted signals cause a type of signal to be produced from the ground which is absent during PI receiving periods. This ZVT receive signal is from something called soil magnetic hysteresis. If an asymmetrical (un‑symmetric) coil like a Double‑D is used by a ZVT detector (asymmetrical because the transmit coil is on one side and the receive coil on the other), a signal is produced which depends on the speed at which the coil is swept over the ground (and how close the coil is to the ground), and the audio tone will be higher going in one direction (for example left to right), and lower when sweeping in the other direction, which would clearly be unacceptable." The text goes on to say the Super D coil design is employed to avoid this problem. A better word than avoid may have been reduce. The issue has been reduced but not totally avoided. Have you run into it yet? The GPZ producing a rising high tone as you swing one direction, and a descending low tone as you swing the other direction? Another less flattering way of thinking about it is that the GPZ moans and groans as you swing. This is the common response over salt or alkali ground. The intensity depends on the amount of salt in the ground but also on the speed at which the coil is swept over the ground and how close the coil is to the ground. The solution might include changing gold or ground modes of course. But irregardless of that one obvious solution of to simply slow down and keep a very constant swing speed. This will moderate the effect and still allow nugget signals to stand out. The less obvious solution and one that many people will have a very hard time accepting is - raise the coil. Many VLF detectors will overload on bad ground and the simple answer is to raise the coil to eliminate the overload. This is counter-intuitive to people who always scrub the ground with the coil. How can raising the coil add depth? It can and it will if the electronics are being swamped with excessive receive signal. Once again from http://www.minelab.com/__files/f/254716/KBA 24-1 Basics of the GPZ 7000 Technology Zero Voltage Transmission (ZVT).pdf "In any of the above settings, it pays to swing the coil an inch or so above the soil surface if the soils are considered saturable (VRM). Saturable means that a detector ground balances well if the coil is raised and lowered down to about a few centimetres above the soil surface, and for the worst saturation, down to several centimetres, but not if the coil is swung up and down to a height lower than these saturation ‘height thresholds’ (e.g. down to the soil surface.) In addition, the degree of (VRM) soil saturation is considerably less for Difficult or Severe than Normal. As the metal detector coil is moved towards a soil, the transmitted magnetic field in the soil gets stronger. This causes a (very) small degree of VRM signal ‘saturation’ that happens to cause the resistive signal relative slope of the tilt to change. This is why the amount of VRM soil saturation is far less for Difficult and Severe than Normal. Soil saturation often requires the user to operate the coil several centimetres above the soil surface for best results. However, whilst soils do have resistive signal that are very accurately log‑linear, unfortunately this is not perfectly accurate for some soils, and, because the GPZ 7000 has such very high sensitivity, even miniscule deviations in the straightness of the line of the log‑linear resistive signal will cause ground noise signals. Severe is less sensitive to these miniscule deviations than Difficult. Whilst the GPZ 7000 does not have a dedicated ‘salt’ detection setting (saline soils), the best Gold Mode setting for salt soils is Extra Deep." Extra Deep is an extra long time constant mode and so is less sensitive to weak signals from both salt ground and small gold. It is the classic metal detecting trade - you cannot get super sensitive to gold without getting sensitive to salt. Machines can totally eliminate salt effects but never think it does not come at a cost in lost gold. The trick is to get the larger stuff, and the tips above are the same you would employ with any hot VLF in an attempt to deal with saturable ground. The simplest one was the one I wanted to highlight because it just goes so much against the grain. Raising your coil above the ground can actually add more depth! None of these solutions is a magic bullet or will totally eliminate the issue on the GPZ 7000. It will succeed to a greater or lesser degree in different locations with different soil conditions.

I have found thousands of nuggets with the various Goldmaster models. Great detectors, no doubt about it. The bottom line is the Gold Bug 2 has a small advantage on the tiniest gold due to the much higher operating frequency. I also like the compact light weight design and option to hip or chest mount. However, the Goldmasters will penetrate deeper on larger nuggets than the GB2 - like everything detecting there is a trade off for jacking that frequency so high. But if it is bigger deeper I am after, I will use a PI. Last fall I had a Goldmaster V/SAT, GM3, GMT, and Gold Bug 2. Too many overly redundant machines, with the older ones kept out of nostalgia more than anything. The fact is if I needed a hot unit the GB2 was always the one I grabbed so I sold all the others.

I have my PI detectors pretty well sorted out but the VLF units are driving me bonkers. The vast majority of my hours are spent using a PI yet I have a pile of VLF detectors. I just have a hard time compromising and tend to have several machines when realistically one or two would do the trick. I am determined to weed them out but may have to throw a couple babies out with the bath water. There are only two right now I think I can say for sure I will keep. Fisher Gold Bug 2 - 71 kHz screaming hot on the tiniest gold. Great for lode prospecting in particular. White's V3i - 2.5 kHz or 7.5 kHz or 22.5 kHz or all three simultaneously. If this were not enough it runs my Bigfoot coil. My urban jewelry detector.

What caught my eye on the Treasuremaster Pro is optional automatic ground tracking for under $400. I do not always use ground tracking and in fact used to generally avoid it, but newer algorithms are making it a more viable option all the time. The SDC 2300 for example only operates in tracking mode and although the GPZ 7000 offers a manual ground balance mode so far mine has stayed in ground tracking mode. Bottom line is if I have the choice I want my detector to have BOTH fixed and automatic ground tracking but usually you pay a lot more for that option.

My goal is to get down to six or no more than eight detectors but that is going to be really hard for me. A couple detectors I really like may have to go. Tom, many prospectors make money with their detectors and so they are an investment. The gold found with the last detector pays for the next one.

Oops. It is DI2 on the FORS CoRe and BST (Boost) on the FORS Gold. I have both detectors. Different names for same mode. DI3 is a three tone more more suited for coin detecting. Straight all metal mode is the General mode. I corrected the original post. Sorry for the confusion!

You're welcome! Lower frequency, will penetrate deeper on large gold than the GB2.

Long Scan just means it is longer than it is wide. Remember, elliptical coils were still rare back then so just the shape was unique. It is a concentric coil that came with the Goldmaster II and V/SAT.

I really really like my FORS Gold. But I can find gold about as well with any 13 - 19 kHz machine and I assume most people can also.

I never buy gold. Never will. I subscribe to the LuckyLundy school of thought - Find Low and Sell High! It is easier to sell high when the price is high, but right now the price can go low as possible as far as I am concerned. People will stay home and I will have the goldfields to myself, and maybe more claims would get dropped, opening up even more places to prospect.

Hi John, The FORS Gold Pro Pack with three coils, recharger system, etc is a bargain here in the U.S. at only $850 As a 15 kHz unit it will not touch the Gold Bug 2 nor even the GMT for small gold capability. Since you also already have the 14 kHz MXT the FORS Gold would be redundant.

Goldmaster concentric coil by itself on eBay right now at http://www.ebay.com/itm/Whites-Goldmaster-II-2-10-6X10-Longscan-Metal-Detector-Search-Coil-50-kHz-/151683818463?pt=LH_DefaultDomain_0&hash=item23510f63df Looks brand new. And a GM3 on eBay also at http://www.ebay.com/itm/whites-goldmaster-3-missing-coil-and-lower-rod-/281694120735?pt=LH_DefaultDomain_0&hash=item4196472b1f

Hello John, Yes, Goldmaster II, Goldmaster V/SAT, GM3 and GM 4/B all came with the concentric coil. The 6" x 10" DD was introduced as an optional accessory soon after the GM 4/B was introduced and is the stock coil on the GMT. Get a concentric coil or the GM3? The only way to get the concentric coil generally is to buy one of the old models like a Goldmaster II as cheap as possible. The GM3 comes up for sale now and then on eBay. Lots of information on Goldmasters and coils on this website at http://www.detectorprospector.com/gold-prospecting-equipment/whites-electronics-gmt-metal-detector.htm

I am using a Camelback style rucksack with the GPZ bungee attached to the right shoulder. Not as bulky as the full Minelab harness and seems to provide me with sufficient support for long days of detecting. While also giving me a ready water supply and place for emergency gear.

Here is a chart from an interesting article at http://www.kitco.com/ind/Holmes/2015-04-06-SWOT-Analysis-Could-Gold-Production-Peak-in-2015-as-Exploration-Spending-Drops.html that speculates gold production will peak this year and drop going forward due to a dearth of new discoveries in the last 20 years, even as gold prices moved higher.

I hope the world does not fall apart. I do think supply and demand does matter with gold however. We have pretty much exhausted the easy sources of gold and are approaching a "peak gold" production point any moment now. New mines are not being discovered and developed at the same time the number of potential buyers is expanding worldwide. Demand will only increase while supplies get ever tighter. The price is almost bound to strengthen long term.