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Found 100 results

  1. No, I'm not talking about politics and being a Moveon.org trainer. I'm talking about resistivity detecting. Electrical resistivity tomography From Wikipedia, the free encyclopedia Electrical resistivity tomography (ERT) or electrical resistivity imaging (ERI) is a geophysical technique for imaging sub-surface structures from electrical resistivity measurements made at the surface, or by electrodes in one or more boreholes. If the electrodes are suspended in the boreholes, deeper sections can be investigated. It is closely related to the medical imaging technique electrical impedance tomography (EIT), and mathematically is the same inverse problem. In contrast to medical EIT however ERT is essentially a direct current method. A related geophysical method, induced polarization, measures the transient response. The technique evolved from techniques of electrical prospecting that predate digital computers, where layers or anomalies were sought rather than images. Early work on the mathematical problem in the 1930s assumed a layered medium (see for example Langer, Slichter). Andrey Nikolayevich Tikhonov who is best known for his work on regularization of inverse problems also worked on this problem. He explains in detail how to solve the ERT problem in a simple case of 2-layered medium. During the 1940s he collaborated with geophysicists and without the aid of computers they discovered large deposits of copper. As a result, they were awarded a State Prize of Soviet Union. Andrey Nikolayevich Tikhonov, the "father of ERT" When adequate computers became widely available the inverse problem of ERT could be solved numerically, and the work of Loke and Barker at Birmingham University was among the first such solution, and their approach is still widely used. With the advancement in the field of Electrical Resistivity Tomography (ERT) from 1D to 2D and now-a- days 3D, ERT has explored many fields. The applications of ERT include fault investigation, ground water table investigation, soil moisture content determination and many others. In industrial process imaging ERT can be used in a similar fashion to medical EIT, to image the distribution of conductivity in mixing vessels and pipes. In this context it is usually called Electrical Resistance Tomography, emphasising the quantity that is measured rather than imaged. https://en.wikipedia.org/wiki/Electrical_resistivity_tomography Here is one unit being offered by Kellyco. https://www.kellycodetectors.com/blog/find-gold-resistivity?utm_source=email&utm_medium=BlogBUTTON&utm_content=BlogGoldResistivity&utm_campaign=MSTRBlogGoldResistivity20170624&utm_term=Lead_SuperBowlGiveaway2016 Mitchel
  2. As a rule do the lower vlf frequencies punch deeper than the higher ones, say 4.8 verses 14khz? But what is the trade off? Are some frequencies better for silver coins? How does iron enter into this? Need to understand how this all fits together! Thanks for any and all answers.
  3. A lot of detectors let you notch out (silence) a target identification (TID) band but are there any that let you choose which tone (audio frequency) to assign to a band?
  4. I do what I can to foster competition that develops alternatives to the all too common single frequency VLF detector. There are plenty of options out there, but in my opinion they all weigh too much or cost too much. Usually both. I envision people out there with a popular VLF prospecting machine like the Gold Bug Pro, GMT, AT Gold, X-Terra 705, etc. These machines all sell for around $700 and weigh 2.5 - 3.9 lbs. They would like to add a ground balancing PI (GBPI) to what they have. I think that for "normal people" with normal budgets a machine under $2K and under four pounds just makes sense. It would be more than twice what they spent for their VLF, and in this day and age there is no reason why a decent PI should weigh over 4 lbs. To clarify what I am talking about here, I should say that for many people a $700 single frequency detector is a great place to start and in many cases is all a person ever needs. However, there are places where extreme ground mineralization and mineralized rocks (hot rocks) severely impede the performance and use of single frequency detectors. Alternative technology to deal with these conditions has been developed, by far the most familiar being the Minelab ground balancing PI (GBPI) detectors. These differ from common PI detectors by having the ability to ground balance. Other brands have offered the Garrett Infinium and ATX and the White's TDI models. These detectors are used not just for prospecting but also by relic hunters, beach detectorists, and others who face challenges regarding ground mineralization and single frequency detectors. Frankly, in my opinion GBPI technology is largely maxed out. The main room for improvement comes now in better ergonomics at lower prices. This challenge therefore limits detectors to those that weigh under 4 pounds with battery included, and which sell brand new with warranty after discounts for under US$2000. Detectors need not be ground balancing PI models, but must offer similar ability to ignore mineralized ground and hot rocks that trouble single frequency detectors. I am going to rate detectors as to their relative performance using what I call the "Minelab Rating Scale. Details here. 1. Minelab SD 2000 - crude first version, very poor on small gold, excellent on large deep gold 2. Minelab SD 2100 - vastly refined version of SD 2000 3. Minelab SD 2200 (all versions) - adds crude iron disc, ground tracking 4. Minelab GP Extreme - adds greatly improved sensitivity to small gold, overall performance boost. 5. Minelab GP 3000 - Refined GP Extreme 6. Minelab GP 3500 - Greatly refined GP 3000, last and best of analog models 7. Minelab GPX 4000 - First digital interface, rock solid threshold 8. Minelab GPX 4500 - Refined GPX 4000, solid performer 9. Minelab GPX 4800 - Released at same time as GPX 5000 as watered down version 10. Minelab GPX 5000 - Culmination of the series, current pinnacle of GBPI prospecting machine technology. All Minelab models leverage an existing base of over 100 coil options from tiny to huge. I am a very practical person when it comes to prospecting. I know all the existing models and options by all brands very well, perhaps better than almost anyone. This is the way I look at it is this. If I personally were to spend a lot of money to go to Australia for one month, and needed a GBPI detector, considering machines past and present, what would I take and in what order of choice? Put aside concerns of age, warranty, etc. just assume functioning detectors. Here is the issue in a nutshell. On the Minelab scale of one to ten as listed above, I would be generous in rating the White's TDI SL as a 2. Same with the Garrett Infinium which I will mention in passing as it is no longer being made. If I was going to spend a month of my time and a lot of money going on a prospecting trip to Australia, I would choose a TDI in any version over the SD 2000. I might go with a TDI Pro over a SD 2100 but I would have to think real hard about that, and when push comes to shove I would go SD 2100 were it not for the realities of age I said to ignore. A newer TDI Pro might be a better bet than a very old SD 2100 from a reliability standpoint, but again, this would be a tough choice. The TDI SL not really. In my opinion I would be shooting myself in the foot to go on this hypothetical trip with a TDI SL instead of a SD 2100. You see the problem now? The Garrett ATX fares better. I would rate it a 3, roughly analogous to the SD 2200 variants. Still an agonizing choice really and the ATX being new versus SD 2200 being old might again be the tipping point, but from a pure prospecting options perspective the case can be made that the SD 2200 might be the better way to go. The problem for this challenge is the ATX weighs over 4 lbs and sells for over $2000 That's it folks. That is reality. The best of the best that the competition can offer can only go solidly up against models Minelab has not made in years. I am not saying that to be mean or as some kind of Minelab toadie, that is my pure unvarnished opinion as a guy who is pretty well versed on the subject. Let's bring it all home. This person with the $700 machine really, really wants that under 4 lb, under $2K GBPI machine, but if they do their homework they discover that truthfully, they would be better off shopping for a used Minelab than what the competition offers new. With the TDI SL rated as a 2 the ATX in a much lighter box at under $2K is a solid win as a 3. A well designed ATX with standard dry land coils would look very enticing as compared to the GP series Minelab's and with a stronger battery system might rate 4 to 6 on my comparative scale. But Garrett refuses to budge! White's can certainly do something, anything to improve the TDI SL. A battery that lasts all day would be a good start. In the end they are limited by the basic single channel design of the machine. The SD 2000 dual channel design was literally the answer to and the improvement on the single channel technology used in the TDI, the basics of which predate the SD 2000. Still, White's currently owns the under 4 lb under $2K GBPI category so they have the first out of the starting gate advantage. Anything they do would at the very least just show they have not given up. The Minelab MPS patent that formed the basis of the SD series has expired. Not sure about DVT, which formed the basis of the GP series. Where is the competition? What the heck is going on here? Much gnashing of teeth and pulling of hair is going on here, that's what!!! That is my challenge to the manufacturers. Under 4 lbs, under $2K, on the 1-10 scale I am offering, what is the best you can do? The TDI SL as a 2? Really? Yes, really, that is currently the best of the best in the brand new ground balancing PI, full warranty, under 4 lb, under $2k category. You can pick up a 3.5 lb TDI SL right now brand new for $1089. The White's TDI SL takes the crown. Hopefully we will see more competition in this wide open category soon. I have been beating this drum for years to no avail, but I do have reason to believe we are finally going to see more alternatives soon. I hope.
  5. Can someone please explain the differences in a PI machine and a VLF machine in layman's terms or point me in a direction on the site if it has already been posted up some where just trying to learn
  6. A common misperception among those new to metal detecting is that metal detectors can identify one metal from another. How much we wish that were true. The reality is that for all practical purposes the common metal detector target id scale is based on a combination of the conductive or ferrous properties of the item multiplied by the size and shape of the item. There are two common terms in use for this scale. The Target ID or TID scale is the most generic. White's also popularized the use of Visual Discrimination Indicator or VDI numbers. You will see references to both TID and VDI numbers and both refer to the same thing. The problem when you use Google is that TID also refers to Terminal ID number, which is for credit card machines. VDI gets far better results as the preferred term and so is what I will use from now on. The VDI scale is almost always arranged the same way by common convention although in theory it can be rearranged any way you want. The common scale has ferrous items on the low end and non-ferrous items on the high end. Ferrous items are like mirror images of non-ferrous items and so the most common arrangement of the VDI scale is with small items in the middle with ferrous getting larger in one direction and non-ferrous getting larger in the other direction. The ferrous and non-ferrous ranges actually overlap in the middle. Large Non-Ferrous Medium Non-Ferrous Small Non-Ferrous Tiny Ferrous/Non-Ferrous Overlap Small Ferrous Medium Ferrous Large Ferrous We can assign a numeric range to this basic VDI scale any way we want. Many early machines went with a 0 - 100 scale, with the ferrous compressed into the low end of the scale: 100 Large Non-Ferrous 50 Medium Non-Ferrous 20 Small Non-Ferrous 5 Tiny Ferrous/Non-Ferrous Overlap 3 Small Ferrous 1 Medium Ferrous 0 Large Ferrous The idea of ferrous as negative numbers made sense due to the mirror imaging in size between ferrous and non-ferrous. A very common White's scale runs from -95 to 0 to +95 95 Large Non-Ferrous 50 Medium Non-Ferrous 15 Small Non-Ferrous 0 Tiny Ferrous/Non-Ferrous Overlap -15 Small Ferrous - 20 Medium Ferrous - 40 Large Ferrous The "positive only" 0 - 100 VDI scale seems most popular these days with other manufacturers, but the scheme varies. Two very common setups are 0-40 ferrous and 41-99 non-ferrous OR 0-10 ferrous and 11-99 non-ferrous. But as I noted you can set this up any way you want and so other scales do exist. When we look at just the non-ferrous part of the scale, what is important is how the detector "sees" the target. In very simple terms conductive targets are either very weak or very strong or somewhere in between. Small items are weak targets. Low conductive metals are weak targets. Large items are strong targets. High conductive metals are strong targets. The shape matters. Irregular shapes or thin items are weak targets. Rounded and thick items are strong targets. On a conductive scale of 0 to 100: 0 = very small targets 100 = very large targets 0 = very thin targets 100 = very thick targets 0 = very low conductive metals 100 = very high conductive metals 0 = very irregular shaped targets 100 = very rounded targets, especially is a hole in the middle Add this all up and small gold items are low on the VDI scale and large gold items high on the scale. Silver being a better conductor than gold, a silver item will read higher on the scale than the identical size and shape gold item. In general silver will read higher than gold. However, a very large gold item can read higher than a very small silver item. Chasing thin hammered silver coins in the U.K., especially the cut varieties, is not that different than hunting gold nuggets. What you rapidly figure out is the metal detector VDI scale can only get repeatable results on certain man made items that are the same every time, like a U.S. nickel or a U.S. dime. And even these signals degrade when deep in the ground or in proximity to other items under the search coil at the same time. Given all the limitations, it is a wonder we get any degree of accuracy at all with detector discrimination systems. With that, I give you a standardized White's VDI scale taken directly from the control box of my White's DFX. This -95 to 0 to +95 scale is common on many modern White's detectors. Nearly all other detectors have the same relative positioning of items just with different numeric scales, an exception of note being the Fisher CZ detectors, which use a rearranged scale. This DFX scale is helpful because it includes gold coins. The main thing I want you to focus on here is the relative positioning of items on the scale. As a detectorist operating in the United States, I always pay attention to just three things 1. where do the ferrous numbers start? 2. where does a U.S. nickel read? and 3. where does a U.S. dime read? If I know those three things, I can adjust almost instantly to any detector scale in existence, because I know how everything else reads in relation to those three points on the scale. Looking at the scale you can use gold coins as a rough guide to where large gold nuggets will read, although coins being pure gold and round will read much better than gold nuggets of the same size. It might take a one pound gold nugget to read the same as a one ounce $20 gold coin, which in turn reads very close to the U.S. silver quarter reading. On the other end, tiny gold, tiny ferrous, and salt water, being a low conductive target, all overlap. This is why if you tune out salt water on the beach, you also tune out single post gold ear rings and thin gold chains, which read like small gold nuggets. If a prospector tunes out salt alkali readings on a salt lake, there go the small gold readings. And the chart shows that if you get too aggressive in rejecting all ferrous items, good items can be lost also. When I say small it is important to note what we are really talking about is small/weak readings. A large gold item buried very deep in mineralized ground will have a very weak reading and appear as a small target to the detector. This means a very deep large items can appear just like a very small gold item and be lost for the very same reasons as those small items. Again, think weak targets and strong targets to get a better feel for how things react in the field. To sum up, gold and platinum are low conductive metals, and when also small in size read very low on the VDI scale, even dipping into the ferrous range. The foil range is the sweet spot for ear rings, thin gold chains, small womens rings, and platinum items. In general women's gold rings will read below a U.S. nickel and men's gold rings will fall above a U.S. nickel on the VDI scale. Nearly all gold nuggets found by most people are going to read nickel and lower just because nearly all gold nuggets are small. However, as this photo I made using my DFX and some gold nuggets shows, gold nuggets can read all over the place due to their shape and purity. Surprisingly, if you add silver to gold the conductivity drops as alloys are less conductive than pure metals. This makes many gold jewelry items and gold nuggets far harder to detect than would be the case were they pure gold. See this article for details on this nugget photo Some Gold Nugget VDI Numbers You can get some great spreadsheets for jewelry VDI numbers for White's and Minelab detectors here. There are no doubt many people who have read this who are just shaking their head and thinking "this is why I just dig everything". I absolutely agree, when at all possible, that is the best solution. Unfortunately it simply is not possible in some locations where trash targets outnumber the good by thousands to one. This is where knowing the VDI scale and how it works can pay off. The best book ever written on the subject of discrimination is "Taking A Closer Look At Metal Detector Discrimination" by Robert C. Brockett. It is out of print but if you find a copy grab it, assuming the topic interests you.
  7. I know this topic has appeared off and on over the years, but I'd like to better understanding on the theory and principle of using one over the other, ie. depth, and target id and what compromises do I induce. The reason I ask is the new V4 for XP Deus has the ability to set a minus discrimination. It kills the ability to use the "horseshoe" screen for ferrous target ID, but VID numbers are tolerable. What theoretically happens if I set a negative discrimination, but use Notch to handle ordinary ferrous trash?
  8. Is Minelab the only one that uses electronic noise cancel feature?? Do they have patents associate with this feature? Would like to see other manufacturers use some thing similar on their detectors. Or a manufacturer should provide actual visual indication of emi levels depending on frequency used to include offsetting. Not have the user have to use their ears to decide or even try comparing on buried targets. Should not be trial and error. And maybe even a system were the operator is warned,,say if emi changes and the current selected frequency is possibly not operating at optimum. I do realize with a coil being swept over the ground, this could be difficult to do.
  9. I am going through one of those periods where I load up a bit on new detectors and let it all sort out. Darwin's Survival Of The Fittest Detectors! This winter a number will not survive and will be looking for new home. This is the only way I have found that works for me. Detectors that serve a good purpose for me get used, others end up sitting. If they sit long enough, they are no longer needed. I have my nugget detecting fairly well sorted out. The GPZ 7000 gets used 90% of the time. I might pull out a VLF for a really trashy place, or for where the gold is smaller than the GPZ can hit (really small!). I do keep a Garrett ATX around to handle salt ground or oddball hot rocks the GPZ has trouble with but those situations have proven quite rare so far. So the GPZ is an obvious keeper. The ATX does double duty as my favorite water hunting machine so there is another. In the land of VLF however it is more complicated. I have this idea that a good selectable frequency detector might really do the trick in replacing two or more other models. The key there however is what I am going to go ahead and call "frequency spread" for lack of a better term. What do I mean by frequency spread? Simply put, the number of kHz between the lowest and highest frequency the detector can operate at. The lowest frequency is basically the "large item" frequency that more easily handles bad ground, and the high frequency is the "small item" frequency that tends to have more issues with mineralized ground or hot rocks. The high frequency option is critical for a person like me who nugget hunts. To really be able to replace machines like the 45 kHz Minelab Gold Monster 1000, 48 kHz White's GMT, 56 kHz Makro Gold Racer, or 71 kHz Fisher Gold Bug 2, the highest frequency option of the detector needs to be 30 kHz or higher or as close to that as is possible. Low frequencies in the single digits are great for coin hunting or very large gold nuggets in bad ground. Frequencies in the teens are a great compromise. Some examples: Nokta Impact 5 kHz, 14 kHz, and 20 kHz (15 kHz lowest to highest) XP DEUS Low Frequency Coil 4 kHz, 8 kHz, 12 kHz, and 18 kHz (14 kHz lowest to highest) Rutus Alter 4.4 kHz to 18 kHz in 0.2 kHz steps (13.6 kHz lowest to highest) White's V3i 2.5 kHz, 7.5 kHz, 22.5 kHz (20 kHz lowest to highest - bonus - runs in multifrequency mode) I am still waiting on the XP DEUS High Frequency Elliptical Coil 14 kHz, 30 kHz, and 81 kHz (67 khz lowest to highest). The XP HF 9" round running at 14 kHz, 30 khz, and 59 khz (45 kHz lowest to highest) is currently available. In theory the White's V3i is a real winner here but I have just never really taken to the V3i as a prospecting detector. I have to be honest and say that so far the Impact floats my boat more in that regard due to its more traditional approach to a detector interface, all metal modes, and ground balancing. The problem with all of them though is they just don't reach high enough to be used both as coin and jewelry machines and yet still be capable of retiring the high frequency nugget detectors. And that is why I am still patiently waiting for that XP Deus V4 high frequency elliptical coil. At 81 kHz (or 59 kHz in 9" round version) the Deus HF coils on paper at least could in theory make the high frequency nugget detectors redundant. I have to admit I still have doubts however. So far dedicated specifically tuned single frequency detectors have always won the day. For a lot of people however, a selectable frequency machine might prove to be "good enough". The downside with the Deus is that to get the deeper seeking lower frequency large coil option you have to wrap up quite a bit of money into two coils. The 9.5" elliptical is just not going to reach real deep due to its small size. I have the 11" round low frequency coil which can run as low as 4 kHz, so together the two coils make a pretty formidable package. The other machines however can run both much smaller and much larger coils, and at considerably less cost than what DEUS coils cost due to each one being a self contained metal detector. It may be that the XP HF 9" round running at 14 kHz, 30 khz, and 59 khz (45 kHz lowest to highest) is the better compromise option for most people than the 5.5" x 9.5" elliptical. The Impact does suit me as far as the way it functions and I like the excellent inexpensive coil selection. It is a shame it weighs twice as much as the DEUS, but that may actually be a benefit when it comes to balancing large coils. Overall at the moment I am really liking the Impact - I just wish the frequency had topped out higher. I really wanted more like 5 - 15 - 30 kHz. Going from 14 kHz to 20 kHz is not quite providing the extra "pop" on tiny gold I would like to see.
  10. The following information is from an apparent leak from a First Texas distributor meeting? The link is posted at http://www.detectorprospector.com/forum/topic/555-new-fisher-pulse-induction-multi-frequency-detectors/?p=10571 as part of the thread about upcoming Fisher products that have been circulating for a couple years. These leaks seem to jive with previous statements by Tom Mallory of First Texas. The main one of interest to the people on this forum would be a new CZX model aimed at gold prospecting. Here is the text from the posted screen shot: CZX - Fisher and Teknetics This machine is ground breaking technologyTurn on and go2 frequency - 9:1 ratioNo need to ground balance or adjust the detector to the environmentIt automatically senses the ground and makes changes accordingly.First detector birthed from this platform is a gold unit priced around $1000, but deeper than current VLF, this detector will also see through red dirt, and highly mineralized soil.From this platform other machines will develop. We intend to develop the CZX and MOSCA platforms to offer more machines in the $1000 to $2000 range than have ever been available.Target release 2016We have senior engineer Dave Johnson on this projectThe "Mosca" platform referred to is further described and apparently is aimed more at being a general purpose non-prospecting detector (coins, jewelry, relics). Again, here is the text from the posted screen shot: "Mosca" Fisher and Teknetics Waterproof up to 10' (3 meters)Wireless headphones - Waterproof loop and connectors for headphones2 frequency - 7:1 ratioHobby/Treasure Market - Great for Saltwater, Relic, CoinAuto Ground TrackingSingle Pod DesignLCD Pad, control buttons, 2 AA batteriesArm Pad in rearRetail target - $1200 - $2000Target release 2016We have dedicated engineers on this project OK, so a gold unit around $1000 that goes deeper than current VLF designs. I also have high hopes that knowing the proclivities of the engineer, Dave Johnson, that it will be relatively light and ergonomic. Dave also prefers simple and the design statements reflect that. We seriously need something that brings gold detector weights and prices back to earth and so hopefully this will be it. I have stated over and over again I would be very happy with ATX equivalent performance in a less expensive lightweight package. Garrett so far seems disinclined to make that unit but they have a year at least before it may be a moot point. The CZX would have to obsolete the White's TDI as it is aimed squarely at or below the same price point and unless it beats TDI performance would be dead on arrival. We will not have long to wait - 2016 is coming fast!
  11. For over a decade I've ask for one small feature to a good detector. Say for instance on the Fisher F75 detector or another machine of comparable abilities. Add a two tone function in the motion all metal mode. Nothing fancy, just one tone for ferrous and another for non-ferrous. Being a computer programmer for several years I can't imagine this would be very difficult. Now on the F75, while in motion all metal mode the machine gives better depth and also gives an ID for detected metal objects. So since nothing is really needed except assigning a tone to the ID number scheme why is it so hard to acquire a unit with that feature. I know the V3i has a feature similar, but it lacks the depth capability of the F75 in my ground. Now I've ask again. I'll check back in another decade.
  12. How many of you are "beepers" vs. "peepers"?
  13. On subject of coils and systems... I was out working some areas for relics with a couple others and one guy was killing it with an very vintage 70s Garrett Master Hunter BFO unit with a large home made looking square coil of pvc looking material. After looking into I found that BFO is Beat Frequency Oscillator and was popular before T/R VLF format machines. BFO was not good for small coin shooting and nugget hunting and lacked ability for quality discrimination from what I read but excelled in depth ability, especially on large ferrous cache targets as well as finding mineral deposits like drifts of black sands or veins of ore. So are there currently any units that still use a BFO mode or format? I can find vintage BFO type units available very reasonably priced, is there any information out there on how to bring them up to current on a battery system and build large coils suitable for this type of cache detecting?
  14. Detector coils are not antenna. They are part of a highly tuned inductive coupling system.
  15. Good afternoon everyone, I am looking for a long range detector and I would like to know if anyone can design/produce a stand-alone (not hand held) long range detector suitable for detecting gold from a 30-50 metres height. This is a serious enquiry which foresees the purchase of large quantities of such locators/detectors as well as the development of different detectors for other metals/minerals. For a better idea of what I am looking for, please see my drawing below. Thanks, Law-Italy ( lawrencebon@hotmail.it )
  16. Everyone needs to watch this video. We talk all the time how lower frequencies ignore ground better and penetrate deeper on larger targets, but how high frequencies are better at getting small targets to respond. This video does a superb job of illustrating how high frequencies do a better job at "lighting up" a small gold target. The key is we are using one detector and coil with all the settings just the same - the only thing that changes is the frequency. This eliminates other extraneous factors that usually play into comparisons of this sort. What this video does not show is how higher frequencies not only "light up" the target but also mineralized ground, creating difficulty with penetrating deeply in that ground. One of the great lessons in metal detecting is that there is no free lunch, and very often improving one thing comes at a cost somewhere else. You can skip right to "the good part" at 2:45
  17. The whole depth with VLF detectors thing in my opinion has been nothing but a red herring for decades. I have read a thousand posts from people wanting VLF detectors with "more depth". Yet VLF detectors maxed out for usable depth by at least 1990 if not before. I have not used any VLF metal detector since 1990 that got more depth on coins than my Compass Gold Scanner Pro. The only real improvement we have seen and are still seeing is in the ability to find and correctly identify items that are masked by the ground itself or adjacent undesirable targets. There are an amazing number of targets in the ground at depths achievable by any decent detector made in the last 25 years, but that are being missed because they are improperly identified and ignored or just completely masked and invisible. This is an area where the Minelab BBS and FBS detectors have excelled. They do not go deeper. They simply get more accurate discrimination at depths exceeding what most detectors achieve. Machines like the DEUS and a lot of other Euro machines are excelling not for the depth they get, but this ability to acquire and accurately identify targets at shallower depths that are missed by other detectors. If we had a detector that could simply see through everything and accurately identify coins to 10" the ground would light up with countless missed finds. I get a chuckle out of all the deep coins I see people talk about on the forums when the best detectors made can't accurately identify a dime past 5-6 inches in my soil. Anything deeper just gets called ferrous. There is huge room for improvement in metal detectors still not by getting more depth, but by simply finding shallower targets that have been missed by other detectors made up until now. How To Make Yourself Crazy!
  18. Note: thread was split from this previous thread Tone By TID Selection Option? Thanks for posting that reminder on the F44 Mike. I had forgot about it, and added the chart page to your post. To my mind for coin and jewelry detecting I simply have no interest in owning machines that do not allow me to customize tone ranges and tones. My current stable of coin/jewelry machines are the White's DFX, Minelab CTX, Nokta Impact, and XP DEUS, and all four offer this capability (the ability to cusomize tone ranges and tones) in one form or another. It really is a killer feature on the F44 at such a low price, only $349 these days. If all I could have is one detector and had to buy a new one under $400 I have no doubt the F44 is what I would end up with. Funny that it gets so little interest on the forums but I guess that reflects the fact most of us tend to be using higher end product. This is a case where Fisher may have sold more by pricing it higher! People may snicker at that but there are sound sales reasons for why that may be true. Look at what you get in a Gold Bug Pro and you would think it should be $349 and the F44 should be $649.
  19. For background on electrical interference in VLF detectors here is a great essay on electrical interference by Dave Johnson of First Texas Products. You can also find a more detailed discussion that includes PI detectors in section 2.1 of this Minelab document by Bruce Candy. OK, so I am bench testing my new Teknetics G2 at home recently. The 19 kHz models are renowned for being immune to EMI (ElectroMagnetic Interference). No electrical interference ever (well, almost never) even at highest gain levels. As a rule, the lower the frequency, the more issues you have with EMI. It is especially bad under 10 kHz. DEUS owners may see significant EMI at 4 kHz, only a little at 8 kHz, and none at 12 and 18 kHz. Another reason why manufacturers favor mid frequency over low frequency detectors these days. I have been bench testing detectors in my house for years so think I know the EMI levels. No issues with previous 19 kHz units like the Gold Bug Pro and F19. Yet this new G2 chatters like crazy! I fire off an email to First Texas asking if some change I was unaware of. Nope. And could not be a bad coil because both coils I have did it. Then on another go I noticed the EMI was bad on one end of house but not the other. I walk around and the detector leads me to a new LED bulb I installed recently. This thing is pumping out 19 kHz EMI like crazy! Not long ago I installed a number of these cheap LED bulbs in my house. https://www.amazon.com/Feit-Electric-Replacement-CEOM60-927/dp/B01BJ0Y1MC Looks like my mission to upgade my house to all LED just ran into a snag! More on LED bulb interference - https://www.google.com/search?num=30&q=led+bulb+electrical+interference&oq=led+bulb+electrical+interference Just shows how more and more we are surrounded by new forms of electrical interference to make life harder for detector engineers.
  20. The "holy grail" of metal detecting has been a detector that can offer VLF type discrimination to PI detector depth. Many years ago I put it as "a White's MXT that can detect as deep as a Minelab GP". I once offered $10,000 for such a detector, back when it seemed ludicrous to think detectors would ever reach such a high price. We have had a lot of progress in the last 30 years on sheer depth of detection, but really not much at all when it comes to how deep a target can be detected and identified with decent accuracy. When it comes to accurate target id at depth multi frequency units set the standard for performance in all soil types. The Fisher CZ and Minelab Sovereign both came out in 1991, and in my opinion other than refinements nothing has really changed since then when it comes down to the classic question of "how deep can you detect and correctly identify a U.S. dime?" For single frequency detectors my old Compass Gold Scanner Pro back in 1989 punched as deep on a dime as anything made today. We need some sort of real breakthrough. What this would really mean is a machine that handles and eliminates ground better to deliver depth as close to air tests as is possible while retaining good discrimination. The long rumored (since 2015) Fisher CZX promises "groundbreaking technology" in the form of a two frequency detector that is "deeper than current VLF, this detector will also see through red dirt, and highly mineralized soil." For even longer we have known about the White's Half Sine Patent that states "A new hybrid metal detector combines induction balance and pulse induction technologies. Target signals are generated from a transmitted wave that has both induction balance and pulse current inducing characteristics and uses pertinent sampling of the receive data. Combining the two data sources provides eddy current target identification while excluding ground permeability and remanence obscuration." Now, the Fisher price target was said to be in the $1000 - $2000 range. Frankly, that seems way too low for something that would knock the industry on its ear if it came to pass, but it may be we are all assuming the CZX to be more than it really is. The talk is mainly about being simple and handling bad ground well, but how well it can identify targets at depth is really not discussed. All the CZX may turn out to be is my long hoped for ergonomic detector that outperforms the White's TDI in the $1000 - $2000 price range. The Mosca machine mentioned on the same thread has different engineers involved and so these are probably two separate projects. OK, long lead in to the AKA Intronik STF as described at http://md-hunter.com/aka-intronik-stf-price-starts-from-12000-the-most-expensive-detector/ and said to be selling for $12,000.00. Another thread here states "AKA succeed working out VLF detector working 2 frequency at once. This detector sees no differance if ground is heavely mineralized or it's a non salty sand or even air, it's not being influanced by mineralisation at all. It's deep as Signum MFT but with right identification at any depth." Looks to be translated poorly from original Russian, or at least I hope that's the excuse for the butchered English! However, what the AKA Intronik is promising is a two frequency machine that ignores ground mineralization, and that sounds a lot like what the Fisher CZX is promising. The White's is a different beast but same basic result being discussed - a breakthrough in the ability to discriminate targets at depth. And in my book all that means is something clearly better than what we have, not results so close that endless videos and arguments on the internet produce no clear winners. We want something that when put up against a Fisher CZ and F75 and Minelab CTX everyone clearly agrees "this thing accurately sees a dime deeper" Many nugget hunters may be ignoring all this, but the applications for a detector that really can get the depth and identify trash better are huge. In fact, I am willing to bet many of the best finds remaining in the United States at least are in those areas that are full of so much trash that PI operators have barely put a dent in them. Clear open trash free patches have been pounded to death, but there are many places where the volume of deep nails alone continues to defeat even the most patient hunters. People are/were will to pay $8000 - $10,000 for a GPZ 7000. How much is a GPZ with discrimination worth? Quite a bit perhaps to many gold hunters. What I wonder however is what the limits are for the coin and relic hunters. My gut feeling was that the coin hunters were not as willing to spend big bucks as the gold hunters. It is easy to rationalize high price gold machines if you are the sort of person who is confident you can find enough gold to pay for your detector. The thing is I never thought the GPZ would sell very well because it as priced so high. Then I opened my eyes. There are people here in the U.S. buying GPZ detectors that have found little if any gold in the past with detectors. There are people that show up at outings with a 24 foot motor home pulling a side by side ATV behind. There are people for whom buying a $10,000 metal detector is no different than buying a high price set of golf clubs or a snowmobile or a boat. Yes, I understand many people have tight budgets, but it is also obvious many people have lots of money to throw at their pastimes and playthings. The GPZ 7000 shocked me with how many people bought them. I was honestly hoping the price would limit the numbers seen in the field for at least a year or two. The relic people seem to be the same way. There was little resistance to moving up to the GPX 5000 back east in the big relic hunts when it became obvious those machines would deliver the goods VLF detectors missed. The GPZ has not has made as much impact there simply because it is too sensitive to tiny trash so a relic hunter is normally better off with a GPX, which has more ability to deal with at least some trash. Lots of beach hunters are using GPX detectors now. And even some park hunters in the never ending quest for more depth. So I am wondering just how much more I would be willing to shell out to be the first kid on my block to have a real leg up on the competition with a machine that could make silver coins easy to find again in U.S. parks by offering better discrimination at depth. I then of course I figured I would ask you all the same question. What is the most you would shell out for such a machine if it really delivered the goods? Me, I looked at the $12,000 for the AKA Intronik and initially thought that was crazy. The more I think about it however I am not so sure - if it really worked. Sure, that would price many people right out of the thing, but oddly enough that would make others crave it even more. There is always something attractive in basic marketing 101 for people having possession of something other people can't afford. What say you forum members? Would you buy an AKA Intronik if it really performed as advertised and for such a high price? If not, what would it be worth to you? Please note - I am not saying the AKA Intronik does do what it says in any way. I truly have no idea. But if it does, what is the "right price"?
  21. I am going to bring this up for you to maybe shed light on. Since you have been it seems testing and using detectors for a while. First up,,,has any manufacturer who you are testing a detector for,,,have they ask you if you are currently testing any other manufacturer's model detectors (prerelease)?? Next since you likely signed non disclosure agreements,,,and they are pretty straightforward,,,like you can't discuss or talk until you are given ok to do. I consider you a very ethical person btw,,,this next question is not to insinuate anything,,,I just want to hear your thoughts here. What about if you are testing a unit,,,and let's say the testing phase is more or less concluded,,,but this specific detector model isn't quite released yet,,,and you happen to be testing another unit from a different manufacturer. Is it proper to use this detector you have already tested (not released yet) and do head to heads with another test unit,,,and this other unit let's just say is still further from official release than this other unit. So in keeping all this head to head under wraps,,,but when the first unit you tested is released,,,obviously the non disclosure agreement is null and void on this unit,,,,so with maybe some previous head to head testing done before this first detector release,,,so then a tester could actually maybe provide comparison data (done before first detector release) to the second detector's manufacturer when the first one releases. I hope this makes sense. Remember I'm not insinuating anything,,,you are far more expert in this dept than I. And obviously comparing a detector under formal testing to an already publically released detector is a different animal,,I see no problems doing this. Steve do you think a person should be testing 2 or more detectors (pre release) simultaneously from different manufacturers??
  22. From http://www.detectorprospector.com/forum/topic/3331-how-low-will-they-go/?do=findComment&comment=37171 Tom, Unfortunately I am out detecting a lot, or when home I'll be on two or three other Forums and don't monitor Steve H.'s site as much as I guess I should. Therefore, I haven't kept up with many of your posts, but this one left me wondering a bit. You list yourself as being "White's Media Guy" but let me ask this. How long have you been with White's, and anything other than just doing 'media' work? How long have you been metal detecting? What types of detecting do you prefer to do the most (Coin & Jewelry Hunt, Beach Hunt, Relic Hunt, Electronic Prospecting, etc.)? Have you been involved in the metal detecting industry for long, or at all, before going to work at White's? tboykin: I think it's a matter of finances for most companies. As volume in sales drops, they have to lower the price to keep the bottom line looking good. ... Sometimes a manufacturer drops a price in order to be competitive in the market. One example would be the Nokta FORS CoRe that had a price reduction about two years ago. It wasn't to "keep the bottom line looking good" but a readjustment of the MSRP of a newer and very competitive model on the market. FTP has offered the basic Teknetics T2 'Classic' at a much lower price now for about two years, and recently offered a reduced-price Fisher F75. I don't think that "it's a matter of finances" with them, either, as these were models that started in the market in 2006, I believe, with the T2 and later the F75. Sales have been just fine, so I think the 'price drops' were because [1] they need to be competitive on the market and [2] they just might be planning on newer models soon to replace the position these models held. tboykin: This happens when companies don't bring new products to market or constantly release "rehashes" of old tech...."Rehashes" you say, because nothing new was brought to market? Would that be anything like the essentially same 6000 Pro XL being unchanged but renamed the XL Pro? How about the Classic IDX being renamed the IDX Pro? The 'Spectrum XLT' relabeled the XLT e-series? Introducing the Prizm series, which were poor sellers, so the color was changed to burgundy and the name of these same detectors was changed to Coinmaster? The MXT Pro was a nice improvement of the original MXT, but less than four years ago it was 'renamed.' or 'rehashed,' the MXT 'ALL' Pro. There were no circuitry or packaging changes, other than an 'All' sticker added to the side decals, and a move from the 950 Concentric coil to the 10" D2 DD coil that had a history of coil failures and/or poor performance. Seems like there has been a lot of 'rehashes' over the past seventeen years or so do in Sweet Home. tboykin: The great thing about this is that as newer companies advance technology, the dinosaur brands will have to keep up. Or they will die. Just dropping the price isn't going to be enough to keep things afloat - you gotta play ball and offer something the world hasn't seen before.... "New Companies" would include Makro Detector, Nokta Detectors, XP Detectors who all have newer models the past several years that are very proven and well tested performers. there is a pretty fair amount of "newer advanced technology" for consumers to select from. I think you are right about "dinosaur brands that have to keep up" and sometimes that does mean dropping the MSRP, if necessary, to stay competitive. It has to be pretty tough to try and sell 'older' models with 'older' technology that have been outclassed at a suggested retail that is significantly higher than comparable detectors on the market. Again, let's revisit the MXT Pro, or re-hashed / re-named All Pro. It is still listed at $899.95 USD. The MXT Pro used to be one of my main-use detectors until a little over two years ago when it was wiped out of my personal detector arsenal because it was simply out-classed and out-performed ... by a model with a renewed lower MSRP of $699. if you are familiar with the competition out there, look how many competitive models to the MXT series offer manual, VCO Audio, backlighted displays, adjustable Tone Break, Ferrous Audio Volume control, Audio Tone Adjustment, and the ability to Save personal settings or restore a Factory Default ... and several of them sell for $100 or more less than the MXT All Pro. You did say "you gotta play ball and offer something the world hasn't seen before" and I think that's a good thought. But TO ME, if a good company is capable of engineering a newer detector, an advanced detector, a state-of-the-art detector that can set a high standard in the industry, I think that company ought to be able to make that engineering move by designing their own search coils that they also engineer to provide the best source for performance from their own detector. We read a couple of years back where to get the better performance from your top-dollar V3i you needed to buy the after-market Detech Ultimate coil. Last year you folks speedily rushed the MX Sport to market plagued with circuitry and hardware flaws, and didn't even make a smaller-size search coils for it. Then, low-and-behold, a new 7" appears .... also from Detech, the Bulgarian manufacturer. tboykin: It's a good thing for everyone - the aging workhorse machines become cheaper for entry-level users, and the power users get new technology to play with.... I think that 17 years after the original MXT was introduced, with a few remedies to bring us the MXT Pro / All Pro, it is a bit aging, and is priced much higher than competitive models with more features, better weight and balance, and also better in-the-field performance. To stay competitive the MSRP should have been reduced a while back. The only other newer models in the past couple of years have been the Treasure Master and Treasure Pro, not especially hot items, and the Made in China White's XVenture which is a very low-priced model that was marketed by White's factory directly, Amazon and a couple of other sources. Most dealers I have spoken with don't have it listed, didn't know anything about it, or were not pleased with the fact that White's is selling a bargain priced model against their own dealers. If Chuck and some others have an MX Sport that is working properly and they like it, fine. I was hoping the new model was going to be an improved progression of the MXT series, but the several I have handled didn't convey that feeling to me, were nose heavy, and performance was lacking. Admitted, those were some of the early releases that were in dealer's shops, but they soured me enough to not have tried one now they are supposed to be fixed. Again, you were right it saying "newer companies advance technology" and they are out there. I am in the growing group of avid detectorists who are waiting to see what White's might do with some dinosaurs or lemons, adjust prices for reasonable competition, and bring something with newer technology to the market. Something that is newer, field tested, and evaluated by consumers to be sure it will likely be problem-free and not a rush-to-market new model with failures. My first factory-produced detector was a Whites in the summer of '68 and I would honestly like to see White's rise back to the upper ranks of detector manufactures like they used to be. I think it is going to take a bit of effort, however, since the detector market used to be especially strong in the USA way back when, but it is more of a global market today and dwindling in popularity here in the US.
  23. I just got my May issue of Lost Treasure and here is another detector put out by Tesoro called Mojave. It says the MSRP is 279.00 with what I think on all their detectors a life time warranty. Now for me that may not be a long time but for others it could be. Every time I turn around you got a company lowering their price of a detector that's been on the market for a long time. Then it's others coming out with a new product we've never seen before. You take any of the lower price detectors ( we won't say cheap ) and if it's a coin detector it finds coins. Here Minelab has another detector and it's a nugget hunter I'm sure it will find gold. I know if I wanted to get in coin hunting I'd be more willing to spend 2 or 3 hundred than 7 hundred on up until I find if this is for me. I know for most this stands true for anyone wanting to get into nugget hunting. Everyone on this forum has a opinion and I'd like to hear it. You ever been fishing and the fish biting so fast you had to stand behind a tree to bait your hook ? You ask what does this have to do with detectors and I'll tell you NOTHING.haha Chuck
  24. I don't believe it's necessary to say the name of any detector. I do find if I swing with the right hand on some detectors all is well. Then others would be best if in the other hand.A lot has to do with what side the controls are on. Like some you find them on the side of the control box. Then others it has to do with the headphones and where they plug in. I dislike a detector that don't come with a stand. It don't go out the door until I make something to keep it off the ground. I think the best for all is when you find the controls above your hand and can be seen in either. Tell me if you find yourself standing on the wrong side of your detector. Just maybe yours is user friendly. Chuck
  25. Yes, you heard it right. Time may be used in the future to find gold and/or oil. Here is a very technical observation of this technique from 2012: http://spectrum.ieee.org/tech-talk/at-work/test-and-measurement/prospecting-for-oil-or-gold-check-the-time