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Found 236 results

  1. I have used many metal detectors over the years, and right now I have to say that the new Makro Racer 2 has perhaps the easiest to understand, best laid out, most practical display and menu system I have ever seen in a top end detector. Now, you can sure say you hunt by ear and do not need a screen and I get that, but if we are going to put a screen on a detector, then let's do it right. Simple detectors with few functions are easy to make screens for - there is not much you need. But even then just the basics are often wrong. Machines that feature target id numbers, what is the thing you will most look at on screen? The target id numbers! Yet these are often way too small or off to the side as if an afterthought. The Makro Racer 2 id numbers are huge, much larger than on the original Racer and Gold Racer, which are already good sized. The number 88 display in the diagram above is fully 1.5" x 1.5" in size in real life. Other machines have some pretty big numbers but I think this sets a record as I can't think of any machine with larger id numbers on screen though some are close. Makro Racer 2 LCD display and controls Makro Racer 2 screen layout Makro Racer 2 screen and control descriptions The number can be the ground balance number, target id, or depth reading. You get a text display just above the number confirming which it is. Below the numbers are three zone references, Fe, Gold/Non-FE, and Non-Fe, that are used to set tone breaks and audio for the three main zones or bins as they are sometimes called. Another basic feature lacking on a lot of machines - the meter backlight. With the Racer 2 you get off, intermittent, or full time backlighting, and it includes the translucent red control buttons. The control ranges between 0-5 and C1-C5. At 0 level, the keypad and display backlight are off. When set between 1-5, they light up only for a short period of time when a target is detected or while navigating the menu and then it goes off. At C1-C5 levels, the keypad and display will light up constantly. I do not know of anyone doing a better backlight. The right side of the meter is informational - ground phase (ground balance number), mineral % (ground magnetite content), coil warning notices, and a six segment battery meter. Across the top below the 0 - 99 reference sticker, is a series of 50 "bullets" each of which covers 2 target id numbers. Open bullets (which appear gray in the diagram but are invisible in real life - see top photo) indicate accepted target id numbers. Blacked out segments show what discrimination and notch setting you have programmed in a single quick glance. When a target is detected, the big number on the display will be mirrored by one or more of the bullets flashing dark. The four control buttons are simple as can be - up and down takes you through the left hand menu area. Right or left lets you set each function selected by going up and down. The menu is basically the entire feature list just laid out right there for you to see. You want to know what this machine can do, just look at the screen. Most other machines you have no clue without reading the owners manual or at least pushing buttons to see what functions appear. Some settings like the backlight are system wide for all modes. All other settings like Gain are independent in each mode, and can be saved independently in each mode. This means you can play neat tricks like setting up a couple modes with dramatically different settings and then flip back and forth easily between two modes for target checking. You even get to decide what mode is the default start up mode. The Racer 2 starts up in the last mode where the save function was performed. If you always want to start in Beach mode, just modify and save something in Beach mode. Next time you start the detector, you will be in Beach mode. It is simple. It makes sense. No cryptic abbreviations or acronyms. No sub menus. It is, in metal detector terms, a work of art. Whoever designed this should sign it so I can frame it and hang it on my wall.
  2. This could be an exciting development for prospectors if the cost is something most of us could afford. "Instead of a pan and a pick ax, prospectors of the future might seek gold with a hand-held biosensor that uses a component of DNA to detect traces of the element in water. The gold sensor is the latest in a series of metal-detecting biosensors under development by Rebecca Lai, an associate professor of chemistry at the University of Nebraska-Lincoln. Other sensors at various stages of development detect mercury, silver or platinum. Similar technology could be used to find cadmium, lead, arsenic, or other metals and metalloids." Read more at: http://phys.org/news/2016-02-hand-held-gold-sensor.html#jCp
  3. There has recently been some discussion somewhere in the forums about 20-30 KHz detectors recently and their applications for prospecting. I ran across this while reading a link on a thread at NASA Tom's Forum, a quote by Dave Johnson, design engineer. "Metal detector manufacturers generally avoid the 20-30kHz range because of electrical interference from military communications." Here's the link to the interview- http://www.fisherlab.com/hobby/davejohnson/davejohnsonjohngardinerinterview.htm Merton
  4. Some detectors have an "Iron Audio" feature. With "iron audio- on" it lets the operator hear the iron targets. So, does this feature just basically turn iron discrimination off so that you get an "all metal mode"? I ask because I am interested in the AT-Pro which has this feature but am wondering exactly what it does. I notice some guys in videos using the iron audio on setting yet they still turn up the iron disc. When I hunt with the FoRes CoRe I turn the I.D. Mask all the way down to 5 or less so that I can hear everything and let my ears do the discriminating. Am I basically doing the same thing as "Iron Audio-On" ? Thanks! Dean
  5. Hello Steve, I think it was about this time last year you posted your thoughts on new detectors for the upcoming year. Any insight on new PI or multi-frequency detector for 2016? For the most part, it seemed like 2015 was the "year of the low end detector".
  6. This subject comes up so often it is time to get it into its own thread so I can just link to it in the future. It is best to think of metal detectors made for prospecting as "nugget detectors" as that is the truth of the matter. Nuggets have some size to them. Metal detectors are electromagnetic devices, and as such can detect items that are conductive and non-magnetic, like gold, or non-conductive but magnetic, like magnetite. Or both, like metallic iron. When dealing with gold you are dealing only with conductivity. The more conductive the mass, the easier it is to detect. In general what this means is bigger is better. Any detector has a limit to how small an item it can detect. Here is the kicker. Multiple undetectable targets do not add up to create a detectable target. I do not know how many times I've seen or been told of people throwing a vial of small gold on the ground and running a detector over it and declaring the detector will not find gold because it does not pick up the vial of gold. Or people thinking the detector has a problem. Let us say that on a scale of 0 - 10 zero represents an undetectable piece of gold, and 10 one that really beeps. 0 + 0 + 0 + 0 + 0 still equals zero. So lots of tiny gold is just as undetectable as a single piece of tiny gold. You need a single conductive mass. Fine gold usually has a coating, and putting a bunch of fine gold in a vial still results in little or no signal. If the gold is super clean and packed tightly you will get a weak signal. Melt it all together, and now it goes beep. Another way to look at it is take some fine gold and pour it in a pile. Get a multimeter and test your little pile of gold for conductivity. It is hard to get much current if any through a loose pile of gold. So bottom line is you might have 5 ounces of fine gold right under your feet, and you will walk right over it with your metal detector. Rich gold ore where the gold is finely dispersed in the rock will be hard to detect or undetectable. Wiry or spongy masses of gold are hard to detect. Jewelry hunters run into this when trying to detect lost necklaces. A fine chain is very hard to detect as each link is undetectable and the connection between the links is poor enough the signals does not add up to much. Often all you can detect is the clasp. Rings even display this issue if the weld breaks. A complete ring really gives a great signal. Break the ring, it will be very hard to detect. Now once an item is detectable, it does add up. 10 + 10 = 20 so two large nuggets in the same spot are easier to detect than each by itself. If each link in the gold chain can be detected, then it will add up into a more detectable target. A fun trick with target id detectors is to tape 5 nickels together and run them under the coil. They will read as 25 cents!
  7. Thought I'd start a topic of a different nature. What detector/s would you like to see reintroduced and why, and maybe a new feature or two if you dare. The reason I'm starting this is because there's been some real fine units come and go over the years, and I think some are worthy of some new time in the limelight. Model: Brand: Why should it be reintroduced? New features that would be nice: Okay, this is really hard, but I'm going to limit it to 3: Model: Sovereign GT Brand: Minelab Why should it be reintroduced? Still one of the best discriminating beach/shallow wading machines ever made New features that would be nice: A more compact control box that was at least weatherproof so i didn't have to chest mount the control box. Model: Goldmaster 3 Brand: Whites Why should it be reintroduced? Seems like the appreciation for the GM3 came after it was long gone. New features that would be nice: Auto Tracking option like on the GMT, and would be awesome to add a lower frequency to make it a bit more versatile for relics, hotter soils etc. Sort of like a GMT/MXT hybrid but in the old style chest mountable control box. Model: Diablo uMax Brand: Tesoro Why should it be reintroduced? So I could try one, and see what all the fuss is about :-) But seriously, a very lightweight "utility" gold machine should sell well, as long at it works. New features that would be nice: A Disc mode with ground balance like the original lobo so you could use it for coins, jewellery and relics
  8. Take a look at this, an app based metal detector, I suppose it was only a matter of time. Don't know if it is any good but sure looks cool http://teslamd.ru/
  9. Has anyone heard any new information on the Fisher/ Teknetics CZX gold machine coming out soon? Fisher claims a new ground breaking technology, that will be able to see through highly mineralized soil, and red dirt? Dave
  10. Here is a good Sunday read for you. Reg wrote what is still the best introductory text on PI detectors. Recently he added extra chapters at the Findmall forum. Even if you read the original before it is worth reading again. Understanding The PI Metal Detector by Reg Sniff Part One http://www.nuggetshooter.com/articles/UnderstandingPIdetector.html Understanding The PI Metal Detector by Reg Sniff Part Two http://www.nuggetshooter.com/articles/UnderstandingPIdetector2.html Deepest PI Detector by Reg Sniff Part One http://www.findmall.com/read.php?34,1777531 Deepest PI Detector by Reg Sniff Part Two http://www.findmall.com/read.php?34,1777531,1777710#msg-1777710
  11. This is an informal survey, just out of curiosity. For those of you who have been out prospecting in the last year (back to Sept 2014) and actually have found gold nuggets, what detector or detectors did you find the gold with? The poll is not meant to prove anything. I am just wondering what detectors are most commonly in use now for finding gold nuggets by those who are actually finding the gold. I am posting this on the most of the active US forums so please do not post your answer in more than one place. In a week I will compile all the answers from all the forums and post the results back to each one. Thanks in advance for you participation. I own a number of units but so far in the last year my gold was found with the Minelab GPZ 7000, SDC 2300, and a few nuggets in trashy areas with the Makro Racer.
  12. I see this over and over on the forums. People requesting that this machine and that machine be air tested on a dime to see which gets better depth. All it really does is tell you how well the detector can find things in the air, but I do not use a detector for that myself. I do a lot of air tests, but I am only looking at depth from a relative perspective and not as how two different models compare for depth in the ground. In other words, if I have two Gold Bug detectors and set up identically if one gets far less depth than the other there is a problem with the detector. Detectors will rarely detect deeper in the ground (I did not say never) than they do in the air, so if a detector air tests on a dime at 10" I am not going to expect it to do better than that in the field as a general rule. If a detector cannot detect a tiny nugget in an air test, I do not expect it to get that ability in the ground. Air tests generally tell you about a detectors maximum possible performance, and in the ground things will usually go downhill from there. I also like air tests to learn how a discrimination system may identify certain items since different detectors use different sounds and id number scales. Very often I just want to hear how the detector sounds. Is the signal modulated or boosted? Does it employ VCO audio? Short chirps or big booms? I have to listen to the thing all day long so I prefer something that is pleasant for me to listen to. Air tests can also teach me a lot about how a coil responds, especially to small targets which do radically strange things under DD coils at close range in particular. Depth though, when we are metal detecting, is all about how detectors handle ground. In fact there is almost nothing more important than how the detector handles the ground. Without the ground, depth tests can mean nothing at best and at worst can be quite deceiving. With VLF detectors low frequency models generally handle ground better than high frequency detectors, but high frequency models often air test very well. A Fisher Gold Bug 2 air tests really well, but the depth in ground drops off faster than most any other detector made due to the very high 71 kHz operating frequency. When I was up at Moore Creek I had a guy insist that the Fisher Gold Bug 2 would detect a large nugget deeper than a Fisher F75 because, by golly, he had air tested them. No amount of talk would convince him otherwise, so we buried a 1/4 oz nugget and the F75 easily hit it deeper than the Gold Bug 2. The guy was amazed by something I thought would be very obvious. I forget people do not know how metal detectors work and the effects of the ground at different frequencies. It is not always true but a generality is low frequency detectors will tend to retain depth better in ground than high frequency detectors. Pulse induction detectors are sort of like super low frequency detectors in that ground is relatively invisible to them. Not totally so by any means but compared to a VLF a PI has built in ground capability just because of the way they work. Often a PI detector will not air test very well compared to a VLF, but put them in bad ground, and the PI loses very little if any depth while the VLF takes a big hit. The worse the mineralization the worse the VLF does by comparison to the PI detector. So another generality is that pulse induction detectors do not air test well compared to VLF detectors. A lot of very good but less expensive coin detectors have no ground balance control. They air test just fine against far more expensive detectors. Put them on bad ground however, and the lack of ground balance control just kills them. Something rarely ever discussed is ground balance systems and how they work. Ground balance methods vary and often are proprietary and closely guarded secrets. These days it is far more than just a knob. Detectors like a White's GMT or MXT were among early models employing software algorithms to ground balance the detector. Minelab multi-frequency detectors employ very sophisticated ground balancing methods that help account for how well those machines work in differing soils and even saltwater environments. They are designed with the goal of delivering accurate target id information as deep as possible as opposed to absolute depth and the accuracy they deliver is cutting edge. Ground balancing and accurate target id go hand in hand. It should be obvious that a detector that has factory preset ground balance is going to suffer in bad ground. But past that point, what do you really know about the ground balance method employed by a detector and how good it is? More importantly, how is air testing going to help teach you about it? Yet another generality is that multi-frequency detectors do not air test well against single frequency detectors. You can go farther and just say air tests teach you nothing about ground handling capability. The degree and efficiency with which a metal detector handles the ground conditions it encounters is the most important thing there is when it comes to depth in the ground, and air testing does nothing to reveal this most important attribute. It is very easy to have detector A go twice as deep in an air test as detector B and see the situation reverse in the field. In theory if you air test two detectors, both the exact same model, and they air test the same then they should get the same depth in the ground, right? But what if one detector has a ground balance system that is not functioning properly? They air test identically but one still performs poorly compared to the other in the ground. The absolute most important advances in the metal detecting world have been in ground handling and most of the real breakthroughs in recent years have been in pulse induction detectors employing very advanced methods to deliver depth unmatched by other detectors. These advances are only apparent in the worst ground conditions and so leaving the ground out of the testing is nonsensical when you think about it. To sum up, we use metal detectors to find items buried in the ground, and when prospecting in particular highly mineralized soil can have severe impacts on detection depth. Only in ground testing has anything like any validity, and even then freshly buried target responses are suspect due to the ground being disturbed. Even buried test targets however are far preferable to air tests. A lot can be learned from air tests, but how a detector will perform in the ground is just about last on the list when it comes to relevance.
  13. Every piece of gold I have run across my machine I get a reading between 42 and 48.... Someone showed me a 1oz. nugget and when I ran my machine over it the target i.d was 82 so I was guessing that it wasn't a good quality if any gold at all...the person said because of its size the reading was higher....WEEEELLLLLLL when I got home I ran a 1/2 oz and a DWT piece over the coil and each pulled a reading of 44 and 47... I ask if this is correct because while hunting I have run across targets of 80 and up and from my experience with my machine that is usually bird shot or some other metal other than gold and I ignore some targets because of this...AM I PASSING UP GOLD NUGGETS???
  14. While looking around on the Minelab site I came across this article by Bruce Candy. It will certainly be a re-read for some but for me it was a first. There is much more than just Minelab in the article. It included ground balancing, discrimination, gold detectors, coin detectors and a host of other related issues with knowing some of the technology about target detecting. It doesn't yet include ZED technology but does explain why it is so hard to have a gold detector that discriminates. (When you discriminate you lose targets!) Metal Detector Basics & Theory by Bruce Candy
  15. I am different! I want to know why and what makes it work, what makes it different. I want to know the technical differences between products. The manufacturer can give a detector a name and claim that his detector is the best for detecting for gold. Sorry, manufacturer's claims come in one ear and out the other. Give me the facts and let me decide. I am going through the process of de-coding manufacturer claims and guess what. It is real hard to just find the facts. Right now I am searching for a list of the operating kHz frequencies of all metal detectors. Let's face it, a coil just creates a magnetic field and the only variables on any coil is the kHz frequency and the size of the coil. At least those are the two variables that I have found so far. I really need to know whether the kHz frequency is determined by the operating frequency for the Detector control box or is it controlled by the operating frequency of the coil? It makes sense to me that when you wind the copper wire into a coil that you should be able to determine the coil's kHz frequency by the number of winds of the copper wire, when you are making the coil. So, I am thinking that the coil actually determines the frequency that is built into the control box of the metal detector. Am I right? What I need now, is for someone who knows more about the industry to step up to the plate and provide a list of the kHz frequencies of the metal detector coils that are currently on the market. Any two coils that has the same kHz frequencies, whether it is made by the same manufacturer or not, should be interchangeable. A magnetic field is just a magnetic field. The operating kHz frequency, does it affect the magnetic field? If so, I need another expert to tell me whether different frequencies get better results, depending upon what the prospector is searching for. Please, do not respond to these questions unless you have scientific facts to back up what you say. If anyone can set me straight and help me get the facts I'm looking for, I would appreciate your time and effort. Don't worry, any response you give will not offend me. Thanks, Professor Hester
  16. I heard this rumor once white had chance at buying out minelab, any truth to this? It was years ago.
  17. With modern ARM or similar type MCU's with some of the DSP capabilities built in and programming easily altered or updated I'm not sure I understand anymore why we are still stuck with the solid state mindset that x detector has to be y frequency only. A guy shouldn't have an issue switching to 60khz or 30khz or 7.5khz or whatever he wants without having to buy proprietary peripherals like special coils. This doesn't have a lot to do with the Makros in particular, but this line of thought leads me to really wonder when we see the first "open source" detector. IE, one that allows us to go in and hack around in the programming, and open source schematics so we can make custom mods without figuring out how to dissolve 5 layers of epoxy potting without killing the components or having to brute force decrypt MCU coding. So, since I know the Makro guys read this forum, if a company really wanted to take the next step and to be revolutionary in the detector world - provide us all with 2 open source platforms (meaning both software and hardware open source) - a PI and a VLF. Breakout all the relevant MCU pins too or allow easy access to hook up another dev board like the BeagleBoard, Raspberry PI, etc along with the interface to a computer for programming. Detectors, even Minelab, until the last few years have really been stuck in the stone age it seems to me any computer or phone nowadays allows for all kinds of mods and hacking. I think you'd see a lot of real interesting innovation happening by DIY'ers within a few years with a platform like this, and it might give Minelab some pause at offering detectors at (disclaimer, just a guess) $8,000 or whatever. Sorry to ramble, this post just got me thinking.
  18. I did not want to get off topic on another post so I figured I better start a new one to find out the answer to a reply Klunker made " My thanks to Nokta for communicating with the folks that actually use detectors. Gold brick;- I have a P.I. detector that has nearly 100% accurate discrimination." O.K. klunker, I'll bite . Although I know it is probably a mistake and I am gonna get Klunkered for some reason I can not help but ask the question " Pray tell, what PI would that be, Klunker?" I think I am gonna regret getting up this morning............
  19. Hi guys! I asked for advice on choosing a forum detector (http://www.detectorprospector.com/forum/topic/91-choose-detector/#entry632) . I was planning to buy an inexpensive VLF detector. But I got a bonus at work and bought a used GPX 5000. I went with this detector on some old gold deposits. I found 6 nuggets total weight of 6 grams. GPX 5000 detector is good, but I dug a lot of iron objects. I lost a lot of time digging for iron things. Gold mines are very old, so the soil forged nails, small pieces of wire. I think in addition to the GPX 5000 I need a second detector. The main requirement for the detector - good discrimination. Now I look at the detectors: 1. Whites MXT 2. Whites GMT - because things are little nuggets (less than 1 gram). Am I right to think ?: GMT will be deeper than GPX to 0.5 grams of gold nuggets? 3. Minelab X-terra 705 4. Minelab Explorer SE 5. Fisher Gold BUG Pro/F19. This detector (thanks to Steve for information) shows VDI targets all metals mode, it's good! I know what to look for in the "all metal" because discrimination reduces sensitivity. But I would like to be able to include disc. whenever I want. What do you think of the detector to hunt for nuggets in the tailings. Any thinking please!
  20. Like many nugget hunters I cut my teeth in this hobby on PI machines. If it beeps you dig it. As time goes on we may not have the physical attributes we once had. I know if I dig 6 DEEP nails I am about done for awhile with the PI. I am likely to start using a VLF if one is handy (or take a nap LOL). The Question is- which VLF to grab? Every detector has certain attributes that make it more or less attractive for nugget hunting. I had been pondering this subject because I was contemplating buying another detector, specifically a Notka Fors Core. I need another detector like I need a hole in my head but I just like detectors and find them interesting. Recently I sold my MXT to my Brother-in-law so he could start coin and relic detecting, so I have room in the RV for a new detector. I hardly used my MXT as I would grab either my Deus, GBII, or GB Pro along with my GPX depending on what I had in mind for the day. Frankly, the MXT is just too heavy when there are light weight alternatives available. So let's talk about my possible purchase. I had a laundry list of features I hoped to get. Light weight, dependable, VID in All-Metal Mode, fast target separation in trash, and adjustable low tone break. I would love to have accurate VID in hot ground but that's just wishful thinking. I have been closely following the informative discussions on this forum started by Steve H. and on the Nasa Tom forum posted by some smart coin and relic detectorists about tone breaks, target separation, target masking and mineral degradation of targets. What is sticking in my mind is the adjustable low tone break. Just how important of a feature is it for nugget hunters? Obviously not very important if you only hunt in All Metal when using your VLF. Myself, I love to hunt around the old habitation sites and mines in gold country. A lot of times these are the only areas that have not been beat to death due to the extreme amount of trash. Plus I enjoy finding old coins and relics right along with the gold, it's all treasure to me. Due to the amount of trash around most of these sites All Metal Mode even with a VID on the screen is not my preferred option. I just do not enjoy detecting with eyes glued to a screen so a mode with two tones is my choice. But we know that gold co-located with ferrous or small gold in hot dirt can read down in to the ferrous TID range. So we need to adjust our low tone break somewhere into the upper ferrous range to ensure we don't miss co-located or deep gold. If the detector you have purchased does not have an adjustable break point and is factory set at ferrous/non-ferrous how much gold will you miss because it gave a low tone on those nuggets in the midst of trash? Or the DEEP nuggets at the fringe of detection in hot dirt? I do not think we can answer that question in a quantifiable manner but we should be aware that it is occurring. How high should we put this feature of adjustable tone break on our laundry list of detector attributes? How much will it drive up the price of the detector to get it? By thinking about the tone break and weight issues I believe I talked myself out of buying a detector and saved a grand. LOL The Notka is kind of heavy and does not have adjustable tone break to my understanding from reading the manual. If I am mistaken please correct me. I may have to wait for Notka's promised PI before purchasing from them. Obviously I put the Tone Break Issue near the fore front of my desirable attributes I would like to see a VLF have. I may just have to stick with the GB Pro and the Deus as my VLF nugget machines for now as they both have that feature. There must be other mid-frequency detectors with adjustable Tone Break, is the CTX one? Merton
  21. I remember when I purchased my 1st metal detector, a GP 3500. My family and friends thought I was insane to pay over $3000 for a metal detector LOL. It was instant love for me when I held her in my arms. Yet just like when the shine is wearing off your most recent girl friend and some habit of hers is starting to bore a hole in your brain..........it did not take long for me to tire of packing that lead acid battery around. What did that thing weigh? 9 lbs? Before you could say Pocket Rocket, I had one hanging off the side of my Baby. Now it is almost 2015 and battery tech has advanced by leaps and bounds. I know next to nothing about how the engineers have done this but I know the batteries in my XP Deus must be something special to weigh so little but pack so much punch. Will it be battery technology that will finally allow a new PI to offer performance close to what Minelab PI's are famous for yet weigh under 4 pounds? Is this a realistic goal to ask of metal detector manufacturers? We may soon see some interesting PI machines marketed. Fisher is working on one as is Nokta/Makro promising PI and hybrid machines. Nokta/Makro is shaking up the VLF world through their customer service and quality manufacturing and would it not be wonderful if they provide some real competition to Minelab? Personally, I believe if a manufacturer can develop a lightweight PI with improved discrimination it does not have to obtain the impressive depths Minelabs are capable of. If I can ignore most iron and dig more non-ferrous targets even though I occasionally miss deeper nuggets I am going to have more gold in my poke at the end of the day on a consistent basis. Some desert gold hunters might disagree and maybe rightfully so but if you hunt in areas where logging has occurred I surmise you may concur. Just as the Minelab 2300 has taken the prospecting community by storm by finding more small and/or spongy gold while giving up some capability on big, deep nuggets, a PI with improved discrimination is going to allow you to dig more gold and less nails, wire, and degraded cans. You would effectively view more dirt in a day by not spending so many of your precious prospecting hours digging ferrous targets. JMHO Merton
  22. Minelab has a lot of critics that accuse them of "drip feeding" us the technology. The SD 2000 was introduced in 1995 followed by the SD 2100, SD 2200, GP Extreme, GP 3000, GP 3500, GPX 4000, GPX 4500, GPX 4800, and finally GPX 5000. As if any of the critics have ever brought a successful product to market and then tried to make genuine improvements to it. It is not as easy as it looks. Genuine breakthrough products are very rare in the metal detecting industry, so most of what takes place is just tweaks and twiddles of the breakthrough after it occurs. Yet I would submit that although the improvements were incremental, the reality is Minelab with each succeeding model did make genuine improvements. These have added up over time to where the gulf between the original SD 2000 and GPX 5000 is quite considerable. Night and day really. See my page at http://www.detectorprospector.com/gold-prospecting-guides/steves-guide-differences-between-minelab-sd-gp-gpx-models.htm for details on the differences in the Minelab models. Now let's take a look at White's Electronics recently. The White's MXT was introduced in 2002. Then we got the MXT 300. Exact same detector with a matte black paint job and a larger coil. Then came the MXT Pro. The MXT Pro added multi-tones and a meter backlight plus a redesigned pod with a touch pad. Nice touches but the actual detecting modes offer no change in actual performance. It is still just an MXT. Then we get the MXT All Pro - another change up in the coils offered as standard. Along the way we got the M6 and the SST, which are stripped down feature limited versions of the MXT. That is 6 models over 12 years, not one of which is any better at detecting a target than the original MXT. Finally, in 2014 we get the MX5, which not only gets a new housing but a faster processor. Finally, a genuine functional difference. Sadly, they locked it into ground track mode and narrowed the possible ferrous range settings to just a few, making it hard for me to consider it an improvement. I guess I will wait for the MX6. I honestly am not trying to pick on White's here. At least they are mixing it up a bit. That is better than the situation with the poor Garrett Gold Stinger, neglected and unloved since 1990. Coming up on 25 years as the detector with the worst battery replacement scheme in modern detectors. It really has functionally been replaced by the AT Gold, but the Stinger lives on, the model that wouldn't die. All the manufacturers are guilty, or none of them are guilty. It is just the way the consumer electronics industry works. Apple and Android put the metal detecting industry to shame when it comes to continual drip feeding of incremental improvements designed to keep people on the upgrade path forever. With the added double whammy of new software or apps that will only work well on the newer hardware which almost forces an upgrade at some point. At least that old Stinger will work for as long as you want to buy batteries for it!
  23. I have an application for a specialized metal detector coil. I want to use a Whites MXT to provide ferrous/non-ferrous discrimination information on targets which are deeper in quartz than common metal detector depths (2-30 feet). These targets were not found with found a metal detector. I want to insert a metal detector probe encased in PVC pipe into a 2” dia hole bored into the quartz. Reading Carl Moreland's “Coil Basics” tutorial at http://www.geotech1.com/cgi-bin/pages/common/index.pl?page=metdet&file=info.dat it seems to me one of the figure 8 configurations would work well in this application. I would insert the probe on adequate length sections of PVC into the drilled hole and connect to the MXT. I’m armed with no metal detector probe building experience, a lot of RF experience, adequate test equipment. Will this idea work in general? Is one of the figure 8 configs the right topology? Any other hints on making this probe before I start? What distance from centerline of 2” dia drilled hole can I expect to discriminate on a US nickel sized object for ferrous/non-ferrous?
  24. VLF metal detector discrimination works well on isolated targets in an air test. The problem is in the field what is reported by the detector is the sum of everything the coil "sees". This means the ground mineralization, the gold nugget (or any other item you are trying to find), other metal under the coil at the same time, and even electrical interference. Sweep speed matters also as does the angle of the item in the ground and the direction from which the coil approaches it. Add it all up, and it is a miracle discrimination works at all, and the reality is it is wrong very often. Almost any ground with iron mineralization will cause non-ferrous items to read as ferrous. Usually it is something that happens right on the edge of detection depth. However, the more iron mineralization, the less depth it takes for the item to flip over to ferrous. It does not matter how large the item is either. Small non-ferrous items are more prone to reading ferrous but even very large items will flip in very bad ground. Bury a two ounce nugget deep enough in bad ground, and it will read ferrous. The ground mineralization pulls the VDI numbers down, and the deeper the item is buried, the lower the VDI number gets until it passes into the ferrous range. This happens with coins when coin detecting. A person using discrimination is looking for items that read in a certain number range. The problem is that mineralization pulls those numbers lower and then the items reads instead as a trash item, and is left behind. The simplified explanation is the detector is seeing a little bit of non-ferrous signal and a lot of ferrous ground signal. The White's GMT is a rare machine that tries to show you this graphically. It will say a target has a 40% chance of being non-ferrous. Most machines have to call it one way or the other and in this example just go ahead and call it ferrous. Which is it? Ferrous? Or 60% chance of being ferrous? Would you dig something if you knew it had a 40% chance of being a nugget? A picture says it all. See the one below. This is such a well known thing that White's has for a long time shown it on their simplified VDI (Visual Discrimination Indicator) scale. On most White's 1 through 95 indicates non-ferrous, and the negative numbers -1 through -95 indicate ferrous numbers. Notice how ferrous readings as low as -20 could indicate gold. Yet nearly everyone using any discrimination at all will tune out this range to eliminate finding small ferrous trash. This happens on all VLF metal detectors that employ discrimination. Good old Ganes Creek, Alaska is a VLF test bed on a massive scale. Tons of ferrous trash is buried intermingled with gold nuggets in tailing piles. The ground is not all that mineralized and VLF detectors work well there. Because the hunting was pay-to-mine competition style a VLF made more sense than digging hundreds of ferrous targets with a PI while your buddy was cherry picking nuggets around you with a VLF. The reputation of the White's MXT as a nugget finder was largely built at Ganes Creek, but many other VLF detectors did well. I saw a couple things over and over at Ganes Creek. First, we ran detectors in either of two modes. Dual tones with low tone ferrous, high tone non-ferrous was the most popular. Or there were some who ran in all metal mode then analyzed the target VDI once located. I did both. In either case you could get two results very often. In my case running a F75 in all metal I would get a target. I would then sweep it and watch the meter VDI numbers. What I learned is if there were five sweeps that said ferrous and just one that read non-ferrous, then dig it. Most people are looking for reasons not to dig. Getting five readings ferrous and one non-ferrous, most people would take that to mean a ferrous target. What I found more often than not is that if I could just get the target to read non-ferrous even once, it was worth digging. These were usually items reading borderline anyway. The only stuff relatively safe to walk away from is items that give strong ferrous readings repeatedly. With dual tones the same thing applies. If you get five low tones but then get it to bounce high tone even once, better dig it. The real proof was the simple kick test. You go along, get a ferrous indication, and kick a couple inches off the surface and bingo! the ferrous item turns non-ferrous. Pretty amazing stuff. Keep in mind folks, this is relatively mild ground! What not to do. If you take any detector and tune it to completely ignore ferrous targets, you are in big trouble. The Gold Bug 2 for instance. If you flip to Iron Disc mode iron targets are ignored as if they are not there. Yes, some will click or pop but most simply get ignored. Any detector with a simple knob, like a Tesoro Lobo in disc mode, you can turn up until a small nail will be ignored. Hunting directly set up to reject ferrous is very problematic. Now you can find gold doing this. I have and many people have. The problem is as you go along you only get one chance at the target. If you hunt in all metal, you will always get the target, and then you can analyze at your leisure, or just dig it up. In dual tone you will always be alerted to the target, so you can check it again. But if you set to reject, and the detector makes a bad call on the first sweep, you pass over the target and never know it was there at all. Part of the problem is in targets that you only get partly over on the first pass. For the discrimination to have its best shot, you need to be centered on the target as much as possible to get the strongest signal. An on edge pass will usually be wrong, but if you are alerted you can make multiple sweeps to get centered on target for the best reading. Any detector running in disc mode will have a search field that is more limited in extant than that you experience with the detector in true all metal mode. In disc mode you need to be well centered. In all metal, the coil reaches wider and deeper to gather signals. The reason I usually run in all metal is it gives me the best chance of capturing the target, then I can decide what to do with it. Running directly in disc gives you more chance of missing the target entirely. Keep in mind these issues vary wildly with the amount and type of iron mineralization in the ground. I saw some ground in Alaska recently that you would not think was very mineralized. No intense red colors, not much in the way of hot rocks. And yet there was something about the iron in the ground that made fairly large nuggets and even .22 shell casings read as ferrous when sitting directly on the ground in plain sight! Very, very scary stuff. Now having said all that, there are times I will crank up the disc and eliminate the signals. Sometimes they are overwhelming in number and it is the only way to deal with it. Maybe I am just tired and not in the mood to analyze every target. Maybe time is very limited and I need to do a quick cherry pick run of the ground. There are no absolutes in metal detecting. The main thing is to have the knowledge required to make the best choices you can, to get the best odds for the situation. Hopefully this little article will help. Here is another.
  25. How important is a warranty? Are defects common in metal detectors? Should a warranty or lack of one be a big influence? Those of you who have owned many detectors, have you had many failures?
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