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  1. A post I made 11 years ago.... https://www.findmall.com/threads/whites-official-audio-volume-fix.127081/post-802630
  2. 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. Standard White's VDI 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 Target id numbers for naturally occurring gold nuggets 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.
  3. I am new here so there may be a better forum to ask this question so redirect me if needed. I have a Teknetics Delta 4000. I need to probe a fiberglass tube 2 inches in diameter to see if I can detect a copper beryllium strip which should be inside. Unfortunate I cannot get closer than 16 ft to the tube. I have found a 25 foot 5 pin DIN cable that would extend the cable that is on the 4000. I could then detach the pickup coil and mount that on a 16 ft PVC rod leaving the electronics and readout with me. I only need to know if there is something there or not there. The rod is 100 ft off the ground and 16 ft out from my closest reach. Anyone ever tried to extend the cable?. I know it is not a perfect situation but I would save me a lot of money if I can detect the metal strip. Regards Mike
  4. Hello, I'm looking for detector that can detect up to 4 meters (~13 ft) with > 10 grams of gold on orchard ground I've bought "BR gold step" but it was useless now I'm looking on "minelab GPZ 7000" but I wanted to ask here if there it will be good one for my case or there is another choice my budget is 10,000$ PS: can I use GPZ 7000 with my gold step to get more accurate reads ?
  5. Hello all, I was reading Steve's post on "Best detector values under $500 dollars"! And noticed something! I noticed that MineLab is the only manufacturer that listed the operation temperature, and storage temperature of their equipment! Being a Native of South Florida with its oppressive heat, humidity, and salt air, most of the year! I have experienced first hand what happens to electronics, plastics, adhesives, etc... that many of you in certain States, and Country's, have also experienced! Suffice it to say to the uninitiated, that it is a bad idea to leave these items in an enclosed vehicle for an extended period of time!♨️ The last couple of weeks, i have been trying to figure out if coil or detector color, can adversely affect function and longevity, in these types of conditions! (not just inside vehicles)! Proof has been hard to find, without the advantages that the designers, and bench testers, have at their disposal! I know "most" electronics have overload protection built in; from energy spikes , as well as heat! That would be an obvious "failure"! But short of this "failure", will detection depth, or circuit function be appreciably reduced based solely on the surface, and internal temps of the parts themselves? Especially the copper windings of the coil! Are PI detectors more likely to suffer, due to the added power output? And is this a cumulative, or situational effect that goes unnoticed? ( loss of depth with hot coil, or circuit function)! Just wanted to get that out there for any input you all have!! Based on the huge knowledge base on this forum!👍👍
  6. I am somewhat new to metal detecting and was recently told, by a veteran detector, that all machines are multi frequency. I was also told to not buy into the multi frequency hype and that machines advertised as ones, is a marketing ploy. Please help! Is he right?
  7. Is this detector able to detect diamond? I am trying to find a diamond from a ring that fell out a number of years ago in my garden. My friend Aberal Molzesman said in his blog tha it is possible.
  8. How good is this for our hobby? From looking at new members each day here and other forums seems to be a lot of newbies. They have a bunch of great choices that won't break your bank account. They can pick from the Garrett Ace line, AT Pro, Nox 600 & 800, Simplex+, Vanquish series, the new Garret Apex and maybe several new detectors from Minelab next year. Maybe some old times can tell us if there was a similar period of great detectors to pick from.
  9. Looked interesting enough to share https://hackaday.com/2020/05/02/a-smart-diy-metal-detector/
  10. What machine that you were able to use at a certain time gave you an advantage over others at certain places you hunt.The first for me was having a minelab explorer in Jan of 2000 for hunting coins in parks. Even being too selective when I first started hunting with it I still cleaned up because the machine was that good. The problem was there were many good explorer users in my area which made it much harder to find coins like we did in the past with such ease.The Nox is a great machine but it was not available in( 2000- 2007 ) when the explorer ruled the parks.That machine and that time will always be special to me.Mike Moutray who was one of the best explorer users I saw would go around the country and would hunt places people on the forums would take him to.My friend got in touch with him and he would hunt a old racing track with us . 6 explorer users in all.He made the most finds out of all of us.He was that good.Yet he hunted 3/4 of a 200 year old oak tree and went to the bathroom. When he came back he did not go back to finish the tree. I went to the tree and got a iffy deep hit and dug,putting the dirt in a gold pan.Out came a 1909 2 1/2 $ gold coin.I then put the Sunray probe in the hole and got a pulltab hit.Out pops a other 1909 2 1/2 $ gold coin.Put the probe in the hole and again a pulltab hit. This time a fired 22 slug.The song says 2 out of 3 aint bad.The explorer was way ahead of its time.
  11. Okay all you propeller heads...... When it comes to PI detector power, it’s Amps that matter first.....correct ? Minelab PI’s: Operate around the 7.2v but draw close to an Amp White’s TDI: Operate at 12v to 16v but draw about half an Amp So voltage is “electrical pressure” but Amperage is “the rate of electrical flow”....... What controls the Amps........just the MOSFET Steve......didn’t know where to post this question so feel free to move as needed. Thanks Tony
  12. Well it’s official. The Garrett GTI 2500, the flagship of the Garrett metal detector lineup, was over 20 years old in 2019. The GTI 2500 was introduced in 1999. Twenty years is an awfully long time in technology land, and I’d say it’s well past time for Garrett to do something about that. What would you like to see from Garrett in 2020? Garrett GTI 2500 Data & Specifications
  13. I love analogies. Maybe this one will help some people. Low recovery speeds magnify signals and fast recovery speeds truncate signals. Digital machines usually chop signals into discrete portions. A target is “grabbed” and then it is “released”. A new target cannot be “grabbed” until the last one is “released”. Imagine a conveyor belt going by with a line of wooden blocks. The blocks have anywhere from 9 to 16 sides. You are standing there blindfolded as the blocks go by. You can pick up a block and feel it for as long as you want to try and decide how many sides it has. The longer you roll it around in your hands, the better. Your chance of deciding if it is a thirteen sided block or a fourteen sided block is better if you have more time. However, you are being graded by how many blocks you identify correctly, and if you hold one too long some pass by before you can pick them up. The conveyor is passing 8 blocks per minute past you. If you have a recovery speed of 1 you hold each block one minute and you get a great “signal” on that block. But seven other blocks go by as you are taking your time identifying the one block. You increase your recovery time to three and now get 3 out of 8 blocks but have less time to hold each block. Less signal information. Still, you get them all right. Now you increase recovery time to 5 and are only missing three blocks. Your slower buddies are having a hard time keeping up now and making mistakes, misidentifying blocks, but you are doing great. You notice that people standing back are having to reach farther to grab a block and put it back. They are “going deeper” but it is costing them time. You step closer to the conveyor belt so you don’t have to reach as far, and are now a little faster by not reaching as far. You lose a little “depth” but gain some speed. You go to recovery speed seven and your arms are a blur. Your buddies all give up and stand back in awe as you pick up and put down blocks at lightning speed, and are still calling them right but you can tell you are at your limit. You finally go to 8 and still get almost all right it every now and then you have to put a block back down before you can tell what it was. You don’t have enough time, enough signal to work with. You also get to change the conveyor speed. You can swing your coil slower, and now you have more time to look at each target. That means you can lower the recovery speed and still keep up with the targets. Great for the slower workers (detectors) who have a hard time keeping up. That is a decent analogy for recovery speed and what it does for the ability of a detector to clearly examine a target versus how many targets it can process and how far it can reach. Slow detectors, slow conveyor workers, don’t have a chance. Only the fastest workers, the fastest machines, can pick up and process all the targets correctly in a short period of time. They are a rare breed. One of the biggest advantages you possess in Equinox is the lightning fast recovery speed. I see far too many people throwing that advantage away thinking a lower recovery speed gets “more depth”. No point in getting an Equinox then, just stick with the slower machine you already have. Give Equinox a real good go at the default higher recovery speeds before deciding to toss away what is perhaps the most important advantage the machine has - lightning fast recovery time coupled with accurate target id and minimal depth loss at those high speeds. That is the Equinox difference. Don’t waste it. Recovery Speed, Recovery Delay, And Reactivity
  14. Hey guys n girls I have a doozie of a question for anyone that may be in the know. I'm not sure how to ask this without being negative towards a great detector Minelabs GPZ7000 approx $9000 Australian dollars. I was watching some YouTube videos on the Ajax Segma 3d metal detector. It has an 8m depth. Finds all types of metals, water even under ground caves. The cost is A lot less than a GPZ7000 My main question is why have we not seen or heard more about this in Australia. I mean if not for general gold detecting, but for bigger companies using it to find the depth of the gold they need to mine. Check out the detector by Ajax and I think the other one is a company called Ger from Germany.
  15. Just curious, how many prospectors are still swinging around a Minelab SD series, GP or even GPX4000?? These models hardly get a mention these days. For those that are swinging these older models, here's a few additional questions do get a bit of chatter happening....maybe Have you tried any of the new flat/spiral wound coils? Have you tried modern boosters, or aftermarket battery options? On a personal note, I still have a SD2100e and a GP3500 but they don't get any serious use. The 2100 is very sentimental model to me as it was the detector I found my first nugget with. The GP3500 was my baby, where Minelab added everything I wished for. It still has the best audio in any prospecting detector I've used to date (admittedly she's a bit on the quiet side).
  16. Hi All I've been hearing rumours of a new gold machine in the works ? Is there any truth in this and if so what are some of the rumours or truths about it. Cheers
  17. I’ll post link here. Folks can comment if they wish. Saves me time by not posting in detail on all forums. I like this forum very much. Hope I am not breaking rules here or am not upsetting anyone. http://www.dankowskidetectors.com/discussions/read.php?2,173272
  18. any thoughts on the use of a geiger counter instead of a metal detector for prospecting ....U , TH , TE , IN , RB , RE , PT
  19. 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 http://chemelec.com/Projects/Metal-1a/Understanding-the-PI-Detector.htm Deepest PI Detector by Reg Sniff Part One Link deleted since Findmall update broke old links Deepest PI Detector by Reg Sniff Part Two Link deleted since Findmall update broke old links
  20. Hello Guys, I'm new on this forum and like Alexandre Tartar, I live in north of France. I was a young prospector in the 90's and asked my father (electronic engineer with good knowledge in magnetic field theory) to build a PI to hunt the beaches. So we have made, in a few months, an home-made PI metal detector 25 years ago, based on the technology of the old White's Surfmaster PI (mono coil). I remember the use of FETs (Field Effects Transistors to make 200 volts pulses). It worked, but unfortunately, my father was afraid by a so powerful magnetic fields and has continued his research on VLF detectors, until today ! After this short presentation, here's my question : Is the Impulse AQ a bipolar detector ? Le Jag has explained us on the french forum "detecteur.net" this technology developped by Alexandre : Positive and Negative pulse are alternatively sent. The positive one light the gold ring but magnetize the soil. The negative one demagnetize the soil. What about it ?
  21. http://www.dankowskidetectors.com/discussions/read.php?2,172859
  22. From the Codan news release at http://www.codan.com.au/Portals/0/investorpubs/22 AXS Announcement - Minelab awarded $6.7m contract.pdf (copy below): "Cooperating with NIITEK Inc., the HDD will combine Minelab’s new Multiple Frequency Continuous Wave metal detection technology and NIITEK’s advanced ground penetrating radar." 31 August 2016 MINELAB AWARDED CONTRACT TO DEVELOP NEW HANDHELD DEVICE DETECTOR FOR THE AUSTRALIAN DEFENCE FORCE Minelab Electronics, a wholly owned subsidiary of Codan Limited, has been awarded a $6.7m contract by the Department of Defence to develop a new Handheld Device Detector (HDD). The funding received under this contract is to further develop a dual sensor metal detector which incorporates ground penetrating radar. It will partially offset the development costs of the product, and the project is expected to be completed by 2018. The development of the HDD builds on Minelab's success in technology development and product innovation for use in military programmes. Codan is particularly pleased to be of service to the ADF and to provide an enhanced capability that currently does not exist. Once the HDD enters into service with the ADF, we are confident that other militaries will seek the same level of capability, broadening our market for countermine products. The contract supports Codan's stated strategy of growing its profitability by improving and broadening our product offerings while ensuring our value propositions remain relevant and leading-edge. Previous to this award, in March 2014, Minelab was selected by the Department of Defence's Rapid Prototype Development and Evaluation (RPDE) programme to receive $1.0m in funding to further integrate metal detection and ground penetration radar technologies into a lightweight and compact mechanical platform. In December 2014, RPDE provided an additional $1.3m in funding, and Minelab subsequently produced an advanced prototype of the HDD. Cooperating with NIITEK Inc., the HDD will combine Minelab's new Multiple Frequency Continuous Wave metal detection technology and NIITEK's advanced ground penetrating radar. The HDD was designed taking into account the comprehensive requirements of the ADF, supplemented with feedback from Army User Groups. It will include advanced detection technologies as well as new standards of compactness and ergonomics. On behalf of the Board Michael Barton Company Secretary MORE INFORMATION ON THE NIITEK/MINELAB GROUNDSHARK Minelab Mineshark
  23. Show simple targets you swore were gold. These were 12" inches plus in depth (all lead)....... Found with a borrowed GPX 4500
  24. The GB knob on my Tejon is super loose now after the tons of hours I put on it and I get a little waver in the threshold. Trying to find who sells damping grease in really small quantities as the stuff is horribly expensive. Mcmaster has some at $111 + shipping, Amazon has some in the $30 range and all more expensive than the potentiometer itself. I could replace it but rather not start soldering in parts if I don't have to.
  25. HOW MAKE A SERIOUS COMPARATIVE TESTS PROCEDURE First rule Blind tests are mandatory to be serious. Second rule if you do not agree refer to rule number 1 😊 The purpose of this playground, and not to take into account the feeling of the prospector. It is too easy for a participant to indicate that he is correctly detecting the target. But in general he does not detect it or he thinks to detect it. It often detects a ground effect. During our long experience and our meetings with prospectors at the beach, we realized that the prospector was often influenced by the pride placed in his detector. This is why we have implemented this drastic and non-falsifiable comparative tests procedure. Of course for this test you have to be 2 people. A person who hides targets and a person who tries to find them. The depth tests can be done simultaneously. It is obvious that here are static tests. The reality is even more difficult! See for yourself the catastrophic results .... Document here : ******************************* https://www.casimages.com/f/qyqU0eUlCSb ******************************* COMPARATIVE TESTS PROCEDURE.pdf
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