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  1. 3 points
    The secret to the Minelab GPX series is thoroughly understanding the timings and when to use each one. Timings are variations of the basic pulse induction technology at work in the GPX series that gives you far more flexibility than exists in other pulse induction detectors. Unfortunately this extra flexibility also adds complexity, and so it is not unusual that some people may not be using the optimum settings in many cases. It is very important when investing in a Minelab GPX detector to take the time to read the manuals and study until you fully understand what the settings do and how to adjust the detector for the best performance. Otherwise you will not be getting all the potential out of your investment. The chart below shows the timings and what GPX models they are available on along with a general description. The descriptions are from the owners manuals that are available by download at the bottom of the page. In general you should always use timings as near the top of the chart as possible, with the exception of the Salt settings. Those are for alkali flat and salt water beach areas only. Using timings designed for more mineralization than is actually required may result in less depth on desired targets. Imagine the timings as another sort of ground balance setting. Low mineral settings are more powerful than high mineral settings and should be used whenever possible. Some confusion is the result of the timing names. Some people assume the Fine Gold timing is best for fine gold. This does make a sort of sense, but the fact is Fine Gold is just better than other high mineralization timings on smaller gold. In milder ground Sensitive Extra will obtain better results on small shallow gold. It is also very important to know that some timings work better with one coil type or the other. Minelab GPX Timings Chart Little or No Mineralization Coin/Relic (GPX 5000 ONLY) Coin/Relic is for use in lightly mineralized soils including many beaches and loamy soils. It offers maximum detection depth on a range of target sizes, significantly greater than any other timings. However, if the ground is any more than lightly mineralized, the detector may not ground balance properly. On ocean beaches containing significant quantities of black sand, better results may be had by using Normal or Salt settings. Mild Mineralization Sharp (GPX 4500, 4800, 5000) Sharp is similar to Normal but creates a more powerful detection field. It is capable of an improvement in depth, but is more susceptible to interference and will increase the severity of false signals in difficult grounds. This timing is best used in quiet conditions and can work well in combination with Deep Search Mode with a reduced Rx Gain setting. Sharp is an excellent tool for pinpointing faint signals due to the very "sharp" signal response. Sharp will work best with DD coils in most gold field locations. Medium Low Mineralization Sensitive Extra (GPX 4000, 4500, 4800, 5000) This timing may increase the signal from certain hot rocks near the surface, but can actually help smooth out the Threshold in certain ground types, particularly with Double-D coils. In mild ground conditions Sensitive Extra will provide the best signal response on a small, deep target. Medium Mineralization Normal (GPX 4000, 4500, 4800, 5000) Normal gives you the best performance on a wide range of soil conditions, and it will provide the best depth on a wide variety of target sizes. It works particularly well with the supplied 11" DD search coil for general detecting. You should always use Normal in new areas where you are unsure of the soil mineralization and the depth of targets. Medium High Mineralization Salt Coarse (GPX 4000, 4500, 4800) The effect of alkaline salt mineralization is vastly different to the effect of ironstone and mineralized clays. Normal should be tried first in these areas, but if the Threshold is too unstable then better performance will be obtained in Salt-Coarse. Using the Salt-Coarse timing may result in a loss in signal response to smaller targets. However, the response on larger items remains relatively unaffected and ground noise is usually minimized. Medium High Mineralization Salt/Gold (GPX 5000 ONLY) Provides the best signal response on small to large gold in salt saturated and mineralized ground conditions. It should work well on dry inland salt lakes, high salt concentrated goldfields, and mineralized saltwater beaches. Extremely salt saturated soils may still need to be searched with the coil switch in Cancel (using a Double D coil). High Mineralization Fine Gold (GPX 5000 ONLY) Fine Gold is sensitive to smaller targets in highly mineralized ground. It provides a sharper signal on small gold compared to Enhance, and improves the detectability of rough/flaky gold and specimens, while ignoring most hot rock signals and false ground noises. Shallow, highly mineralized ground where gold has been found previously should be re-examined with Fine Gold, and best results will be had by using the optional 8” and 11” Commander Monoloop coils. Note: Sensitive Extra will provide superior results on small gold in milder ground. Very High Mineralization Enhance (GPX 4500, 4800, Improved in GPX 5000) Runs quietly in most heavily mineralized, variable and "hot rock" infested grounds using a monoloop coil. It is more sensitive and detects deeper than Sensitive Smooth but can be slightly more affected by severe ground mineralization. Severe Mineralization Sensitive Smooth (GPX 4000, 4500, 5000) Sensitive Smooth is optimized for an improved response on smaller, shallow nuggets in severe soils. There is a loss of depth on bigger targets; so you should not use this setting when seeking out large, deep nuggets. Sensitive Smooth is best suited for use with monoloop coils in difficult soils. It eliminates most false signals from hot rocks, and ground mineralization, whilst retaining excellent sensitivity to small targets. The example below shows three common timings and where they should be used. It also highlights why using the wrong timing for the conditions can result in missed targets. Minelab Mineralization and Timing Example The following chart illustrates the procedure for finding the correct timing for each situation. In general, always start with the Normal timing. If the detector is stable and quiet, try timings on the left - Sensitive Extra, Sharp, or in rare cases, Coin/Relic. If ground noise or hot rocks present problems in Normal, then try timings on the right - Fine Gold, Enhance, or Sensitive Smooth. Salt settings should generally only be used on alkali ground (salt flats) or salt water beaches, but may have applications in other ground. The goal is always to find the most powerful setting that allows for stable operation. Each timing can be adjusted within certain parameters, primarily through the use of the Gain and Stabilizer settings. Adjusting for a lower Gain, for example, may be preferable to going to a less powerful timing. Minelab GPX Timing Selection Chart - Click on image for larger version Finally, each timing may work best with a certain type of coil (DD or Mono) and the timings have varying level of resistance to Electro Magnetic Interference (EMI). The matrix below attempts to show which timings offers which benefits and strengths/weaknesses. Minelab Timing Coil EMI Matrix - Click on image for larger version The simple chart below can be printed out and taped or glued on your detector shaft as a reminder in the field as to which timing may be best. Click on the image to download a large version. Minelab Timing Decal - Click on image for larger version Minelab GPX 4800/5000 Instruction Manual Download Here Minelab GPX Series Quick Start Guide Download Here Minelab GPX 4800/5000 Product Brochure Download Here Minelab Commander Coil Brochure Download Here Minelab GPX 4500 Instruction Manual Download Here Minelab GPX 4000 Instruction Manual Download Here ~ Steve Herschbach Copyright © 2011 Herschbach Enterprises
  2. 1 point
    The Minelab GPX 5000 detector was released in the fall of 2010 and is still in production. I got one the same year - see First Alaska Gold with the Minelab GPX 5000 at Steve's Mining Journal. The Minelab series of pulse induction (PI) metal detectors starting with the SD 2000 are widely acknowledged as being some of the most powerful gold nugget prospecting detectors currently available. The GPX 5000 is the latest and most refined in the series. I can say that having used all the models the changes from model to model were gradual, but the difference between a Minelab SD 2000 and a Minelab GPX 5000 is nothing short of astounding. Minelab has dramatically refined this technology over the years. See Steve's Guide to Differences of Minelab SD, GP, & GPX for details. I believe that Minelab has really squeezed about all the performance I think I can expect out of a pulse induction (PI) with the GPX 5000. The stability, depth, and sensitivity are superb, as is the ability to adjust the machine to handle almost any ground mineralization or hot rocks that may be encountered. There are only two things that I can see that realistically can be improved on at this point. First, the the iron discrimination system, which is unreliable in general and of no use at all on deep targets. Second, the overall physical package, which has changed little since the SD 2000 first came out. The harness and bungee system is actually quite effective and comfortable for long hours of detecting but the separate battery and lack of speaker are an issue. However, it is possible with modern high capacity batteries to eliminate the separate battery/cable system and add an external speaker. Minelab would then be doing for people what many are now doing with aftermarket add on equipment. Still, there is no doubt at this point that for the serious, dedicated prospector, the Minelab GPX 5000 represents the current state of the art in pulse induction detectors. It is the detector of choice for many prospectors around the world. Minelab GPX 5000 - state of the art in pulse induction metal detecting My own GPX 5000 was exceptionally good to me, helping me locate the best gold nugget find I have ever made. I spent a month metal detecting in Alaska in 2013 in the Fortymile area. The month was about up and from July 22 to July 28 six days of metal detecting had netted me only three gold nuggets. That is a lot of detecting and digging for just three happy moments! I was getting burned out plus missing my wife and new home. My wife had also let me know one of my dogs was not doing well. It all just added up to time to go home. Besides, I had about 5.5 ounces of gold, not bad at all and better than I had hoped for. Good weather, good gold, good times with friends, it really had been a near perfect trip. Therefore on the morning of the 29th of July I wandered up to Chris and Bernie's camp and told them I was done. I was paid up at Chicken Gold Camp through the 31st so my plan was to be packed up and hit the road for Nevada early on August 1st. I had just a few days left so had to decide what to do. There is an area on upper Jack Wade known to have produced big gold in the past. Like nuggets weighing pounds, and a 10 ounce nugget had been found there by a dredger the previous season. It was on the ground owned by a miner I had a deal with. I had of course hunted it previously but only found a few small nuggets and lots of little ferrous trash. It was a gorgeous sunny day and the area was relatively open and level so easy hunting. I fired up the Minelab GPX 5000 with Nugget Finder 14" x 9" mono and crossed over the creek to give it a go. I was really relaxed because mentally I was done working and just happy to be out beeping a couple more days. It was really a nice feeling knowing I would soon be heading home. I barely had got started when I crested the top of a small ridge of tailings and got a massive boomer signal. Just a huge descending low tone, the type you might get if you buried a huge bolt or some other large ferrous target not too far down. There was a recent dig hole on the target, and I thought "well, let's see what he left in the hole" and gave just a couple big scoops. It was sandy easy digging stuff, and as it slid down the hill I glimpsed gold. I thought "no way!" and as I grabbed it could feel the weight. I stood there looking at 6.5 ounces of solid gold in my hand! The Selfie We All Want To Take - Steve With 6.5 Ounce Gold Nugget There is no doubt in my mind about the addictive nature of nugget detecting. It is not easy to do and the gold is not easy to find. There can be lots of false starts and disappointments along the way. It is all that however that makes it so sweet when gold is finally found, when all the hard work and effort is rewarded. I get a thrill out of every nugget I find, no matter how small, because I work hard for every one of them. The really big finds are much rarer yet, so much so that few people ever get to say they found a nugget weighing one ounce or more. The feeling of accomplishment is indescribable because it verges on feeling like a miracle has occurred. Once you get a taste of that feeling you want to feel it again, and it is that quest that powers me and others through days, months, and years of effort. The thrill of finding gold! Just Out Of the Ground, Unwashed, And On The Scale After an hour of photos and just plain soaking up the moment I proceeded to hunt that area extra well, because as you can imagine after a find like that visions of piles of nuggets enters your mind. If one got lost, might there not be others? Unfortunately it does not seem to work like that, and continued careful hunting of the location only produced one more nugget, a clean little 1 gram piece. No surprise there. How even one nugget like this gets lost is something we all wonder about. How does a half pound of solid gold end up in a tailing pile? Who knows, I am just happy it did. For a combination of size and the solid gold content it is the best nugget I have ever found. Minelab GPX 5000 With 6.5 Ounce Nugget At Dig Location The biggest question of course is who started to dig that nugget and then quit? The material was easy digging, about as easy as you could ask for. I surmise it had to be a Minelab operator. If you run a Minelab long enough you get huge boomer signals very often, and they are almost always a can or bolt or some other shallow, large junk target. They can also be very large gold nugget but if you get that signal enough times and dig it up, only to find junk, your brain gets trained to think that is all it could be. "Too big to be gold" - have you ever thought that? I wonder how many people have done like this unknown person, got a target, and then decided nope, it has to be junk, and walked away? I know I have done it and I am pretty certain it has cost me. It may be that a small percentage of the very biggest nugget signals are still out there, having been detected and left for junk. In fact, I am willing to bet that is the case, though there are a couple less now. View Of Both Sides, Just Rinsed In Creek I first went and showed the nugget to the claim owner and then Bernie and Chris. However, I asked them to keep quiet about it. The trip had been so enjoyable, and finding something like that right at the end, well, it was obvious I was going to be back in 2014. There was a lot of public area left to hunt on the creek still, and I saw no reason to possibly start a little gold rush to the area before I got the chance to come back and give it another go. That trip has now come and gone at Steve's 2014 Alaska Gold Adventure and so now finally you get to hear the rest of the story. Speaking of the public area, Bernie and I went and hit it the very next day. We had mostly taken advantage of our access to areas not available to the general public while we could and had been leaving the public area for later. There is information about it at the 2104 tale. We both started out with our GPX units but I could tell Bernie was less thrilled than I to be digging junk, so I suggested we go back to the truck and grab our VLF detectors. We did just that, and I no more than got my Gold Bug Pro swinging when it made a loud beep, and up pops a 5.9 dwt nugget practically off the surface! It was just another over the top easy nugget after all the days of digging nothing but junk. Even wilder is that fact that in 2014 several days detecting by several people including myself in this same location produced no gold at all. It is liked I walked up and banged the only nugget there. The next day and a half produced no other nuggets but I am certainly not complaining about that. My trip had gone from great to off the charts fantastic with just over a Troy pound (12 Troy ounces) of gold found. 12.3 ounces actually found in exactly 30 days of time spent actually nugget detecting. Not a get rich quick scenario by any means but not bad at all either. All the gold except a few smaller nuggets were found with the Minelab GPX 5000. Overall the time spent in the Chicken area during the summer of 2013 will go down in my memory as one of my best times ever. There are many more photos from this trip in the Photo Gallery. ~ Steve Herschbach Copyright © 2014 Herschbach Enterprises Troy Pound Of Gold Nuggets From Jack Wade Creek, Alaska 2013 Official Minelab GPX 5000 Page Minelab GPX 5000 Instruction Manual Beginner's Guide to Tuning the Minelab GPX 5000 Minelab GPX 4000-5000 Timings Charts Difference Between Minelab SD, GP, and GPX Models Forum Threads Tagged "minelab gpx" Minelab Metal Detectors Forum Minelab GPX 5000 Technical Specifications* Internet Price $3999.00 Technology Ground Balancing Pulse Induction (GBPI) Frequency 1100-4500 PPS? Autotune (Motion) Mode(s) Very Slow, Slow, Medium and Fast Ground Rejection Slow, Medium, Fast Tracking, Fixed, and Off Soil Adjust Eight settings (timings) - see chart below Discrimination Variable 1-10 and Off in Menu Volume Control Variable 1-20 in Menu Threshold Control One turn control Tone Adjust Variable 1-100 in Menu Audio Boost Quiet, Normal, Deep, Boost in Menu Frequency Offset Automatic Tune plus Manual 0-255 in Menu Pinpoint Mode No Audio Output 1/4" headphone socket (No speaker) Headphones supplied Hip Mount Shaft Mount Only Standard Coil(s) 11" round DD and 11" round Mono Optional Search Coils Over 100 accessory coils available Battery Rechargeable 7.4VDC 9.2A/hr Lithium Ion Operating Time 14 - 15 hours Weight 5.3 lbs (w/11" coil, excluding battery (1.7 lbs) Additional Technology Multi Period Sensing (MPS) Dual Voltage Technology (DVT) Smart Electronic Timing Alignment (SETA) Numerous Audio Adjustments via menu Coil (Double D/Mono/Cancel) - 3 pos. switch Notes The GPX 5000 employs an external battery carried on a backpack harness and connected to the control box via a power cord. The detector is normally suspended from the harness with a bungee cord, allowing for nearly weightless operation in level ground. *Notes on Technical Specifications - Detailed notes about the specifications listed in this chart.
  3. 1 point
    This page has links to a collection of online "books" about prospecting and metal detecting subjects of interest. Most of these were actual printed books or brochures that are now available as html or pdf documents. In the case of pdf documents especially you can download and save these creating your own library of essential information. Many of these are out of print and hard to find so we are very lucky they are being scanned and made available on the internet. Metal Detecting How Metal Detectors Work by Mark Rowan & William Lahr - Originally published by White's Electronics as a booklet P/N 621-0395. Basic but rather technical information on how induction balance and pulse induction metal detectors work. Metal Detector Basics and Theory by Bruce Candy - Bruce is a co-founder of Minelab and the man behind their most advanced designs. This information delves into much greater detail than the above link and has many more illustrations and diagrams. Metal Detecting Terminology - Metal detecting terminology and definitions, with an emphasis on Minelab technology wording and descriptions. Gold Prospecting with a VLF Metal Detector by Dave Johnson. Dave is the Chief Designer for First Texas Products and has been involved in designing most of the VLF gold prospecting detectors sold over the last 30 years. This is an excellent primer on using VLF detectors to prospect for gold. The History of Metal Detectors, with Emphasis on Gold Prospecting from First Texas (Bounty Hunter, Fisher, Teknetics) by Dave Johnson. A talk given to the El Paso Chapter of the GPAA February 12, 2008. Metal Detecting Technologies for Gold Prospecting from First Texas (Bounty Hunter, Fisher, Teknetics) by Dave Johnson. A short essay of key technologies for gold nugget detecting. Understanding the PI Metal Detector by Reg Sniff. An excellent, understandable primer on pulse induction metal detectors. Metal Detector Information - Get lots of great answers to basic detecting questions along with info and field reviews of Tesoro detectors. Common Questions About Metal Detecting from White's Electronics. Recommended Recovery Methods by Robert H. Sickler - Do not damage the turf! Fisher Intelligence 5th Edition by Thomas Dankowski. Thought provoking articles on aspects of metal detecting not often talked about. Advanced Nugget Hunting with the Fisher Gold Bug Metal Detector by Pieter Heydelaar and David Johnson. This out-of-print book is a good basic text on nugget detecting. Although it uses the original Fisher Gold Bug as an example the information applies to most nugget detectors. Part 2 by David Johnson is an excellent primer on hot rocks. The Painful Truth by Thomas Dankowski - There is more good stuff left to be found but hidden from current technology - read why. A follow up to Dankowskis classic Beneath The Mask article. Head-To-Head Comparison Testing by Thomas Dankowski. It is not as easy as it looks! Why people get different results testing metal detectors, and how to do it properly. Halo Effect & Related Ground Oddities - from Fisher by Dave Johnson. An explanation of factors that can possibly enhance detector depth - myth or reality? Steve's Guides - Articles about basic metal detecting and gold prospecting subjects. Metal Detector User Guides & Catalogs - User guides, catalogs and brochures from various manufacturers. ads by Amazon...
  4. 1 point
    This is my latest "Nugget Detector Guide", now published for over fifteen years, updated January 2019 with some of the latest model information. Each model has a short description, followed by a very PERSONAL OPINION. Copyright 2002-2019 Herschbach Enterprises - Please do not reuse or repost without my express permission. This is offered as a simple guide for those wanting a general comparison of the various nugget detectors available new with warranty, along with some kind of real opinion about them. That's all it is, folks, so take it or leave it for what it is worth. It's just that listing specs is of little help to people, and so I take my best stab at providing some guidance for those newer to detecting. These are only my opinions based on my experience with various detectors over the years. While I do have a lot of experience, I must throw in the caveat that I have not used all detectors under all conditions. What may be considered a good detector at one location may not be so good at another location due to differences in ground mineralization and the gold itself. Detector performance is site specific and so your mileage may vary. Never forget that when reading comparisons on the internet. Although many detectors sold today can potentially find gold nuggets, I've chosen to only list current models from major manufacturers that are sold and marketed primarily as prospecting detectors or that at least have a specific prospecting mode. I no longer list general purpose VLF detectors running under 17 khz because they are just too common and that being the case they offer nothing special to the potential gold prospector. If you are interested in other general purpose detectors that might make good prospecting machine but are not listed here, look at my more comprehensive reviews list. Many discontinued prospecting detectors are also listed there. The list below has over twenty models listed and still may be too much for some people. In recognition of this I have made my best shot at picking three possible options I am calling Steve's Picks. Click the link to jump there at the end of this page. Various popular gold nugget prospecting metal detectors Please, if you own one of these detectors, and I call it like I see it, don't take offense. Any nugget detector made will find gold in capable hands, and the owner is far more important than the detector model. I'll put a good operator with almost any detector on this list up against a novice with whatever is deemed "best" and bet on the experienced operator every time. The person using the detector finds the gold. The detector is actually one of the less important factors in nugget detecting success or failure. A quick note to those who know nothing about these machines. These are metal detectors. There is no such thing as a "gold only" detector. These detectors will also find lead, copper, aluminum, and other metals. These units are best used to look for relatively larger pieces of gold at relatively shallow depths. Concentrations of gold dust are not detectable. Some of these units can hit gold that weighs as little as a grain (480 grains per ounce) or less but only at an inch or two. Only the larger nuggets can be found at depths exceeding a foot. Only world class nuggets weighing many ounces can be detected at over two feet. The vast majority of nuggets found are found at inches, not feet. The detectors are listed in order based on the lowest price normally advertised on the internet as of the date below. Steve's Guide to Gold Nugget Detectors - Updated January 2019 Fisher Gold Bug ($449, 19 kHz) - Not to be confused with the Gold Bug from the 1980's, this new model runs hotter than that old model, and offers full LCD target identification. The target ID makes the Gold Bug good for more than just nugget hunting, and it finds favor also with jewelry and relic hunters. This model normally comes with a 5" round DD coil to enhance the sensitivity to small gold but other stock coil options are available. The Gold Bug features an easy to use ground balance "Grab" function. Weight including a single 9V battery is 2.5 lbs. Many accessory coils are available for the Gold Bug. Steve's Opinion - Lightweight, sensitive, and full target identification. The Gold Bug is a good choice for prospecting, relic, or jewelry detecting and does fine as a coin detector also. This is a decent entry level detector for the price. It does not have nearly the features of the Minelab X-Terra 705 below but for a person who wants to keep it simple that may be an advantage. The main drawback is the model at $449 comes with a 5" round coil that is too small for general use. See the Gold Bug Pro below for more options. Minelab X-Terra 705 Gold ($499, 3, 7.5, 18.75 kHz) – This detector has a unique design feature. The standard unit comes with a 5" x 10" DD 18.75 kHz coil. Accessory coils are available not only at 18.75 kHz, but also at 3 kHz and 7.55 kHz. You can literally change the frequency of the detector by changing the coil! The X-Terra 705 has a large number of features and operating modes making it suitable for almost any type of metal detecting, be it for coins, jewelry, relics, or gold nuggets. Weight including four AA batteries 2.9 lbs. Over ten accessory coils are available for the X-Terra 705 (Minelab, Coiltek). Steve's Opinion - I like the X-Terra 705 very much indeed. It has a very powerful all-metal Prospecting Mode. The X-Terra 705 offers both ground tracking and manual ground balance; I like having both options. I particularly like its very compact and lightweight design. What really sets the X-Terra 705 apart however is all its other features. The X-Terra 705 is a good choice for somebody who wants all the coin and jewelry detecting options important to urban detectorists. It has discrimination and tone options equaling far more expensive detectors. This is the machine for somebody who really wants all the features a top end detector offers and still have a good prospecting detector. 2019 Note - a new lower internet price of $499 (down from $699) makes this detector a real bargain alternative to the Gold Bug Pro below for those wanting a full featured do-it-all detector. Fisher Gold Bug Pro ($549, 19 kHz) - Essentially the same as the Gold Bug above with the addition of manual ground balance. The target ID makes the Gold Bug Pro good for more than just nugget hunting, and it will find favor with jewelry and relic hunters. The manual ground balance gives expert operators the control they desire to get the best depth possible. This unit normally comes with a 5" round DD coil to enhance the sensitivity to small gold but other standard coil packages are available. Weight including a single 9V battery is 2.5 lbs. Many accessory coils are available for the Gold Bug Pro. Note - This model is also marketed as the Teknetics G2. They are the same detector except for the rod/handle assembly and coil. Steve's Opinion - The Pro is the final version in this series which saw several early variations including the Gold Bug above. It is a excellent choice for prospecting, relic, or jewelry detecting and does fine as a coin detector also. I particularly like the fact that the meter always runs in discriminate mode when the detector is in all metal prospect mode - like running two detectors at once. The weight at 2.5 lbs. with the 5" coil is a dream come true. Get the 5" coil version and the optional 10" x 5" DD coil for a great package. For a basic VLF prospecting detector the Gold Bug Pro is an excellent choice for most people. A Steve's Pick. Makro Gold Racer ($599, 56 kHz) - A model from a company rather new in the United States. Makro is the sister company of Nokta, the manufacturer of the Nokta FORS Gold listed above. The new Gold Racer is based on the original Racer model released in February 2015. The Gold Racer at 56 kHz is rather unique in having all the features normally associated with coin and relic detectors yet it's running at a very high nugget detecting frequency. This makes it more of a general purpose detector than a dedicated nugget detector. The Gold Racer comes with a 10" x 5" DD coil and has three accessory coil options. The weight including four AA batteries is 3.0 lbs. Steve's Opinion - I like the Gold Racer as it really is something new instead of just another mid-frequency do-it-all detector. The compact lightweight design appeals to me as does the high frequency sensitivity to small gold nuggets. It is the only machine in it's class that can run a large (15" x 13.5" DD) high frequency coil and as well as having a concentric coil option. Best of all it offers a full range of discrimination features not seen in other high frequency nugget detectors, all at a very aggressive price. Garrett AT Gold ($638, 18 kHz) - A totally new concept in metal detecting from Garrett Electronics. This full featured detector has everything you would expect from a dry land detector - LCD display, full control set and functions, speaker, interchangeable coils, and light weight. But it is submersible to 10 feet! Even the speaker is waterproof. Note that the unit itself may be submerged but if you want to put your head underwater you will need optional submersible headphones. Weight including a four AA batteries is 3 lbs. The stock coil is a 5" x 8" DD elliptical. Many accessory coils are available for the AT Gold. Steve's Opinion - Usually you are going to sacrifice a lot for an underwater machine but the AT Gold has all the features of an above water detector and is waterproof. It also weighs less than many dry land units. There are optional coils, a real rarity in underwater detectors. Garrett has above water and underwater headphones for the unit, but an optional adapter will let you use you old favorites. There is a speaker for above water use that can be safely submerged - a genuine first. And best of all, ground balancing 18 kHz operation with a true threshold based all metal mode. I have found gold nuggets with this detector and it would be an excellent choice for jewelry detecting in fresh water lakes. Note that the AT Gold is too hot for use on wet salt sand or in salt water. For salt water Garrett makes the AT Pro, a toned down version of the AT more geared to coin and jewelry detecting. My bottom line on the AT Gold is that for dry land use I prefer to forgo special o-ring coil and headphone connectors. They are silicone lubricated and want to collect dirt. But for detecting in and around fresh water streams or in heavy rain the unit is a no-brainer. If you want to mask and snorkel for gold with a VLF detector this is the unit to get. Just do not forget to get the waterproof headphones also. ads by Amazon... Minelab SDC 2300 ($3750, Pulse) - This model is unique as Minelabs first waterproof pulse induction metal detector. A key feature is that the detector is physically packaged in the proven F3 Compact military housing that is waterproof to ten feet and folds down into an incredibly compact package only 15.7" long and weighing 5.7 pounds including four C cell batteries. Steve's Opinion - I have used the Minelab SDC 2300 for a over a year now and I must say I am very impressed. The waterproof compact design is perfect for hardcore backpack style prospecting. The main thing however is that the SDC 2300 comes as close to VLF type performance on small gold as you can get while being almost impervious to the ground mineralization and hot rock issues that plague said VLF detectors. In fact, the SDC 2300 will find gold nuggets smaller than most good VLF detectors can detect even under favorable conditions. The SDC 2300 is also one of the simplest detectors to use and master on the market. The main caveat is that the detector is optimized for small gold with the hardwired coil and so other ground balancing PI detectors are a better option for large nuggets at depth. It is also nearly twice the price of the Garrett ATX above and so you are paying quite a premium for a little better performance on small gold. Still, for novices in hot ground that can afford the price, the SDC 2300 is almost impossible to beat if the goal is just to go find some gold, any gold at all. Minelab GPX 5000 ($3999, Pulse) - This Pulse Induction (PI) unit essentially ignores ground mineralization and most hot rocks. The GPX 5000 is designed specifically for nugget detecting and so it has many adjustments for mineralized ground not available on other PI detectors. The GPX 5000 is the culmination of over 10 years of innovation in pulse induction technology. The GPX weighs 5.3 lbs. not including the harness mounted battery, which weighs another 1.7 lbs. The detector comes with both an 11" round mono coil and 11" round DD coil. Over 100 accessory coils are available for the GPX 5000 (Minelab, Coiltek, Nugget Finder)! And more coils are being released every year. Steve's Opinion - It is simple. The Minelab GPX 5000 is the safe choice for best all around pulse induction gold prospecting performance. It has been out for many years, is well proven and reliable, and has a vast selection of coils and accessories to cover almost any situation. Despite the new GPZ 7000 below this is still the unit most people should be looking at though the even lower price GPX 4500 above should also be considered. A Steve's Pick. Minelab GPZ 7000 ($7999, ZVT) - The new Zero Voltage Transmission technology from Minelab promises to take gold prospecting to the next level. The new platform represents a break from the past SD/GP/GPX series in more ways than one, with a new weatherproof housing design based on the Minelab CTX 3030. The GPZ 7000 weighs 7.32 lbs. and comes with a waterproof 14" x 13" coil. There is one accessory coil available at this time. Steve's Opinion - The GPZ 7000 represents the future and I am convinced it offers a performance edge when compared to the earlier Minelab PI detectors. For this reason I have sold my GPX 5000 and switched fully to the GPZ 7000. The only weakness the machine seems to have at this time is an inability to deal quietly with wet saturated salt or alkali ground and certain volcanic hot rocks. That said I have not regretted for one second selling my GPX 5000 due to the overall advantage I feel I get with the GPZ 7000 in my ground and on my gold. A note on multi-frequency detectors: Most VLF detectors process a single frequency which is quoted as a key specification on gold nugget detectors. In general, higher frequencies are more sensitive to small gold. There are detectors on the market that process multiple frequencies, most notably a number of Minelab models (ETRAC, CTX 3030) but also a few other manufacturer models such as the Fisher CZ-3D or White's V3i. There is an assumption made that these units will detect gold nuggets as well as single frequency detectors because they do process some higher frequency signals. For various reasons this does not prove to be the case. Although these models can certainly find gold items none of them are any better than most general purpose coin detectors at finding gold nuggets. In fact, they are usually a poorer choice. The V3i is a special instance because unlike the Minelab or Fisher multi-frequency detectors it can also be run on any single frequency, in this case the 22 kHz frequency for gold. The lesson here is do not fall for marketing hype and believe that multi-frequency offers the best performance on all targets. They do not. Note 2018 - the jury is out but the new Minelab Equinox 800 may be the first detector that excels at nugget detecting in multifrequency mode. If I can offer one final word of advice, it would be to pay particular attention to what experienced nugget hunters are using in any particular region. Do not assume you are going to outsmart them and find some model they have not already tried and set aside as less than optimum. Serious prospectors in any particular location will end up focusing on certain units that do the job. In areas of extreme mineralization this is usually a PI detector. In areas with less mineralization and lots of ferrous trash VLF units often are preferred. If you can discover what models the locals prefer it will give you a head start in knowing what to use yourself. Above all, whatever detector you finally choose, dedicate yourself to mastering it. It takes at least 100 hours of detecting to become proficient with a detector model. Any less, and you are still practicing. Knowing your detector well is more important than what particular model of nugget detector you own. Steve's Picks I decided to add something new to this page. The list above has grown so much over the years that even it is really too long for some people. So I have decided to just pick my favorites in the three essential categories that I think every serious prospector should consider: 1. The super hot VLF 2. The medium frequency VLF 3. The ground balancing pulse induction (GBPI). The explanation that follows gives some rationale for my picks, but a huge factor is a good proven history in the field by many people under a wide range of conditions. Just being the latest new thing does not do it for me as much as being tried and true when it comes to my recommendations for others. It is very wise to wait about 6 months to a year after any new detector is introduced to see how others fare with it in the field before committing your hard won dollars. I also lean to detectors that are designed just for gold prospecting as opposed to "do-it-all" detectors that may offer nice features, but those features can also get in the way of a person who only needs a gold prospecting detector. And that is the focus here. Widespread dealer support and service options are also very important. Category one is the hot induction balance detector for finding tiny gold nuggets no other detector can find. These would be detectors running over 30 kHz. Contenders are the Fisher Gold Bug 2 at 71 kHz, Makro Gold Racer at 56 kHz, Makro Gold Kruzer at 61 kHz, Minelab Gold Monster at 45 kHz, and White's GMT and Goldmaster 24K at 48 kHz. This is a tough one because so many of these detectors get the job done so well. My pick at this time is the Minelab Gold Monster 1000. This detector has proven itself with prospectors both new and old around the world and if all I need to do is find tiny gold, the GM1000 is the detector I grab. Category two is the medium frequency VLF. The main goal here is to have a detector that can punch deeper on large nuggets in bad ground than the super hot VLF detectors and do a good job of discriminating out ferrous trash. These would be the good detectors for working trashy campsites and tailing piles. They are also the detector for a person wanting more versatility for other detecting tasks than offered by the dedicated high frequency detectors. The potential contenders list is very long - see above. For now my pick remains the Fisher Gold Bug Pro although the Minelab X-Terra 705 Gold offers more features for less due to a dramatic drop in price. I am recommending the Gold Bug Pro more for its simplicity - all the extra X-Terra features can get in the way if what you mostly want is a prospecting detector. Category three is a detector to handle the worst hot rocks and bad ground. For many serious prospectors this will be the primary unit, the one to find gold with. The obvious choice here (for me anyway) is a Minelab GPX 5000. This detector is the culmination of years of development by Minelab and it has incredible aftermarket support in the form of coils and other accessories. For those with the money and a desire to be on the cutting edge of new technology the Minelab GPZ 7000 is an alternative but the GPX 5000 is a safer choice for a wider range of conditions. Those who want a GPX 5000 and who can't quite afford it should instead consider the GPX 4500 at half the price. If a GPX is too intimidating, then the Minelab SDC 2300 may be just the ticket. Steve's Short List of The Prospecting Metal Detectors January 2019 1. Minelab Gold Monster 1000 (category 1, small gold sniper) 2. Fisher Gold Bug Pro (category 2, basic general purpose prospecting) 3. Minelab GPX 5000 (category 3, ground balancing pulse induction) In my opinion a well equipped prospector needs two detectors. One a high power GBPI for most nugget detecting and a VLF for trashy areas and as a backup. A GPX 5000 plus a Gold Bug Pro or Gold Monster would be a hard combination to beat. A special note of the Minelab GPZ 7000. This detector represents a fourth category, the "hybrid" detector that uses continuous wave technology like a VLF but also employing time constants much like a PI detector. These detectors act like a "Super VLF" with the ability to detect gold missed by GBPI detectors but with the ability to get depths on par or exceeding those previously seen only with GBPI detectors. I hesitate recommending it over the GPX 5000 to just anyone because of the high price tag, weight, and lack of coil options. The GPX 5000 in my opinion is the safer choice for overall versatility. So there you are. Hopefully this helps some people out. I can be found daily on the Detector Prospector Forums and would be pleased to answer any questions you have on metal detecting and prospecting. Also check out Steve's Guide to Metal Detecting for Gold Nuggets. Sincerely, ~ Steve Herschbach Steve's Mining Journal Copyright © 2002 - 2019 Herschbach Enterprises - Please do not reuse or repost without my express permission.
  5. 1 point
    The White's MXT was released in 2002 and is still in production. I helped popularize the use of this detector for searching tailing piles for large gold nuggets. Hundreds of ounces of gold have been found at Ganes Creek, Alaska alone by people using the White's MXT. My own largest gold find, a 6.85 ounce specimen, was with the MXT at Ganes Creek. I have a couple stories on Steve's Mining Journal that highlight the MXT. See Infinium & MXT at Ganes Creek and GP 3000 & MXT Get Fortymile Gold. My most recent find of note with the MXT Pro was a 267 AD Roman coin found while on a trip to the UK in 2010. See Metal Detecting Ancient Coins at Colchester, UK The MXT is extremely popular because it does almost everything very well; coin, relic, jewelry, and nugget detecting. Despite being so versatile the MXT is also a bargain priced detector with performance rivaling much more expensive detectors. It is remarkably easy to operate, with a condensed operating guide actually printed on the bottom of the control box. Three knobs and three switches are all the controls you need. The controls have specially marked settings so that if you do not know what the controls do, just set everything at the little triangle marker and you are off and running. A major feature on the MXT is the LCD screen that gives you visual information about the items detected as well as battery readings. White's employs a numeric target identification system that runs from -95 to +95, with ferrous targets reading as negative numbers and non-ferrous targets reading as positive numbers. White's calls these "Visual Discrimination Indicator" numbers usually referred to as VDI numbers. The MXT also comes with one of the best manuals and DVDs of operating tips that I have ever seen come with any detector. The MXT is almost perfectly balanced due to the control box being slung back under the elbow. One simple thing about the MXT also pleases me - it does not fall over on its side like nearly all the other detectors I use when I set them down! The control box is very water resistant. I have used the MXT in the rain all day long with no adverse effects. White's MXT All Pro metal detector for coins, jewelry, relics, and gold nuggets There have been several MXT models. There is the original MXT which comes with a 9.5" round concentric "950" coil. This version of the MXT was discontinued in 2017 and is essentially the same detector as originally released in 2002. The was also an MXT 300, also no longer in production, which was the same detector with a 300 mm (12") search coil and a matte black paint job for $100.00 more. The MXT 300 was replaced by the MXT Pro for the same $899.95 price. The MXT Pro added multi-tones and a meter backlight plus a redesigned pod with a touch pad. The new features do not really add anything needed from a nugget detecting perspective but are popular with coin and jewelry hunters. There is a "Ground Grab" that is nice for nugget detecting but just for convenience. Instead of switching to ground tracking for a minute and back to fixed it is possible to just remain in fixed and hit the grab button to update the ground balance setting. A very good way to compare the MXT and the MXT Pro is to download and read both operating manuals linked to below. You can also find a quick comparison reference chart at Jeff Foster's website here. The target reference in the MXT display above is replaced by three touch pads on the MXT All Pro. An audio pad controls various audio options, the "Ground Grab" button resets the ground balance, and there is a pad to toggle the display backlight on and off. MXT vs MXT All Pro display pod showing new touch pad buttons The MXT came with the 9.5" round concentric coil and the MXT All Pro is offered with either the 9.5" concentric coil or 10" round DD coil. My personal preference is for the MXT All Pro as I do like tone id for general detecting and the Ground Grab button alone is worth the extra money as far as I am concerned. I prefer to leave automatic ground tracking off most of the time and update via the grab function. The ground grab button alone is enough to make me prefer the MXT All Pro for gold prospecting. It is also a little known fact that the MXT was designed to work best with DD coils. Here is a post by Dave Johnson (one of the engineers of the MXT) on the TreasureNet forums 2/3/2013: "Back in the late 1990's and very early 20th century, the MXT was developed around the 10x6 elliptical DD. When you're used to that searchcoil, stick a 950 on and the 950 feels downright clumsy with its muddy response and bad masking characteristics. Downright insufferable. The 950 searchcoil geometry was designed for completely different platforms. But, if you ask "does the 950 work?", well, yeah, it does. Wrong question. I ain't gonna knock the MXT, it may be an old platform but it still works good. More than 10 years after, if you demand "ground tracking" (not that I say you should demand that), the GMT/MXT have the best in the industry. Not even Minelab (!) denies that! And as far as I know, the MXT/GMT are the only VLF-IB machines on the market with active transmitter regulation that makes it possible to work (with reduced performance) in heavy magnetite black sand, a circumstance otherwise left up to PI's. We're talking very good machines here. They may be a bit old in the tooth, but this is an industry that takes time to weed the turnips out of the beet patch. Ain't like celfonz where in 6 months the whole world has decided what kyckes and what szux. It takes time to deliver good beep verdict. MXT. 10x6DD is the foundation. Everything else is an accessory. I am telling you this because if you are a White's loyalist, I want you to spend that extra buck, the folks in Sweet Home are my friends!" Having noted that commentary, many users prefer the concentric coil options for beach use or low mineral parks where bottle caps are common. Concentric coils generally identify flat ferrous targets more reliably than DD coils. The large 12" concentric coil and even the 9.5" concentric coil do not handle extreme ground mineralization very well, and the 12" is too large for many other tasks, like coin detecting trashy locations. The 6" x 10" Eclipse DD coil is possibly the best all around prospecting coil for the MXT for those that do not already have the 10" round DD coil and want to add a DD to the MXT. The solid construction is less likely to hand up on stubble and the narrow profile is good for getting into tight locations. However, if you have an All Pro and already have the 10" round DD coil it is a less useful upgrade. In that case I would tend to recommend the 4" x 6" Shooter DD coil for trashy locations and small gold nuggets. To sum up, I recommend using either the 10" round or 6" x 10" elliptical DD coils for hunting heavily mineralized ground. To get the best performance on small gold, use the 4" x 6" elliptical DD (Shooter) search coil. The 9.5" concentric 950 coil and 12" concentric are best used for hunting tailing piles, beach detecting, or coin detecting in parks. The little 6" round concentric (Eclipse 5.3) is a good little coil for almost any use, including gold prospecting for small nuggets in low mineral ground. The MXT is blessed with a large number of aftermarket coil options due to its popularity. There are so many in fact it is impossible to keep up with them so I will leave that for the reader to discover via Google. White's MXT DD search coil options White's MXT concentric search coil options The MXT Pro does have an undocumented feature it is worth knowing about. The MXT in Coin & Jewelry Mode has a "Pull Tab Notch" feature when the trigger switch is locked forward. Meter readings of VDI +28 to +49 are silenced, knocking out common pull tab responses while still allowing US nickels to signal. The MXT Pro eliminated this function (trigger switch forward locks the pinpoint mode) and instead added the seven tone audio identification used by the White's M6 detector. The intent was to have the option for different tones for preset VDI ranges while in the Coin & Jewelry Mode. The multi-tone feature was not intended for the Relic or Prospecting Modes. However, through a bug that is not documented in the owner's manual you can activate the multi-tone mode by getting your MXT all set up in Coin & Jewelry Mode and then selecting multi-tone by pressing the "Musical Note" button. Now flip the toggle switch to either Relic Mode or Prospecting Mode and the multi-tone function will remain engaged. However, if you touch any of the control pads at any time now the multi-tone function will shut off. White's decided this "bug" might actually be useful so has left it as is for you to experiment with. There is a book written about the MXT that has no equal - The MXT Edge by Jeff Foster. If you have an MXT do not hesitate to get a copy. An interesting note is that the White's GMT and the MXT share a common heritage - see the MXT Engineering report below. Official White's MXT Page White's MXT 950 Owner's Manual White's MXT 300 Owner's Manual White's MXT Pro Owner's Manual Forum Threads Tagged "whites mxt" White's Metal Detectors Forum Unofficial MXT User Support Page MXT Engineering Guide Steve's Guide to White's Electronics GMT versus MXT White's MXT Technical Specifications* Internet Price MXT All Pro $823.00 Technology Induction Balance (IB) Frequency 13.889 kHz Autotune Mode(s) Variable Self Adjusting Threshold (V/SAT) Ground Rejection Tracking and Fixed Soil Adjust (Ground/Lock/Salt) Three position switch Discrimination One turn control, Visual ID, Tone ID Volume Control No Threshold Control One turn control Tone Adjust No Audio Boost No Frequency Offset No Pinpoint Mode Yes Audio Output 1/4" headphone socket & speaker Hip Mount Shaft Mount Only Standard Coil(s) 12" round DD Optional Search Coils Over 15 accessory coils available Battery Eight AA Operating Time 30 - 40 hours Weight 4.3 pounds Additional Technology Notes Alaska's most successful gold nugget detector for tailing piles *Notes on Technical Specifications - Detailed notes about the specifications listed in this chart. Here are a few nugget detecting tips for the MXT. I highly recommend that if you are new to detecting you seek out a sandy location like a freshwater beach or volleyball court or the woodchip area around playground equipment to practice and learn your new MXT. The goal is to set up the detector as if you are nugget detecting and to dig everything that signals. It does not matter what it is, the goal is to learn. You should be trying to find the smallest items possible, and attempting to learn how to separate ferrous from non-ferrous signals. It is always best to dig all targets when nugget detecting, but some areas are so full of ferrous trash that it is something that must be tuned out to some degree. Aluminum is a very common find, and that is good. Aluminum and gold respond identically on a metal detector, and the smaller and/or deeper the aluminum is, the better your detecting skills. Concentrate on the faintest signals. Hours spent practicing like this will save many more hours wasted time and frustration in the field. Normally when looking for gold it only makes sense to use the MXT Prospecting Mode. This pretty much turns the MXT into a GMT although a bit less sensitive to very small gold. Start with the Gain at the preset (small triangle) setting. The Threshold should be set as low as it can go while still being audible. You want to be able to hear variations in the threshold sound but you do not want it so loud as to be annoying when listening to it for hours on end. Set the Trac switch to "Ground" and pump the coil over the ground until the sound caused by this pumping action dissipates. the MXT is now ground balanced, so flip the switch to the "Lock" position. This locks in the current ground balance setting. The "Dual Control" while in Prospecting Mode is not acting as a discrimination control. The inner "SAT" section becomes active and a good starting place is the small preset triangle at the "5" setting. SAT stands for self-adjusting threshold. The threshold sound constantly varies and this circuit smooth's the threshold response. The higher the setting, the more aggressive the smoothing effect. Low settings are more sensitive to faint responses but can allow ground variations to also become to evident. Settings that are too high eliminate faint ground responses but can also cause faint signals from gold to become to faint to hear. In general less mineralized ground calls for lowest SAT settings and higher mineralization call for higher SAT settings. ads by Amazon... The Gain when increased does make the detector more sensitive to gold but also more sensitive to ground feedback and so-called hot rocks. The trick is to run the Gain as high as possible while retaining stable operation. Finally, in low mineral ground a locked Trac setting works best, but in ground that varies constantly running the MXT in the Ground tracking mode will result in smoother operation. Novice may want to stay in Ground Trac mode while learning the machine as it is the safe setting that keeps the machine properly ground balanced. In theory the MXT is most sensitive with the SAT set low, the Gain maxed out, and the Trac setting locked. The reality is that increased Gain settings may also call for increased SAT settings. The goal is to seek the most sensitive balance of settings possible while while keeping the MXT stable and smooth. A small test nugget of small piece of lead can be essential for determining what setting most eliminates ground responses while most enhancing nugget responses. In general leave the SAT control at the preset, Trac in locked, and set the Gain as high as you can while still getting stable operation. If need be, switch the Trac setting to ground for smoother operation. In the worst mineralization advancing the SAT control into the Hyper SAT mode will put the MXT into a very smooth mode able to deal with extreme mineralization while still reporting small gold nuggets. Remember, the key is to seek a smooth, stable threshold sound. It is this stable sound, when it varies, that indicates very deep or very small targets. There are a very few detectors that can be run in what is referred to as "mixed mode". These units have the ability to run in all metal and discriminate at the same time. I am not sure who first came up with this feature but Nautilus has for a long time offered units that put the all metal signal in one ear of your headphones and the disc signal in the other ear. The advantage to this is that pure all metal modes detect deeper than discrimination modes. Hunting in regular all metal requires lots of switching back and forth to check targets. Mixed mode gives you both at once. The White's MXT has the Relic Mode, which is a mixed mode. I wonder how many people use relic mode but really do not understand it. Good targets give a high pitched chirp. Junk targets honk. The split between high chirp and low honk is determined by the setting of the discrimination knob. This should be set to just cause iron and steel items , like a small nail, to honk, generally at a setting of 2 or less. Do not set the discrimination too high! Now here is the important part - there is a third, more subtle audio signal that indicates a target is there but the detector cannot identify it because it is too deep. This is the all metal signal. The meter will be blank. When nugget detecting, you want to hear these, and dig down until the target identification kicks in. I think many people focus so much on the other two audio responses that they ignore the fainter deep all metal signal. It is easy to fall into a habit of just digging only those high pitch targets. Not good. The key to mixed mode is simple. Those targets in a good location that are so deep you get no indication on the discrimination channel are the ones you really want to think about. If the area has produced good finds but is now near to being worked out, these deep signals are the ones anyone running in a normal discrimination mode is going to totally miss. Sure, it could be trash. But really deep targets are often the best, and so digging some of these on occasion can produce some really good finds. Steve with MXT and 6.85 ounce gold specimen found with it at Ganes Creek, Alaska in 2002 Unlike most dedicated nugget detectors it has a LCD based visual discrimination indicator (VDI) system. This is for the MXT coin and relic modes in particular. It turns out that for certain nugget detecting tasks the MXT has extra capabilities due to the visual target identification system. Alaska has huge areas of old mining tailings that provide great opportunities for nugget detecting. The nature of the old operations was such that many of the very largest nuggets were lost into the tailing piles. Unfortunately there is a huge catch. Some of these tailing piles contain incredible amounts of iron junk, and at any depth. Some creeks were mined many times, and old campsites and dumps were churned up and mixed in with the tailings. This junk can be anything from rusted flakes and slivers of steel on up to cans, bolts, washers and nuts, and finally even 55 gallon drums, and various large steel plates, pipes, boilers, or even larger items. Ganes Creek, Alaska is possibly the best known of these locations. New visitors from areas in the western US where the Minelab SD/GP/GPX detectors have reigned supreme have a hard time adjusting to the concept that there is such a thing as too much power when coupled to a poor discrimination system. If you run a Minelab at Ganes Creek here is a likely scenario. You are in a field of fist-sized and larger cobbles. You get a nice little signal and no iron blanking. You start to dig, as best you can in a pile of rocks. After a great deal of effort you are at two feet, signal is louder, but no target. You pull out another cobble and half the hole falls in. You pull all those rocks out, and get another six inches down. Forty-five minutes has passed. You pull out another rock and the hole caves in again. Fifteen minutes later you are at 3 feet again and really tired. Over an hour has passed since you started this hole. The signal is very loud now...too loud really. You dig down a bit more, then some more, and the whole thing caves in again. You walk away in disgust. Or you keep digging and finally find an old quart-sized can. How deep can you hit a large can with a Minelab GP 3000? How about a 2'x 2' steel plate? How about a 55 gallon drum? There answer is very deep indeed, and they are all there waiting! Normally you would just figure it is junk past a certain depth, but the big question always must be how deep could you hit the 35 oz or 80 oz pieces found at Ganes Creek with metal detectors, or the 122 oz chunk found by the commercial miners at Ganes? Because of this huge junk problem VLF detectors have generally been the way to go at Ganes. The low mineral conditions mean they keep you from wasting huge amounts of time going after junk targets. Most any good VLF machine works well for this, but the MXT gives you some extra capability once you learn its tricks. There are four things to know. 1. VDI numbers increase as the nugget size increases. So a 1/4 oz nugget may read around 25 whereas a 1 oz nugget may read around 40 and a 2 oz nugget may read around 50 on the meter. 2. The larger a nugget, the deeper you can detect it. 3. Certain steel items can give positive VDI numbers and 4. VDI numbers are pulled down the deeper the nugget is buried. A 1/4 oz nugget near the surface will read 25, but at depth might read 10, and at max depth may finally read at 0 or lower and actually be identified as iron. This last point is very important, for if you run a Fisher Gold Bug 2, or Tesoro Lobo, or Troy X5 in disc mode to tune out iron, as is common for many people at Ganes Creek, deep nuggets may read as iron. If they are, the machines will reject them; you will get no signal, and walk past the nugget. You will never know it is there. Or at best you have to search in all metal mode, then constantly switch to the discriminate mode to check the target. With the MXT, there is no switching and you hunt completely by ear. With the MXT I like to run the detector in relic mode, with the disc set precisely at 2. Non-ferrous items will give a high tone, and ferrous junk a low tone. If you get a faint low tone, the first thing you do is kick and inch or two off the surface until you get a honk or a chirp. Now dig a little deeper. If the VDI number rises, keep digging. Targets that read iron initially and rise will often turn into non-ferrous readings, hopefully gold. If the VDI number stays the same or goes even lower, you have an iron target. Once again, be careful to listen for audio signals that give no reading on the meter - these are items being detected by the all metal channel at depths beyond what will cause the meter to react with a numeric id. Where the MXT really shines are on 1/4 oz to 1/2 oz nuggets. Let’s say you get a reading of 24. OK, that is about a 1/4 oz nugget. Now, we know that you can hit a nugget this size at 10-12 inches. You dig a foot, and no nugget. A large, deep iron item of a certain type can also give a 24 reading, but these large items can be detected much deeper than a 1/4 oz nugget. Dig them up if you wish, but once you go past that depth at which it is reasonable to find a nugget corresponding to a certain VDI number you are wasting your time. This method eliminates digging those false positive signals from deep items like steel plates. With the other VLF units the lack of VDI number means you have no way to judge the potential nugget size and so you end up digging deep for what may be a very large nugget when with a MXT you would know the VDI number corresponds to a smaller nugget. For the many smaller nuggets that are found at Ganes this method is pretty foolproof once you get the hang of it. Finally, certain non-ferrous items can be found in quantity, particularly things like .22 shell casings. If you get into a bunch of these, they are usually very shallow. You can easily determine the VDI number of these multiple identical targets and then simply ignore them. You would miss a nugget with an identical VDI reading, but chances are a nugget will vary enough to make it stand out. There is no way to do this with a non-VDI unit. The MXT is a very versatile detector, but I do not think anyone anticipated just how much gold it would end up finding in Alaska. I know one prospector alone who has found over 100 ounces of gold with the MXT. ~ Steve Herschbach Copyright © 2004 Herschbach Enterprises
  6. 1 point
    These are "how to" guides on metal detecting and gold prospecting themes written by Steve Herschbach. Each article focuses on a single subject and they are meant to be relatively short but cover the topic well. Information both for beginners plus advanced topics for the pros. Metal Detecting Steve's Guide to Headphones for Metal Detecting Steve’s Guide to Metal Detecting for Gold Nuggets Steve's Guide to Gold Nugget Detectors Steve's Guide to Beach Detecting For Gold Prospectors Steve's Guide to Gold Nugget Target ID Numbers Steve's Guide to Metal Detector Search Coil Compatibility Steve's Guide to Threshold Autotune, SAT & V/SAT Steve's Guide to Metal Detector Mixed Modes Steve's Guide to Multifrequency Metal Detectors Steve's Guide to Waterproof VLF Metal Detectors Steve's Guide to Differences Between Minelab SD, GP, & GPX Steve's Guide to Minelab GPX Timings Steve's Guide to White's Electronics GMT versus MXT Steve's Guide to White's TDI Coin Settings Steve's Guide to Rebuilding The White's GMT White's MXT Engineering Guide Metal Detector Database with User Reviews Prospecting Steve's Guide to How to Pan for Gold Steve's Guide to Suction Gold Dredges Steve's Guide to Where To Prospect For Gold Gold Prospecting Research Material For Alaska General Other Metal Detecting & Prospecting Websites Steve's Guide to Successful Rock Tumbling Metal Detecting & Prospecting Library Catalogs, Brochures, User Guides, & Owner's Manuals
  7. 1 point
    Well, I'm back from 8 days at Moore Creek. It was a great trip, and one from which I have returned with a certain feeling of relief. The fact is that I got myself and my partners into this property based on my knowledge of the ground from old reports and previous visits. But until now all the gold I've ever found at Moore Creek amounts to about an ounce. Everything in the old records told me the gold should be there, but we had just not had much luck finding anything significant. But I've also not spent much time trying. My father flew out with my cousin Bob and I flew out with our friend Mike. We had lots of other stuff to do while out there this week. We staked some more claims, cleared brush... even put up a real windsock on the runway! We also did some test work panning, highbanking, and a little dredging. But I finally did make time to do plenty of detecting this trip. The result was more gold than I've ever found in a week before. Just over 23 ounces of chunky nuggets - almost two Troy pounds of gold! My fear that just maybe the old-timers had done a better job than I thought have now been relieved. I can attribute the success in no small part to my Minelab GP 3000. I've used the Minelabs for a few years, but had never found the spot to really clean up with one. Either the gold would be too small, like around Anchorage, or way too much trash, like at Ganes Creek. I did have some success in the Fortymile but did not get into those multi-ounce nuggets that really add up. Old mine tailings and pond at Moore Creek, Alaska At Moore Creek I've finally found a place where my Minelab really sings. Good sized gold, minimal trash (except a few areas), and ground VLF detectors do poorly on. The bedrock and ground matrix is a fairly neutral shale rock. But mixed with the shale are both very positive and very negative hot rocks. A combination that generates a tremendous amount of noise from a VLF detector. The only way machines like the my Fisher Gold Bug 2 or my father's Tesoro Lobo would work quietly would be to use the iron id modes. This would more or less eliminate the false signals from the rocks. But any gold under or very near the rocks would be lost and performance is not what it could be. I ran my GP 3000 with the Coiltek 12"x24" mono coil, giving me a double edge. Not only does the Minelab ignore and see through the various hot rocks, the big coil covers more ground and gets better depth on large nuggets than smaller coils. The GP 3000 is not an inexpensive machine, but I paid for it several times over last week. It will be getting a lot more use at Moore Creek in the future. 3.47 ounce gold specimen found with Minelab GP 3000 - fresh out of the ground with rinse in nearby pond A closer view of 3.47 oz gold specimen from Moore Creek - my first chunk over an ounce at Moore Creek As you can see from photos below the nuggets are very coarse and many contain lots of quartz. Quite a few are sections of quartz vein shot through the centers with cores of nearly solid gold. The largest nugget, the white piece in the upper right hand corner, pretty much looks like a quartz rock seen from either side. But seen on edge it has a 1/2" thick layer of gold running through it. I'll be doing specific gravity tests on many of these nuggets to find out the gold to quartz ratios and will report them here later. The total weight of that particular piece is 3.47 Troy ounces. My favorite nugget is probably the 3.15 ounce piece pictured below. It has darker quartz that runs from deep reddish brown to almost black. Between the color and the pitting it looks a lot like a gold meteorite. It's thicker and rounder than the other gold and appears to come from a different source. The 3.5 ounce specimen above is more typical of Moore Creek - a thick layer of gold with a skin of white quartz on two sides. These are chunks of extremely rich gold veins that have broken out of the source nearby and are now scattered down the creek. 3.15 ounce gold specimen found at Moore Creek with GP 3000 The weather was great, the mosquitoes not bad, and the gold fantastic. It's certainly enhanced our feelings about the claims, as at least some of the tailing piles obviously have some significant gold in them. Some of them may be worth reprocessing. Here is the Coiltek 12"x24" UFO coil along with a 0.55 ounce nugget I just excavated. It really puts a smile on my face digging these things up! The UFO coil is very nice. Very light for it's size due to the open spoke design. In brush you need the coil cover (comes with) to avoid hanging up on sticks. My favorite thing about it is that it pinpoints like a dream. Just drag the tip of the coil pointed straight down over the target and you get a sharp signal off the tip. The narrow design works better in the excavated holes than the round coils. 24" x 12" Coiltek "UFO" mono coil for Minelab detectors I actually found almost all iron gave a low tone with the unit as opposed to a high tone for the gold, but a large enough nugget will also give a low tone, so I just dig it all. Luckily, this is not too much of a burden at Moore Creek. I only abandoned one target giving me a low tone since the last few were all iron, but I'll go back and get it someday when I'm not as tired. The combo ignored 99% of the hot rocks, but some were so hot compared to the ground I got a faint signal with the mono coil. Luckily these were always shallow isolated rocks that needed no more than a kick to eliminate them. I can't overemphasize enough how this really is a dream of a lifetime for me... and I know it is for many. I've been involved in various mining claims since the 1970's, but it was on local creeks like Stetson Creek, Cooper Creek, Canyon Creek, and then Mills Creek. They were all "working man's claims" suitable for dredging but just not the kinds of places that are destined to knock your socks off with gold. Good stuff, but you really have to work for it. And the chances of finding "the big one" are nil. In all my years on the Kenai Peninsula I have found only one nugget that is just shy of an ounce. No, what I've always wanted was someplace that I might find larger gold, and someplace I might really be able to mine. I've come close a couple times, and in fact nearly ended up with Moore Creek back in 1998. It would have involved taking advantage of a paperwork snafu by the legitimate owners, and so I backed off. It has paid off as it was my actions at that time that has finally put the property in my hands now. On good terms with all involved. After over 30 years of searching and dreaming it looks like I've found that magic place. I have to tell you that last week, as I sat on top of a tailing pile in the sun with a pocket full of nuggets... well, the feeling was truly indescribable. Anyway, hopefully some of you that do not have the opportunity that I have had can at least live a bit of the dream as I keep the story going. Or maybe it will motivate a few to keep pursuing the dream! Are there mining claims for sale? Well, there always are claims for sale. Most people, including myself, would probably prefer to stake our own claims. The problem is finding good ground open to staking. It's easy to find "OK" ground to stake, but to find real serious mining ground, like a Moore Creek, just sitting open waiting to be claimed is very difficult. Difficult as in time consuming. You basically have to make a job of claims research and constantly looking for a prime piece of ground to lapse for some weird reason, like the owner dying with no heir. But most really good ground stays under claim and in many cases stays within families for generations. Long story short is that buying good ground will get you there quicker. The problem there is of course money. Good ground does not come cheap. In mining claims you often do not get what you pay for. Many poor and worthless claims are sold for way too much money on a regular basis. On the other hand you will have to pay well to get good ground. In that sense you do get what you pay for. Frankly, that has been part of my problem. If I had been offered Moore Creek even just a few years ago I would not have had the money, although I still could have found others to invest to make it happen. Despite being a business owner I really am just a working stiff making a living, and running two daughters through college had me totally broke until very recently. I've just been getting my head above water, so the offer to sell came at the right time for me. Even so I needed others as this kind of stuff just costs way more than I have to spend by myself. I'm not willing to disclose what we paid for the property, but all I will say is that you'd better be prepared to spend hundreds of thousands of dollars for decent claims with equipment. And if you are looking at patented ground, do not be surprised to be looking at millions of dollars. Detecting tailing piles - note parallel paths walked on piles from top to bottom - "corkscrewing" You can find mining claims listed for sale online at Mining Claims For Sale to get an idea of price ranges. In general, claims in the Anchorage area that are suitable for small scale dredging and such, the kind of ground where you might get an ounce of gold in a day once in a while with a 4" or 5" dredge, run from about $5000 to $15,000 per 20 acre claim. I've bought into a couple of these type claims in the past and was happy with the results. As soon as you start talking larger properties with real potential for heavy equipment mining the sky is the limit. It varies wildly due to things like how rich the ground is, access issues, potential restrictions on mining, amount of equipment included, etc. Patented ground, which is in fact private property, carries the biggest premium, as you can use it for more than just mining. One big thing to really watch these days is the "mining restrictions" issue. The Mills Creek claims where good ole Bob(AK) is getting all the beautiful gold have real potential for heavy equipment mining. I think a little hoe and trommel operation in there could make a good go of it. The problem is a rabid anti-mining attitude in the Chugach National Forest. In theory those folks are supposed to support mining under the multi-use concept of our National Forests. That is the way it was as recently as 20 years ago. But it seems they have decided National Forest means National Park, and I've heard lots of stories of small miners being bullied and lied to in the last few years. A guy that knows the law and is willing to stand his ground could mine in the Forest, but they would be waiting to pounce on the smallest error. The feeling today is that State mining claims are the way to go, because Alaska still looks to mining for revenue and jobs. The attitude varies somewhat depending on who is governor, but in general at its worst it is still better than the Feds. The only place Federal claims may be ok are those way out in the middle of unrestricted BLM administered land. I do have to note on partnerships - they can work. In fact, I've always had partners on all the claims I've been involved with. It helps to know the people, but do not rely on that. A good set of written rules, agreed on in advance by all, can go a long way towards avoiding problems. Do not avoid discussing hard issues, like what to do about a disagreeable partner. If these things are not clearly spelled out in advance you can expect trouble. Even then you may have trouble, but with a formal set of rules that is agreed upon, signed, notarized, etc. you have a legally binding contract to handle disputes. The good news is that the process of developing such a set of rules will bring all involved to a common understanding and avoid the problems. Most issues simply develop due to a lack of understanding between partners about certain issues. Here is a simple example. I have three partners. I have by far the most experience nugget detecting. It can be expected I will find more gold detecting. I actually worried about being too successful, and so a guideline I came up with is: 1. 50% of all gold found with a detector goes into the "group claims fund". Division is by weight as decided by the finder. 2. 25% of all gold found by motorized equipment such as dredges or highbankers goes into the group fund. 3. All gold found hand mining, such as in panning or sluicing, may be kept by the finder. The rules apply to everyone, including visitors like my cousin. Although in his case (he found a 1/2 ounce nugget) I'm covering his percentage out of my finds. Now why would I come up with a deal like this when I know I'm likely to find the most gold detecting? Fairness. Be fair with your partners. We all have invested equal sums, but we all have varying abilities and time. If partner A looks on while partner B is finding a bunch of gold on "his" claims and partner A is getting nothing... well, let's just say that smells like potential trouble to me. So I find about two pounds of gold. One pound of my choosing will go in the claims fund. As a group we decide what to do with the fund. We could split it later four ways, in which case I get 25% back. More likely we will sell out of it to raise funds for claim and permit fees and other expenses. This system in a way costs me potential gold finds I may make. But I simply feel better knowing everyone is seeing benefits from their investment. It makes people happy to see the other guy succeed, rather than laying the groundwork for possible resentment. And let's face it, the tables could turn, I could be busy on other projects, and still seeing some gold come my way from a partner who scores at the claims. In the other claim partnerships I've been in it's been keep all you find, and that can work well also. Or all gold can go in the pot, expenses covered, profits split. You just have to look at the particular situation and really do your best to be fair to all involved. Look out for partners that are totally in it for themselves... they will be trouble. Everyone in a partnership needs to be looking out for the group. You want team players, and as miners are rugged individualists this is the root of most problems. Just over 23 ounces gold specimens found by Steve with GP 3000 at Moore Creek, Alaska One other stipulation is that since we are truly and seriously doing exploration and evaluation, all finds must be noted as to location, nature of deposit, amount found, etc. I'm collecting and mapping this info, and already know of several particular tailing piles that I believe have literally hundreds of ounces of gold in them. Information collected like this is of immense value and should not be overlooked. If you get a group of partners that get competitive and secretive about their finds this kind of information will be difficult to develop. Testing is what it is all about. I'm amazed at how many people just get ground and start mining. And then are surprised when they go broke. Real mining should never commence until proper testing has proven it will pay. Too many miners figure the expense of testing is throwing money away they could just use for mining. But to commence mining without proper testing is not mining... it's gambling. Here is another guideline regarding buying mining claims. Never invest a single dollar that you cannot afford to just walk away from. Especially in partnerships. Failure is a lot less painful if you are not hocked to the hilt. Partnerships are easier to handle if you always know you can just walk away from a bad situation. But enough of that talk. We are off and running on our new claims at Moore Creek. Everything looks great so far, what with a pile of chunky gold specimens recovered already. There is a lot of work to do yet, and a lot more test work remains before we really know just how much potential the ground holds. I cannot help be be optimistic at this point that we are really onto something at Moore Creek. ~ Steve Herschbach Copyright © 2003 Herschbach Enterprises
  8. 1 point
    I became involved in metal detecting and gold prospecting at an early age and have been at it now for over 45 years. My quest has taken me all over the world and this journal documents many of those adventures. I hope to offer an idea of what can be done by one person with relatively inexpensive equipment. Keep in mind I have been doing this most of my life, and that I am familiar with the areas I am working. I don't want to imply you can just jump right in and have the same results I have. On the other hand, if one works at it, the rewards can be immense. I'm not talking about just the gold and other finds, but the sheer fun and adventure of the search! So here we go, with the successes, and occasional failures, of a prospector and detectorist from Alaska. Steve with 14.1 Dwt Nugget found at Ganes Creek, Alaska The reuse of these stories and images is strictly protected under the copyright laws. You may not do so without my express permission. Image reuse on other websites will normally only require a credit and a link back to this page... but only if I am notified in advance for permission. This Journal is dedicated to my wife for encouraging and supporting my adventures, and to my father for getting me started on the search for gold. ~ Steve Herschbach Hunting Ancient Gold in England October 2018 The Chisana Story 1973 - 2018 Minelab Equinox Finds Silver Fall 2017 XP Deus 74 Khz Elliptical Coil July 22, 2017 Minelab GPZ 19 Gets First Gold June 8, 2017 Gold With Minelab Gold Monster May 7, 2017 Gold Specimen With GPZ 7000 November 1, 2016 Nevada Gold With GPZ 7000 June 29, 2015 Garrett ATX Return To Hawaii April 10, 2015 Minelab GPZ 7000 Eureka Moment March 11, 2015 Nevada Gold With The Garrett ATX September 9, 2014 Nokta Scores Gold Specimen Fall 2014 California With Nokta FORS Gold October 11, 2014 Sore Feet And Gold September 3, 2014 Minelab SDC 2300 Finds Tiny Gold August 24, 2014 Steve's 2014 Alaska Gold Adventure Detecting Hawaii With Garrett ATX February 4, 2014 Steve's 2013 Alaska Gold Adventure Gold Detecting with Garrett ATX November 20, 2013 Gold and Silver with the Garrett ATX November 2013 Fisher F75 Strikes Gold in Alaska! June 2013 Making Lemonade Out of Lemons May 2013 GP 3000 & MXT Get Fortymile Gold June 6, 2003 GP Extreme in the Fortymile May 23, 2003 Garrett Infinium in Hawaii February 18, 2003 Shadow X5 at Crow Creek September 18, 2002 Infinium & MXT at Ganes Creek August 29, 2002 Detector Reps at Ganes Creek June 17, 2002 Memorial Day at Ganes Creek May 25, 2002 First Gold with White's GMT May 11, 2002 Minelab SD2200D at Fortymile August 18, 2001 Lode Gold at Hatcher Pass August 12, 2001 Exploring Petersville, Alaska August 5, 2001 Detecting Gold at Ganes Creek June 22, 2001 Gold Layers at Crow Creek June 15, 2001 Crow Creek Nugget Rescue November 4, 2000 Fall Mining at Mills Creek September 16, 2000 Detecting Gold in the Fortymile September 1, 2000 Where Gold Comes From August 13, 2000 Detecting Gold at Chisana July 21, 2000 GPAA Claims at Mills Creek June 24, 2000 Minelab SD2200D at Crow Creek June 10, 2000 ads by Google... Alaska Gold Dredging 2013 January 2013 Last Visit to Ganes Creek June 2012 2011 Australia Gold Adventure Fisher F75 & Gold Nuggets June 2011 Ganes Creek with F75 and GPX 5000 June 2011 Ancient Coins at Colchester, UK October 1, 2010 Alaska Gold with Minelab GPX 5000 September 2010 Moore Creek Gold Treated with Acid May 2010 Detecting Micro Gold at Crow Creek September 13, 2009 White's TDI at Moore Creek, Alaska Summer 2008 Minelab X-Terra 50 at Cabo Spring 2006 White's M6 & Surf PI Pro in Hawaii December 20, 2005 Beach Detecting with GP 3500 Fall 2005 Bulldozer Adventure (Moore Creek) Fall 2004 & Spring 2005 White's Surf PI & Platinum in Hawaii December 18, 2004 George's Moore Creek Nugget July 2004 Coin Detecting with Garrett Infinium 2004 Moore Creek Permits & Gold June 2004 30 Years with White's Detectors 1972-2002 Garrett Infinium at Moore Creek Fall 2003 Minelab GP 3000 at Moore Creek August 7, 2003 Moore Creek, Alaska June 28, 2003 Spring Gold Dredging at Crow Creek May 2000 Gold in Hawaii Winter 1999 Sniping for Gold at Mills Creek October 24, 1999 Sluicing Gold at Crow Creek October 17, 1999 4" Subsurface Dredge at Crow Creek October 9, 1999 Metal Detecting at Mills Creek October 5, 1999 Gold Dredging at Mills Creek October 2, 1999 Gold Mining at Mills Creek September 5, 1999 5" Subsurface Dredge at Mills Creek August 21, 1999 4" Subsurface Dredge at Mills Creek August 15, 1999 Mills Creek Cooperative July 17, 1999 Old Stream Layers at Crow Creek July 10, 1999 About Subsurface Gold Dredges June 24, 1999 Detecting Small Gold at Crow Creek May 30, 1999 Tesoro Lobo at Crow Creek May 23, 1999 Flooded Out! of Crow Creek Goldmaster & SD2200D Detectors May 15, 1999 Origin of Gold at Crow Creek May 8, 1999 What's Placer Gold Worth? May 1, 1999 Canyon Dredging at Crow Creek April 24, 1999 Winter Dredging at Crow Creek Fall 1996 First Nugget with a Metal Detector 1973 - 1989
  9. 1 point
    What is metal detector “autotune” or automatic tuning? Not automatic ground balancing or automatic ground tracking. Autotune is something so common now it is taken for granted, but it is a key feature when considering how detectors work, especially those designed to work with a faint threshold sound, like most nugget detectors. Prior to the 1980's most detectors had to be ''tuned''. You held them at a fixed height over the ground and manipulated a ''tuner'' until you got a bare threshold sound. A very faint sound you could barely hear. An increase in this sound meant you had a target. You could hold the detector over the target when you found it, and the increase in sound held steady. When the detector was moved off the target, the sound went away. No motion was required to get a signal, and so this mode of detecting is referred to as the ''non-motion mode''. There were two problems. First, the detectors of that day ''drifted''. The faint sound you set would either get louder or fainter. As the machines adjusted to temperature differences, or as the batteries ran down, the threshold changed. It did so rather rapidly, and so you constantly had to adjust the faint threshold setting manually to keep it on that vital edge. Also, the machines of the day could not ground balance. So if you raised the coil you got a false signal. If you lowered it the detector ''detuned'' and the threshold went away. Faint targets were lost. This was mostly an issue with small depressions in the ground. If you had the detector tuned to a fine edge, going over even the slightest depression gave a false positive signal. What I did myself was hold the detector an inch over the ground, tune it, and then lower it to the ground. This slightly detuned the detector and gave up the fine edge, but eliminated false signals from small depressions in the ground. Early 1970s "Mineral - Metal" ttuner control The first solution to this issue was push-button retune. If the faint threshold you had set got too loud or went away for any reason you just pushed a button, and you went right back to the original threshold setting. It was a great advance in its day, as pushing a button was much easier than turning a knob to get back the correct threshold. The detector “remembered” where you set the threshold, and a push of the button instantly returned it to where you had previously set it. This also made for better pinpointing of targets, as you could get close to the target, hit the button to detune the detector, and then zero in on the sharpest signal. Some detectors today still feature this form of ''non-motion pinpointing''. The next advance was electronic. The detector took note of the threshold you set, and circuits attempted to maintain the same threshold level. Since the original idea was to ''tune'' your detector, autotune was born. The detector automatically tuned the threshold. But a side effect was that if you held the detector steady over a target it was ''tuned out'', as the machine sought to return to the ideal threshold level. You had to keep the coil moving over the target to hear it, and so the “motion mode” was born. The original Gold Bug is the best example of all this. If set in the ''non-motion'' mode you can hold the detector over a target and get a louder sound that does not fade away. The closer you are to the target, the louder the sound. Great for pinpointing. But if you set the Gold Bug in this mode, it drifts. The threshold sound tends to get louder and louder. A button is provided to retune the Gold Bug to the original threshold sound. You must hit it about once a minute. The Gold Bug also has an ''autotune'' mode. This is the mode you would normally use. The detector now reads the threshold setting and keeps it steady. The side effect is that if a target is held steady under the coil, it is ''tuned out'' rapidly. The coil must be kept in motion over the target to get a signal, otherwise the autotune circuitry adjusts it out. It does not matter what causes the threshold to vary. The circuitry just attempts to keep it steady. Nothing is being tuned other than the threshold sound. Fisher Gold Bug controls, with autotune in lower left Various detectors were introduced with this feature. What varied was the rate at which they retuned. A slow retune meant that the detector would not adjust as rapidly to variations in the threshold sound. The slow retune had less of a tendency to ''tune out'' small targets or very deep targets. A fast retune was more forgiving of variations in the way the detector was operated, in particular as regarding the distance of the coil over the ground and false signals, but is more prone to tuning out very small or very deep targets. Whatever retune rate is chosen, it is a compromise. And what works well in one location does not work so well in another. When nugget detecting became popular a new variable was introduced. Ground mineralization, and more importantly, variations in ground mineralization, was something coin hunters rarely had to deal with. It was something a nugget hunter commonly encountered. Detectors at this time developed the ability to ground balance, or adjust out the ground effect that caused early detectors to give a false signal if the distance over the ground varied. Depth of detection dramatically increased. The ground balance control initially was a manual control, and so could be set for a certain ground condition. Any change in the ground mineralization tended to produce false signals. Autotune once again came to the rescue, as evidenced by its use in the original Gold Bug model. Units with a slow autotune had fewer tendencies to tune out small gold nuggets, or very deep gold nuggets. The downside is they had to be operated very slowly to allow the autotune to keep up with ground variations. Units with a fast autotune could handle variations in the ground conditions better, but had more of a tendency to tune out small or deep targets. Overall depth was usually decreased with faster autotuning but ease of operation increased. Another split in the technology came along. Many detectors, especially coin detectors, opted for a “silent search” mode. This mode eliminates the threshold sound entirely, very much like taking a detector with a threshold control and turning the threshold down until it cannot be heard. This makes for a quiet machine and became the preferred mode for many coin detectors. But it gives up a fine edge and so top performing units continued to offer a threshold control. Detectors that are silent search units do not need an autotune circuit. You can test a detectors autotune rate on detectors that have a threshold setting by holding a coin under the coil, and noting how fast the threshold adjusts back to its original level. This can vary from a couple seconds to almost an almost instant adjustment. An interesting side effect of autotune is ''overshoot''. If the detector is swept to one side and encounters a target, it attempts to ''tune into'' the target. If the target is a ''positive'' target, in other words the threshold increases, then the autotune circuitry immediately reads the increase and attempts to adjust lower. As the coil passes the target, there is a brief moment of silence as the autotune now has to turn around and increase the threshold back to its original level. In practice, you normally do not hear this. You hear the increase in tone, but not the decrease that follows. The target goes ''beep-beep'' as you swing back and forth over it. The ''beep'' is centered over the target. Move the coin back and forth under the coil and you will hear the sound. Now hold the coin under the coil until the threshold steadies, then remove the coin. The machine will go silent for a short period, again depending on how fast the autotune circuit is. However, if the target is an iron mineralized rock, most commonly a rock with a high magnetite content, then the threshold ''detunes''. The threshold is reduced and goes silent. So as you pass over the hot rock the threshold sound goes silent. The autotune circuit attempts to adjust by raising the threshold sound. But at this point you have passed over the ''negative'' target. A distinctive ''boing'' sound results since the threshold sound is now too high, and the autotune immediately attempts to adjust back down. The ''boing'' sounds occur to each side of the target as you sweep back and forth over it. The quiet spot, or ''null'' at the point between the opposing boings indicates the actual location of the target. To reiterate, autotune creates two types of signals. A beep-beep signal with the beep centered as the coil sweeps over it in both directions. Or a boing-boing signal, with the apparent target dancing back and forth as the coil sweeps over it. The null between the two boings is the actual location of the target, usually a hot rock. When White's introduced the Goldmaster V/SAT it featured "Variable Self Adjusting Threshold" or V/SAT. Self Adjusting Threshold is White's term for autotune. It is a more appropriate term as it explains what is really happening. People tend to confuse autotune with automatic ground balance. Unfortunately, White's fondness for acronyms is such that most people do not know what SAT or V/SAT stands for. The latest acronym is iSAT by Nokta/Makro for "Intelligent Self Adjusting Threshold". White's GMT Variable SAT Control The Goldmasters are the only nugget detectors that allow you to vary the rate at which the threshold readjusts itself via a knob - anything from very fast to very slow. This allows for more control in varying situations. In general, use the lowest SAT setting that allows for smooth operation. As ground variations increase, setting a higher self adjusting threshold can be beneficial. At low settings, the coil can be swept slower. High settings demand a faster sweep rate. The Gold Bug 2 has a “High”, “Normal”, and “Low” mineral modes. These are actually three preset autotune adjustments, with Low being the slow autotune and High being the fastest. Normal of course is in the middle. With the vast majority of the nugget detectors you have no ability to vary the autotune rate. A few programmable coin detectors offer the adjustment but usually relate it more to sweep speed so the detectors can be set for a slow sweep speed or a fast sweep speed. To sum up, it is very important to know how fast your detector is autotuning. If it has a fast autotune and you move the coil too slowly, you will lose very small and very deep targets as the machine tunes out the faint signal before you hear it. Conversely, if your detector has a very slow autotune rate (rare these days, but common on old detectors like the Compass Gold Scanners) then moving the coil too quickly will also cause very small or very deep targets to be lost. The best way to observe this is to bury a target, and sweep the coil over it. Go real slow, go real fast, and try something in between. You will find a certain speed will produce the loudest and sharpest signal. Going much faster or much slower will muffle the target. Detector engineers try to shoot for a normal sweep speed, and newer detectors are much more forgiving than older units. But sweep speed does impact the performance on many detectors. One thing that sets the pro apart from the novice is that the pro keeps the coil moving at the optimum rate that produces the best signal. When autotune is combined with auto ground tracking, this awareness of optimum sweep speed is even more critical. As a rule single frequency machine can handle faster sweep speeds. Multi-frequency and pulse induction (PI) detectors benefit from slower sweep speeds. People used to one type of detector often have a hard time adjusting. It is very common for operators of single frequency fast sweep detectors to swing PI detectors far faster than they should, resulting in significant lost performance. Do not be one of those people. Experiment with your detector to find the optimum sweep speed, and in the case of the few machines that allow for adjustments, experiment to see how slower and faster settings affect the performance. It can make all the difference between finding that gold nugget and missing it. ~ Steve Herschbach Copyright © 2010 Herschbach Enterprises
  10. 1 point
    When Minelab started developing our EQUINOX detector, we looked very closely at all of the current market offerings (including our own) to reassess what detectorists were really after in a new coin & treasure detector. A clear short list of desirable features quickly emerged – and no real surprises here – waterproof, lightweight, low-cost, wireless audio, and of course, improved performance from new technology. This came from not only our own observations, but also customers, field testers, dealers and the metal detecting forums that many detectorists contribute to. While we could have taken the approach of putting the X-TERRA (VFLEX technology) in a waterproof housing and adding a selectable frequency range, this would have been following the path of many of our competitors in just rehashing an older single frequency technology that had already reached its performance limits. Another option would have been to create a lower cost waterproof FBS detector, but that also had its challenges with FBS being ‘power hungry’, needing heavier batteries, heavier coils, etc., and relatively high cost compared to the more recent advances that our R&D team have been making with the latest electronics hardware and signal processing techniques. When Minelab develop a new detecting technology we aim to create a paradigm shift from existing products and provide a clear performance advantage for our customers. Our Technology History The multi-frequency broad band spectrum (BBS) technology that first appeared in Sovereign detectors in the early 1990’s provided an advantage over single frequency coin & treasure detectors. This evolved into FBS with Explorer, all the way through to the current CTX 3030 (FBS 2). The multi-period sensing (MPS) PI technology that first appeared in the SD 2000 detector in the mid 1990’s gave a significant advantage over single frequency gold detectors. This key technology exists in the current GPX Series detectors today. Zero Voltage Transmission (ZVT) is our latest gold detection technology implemented in the GPZ 7000 and is a recent example of Minelab’s continued innovation beyond ‘tried and true’ technologies to achieve improved performance. Further to our own consumer products, our R&D team also has significant experience working with the US and Australian military on multi-frequency technologies for metal detection. Introducing Multi-IQ Multi-IQ is Minelab’s next major innovation and can be considered as combining the performance advantages of both FBS and VFLEX in a new fusion of technologies. It isn’t just a rework of single frequency VLF, nor is it merely another name for an iteration of BBS/FBS. By developing a new technology, as well as a new detector ‘from scratch’, we will be providing both multi-frequency and selectable single frequencies in a lightweight platform, at a low cost, with a significantly faster recovery speed that is comparable to or better than competing products. We have come out with a very bold statement that has captured a lot of market attention: “EQUINOX obsoletes all single frequency VLF detectors” Multi-IQ achieves a high level of target ID accuracy at depth much better than any single frequency detector can achieve, including switchable single frequency detectors that claim to be multi-frequency. When Minelab use the term “multi-frequency” we mean “simultaneous” – i.e. more than one frequency is transmitted, received AND processed concurrently. This enables maximum target sensitivity across all target types and sizes, while minimizing ground noise (especially in saltwater). There are presently only a handful of detectors from Minelab and other manufacturers that can be classed as true multi-frequency, all of which have their own advantages and disadvantages. How does Multi-IQ compare to BBS/FBS? Multi-IQ uses a different group of fundamental frequencies than BBS/FBS to generate a wide-band multi-frequency transmission signal that is more sensitive to high frequency targets and slightly less sensitive to low frequency targets. Multi-IQ uses the latest high-speed processors and advanced digital filtering techniques for a much faster recovery speed than BBS/FBS technologies. Multi-IQ copes with saltwater and beach conditions almost as well as BBS/FBS, however BBS/FBS still have an advantage for finding high conductive silver coins in all conditions. “* 20 kHz and 40 kHz are not available as single operating frequencies in EQUINOX 600. The Multi-IQ frequency range shown applies to both EQUINOX 600 and 800. This diagram is representative only. Actual sensitivity levels will depend upon target types and sizes, ground conditions and detector settings.“ Questions & Answers What actually is Multi-IQ technology? What does the name stand for? What frequencies does it use? Is “Multi” the same or different for the various Detecting Modes? Is Multi-IQ the same or different for EQUINOX 600 and EQUINOX 800? Why use a single frequency? How does EQUINOX perform in certain environments? How does EQUINOX perform compared to other Minelab detectors? How does EQUINOX perform against other brand detectors? These are some of the myriad of questions we have seen since we published our EQUINOX Product Notice in mid-September. Some of the answers will have to wait until Minelab publishes reports from our field testers and/or you get your own hands on a detector to try yourself. In the meantime, let’s look further into the aspects of Multi-IQ technology. Multi-IQ is derived from: Simultaneous Multi-Frequency In-phase and Quadrature Synchronous Demodulation. We can go to a statement from Dr Philip Wahrlich, our principal technology physicist, about a key difference of Multi-IQ compared to the demodulation taking place in conventional single frequency VLF detectors: “Within the Multi-IQ engine, the receiver is both phase-locked and amplitude-normalized to the transmitted magnetic field – rather than the electrical voltage driving the transmitted field. This field can be altered by the mineralization in the soil (in both phase and amplitude), so if the receiver was only phased-locked to the driving voltage, this would result in inaccurate target IDs and a higher audible noise level. Locking the receiver to the actual transmitted field, across all frequencies simultaneously (by measuring the current through the coil) solves these issues, creating a very sensitive AND stable detector” Precisely measuring these extremely small current variations is quite remarkable if you consider the levels involved. It’s actually parts per billion, or nanoamp signals, we are talking about here! With Multi-IQ, we can derive much greater target ID accuracy and increased detecting performance, especially in ‘difficult’ ground. In ‘mild’ ground, single frequency may perform adequately, BUT depth and stable ID’s will be limited by ground noise; whereas the Multi-IQ simultaneous multi-frequency will achieve maximum depth with a very stable target signal. In ‘strong’ ground, single frequency will not be able to effectively separate the target signal, giving decreased results; whereas Multi-IQ will still detect at depth, losing a minimal amount of target accuracy. This is how we would generally represent the multi-frequency advantage, based on our engineering test data. Let’s hear more from Philip Wahrlich about the technical details: “For each frequency the detector transmits and receives there are two signals which can be extracted which we refer to as I and Q. The Q signal is most sensitive to targets, while the I signal is most sensitive to iron content. Traditional single-frequency metal detectors use the Q signal to detect targets, and then use the ratio of the I and Q signals to assess the characteristics of the target and assign a target ID. The problem with this approach is that the I signal is sensitive to the iron content of the soil. The target ID is always perturbed by the response from the soil, and as the signal from the target gets weaker, this perturbation becomes substantial. With some simplification here for brevity, if a detector transmits and receives on more than one frequency, it can ignore the soil sensitive I signals, and instead look at the multiple Q signals it receives in order to determine a target ID. That way, even for weak targets or highly mineralized soils, the target ID is far less perturbed by the response from the soil. This leads to very precise target IDs, both in mineralized soils and for targets at depth.” “How many simultaneous frequencies?” you may ask, wondering if this is a critical parameter. Minelab has been carrying out detailed investigations into this in recent years. Just as you can color in a map with many colors, the minimum number to differentiate between adjacent countries is only 4 – a tough problem for mathematicians to prove, over many years. Similar to the map problem, it’s perhaps not the maximum number of frequencies needed to achieve an optimum result, but the minimum number that is more interesting. When it comes to frequencies in a detector, to cover all target types, how the frequencies are combined AND processed is now more important, with the latest detectors, than how many frequencies, for achieving even better results. Efficient new technology = lower power = lighter weight = higher performance. The above diagram is intended to be a simplified representation of how different frequencies of operation are better suited to different target types; i.e. low frequencies (e.g. 5kHz) are more responsive to high conductors (e.g. large silver targets) and high frequencies (e.g. 40kHz) are more responsive to low conductors (e.g. small gold nuggets). The EQUINOX 600 offers a choice of 3 single frequencies and the EQUINOX 800 offers the choice of 5 single frequencies. Both models also have simultaneous multi-frequency options that cover a much broader range of targets than any one single frequency can – and they’re different across the Detecting Modes! Our goal was to develop a true multi-purpose detector that could not only physically be used in all-terrain conditions, but also be suitable for all types of detecting for all detectorists, and particularly those not requiring a specialist premium flagship detector optimised for only one aspect of detecting – e.g. coins, beach, gold, jewelry, water, discrimination, artefacts, etc. This multi-purpose requirement is something that could only be achieved by going beyond single frequency and creating the next generation of multi-frequency technology. Equally adaptable to all target types and ground conditions – just select your detecting location and go! An important update on the Detect Modes… Previously we have stated that Park, Field and Beach would run in multi-frequency and that Gold would only use the single frequencies of 20kHz and 40kHz, giving better results for gold nugget hunting. Our ongoing collaborative field testing feedback from around the world has resulted in further improvements to Multi-IQ to the point where multi-frequency is now the best option for Gold Mode as well, and will be the default setting. Please refer to the revised Getting Started Guide for updated product functions. Now, back to the technology: looking into our Multi-IQ diagram further… a single frequency is most sensitive to a narrow range of targets and multiple frequency is equally sensitive to a wider range of targets (e.g. the orange curve versus the white curve below). According to Philip Wahrlich, “From our testing, the Multi-IQ deployed in EQUINOX detectors has shown no significant trade-offs relative to the best single-frequency detectors and exceeded performance benchmarks in many important attributes, especially discrimination. And, for good measure, EQUINOX can also be operated as a single-frequency detector” While we could delve into this aspect further, many of our readers are likely more interested in what happens within the white Multi-IQ band itself, rather than single versus multi. What has Minelab developed new, and uniquely, with frequencies to give better performance across the whole range of targets for different conditions? The Multi-IQ transmit signal used in EQUINOX is a complex waveform where multiple frequencies are combined in a very dissimilar way than our proven BBS/FBS technology in Excalibur II / Safari / E-TRAC / CTX 3030 detectors. If you view the BBS signal amplitude on an oscilloscope, it looks something like this: In comparison, Multi-IQ looks something like this: Hence – Multi-IQ is not a derivative or evolution of BBS/FBS. Multi-IQ is a DIFFERENT method of simultaneous multi-frequency metal detection. We could also debate “simultaneous” versus “sequential” semantics; however the real detection ‘magic’ doesn’t happen with what is transmitted to and received from the coil alone. Remember, in Part 2, we discussed how frequencies are “combined AND processed” as being important for achieving better results? Let’s assess Multi-IQ for the different Detect Mode search profiles: Park 1 and Field 1 process a lower weighted frequency combination, as well as using algorithms that maximise ground balancing for soil, to achieve the best signal to noise ratio. Hence being most suited for general detecting, coin hunting, etc. Park 2 and Field 2 process a higher weighted combination of the Multi-IQ band while still ground balancing for soil. Therefore they will be more sensitive to higher frequency (low conductive) targets, but potentially more susceptible to ground noise. Beach 1 also processes a lower weighted combination, BUT uses different algorithms to maximise ground balancing for salt. Hence being most suited for both dry and wet sand conditions. Beach 2 processes a very low weighted frequency combination, using the same algorithms as Beach 1 to maximise ground balancing for salt. This search profile is designed for use in the surf and underwater. Gold 1 and Gold 2 process the higher weighted combination of the Multi-IQ band while still ground balancing for soil. However, they use different setting parameters better suited for gold nugget hunting. Earlier we discussed the different Multi-IQ “frequency weightings” for the different search profiles. Now let's explain further why it is not a simple matter of just referring to specific individual frequencies for learning more about Multi-IQ technology. Let’s now consider one of the key practical detecting outcomes and then discuss how this was achieved… “A lot of people are going to be surprised at how well the machine works in saltwater. At the outset we weren’t sure whether reliably detecting micro-jewelry in a conductive medium was even possible, but – with the help of our field testers and the subsequent fine-tuning of the Multi-IQ algorithms – we’ve found the EQUINOX to be more than capable.” Dr Philip Wahrlich Background and considerations While Multi-IQ may appear as ‘magic’ to some, to our team of signal processing experts, it’s the result of a significant number of man-years of development. So where did they start? By assessing the metal detectors and technologies available in the market at that time, along with typical customer perceptions about their practical applications; and actual detecting results achieved: So, an important goal with developing Multi-IQ technology was to retain the above simultaneous multi-frequency advantages AND greatly improve performance in the two key areas where many single-frequency detectors typically excel – fast recovery in iron trash and finding low conductors in all conditions. Speeding up the process Most comparable low-power Continuous Wave transmit-receive detectors (for the same coil size) will have a similar raw detection depth at which the transmit signal penetrates the ground and has the potential to energize a target. To increase detection depth significantly typically requires higher power and Pulse Induction technology. This has advantages for gold prospecting, but discrimination is poor for identifying non-ferrous targets. While we continue to push for depth improvements, Multi-IQ also aims to provide substantial speed improvements, resulting in being able to better find ALL non-ferrous targets among trash in ALL locations. You could therefore say “fast is the new deep, when it comes to EQUINOX!” Let’s start with considering signal processing not as a ‘black box’ where ‘magic’ happens, but more as a complex chain of applied algorithms, where the goal is to more accurately distinguish very small good target signals from ground noise, EMI and iron trash. Now, ‘fast’ by itself is not enough – you can have fast with poor noise rejection and poor target identification, giving no great advantage. Fast is also not just a result of microprocessor speed. Processors operate at much higher speed than is needed to ‘do the signal processing math’. You can think of the signal processing chain broadly as a set of filters and other processes which are applied to the metal detector signals to convert these signals into useable, informative indicators, such as an audio alert or a target ID. For Multi-IQ, keeping the ‘good’ properties of these filters, while keeping them lean and removing unnecessary processing, was an important step towards achieving ‘fast’ for EQUINOX. It’s also important to recognize that these filters are not the coarse filters of the analogue electronics hardware of last century – it all happens in software these days. Perhaps think of the older analogue TV standards versus current digital TV. (Standard digital HDTV has approx.10 times the resolution of analogue NTSC.) With metal detectors, a fast higher resolution filter set will result in improved target recognition. Factoring in the ground conditions However, speed without accuracy is not enough to produce a “game changer” detector – and improved accuracy cannot be achieved with a single frequency alone. Why? – “multi-frequency has more data-points” Philip Beck, Engineering Manager. This is worth explaining in more detail… All transmit-receive detectors produce in-phase (I) and quadrature (Q) signals that can be processed in various ways depending upon the response received from targets, ground and salt. This processing happens through ‘channels’ that have different sensitivities to the different signals received. It is important to recognize that channels are not exactly frequencies. This is why it is more complex to explain than just correlating optimum frequencies to specific target types. With a single frequency detector there are two basic channels for information (i.e. I and Q) that respond differently to good and bad signals, depending upon the frequency of operation and whether you are looking the the I or Q signal. It is also possible to scale and subtract these signals, while taking ground balance into account, to best maximize good signals and minimize bad signals. You could thus think of single-frequency being Single-IQ, with a limited set of data (e.g. I, Q, I-Q, Q-I) that works well for a particular set of conditions. To further enhance performance for a different set of conditions, you need to change frequency and detect over the same ground again. Therefore a selectable single frequency detector has an advantage with more data available, but not all at once (e.g. I1, Q1, I1-Q1, Q1-I1 OR I2, Q2, I2-Q2, Q2-I2 for as many frequencies that you can select from). Now, getting back to Philip Beck’s “more data-points”, and just looking at two frequencies, a simultaneous multi-frequency detector would be able to process (for example) I1, Q1, I1-Q1, Q1-I1 AND I2, Q2, I2-Q2, Q2-I2 AND I1-Q2, Q2-I1, I2-Q1, Q1-I2 to give better detection results. Increase the number of frequencies further and the number of extra data-points also increases accordingly. What Multi-IQ does is process different optimized channels of information (not just individual frequencies) for the different modes. We have previously explained this as “frequency weighting” (in Part 3), where the various EQUINOX Search Profiles are matched to the respective ground conditions and target types. Here is a very simplified example where you can see the result of processing more than a single channel of information (remember, a channel is not a frequency): Channel 1 has a strong target signal, but the salt signal is stronger still. Channel 2 has weaker signals for soil, salt and the target. If the detector just responded to either Channel 1 or Channel 2, the target would not be heard through the ground noise. If the detector processes a subtraction of the channels (e.g. ch.1-ch.2), then it is possible to ignore the ground noise and extract a strong target signal. Now, think back to the high number of possible combinations of I and Q for simultaneous multi-frequency compared to single-frequency and the frequency weightings for the modes. All of the EQUINOX Park, Field, Beach and Gold Search Profiles have dedicated signal processing to best suit the conditions and types of targets being searched for. Conclusion Multi-IQ = more data-points = sophisticated processing = better ground noise rejection = more finds Just as targets are more sensitive to certain frequencies, so is the ground – an important reason why air testing has inherent limitations when comparing detector performance. As soon as you have ground to consider in the signal processing equation, it can greatly impact on the ability of a single-frequency detector to accurately identify a target. Also, the deeper a target is buried, the weaker the target signal is, relative to the ground signal. The most difficult ground response to eliminate is the salt response, which varies greatly between soil, dry sand, wet sand and seawater. It is not possible to eliminate the salt response and the soil mineralization response (e.g. black sand) with just one frequency. However, within the carefully calibrated Multi-IQ channels, EQUINOX is able to identify both signals and therefore mostly ‘reject’ them (just as you would notch discriminate an unwanted target) BUT still detect gold micro-jewelry. The above article is a compilation of a series of blog entries taken from Minelab's Treasure Talk. More will be added here as available.
  11. 1 point
    There are a few key things to know about headphones for use with metal detectors. The most important thing is to know that some detectors operate in mono, and some in stereo. If you mismatch headphones you can end up with audio in one ear only, or none at all. In fact, this has happened to me. I took my White's DFX out to do a little detecting, and grabbed an old pair of Fisher Phones I had around, and when I got out I found the phones would not work on the DFX. So most detector phones have a stereo/mono switch, or are specially wired to work either way. Make sure your headphones match your detector for stereo or mono operation. But best case is to only use headphones that can do both so you can use them with any detector. You never know when they might get put to use on a different machine. In a situation where you are determined to use a mono headset on a stereo detector or vice-versa plug in adapters can be purchased at most electronics supply houses. 99% of the detectors out there have a 1/4" headphone plug, but many generic headphones have a 1/8" plug. Sure, you can use an adapter, but it just adds a weak spot in the system. So get a 1/4" plug unless your detector is one of the rare 1/8" models. Again, pay attention to the mono versus stereo issue. The good news is that if you make a mistake there is almost always an adapter that will fix the problem but it is best to try and get the correct match. Does your detector have a volume control? Many do not. It is best to buy headphones that have their own volume controls, so you can use them with detectors that do not have a volume control. Again, you never know when you might switch detectors. Ohm matching can be important, and generally higher ohms is better. This is not always true however and some detectors do work better with lower ohm rated models. It is usually easy to determine what the headphone ohm is but almost impossible to know what the detector rating is. I therefore recommend that you should have your detector in hand and be trying the headphones before you buy them instead of going by specs on this point. Things to look for: 1. How do they sound? Are targets sharp and clear to your ear? If not, you can now pass on this set and try another. Different headphones match up with different machine and different ears in such a way that nothing short of trying them can sort this point out. They either sound good to you personally, or they do not. It does not matter what your friend likes. Some detectors allow you to change the pitch from high to low. Try different pitches with your detector to see what sounds best. How do faint targets sound to your ear? People have different frequency responses, some like low tones and some high, and the type of speaker wired into the headphone can make this sound vary a lot. Get a set of headphones that make faint signals as clear as possible to your particular ear. 2. Assuming they sound good, how adjustable is the volume? A good match will give you the ability to fine tune the sound with the volume control on the headphone. In other words, the volume control will have some range. If you have very high ohm headphones and use them on a high volume machine that has no volume control, the headphones may be so loud you have to set the volume on the headphone nearly off. And then tweak it within a fraction of a turn. Some headphones are too powerful for some detectors! The volume control should run from off at one end and too loud at the other, with lots of adjustment in between. 3. How many volume controls are there? Some people like two, one for each ear. This can be great if you have poor hearing in one ear and need to compensate. I personally prefer a single control that works both ears at the same time, so I do not need to fiddle two controls. So this is a personal preference thing, but your headphones should have one or two headphone volume controls. A note on setting your headphones. Turn the detector volume all the way up, if it has a volume control. Turn your headphones all the way down, then turn on your machine and wave it over a large metal item. Turn the headphones up until the loudest sound you will get over a large item is not so loud as to damage your hearing. Now, set the threshold sound on your detector for a faint buzz. You should now be able to hear faint variations in the threshold, but going over a 55 gallon drum will not damage your hearing. Metal detector headphones showing 1/4" 90 degree jack, coiled cord, padded muffs, and dual volume controls 4. How well do the phones exclude outside noises? Normally, get a set of headphones that will exclude outside noises like running water, wind in the trees, or anything else that might distract you from the detector sounds. Sometimes it may be advantageous to use phones that let you hear outside noises, like in bear or snake country. Or maybe in real hot climates bulky units get too warm. But from a pure detecting standpoint sound excluding headphones are best. Earbuds are perfectly acceptable however for quieter locations. 5. How well do the headphones fit and feel? Imagine they are going to be on your head for 12 hours. Something that feels good initially can feel pretty bad in a few hours. Beware of headphones that are too tight or that have too little padding. I prefer phones that completely cover my ear and seal to the side of my head. I do not like the kind that squash my ear but people's preferences vary. Make sure your headphones are comfortable for long hours of use. 6. How tough do the headphones appear to be? This can be hard to gauge sometimes, but in general avoid anything that looks to have cheap construction. The number one failure point is the cord, so make sure it is strong and well anchored so it cannot pull out. Headphones that feature a 90 degree plug are often desired to reduce strain and prevent the plug from pulling out due to a simple tug on the cord.Some top end models feature replaceable cords so you can carry a spare. I prefer to simply carry a complete spare set of headphones. 7. Finally, be aware that the newest metal detectors are coming equipped with built in wireless headphone capability. Early versions have either been standard Bluetooth, which is too slow, or some faster proprietary method. Standard Bluetooth has a significant lag between detecting a target and the actual audio response heard in the headphone which is bothersome to most people. The problem with proprietary is that you are stuck with very limited options as to headphones. The best option currently for most people is aptX Low Latency (aptX LL) Bluetooth, which is fast enough that most people are satisfied with the speed, and options abound in the choice and style of headphones. To sum up, if buying headphones at Big Box Inc. at the least you'd probably want a set with a stereo/mono switch, 1/4" jack, and volume control/controls just to make sure it will work on most any detector. But remember that headphones are like tires for an expensive sports car. They are one of the only important items on a detector you can customize for optimum performance, the other being search coils. Finding the set of headphones that is just right for you can make a real difference in detecting success, so it deserves some effort in getting the right set. This is where a local dealer with a good selection who is willing to let you try them all out on your detector can really help you out. ~ Steve Herschbach Copyright © 2009 Herschbach Enterprises
  12. 1 point
    This is not intended to get into every nitty-gritty little detail, but instead is a brief overview for those unfamiliar with the Minelab Pulse Induction (PI) detectors. The units released so far are the SD2000, SD2100 (and V2 variant), SD2200D (and V2 variant), GP Extreme, GP 3000, GP 3500, GPX 4000, GPX 4500, GPX 4800, and GPX 5000. The Minelab SD2000 was the first of the series, a genuine breakthrough in metal detector technology. It is the basis on which all the other models were developed. It was the first true prospecting pulse induction metal detector and it had a major impact in the Australian goldfields for which it was designed. The main drawback was a definite lack of sensitivity to nuggets weighing under a gram or two. The SD2100 and SD2100v2 are fairly simple manual ground balance units that refined the SD2000. The frequency could be manually adjusted to avoid interference from outside sources, such as a nearby detector. The SD2200d and SD2200v2 offer automatic ground balancing or a fixed/locked ground balance. They also introduced an iron disc feature of dubious reliability, audio boost, and automatic frequency offset. The GP Extreme offered enhanced sensitivity to small gold that was lacking in the earlier units. Much of this came about from Minelabs patented dual voltage technology (DVT) which was introduced with the GP Extreme and is featured on all subsequent models. There were quality control issues with the unit however and so performance varied on GP Extreme detectors. The GP 3000 is essentially just a refined GP Extreme and the GP 3000 performance is more consistent between units than was seen in the GP Extreme. Threshold smoothness was improved to be less erratic. The GP 3500 offered manual frequency tuning to help eliminate electrical interference and three tracking speeds for the automatic ground balance system. A button was added to the handle to allow for easy switching between the manual and automatic ground balance modes. The GP 3500 was the last of the analog models in the series. Where it all started - the Minelab SD2000 "Super Detector" The GPX-4000 was a break from the past, going to a digital control system. This allows for more adjustments but also more complexity. The GPX models can attain smooth thresholds on par with the best VLF units. A major advance is in the form of various optional "timings" that allow the detector to be customized for various types of ground mineralization and hot rocks that might be encountered. The GPX-4500 is a basically a refined 4000. A pattern develops by now in that Minelab tends to make a major model revision, then follow up with another model that is just a refinement of the earlier unit. Model releases come about every two years with major changes about every four years. The Minelab GPX 4500 was extremely popular and the next model release was delayed to the point that two models came out. The Minelab 4800 was intended as the next release, but before it hit the market developer Bruce Candy came up with a couple new refinements different enough to warrant yet another model, the GPX 5000. The 4800 therefore became a sort of "non-model" as most dealers and users focused on the GPX 5000 as the new top-of-the line detector. The main change is a wealth of new timings allowing the GPX 5000 to get optimum performance in many varied ground conditions. The new Fine Gold timing in particular offers the ability to pull gold out of ironstone hot rocks that previous models missed. Minelab SD2200v2 pulse induction (PI) metal detector I disagree with those that say you can get more depth on large gold from earlier SD units than from the latest models. Having used all the models the largest improvement I've seen over time is vast improvements in threshold stability and the ability to adjust for more varied circumstances. It may be that in a particular location an SD will do just as well as a GPX. But not where I hunt. My SD units all had the famous Minelab "warble" whereby the threshold constantly wavered. This meant that small nuggets or very deep larger nuggets had to give enough of a signal to break through the waver. A far cry from listening to a rock solid threshold for the faintest whisper or "break" in the threshold. You can get just such a rock solid threshold with the GPX units. It is not that the GPX goes deeper, it is that you can hear nuggets you would miss with an SD as they could not be discerned as clear signals. More important on my ground was that my SD units simply could not tune out the intense magnetic basalt cobbles we have to contend with. The cobbles give a faint gold hit. So you either dug them all (impossible) or simply ignored the faint signals. But some of them were small nuggets or very deep larger nuggets. When the GPX arrived at my property I saw so many more small nuggets and deeper large nuggets come out of areas well hunted to the point of being "hunted out" that it was obvious the GPX had a significant edge. I'm not talking a nugget or two - I'm talking pounds of gold. The new GPX timings can allow for a clean solid threshold in areas where that was impossible with earlier units. Those that do not hunt such locations do not see the value in a GPX. Those that do know what I'm talking about. There is no way I'd go back to using an earlier model than the GPX-5000 by choice. Minelab GPX 5000 - pulse induction metal detector technology refined It should be noted is there are quite a few people modifying older SD units to get better performance on par with later units, and I'll admit these modified units are a wild card. Some swear by them and I'm not going to doubt them. But modifying older detectors is beyond where most people want to go so I think there is little doubt these units will only see use by a certain hardcore group of knowledgeable detectorists. The GPX 5000 has refined the platform to the point where realistically it is hard to think of ways the unit can be improved from a detecting standpoint. The only obvious deficiency is the ferrous discrimination system. While it does have its uses the ferrous discrimination on the Minelab PI detectors is notoriously unreliable and only to be used when absolutely necessary. Its use will inevitably cause gold nuggets to be left in the ground, misidentified as iron or steel. This area has been so resistant to improvement, however, that I look more for advances in the physical package as my most desired area for improvement. The general control box and rod design with backpack mounted battery has not changed since the original SD2000. Development of a GPX type detector housed in a package more reminiscent of the new Minelab CTX 3030 would be a major advance in the usefulness of the lineup with no actual change in performance aspects of the electronics. It has been well over two years since the GPX 5000 was released, and so I do not think it will be too long before we see what Minelab has in store next for nugget hunters. ~ Steve Herschbach Copyright © 2013 Herschbach Enterprises P.S. When I wrote this article in 2013 I had no idea that two more years would pass before we saw what Minelab had up next - the Minelab GPZ 7000. It turned out that Minelab also thought the GPX 5000 had taken the pulse induction as far as it could go, so the GPZ 7000 features new ZVT technology. The biggest surprise for me however was that Minelab may have paid attention to my "GPX in CTX housing" comment above. That may or may not make some people happy! And the GPX 5000? Still in production as the top-of-the-line PI from Minelab!
  13. 1 point
    Metal detecting for gold nuggets is perhaps the most difficult type of metal detecting. That is partly because simply having an excellent gold nugget detector does little to insure success. The operator not only needs to be extremely proficient with a capable metal detector, but also needs to have general knowledge about gold prospecting and where gold is likely to be found. This short guide is intended to focus on some of the most important aspects a person should consider when starting out new in the nugget detecting game. Metal detecting for gold nuggets is the gold mining equivalent of big game hunting. Many areas produce fine gold and small flakes, but these areas will not usually prove productive with a metal detector. Only areas with larger gold nuggets will be of interest, and so many locations that are fine for panning and other types of mining will not be worth your time if you plan on going for the big nugget. Researching the area to confirm that large nuggets have been found there in the past will help make your hunt successful. While detecting may limit you to fewer sites and more time between each nugget you find, the fact is that successful detector operators tend to find gold nuggets far larger than the finds of the average recreational miner. Detecting is not nearly as physically demanding as most types of mining, and lends itself well if you enjoy roaming freely rather than working hard at a single site. Steve metal detecting for gold with White's MXT metal detector Here are a few facts and tips to get you started: Today's machines can detect gold weighing under a grain with ease. There are 480 grains per Troy ounce with nuggets under a grain quite literally being pinhead size objects. The depth of detection grows with the size of the target. A one grain nugget may be found at two inches, a match head size nugget at four inches, and a quarter ounce nugget at ten inches. Only the largest nuggets will be found at depths over a foot. Metal detectors will not normally find buried accumulations of fine gold directly. The higher the operating frequency of the detector, the more sensitive it will be to small gold, but with the penalty of also being more sensitive to iron minerals. This can result in more false signaling and difficulty of operation in highly iron mineralized areas. Lower frequency detectors are generally less sensitive to small nuggets, but handle iron ground better. Frequencies on today's nugget detectors range from a low of 3 kHz to a high of 71 kHz. Pulse induction (PI) detectors are a special type of unit that act like they are extremely low frequency detectors. PI detectors main strength is in ignoring the worst ground mineral conditions and finding large gold nuggets at maximum depths though a few models also do well on the smaller gold. Most models feature manual ground balance controls, which allow the machine to be adjusted for the general iron content of the ground. When the ground being searched is relatively homogenous, these controls require minimal adjustments and work well. When the ground being searched has wildly varying iron content or many out of place mineralized stones (referred to as "hot rocks") then these manual controls will have to constantly be adjusted to maintain proper performance. Detectors that feature automatic ground balance will require less adjustment and will have less false ground noise. The best option is to have both manual and automatic ground tuning options in one detector. Nugget detectors find all conductive metals. Most units have the ability to tune out many common iron and steel trash items. Pulse induction detectors are not so good at discriminating out trash items and should generally be considered as "dig-it-all" type detectors.. Any gold located should be treated as an indicator, since rarely will a nugget occur by itself. It is much more likely that more nuggets are nearby, and gold smaller than the detector can locate or beyond its immediate depth of detection is present. Such leads should be followed up with further excavation and sampling with gold pans or other mechanical methods, A metal detectors greatest advantage is that it needs no water, a near-universal requirement for most methods of placer sampling. Use this to your advantage to easily check material that is far from water, such as arid locations or deposits located well uphill from the stream. Large nuggets sing out with a loud signal, but since most targets will be small, train yourself using the smallest detectable nuggets your machine can find. Learn the faint but very distinct sound that small or deeply buried nuggets make. Small aluminum or lead targets can be used as an acceptable substitute for gold. Always use headphones to enhance your ability to hear these faint targets. Coil control is one of the most important aspects of proper metal detector technique. Small items may only be detected at a few inches or fractions of inches. Hovering the coil any appreciable distance over the ground is one of the most common reasons for gold nuggets being missed. The detection field projected underground resembles an inverted cone, with the deepest depth of detection in the center of the coil. At maximum depths only a tiny area is seen by the detector, and so overlapping the sweeps is important when detecting a productive area or "patch". To find gold go where gold is found! Metal detectors can be used to prospect new areas but do not expect to find much gold in areas where gold has never been found. Instead, research and frequent areas with past known production of the kind of gold you want to find. Research is a real key to success. Remember to always obtain permission to detect on mining claims or private property and be aware of any possible restrictions on public lands. Commit yourself to learning your detector. Do not make the investment if you do not plan on spending some time to properly give the method a chance. It will be time profitably spent. The one thing that sets successful detector operators apart from the crowd is their patience and persistence. They enjoy the hunt itself, and consider the day well spent even if no gold is found. Consistent success will only come with practice. I strongly believe there is no one best detector for all conditions. The best detector for each area will depend on how much ground iron is present, how large the gold is, and how much trash is in the area. Operator expertise has by far the greatest effect on success. If you purchase a second detector, having a low frequency model and a high frequency detector will give you more versatility. Identical detectors will also interfere with each other electronically and must be kept far apart, whereas differing models can work side by side. The most important accessory item you can own is a quality set of headphones. A good set will muffle outside noise, enhance the faint sounds most nuggets make, and be comfortable for hours on end. Audio quality is of extreme importance. Insist on trying several headphones with your detector before you buy. The differences can be amazing. Make sure that the headphone has its own volume controls and matches your detector for mono or stereo operation. Several ounces of gold detected at Ganes Creek, Alaska in 2010 by Steve Herschbach Other important accessories include a stout digging tool, such as a stainless steel trowel or a short handle pick. A magnet can easily pick up small steel trash items that may be found and are hard to locate exactly. A plastic scoop or cup is indispensable in helping to separate a small nugget from the soil by scooping and waving the soil over the detector search coil. Snap plastic search coil protectors over the bottom of your search coil to protect it from wear. Carry spare batteries and a plastic bottle for your finds. Check into the possibility of using a belt or chest harness with the detector control box to protect it and remove the extra weight from your arm. Do not overlook accessory search coils. Smaller search coils will be more sensitive to smaller targets while giving up some overall depth. Larger coils will produce more depth of detection on larger targets, but will lose the ability to find some smaller nuggets. Small coils are more popular and will pay off in bedrock areas in particular. They can make a detector of moderate sensitivity perform like a higher frequency detector. Large coils work well for finding oversize nuggets discarded in tailing piles. Coils are not interchangeable between models; only coils made for your machine will work with it. The chart below shows the advantages of using both smaller and larger accessory coils. Coil Size vs Depth Fisher Gold Bug 2 Source - Field Testing the Gold Bug 2 by Gordon Zahara The most important goal is to put yourself on nugget bearing ground. These areas are well documented and can be researched. Check the land ownership and contact claim owners if need be for permission to nugget hunt. If you frequent areas that have not produced coarse gold, do not be surprised at a lack of success. For information and reviews of specific metal detectors see Steve's Guide to Gold Nugget Detectors. A huge resource for questions asked past and present is this website's Metal Detecting & Gold Prospecting Forums. Be responsible! Fill your holes behind you, and remove any small trash you excavate. Proper and responsible practices will keep more areas open to us all. Do not remove gold from mining claims without permission. It is theft and may result in that claim being made off-limits to other nugget hunters. Protect our hobby so we can all continue to enjoy it in the future. Good Luck & Good Hunting! ~ Steve Herschbach Copyright © 2009 Herschbach Enterprises
  14. 1 point
    This entry in Steve's Mining Journal is a bit different. It is a copy of a couple posts I made on some forums regarding the Garrett Infinium as a coin detector. It is part of the Detectorprospector.com goal of collecting all my scattered internet posts into one location. I have found gold nuggets with the Infinium and done well with jewelry using it as an underwater detector. Since the Infinium has a dual tone id system it has some interesting potential as a coin detector. To test this and to simply get in more use with the machine I went out to a local playground to test the unit. There is loose pea-gravel around the playground equipment, and I wanted easy digging material as I wanted to dig all items in this test. The group of coins on the right, plus two pieces of wire and a nail all came up lo-hi tone. Quarters, dimes, and copper pennies. Basically, if I only dug lo-hi tones I would dig nothing but coins and a small amount of trash! The results on the left are from the hi-lo "gold range" tones. This equates to the jewelry range on VLF detectors and as any jewelry hunter knows this is also the foil, pull tab, aluminum range. The Infinium also reveals it's love for wire in this range, in particular bobby pins and paper clips. I found quite a few broken zipper parts. The stuff by the battery that looks like large wire is actually string and other items with small metal connectors. The bent shallow "V" shaped item is a plastic ink tube from a pen, and several of the smallest targets were pen tips. Also a few pencil eraser ends, a common school yard find. There are also a couple very rusted nuts. Most large iron items normally read lo-hi but if they rust enough they sometimes come in as hi-lo, as these did. This is also where you get the nickels and zinc pennies. And jewelry. I found an earring, a couple pieces of broken chains, a couple pins, and a pendant. Coin detecting with the Garrett Infinium It looks to me that if you are in the right area and willing to forgo the nickels (and nobody cares about zinc pennies) then the Infinium might actually work very well as a coin detector. Just dig lo-hi tones only. No surprise on the hi-lo tones. If you go for the jewelry range you are going to dig lots of junk. Not bad on a beach or in the pea-gravel, but it would wear you out in an average park setting. In a nutshell the hi-lo tone equates to the zinc penny and lower range on a VLF detector, and the lo-hi tones equates to copper penny and higher. The wild-card is iron items which can id in either range depending on shape and amount of decomposition (rust). I can't comment too much on the depths as I did not dig anything that was in the hard packed ground under the pea gravel. My main goal was to just dig lots of targets to see which tone I got. Everything was less than 6" deep. However, I did have my Fisher CZ-5 and White's MXT along, and the Infinium easily detected a dime I buried beyond the discrimination range of both detectors while correctly giving the lo-hi id. The only way the VLF machines could hit it was to go to all-metal mode. Needless to say I plan on trying this in a couple heavily worked "old coin" sites later to see what might turn up. One thing I did find is that the Infinium has what is referred to as a "modulated audio" In other words, smaller or deeper targets sound fainter. I did find that I could reliably predict many of the nickels and could have dug less small trash as the nickels really bang out on the Infinium. It hits nickels harder than any other coin due to the machine being tuned for gold range targets. If I did not think jewelry finds were a possibility I think I could get many nickels and dig less trash by paying attention to the intensity of the audio. The wire items also seem to "move" as you walk around the target. The coins stay centered. Steve Herschbach Garrett Infinium Pulse Induction metal detector I went coin detecting with my Infinium... Posted by Steve Herschbach on 5/1/2004 Hi, I finally got my hands on the 14" mono coil for my Infinium. I've been wanting one for some time, as in theory it should get better depth on target in mild ground than the DD coil that comes stock with the unit. I have a ten day prospecting trip coming up the first week of June and so was desperate to get the coil before the trip. I'll have to weigh the mono coil as compared to the stock coil but I immediately liked its lighter weight. The stock coil is just plain heavy. The mono is epoxy-filled so not as light as it could be, but it is big improvement over the DD in this regard. I took the unit to a nearby freshwater beach that has been heavily detected for many years. It dates back to the 1920's. Like most beaches it replenishes with new stuff constantly but the older coins have been detected out of it for the most part. Those that can be reached, anyway. A friend with an Explorer has been trying to get the last few and declared to me a few days ago that he figured he had about cleaned it out. He even went so far as to use the big Coiltek WOT coil on the Explorer. Nice thing about beaches... you can dig big holes! The Infinium has a dual tone system. You get a hi-lo tone on low conductive items and a lo-hi tone on high conductive items and large iron or steel. I've found in the past that smaller nails and other elongated steel items like hair pins read hi-lo as if they are low conductive items. Excepting iron and steel, which can go either way, the hi-lo tone is where you get jewelry, aluminum, zinc pennies, and nickels. Lo-hi tones are copper pennies, clad coins, and silver. What makes the Infinium different from other PI units is the tone system. Most pulse induction detectors are single tone "dig it all" machines. So the Infinium tone system, while far from perfect, allows for some uses that are not practical with other PI detectors. The beach I was at is littered with aluminum trash of all sorts, and deeper down there are lots of nails and other iron trash. And some jewelry. Basically, every swing gets at least one or more hi-lo tones. Lots of noise, but I've found if I keep my headphone volume low its no big deal. What I've found to be rare on the beach is the lo-hi tones. Lots of detecting keeps the beach fairly clean of newer coins. And the larger nails are rarer than the smaller ones. So I set out this morning to only dig lo-hi tones. I headed right for the middle of the beach, one of the most detected places in my town. After only ten minutes I got a nice mellow, lo-hi tone. The sand on this beach is of varying depth, and is on top of a clay-like base. At about ten inches I hit the clay, and there embedded in the clay was a 1953 silver dime! Now, this may not be a very old coin by most standards, but to find it where I did pretty much blew me away. Countless detectors have been over this dime. The signal I got was not weak. It did have a more mellow response than a shallower coin would, but it was a solid signal. So I used the dime as center base and started spiraling around it. Lots and lots of hi-lo tones which I'll go dig some other day. Probably deep aluminum but I'm sure I passed over some deep jewelry today. But I stuck with the program. After a couple hours I had dug 16 targets, four of which were coins. The other three were all wheatbacks from the 1940's. All were in the clay layer below the sand. The pennies were shallower than the dime, which might lead some to wonder why they were still there. All I can tell you is the ground runs about 78 on a White's MXT, so pretty mineralized, and there are hi-tension power lines nearby. So while the depths I'm talking about here my not seem impressive, all I can swear to is that these coins were missed by hordes of detectors over the last 30 years. I was very impressed. The mono coil, while I did not compare it directly, seemed to me to have a clear edge over the stock DD coil for depth. I could pinpoint MUCH easier with it, as the signal were right in the middle where they should be. The mono coil has a traditional cone-shaped detection pattern with best depth and signal dead center. Add the fact that it is light and I have a new favorite coil for the Infinium. I can't wait to get it out nugget detecting next month. But tomorrow morning it is back to the beach to tackle some of those hi-lo tones and see if I can find a gold ring. And look for more lo-hi coins after I get tired of digging aluminum trash! In any case, to use a PI on a trashy beach and be able to come up with one in four targets good as opposed to just digging everything is what the Infinium is all about. It has some real power in dry land areas where other detectors may be having issues due to mineralization, and once you get used to its dual-tone id system you can do things with it that you cannot do with a normal "dig-it-all" PI detector. I really have to caution that the discrimination is not perfect, and in some areas it may be useless, but depending on the mix of targets it can work well, as I think this day showed. Pulse induction is not for everyone, but I have to tell you I'm really having fun with this thing. I can't wait to see the look on the face of my Explorer buddy. He is not going to be happy that a Garrett got coins he missed. ~ Steve Herschbach Copyright © 2004 Herschbach Enterprises
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