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DetectorProspector Magazine

Articles on metal detecting and gold prospecting. Forums about metal detecting for coins, gold, relics, jewelry plus equipment reviews and more.

  • Steve Herschbach
    The Minelab GPX 4500 detector was released in the spring of 2008 and is currently still in production. 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 but the GPX 4500 is only just a step behind it in features and performance. See Steve's Guide to Differences of Minelab SD, GP, & GPX for details.
    The GPX 4500 created a page in gold rush history by being singled out as the detector of choice in Africa for some time. Many large nugget finds were made there with the new GPX 4500 and starting around 2009 demand far exceeded supply as African prospectors were willing to pay any price to get what they believed was the only detector capable of possibly making them rich. Buyers in the U.S. drove prices far over retail due to extreme demand and these units were resold in Africa for prices well exceeding $10,000 per machine. This amazing demand was almost single-handedly responsible for driving Minelab sales and stock prices to all time highs.
    When the GPX 4800 and GPX 5000 were introduced Minelab stopped selling the GPX 4500 in the U.S. and Australia but demand was such that it continued to be sold in Africa. Finally, in 2015 the GPX 4500 was reintroduced for sale again in those countries as an entry level pulse induction model (for Minelab) priced at less than half what the GPX 5000 sells for. This makes the GPX 4500 an exceptional value at this time.

    Minelab GPX 4500 Pulse Induction (PI) metal detector for gold prospecting and more
    I got my own GPX 4500 in 2008 and saw many others in use at my old mine at Moore Creek, Alaska. The GPX 4500 made the ground light up like it had never been hunted with many nuggets found in already detected locations. Here is my report at the time about what I observed at Moore Creek:
    "I have run a little pay-to-mine operation at Moore Creek for four years now. We have old tailing piles that have nuggets in them. Some piles produced quite a few nuggets, and so everyone and their brother has been over them hoping for just one more. For instance, Dean's Hill. Dean found a 6.54 oz nugget a mile below camp on a pile. Rich Lampright found I think about 6 more ounces of smaller specimens on the same pile. Anyway, well over a pound came off this one pile.
    Now, these piles are small hills. You might be talking 300 feet long by 100 feet wide by 40 feet tall. Big but not something a person can't cover every square inch of. There have been probably 50 people hunt Dean's Hill using everything from the SD2200 on up to the GP3500 and probably a GPX-4000 or two last summer. There are other hills with similar reputations, including Bud's Island right near camp. Over 100 people have hunted it since it is so near camp.
    So the guys show up this year with the GPX-4500. A determination was made almost immediately that all ground should be treated as virgin again, and sure enough nuggets started coming out of Dean's Hill and Bud's Island and other places that were well and truly "hunted out". It was simply way too many nuggets to chalk up to anything other than the GPX-4500 being able to hear nuggets previous units could not hear at Moore Creek.
    I attribute this to two things. Previous SD/GP units had a tendency to sound very faintly on hot rocks at Moore Creek. So you got to where you usually ignored those sounds as they were almost always rocks and listened for something just enough different to indicate a real target. It is possible with the GPX to completely and absolutely tune out those faint hot rocks, allowing whisper faint nuggets to be detected. They might not actually be deeper per se, it is just that you could not discern them before. Same difference as far as I'm concerned.
    Plus, with the Gain and extra timings you can crank the GPX up for some insane performance. Steve F got his biggy by running the GPX up to the point where the ground was super noisy. You'd not normally hunt that way but he was focused on one spot, and it did allow him to get an exceptionally deep target.
    The bottom line is I am absolutely convinced the GPX is doing stuff that could not be done before. It was too many people getting too many nuggets out of too many hard hit spots to be anything else. There is no doubt in my mind that money spent on a GPX-4500 is money well spent. Remember, though, it can't make the gold. We had a couple GPX users who simply could not seem to get over nuggets.
    Anyway, hopefully Rob and Glenn and Steve and other Moore Creek visitors will chime in here with some of the settings they were using at Moore Creek to help little old me out. I am headed back up to Moore Creek August 8th to prep ground for next season but plan on firing my new GPX up for the first time finally. I gave away everything I found in June so it would be nice to have at least one nugget to call my own this summer!! Any tips would be most welcome.
    Steve Herschbach
    Moore Creek Mining LLC
    July 25, 2008"
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    The was a period of time after the GPX 4500 was discontinued in the United States that the GPX 4800 and GPX 5000 were the only two PI models available from Minelab. Garrett introduced their new Garrett ATX at less than half the price of those detectors. It was a bargain at $2120 compared to almost $6000 for the GPX 5000. I do not know this for a fact but I believe that Garrett had something to do with the GPX 4500 being reintroduced for sale. The GPX 4500 at $2699 with two coils was close enough to the $2120 ATX with one coil, that it pretty much stopped the ATX dead in its tracks as a prospecting detector. Up until that point I had been recommending the Garrett ATX as a bang-for-the-buck alternative to the much higher priced GPX uits. Given the extra power and versatility of the GPX 4500 at the new lower price, and the GPX 4500 is now my recommendation for anyone wanting a new full warranty high power PI for gold prospecting and possibly even beach or relic detecting.
    Official Minelab GPX 4500 Page
    Minelab GPX 4500 Instruction Manual
    Minelab GPX 4500 Product Brochure
    Minelab GPX 4000-5000 Manuals & Timings Charts
    Difference Between Minelab SD, GP, and GPX Models
    Forum Threads Tagged "minelab gpx"
    Minelab Metal Detectors Forum
    Minelab GPX 4500 Technical Specifications* Internet Price $2699.00 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 Six 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 Search Coil(s) Commander 11" round DD & Commander 11" 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 4500 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.

  • Steve Herschbach
    The Garrett ATX was introduced by Garrett Electronics in 2013. It is a pulse induction metal detector waterproof to ten feet. It is unique in that it is one of the few metal detectors retailed to the general public in a housing developed for military applications. Garrett makes a military land mine detector called the Recon Pro AML-1000. It was developed and marketed after the Garrett Infinium, the only underwater ground balancing pulse induction (GBPI) metal detector made by a major manufacturer. The Recon is notable for the waterproof telescoping compact design with hidden coil cables. The new ATX is a highly refined detector combining the best of the Garrett Infinium and Garrett Recon AML-1000 into a single package. The actual housing is almost identical to that used by the AML-1000. The electronics has attributes from both detectors. It is a considerable improvement over the much older Infinium electronically and folds into a remarkably small package without disassembly.
    I was one of the first individuals to obtain a Garrett ATX when they came out as I had been waiting for a new waterproof ground balancing pulse induction metal detector ever since the Infinium came out over ten years ago. I honestly was a bit surprised Garrett came out with a second generation waterproof GBPI before the competition has released any at all. Ground balancing PI detectors have the ability to work in a combination of salt water and black sand/hot rock environments in unique ways. VLF and even standard non-ground balancing PI detectors suffer under these extreme conditions. The Infinium showed me what might be possible in Hawaii but it suffered from issues common in first generation detectors. There was room for improvement, and I am hoping the ATX addresses the electromagnetic interference (EMI) and salt water instability problems that plagued the Infinium.
    My first impressions were positive, with my first detailed report at Gold and Silver with the New Garrett ATX. I have a separate article on prospecting with the ATX at Gold Nugget Detecting with the Garrett ATX. The ATX is a versatile detector and will see use prospecting, relic hunting, jewelry detecting (above water and under) and even coin detecting. I have two beach detecting articles on the ATX - Beach Detecting in Hawaii With The ATX and Garrett ATX Return To Hawaii.

    Garrett ATX waterproof pulse induction (PI) metal detector with 10" x 12" coil
    The Garrett ATX is uniquely versatile in its physical aspects. It can be extended longer than most people need yet can collapse into a very short diver configuration due to the three piece lower rod design.

    Garrett ATX collapsed for diving use
    For storage or backpacking the ATX folds even shorter yet to only 20" in length due to the rotating/folding coil design. The ATX coils are rather unique in that they are integrated with the lower rod with the wires running through the rod and a rear mounted hinge on the coil. This allows the coil to fold back completely over the rod and/or detector body. The rod/coil assembly can be rotated 90 degrees for hunting walls and to enable a more compact stowed configuration.

    Garrett ATX folded for storage or backpacking
    All the ATX functions are accessed through a top mounted control panel with rubber topped touchpad buttons and LED indicators. A shift button allows each button to have at least two functions allowing for a full feature set in a simplified layout.

    Garrett ATX Control Panel

    Quick Guide to Garrett ATX controls from Owner's Guide  - Click image for larger version
    The Garrett ATX comes standard with a 10" x 12" DD search coil. Optional 8" round and 15" x 20" mono coils with integrated lower rods are also available. New for 2017 are 11" x 13" enclosed coil options in both mono and DD designs.
    The ATX does have a built in waterproof speaker and so does not require headphones. It does come with land headphones that use a waterproof connector, the same connector that Garrett uses on the Infinium and AT Pro/AT Gold models. The same waterproof headphones available for those models work on the ATX and are required if it is desired to put the headphones underwater. The included headphones have a waterproof cable that can be submerged but the headphones themselves must be kept dry. A short adapter dongle is also available to convert the ATX waterproof headphone connector to the standard 1/4" female receptacle so standard metal detector headphones may be used.
    See the Garrett ATX Accessory Page for details on headphones, search coils, and other accessory items available for the Garrett ATX. There is information there on using Garrett Infinium coils on the ATX, and notes on how to chest mount or even backpack mount the ATX control box.
    Finally, the ATX runs off eight standard AA batteries, eliminating any shipping or airline issues that can be a problem with some PI detectors. The detector comes complete with both alkaline and NiMH rechargeable batteries plus a 110V and 12V charger system. The detector runs approximately 10-12 hours on a charge when using headphones, less if running off the speaker. The best method is to use the rechargeable batteries and carry the alkaline set as backup.

    Garrett ATX search coil options
    I have had the Garrett ATX now since the fall of 2013 and so have had a solid year with the detector. It really does take about a year for me to settle down my thoughts about a detector. I tend to be all giddy with the new toy at first, having fun, and discovering new things. The strong points and weak points are revealed with use over time, and now I think I can offer up a fair summary of the detector.
    The ATX is a bit difficult in that Garrett started with the premise of using an existing housing designed to military specifications, and then decided to put a detector in it for consumer retail sales. On one hand this is really great as we get this very unique detector design that would never have been developed just for consumer sales. On the other hand it means for some uses the ATX is just not a very good fit. For other uses it works pretty well.
    It just so happens I am an avid prospector and an avid beach hunter. I do not beach hunt as much as I like but when I do it I really go after it. Because of this the ATX hits a particular sweet spot for me personally. I really do need a good pulse induction metal detector that can be submerged in saltwater. I would keep the ATX for that purpose alone. I am very happy with its performance as a beach detector especially on beaches where there is black sand mineralization or volcanic rock to deal with. The fact it also does very well as a prospecting PI is almost a bonus for me.
    From a straight up prospecting perspective Garrett also scores though nobody needs a seven pound detector waterproof to 10 feet while desert prospecting. However, if all I had was a couple thousand dollars to invest in a brand new, full warranty PI for gold prospecting it would be a Garrett ATX. I believe the ATX is superior to the White's alternatives in overall performance and it is far less money than a new Minelab PI detector. I will not speak for the Australians but in the U.S. the ATX holds its own for PI performance and I feel quite comfortable using it gold prospecting. I could wish for a lighter package but the fact is it works and a person who puts in the effort should do just fine with the ATX. I know I can.
    The ATX does well for relic hunting applications and I have even found I can cherry pick coins halfway well with it. I have always been partial to pulse induction detectors and Garrett has won me over with the ATX. I enjoy using the detector and I can make good finds with it, and that is all I can ask of any detector.

    Some of Steve's finds with the Garrett ATX in the first year of use
    In retrospect I have actually done remarkably well with the ATX since I got it, considering it is only one of several detectors I have been using and not the one with the most hours on it. I have found about 3 ounces of gold and platinum jewelry with the Garrett ATX plus about two ounces of gold nuggets with it. I have found gold nuggets in Alaska, Arizona, California, and Nevada with the ATX under sunny skies and in pouring rain. My ATX has spent a couple weeks of days underwater in rough surf and is none the worse for wear. Many thanks and a hat's off to Garrett for producing my all time favorite Garrett detector.
    ~ Steve Herschbach
    Copyright © 2015 Herschbach Enterprises
    Official Garrett ATX Page
    Garrett ATX Instruction Manual
    Garrett ATX Color Brochure
    How To Disassemble and Clean the ATX Coil Shaft & Camlocks
    Garrett ATX Accessory Page
    Forum Threads Tagged "garrett atx"
    Garrett Metal Detectors Forum
    Garrett ATX Technical Specifications* Internet Price $2120.00 Technology Ground Balancing Pulse Induction (GBPI) Frequency 730 pps Autotune Mode(s) Slow Motion and Non-Motion Ground Rejection Four Tracking Speeds and Fixed Soil Adjust Can ground balance into salt soils Discrimination Dual Tones, Iron Check & Reverse Disc Volume Control Volume Limiter plus headphone controls Threshold Control 25 level push button setting Tone Adjust No Audio Boost No Frequency Offset Automatic Pinpoint Mode Yes Audio Output Proprietary headphone socket, Headphones supplied plus Waterproof Speaker Hip Mount No Standard Search Coil(s) 12" x 10" Open Spoke DD (Or Optional 11" x 13" Coils) Optional Search Coils 8" Round Mono, 20" x 15" Mono, 11" x 13" Enclosed DD, 11" x 13" Enclosed Mono Battery 8 AA rechargeable and disposables supplied Operating Time 10 - 12 hours Weight 6.9 pounds Additional Technology 13 level adjustable gain control Notes Waterproof to 10 feet (requires optional submersible headphones) *Notes on Technical Specifications - Detailed notes about the specifications listed in this chart.

  • Steve Herschbach
    The XP Metal Detectors company of France has been making waves with its new metal detector, the XP DEUS. So much has already been written about the XP DEUS that this page is going to focus on the  Version 4 software release from 2017. This new version of the software combined with new hardware has made the DEUS into a totally different detector. For that reason this website will be referring to XP DEUS V4 specifically as opposed to earlier versions of the detector.
    I purchased a new XP DEUS in 2014 to evaluate it as a gold prospecting detector. The DEUS was originally designed for coin and relic hunting in Europe but quickly found a following in the United States also. As a prospector I was not much interested in the detector, until the version 3.0 software update added a program specifically for prospecting, the Goldfield program. According to Andy Sabisch at Findmall the program was originally developed as a dedicated prospecting detector for the African market. It worked and was subsequently added to the 3.0 software update for the DEUS.
    According to XP "The GOLD FIELD program uses a different detection strategy designed to handle highly mineralized ground containing targets such as gold nuggets. In these ground conditions, small, low-conductive targets are often seen as ground noise or iron, especially when they are deeply buried. To go deeper in these difficult conditions, the GOLD FIELD program uses a true All Metal mode allowing you to accept a whole zone of ground that is usually rejected (Full Range). Rather than rejecting all the ground values below the setting (as on conventional detectors), this new program rejects only the current value of the ground which you have to adjust exactly."
    The short story is I found the XP DEUS and its new Goldfield program to be perfectly adequate for gold prospecting, but that was about it. The innovative wireless design notwithstanding, there just seemed to me to be nothing particularly compelling about the DEUS for gold prospecting. It is the kind of machine that if a person owned it anyway, then they would have a capable gold prospecting detector in addition to all its other uses. Given the price however to buy it specifically for gold prospecting just did not make much sense to me when detectors costing half as much did every bit as well or better. Further, a well respected person on my forum reported that he also ran into issues with the DEUS in its current form when it comes to gold prospecting. You can find my detailed review and his report both at Using The XP DEUS For Gold Prospecting at the DetectorProspector Forum. I went ahead and sold my new DEUS at that time.
    Fast forward to the fall of 2015. Early information about the upcoming version 4.0 software release immediately caught my interest. New coils were announced that has serious implications for gold prospectors. The new elliptical coils are 12cm x 24cm or approximately 4.7" x 9.5" which is very close to the standard established for VLF gold prospecting detectors. There is also be a new round 9" coil. More importantly, the new coils via the V4 software will enable operation much higher operating frequencies. The 9" round coil will operate at 14 kHz, 30 kHz, or 59 kHz and the elliptical coil at 14 kHz, 30 kHz, and an amazing 81 kHz!. This would put the XP DEUS V4 squarely in the realm of high frequency gold prospecting detectors. Currently the Fisher Gold Bug 2 at 71 kHz has the highest operating frequency of the popular prospecting detectors.

    XP DEUS V4 with new 4.7" x 9.5" DD Coil
    These extremely sensitive coils operate on a wide range of 21 frequencies, ranging from 13 to 81 kHz depending on coil choice. The search coils three base frequencies are 14kHz - 30kHz and 59 kHz for the 22.5cm (9”) Round DD coil. The elliptical DD coil has a slightly different base frequency set of 14kHz - 30kHz and 81 kHz. Each coil has a further 7 higher or lower sub frequencies to choose from, allowing a much wider adjustment range (Previous Deus has 3 sub frequencies). The lower frequencies are intended for general use, they provide good sensitivity to a wide range of targets, the higher frequencies will take the Deus to another level. You will instantly notice the enhanced sensitivity and the ability to find small targets that have previously been difficult or impossible to locate when searching mineralized ground with competing devices.
    Apart from the ability to detect through mineralized soil, the HF coils will enhance the signature from weak - low conductive targets or even highly conductive targets, that due to their shape or construction (thin or wired) are beyond the reach of conventional detectors, for example: open rings such as earrings or fine bracelets, wire framed artifacts, gold nuggets, intricate fibula’s, small coins, thin coins, etc. The new HF coils only weigh 350g and are equipped with the latest higher capacity lithium battery (850mA). The new battery is situated in the lower stem; this is a bonus especially if you are working in a remote area far from a power source as optional replacement batteries will be available. Battery life: 20 hours at 15kHz, 27 hours at 30khz and 28 hours at 59 & 81 kHz.
    In my opinion the version 4.0 software upgrade combined with this new coil meant the DEUS was worth another look as a gold prospecting detector. The smaller footprint of the elliptical coil will "see" less ground and better separate small gold nuggets from difficult ground conditions. The boost in frequency will also make the detector hotter on small nuggets. I therefore obtained another new XP DEUS and waited - over a year - for the new V4 update and new coils to appear.
    I finally went out and found my first gold nuggets with the new DEUS elliptical high frequency coil in 2017. I want to emphasize that I am a newbie on the XP Deus. Although I purchased an 11" Deus V3.2 model almost two years ago, it was with the express purpose of being able to test the V4 update with the new high frequency coil options for gold prospecting. I decided I was better off just starting fresh with version 4.0 before really digging in and learning the detector. I do get the hang of detectors quickly but this does show what can be done by somebody who went out barely knowing the machine.
    The other catch is that I picked a location that favors the Deus with relatively mild soil for a gold location, so mild I could run the machine full out to get the maximum possible sensitivity with the machine. These results are not going to be as easy to obtain in extreme mineral ground. You have to start someplace however and being new to the machine I wanted to give myself someplace easy to start. Finally, the goal here was to find the smallest gold I could so for the purposes of this report - smaller is better.
    These nuggets were recovered over the course of a day. Ten nuggets, 4.7 grains total weight. There are 480 grains per Troy ounce and with an average weight of less than half a grain I think you can agree this is some pretty small stuff. The smallest bits are probably near 1/10th grain or 1/4800th of a Troy ounce. Click picture for larger version.

    Gold nuggets found by Steve Herschbach with new XP DEUS HF elliptical coil
    The new HF elliptical coil running at 74 kHz is clearly in the same league as the 71 kHz Fisher Gold Bug 2,  45 kHz Minelab Gold Monster, 56 kHz Makro Gold Racer, and 48 kHz White's GMT. However, the devil is in the details and it will be some time before I sort out how the machines compare under more difficult and varied conditions.
    Again, I am not an expert with the Deus and so the settings I mention are not to be taken as "the best" or anything like that. I was actually gold prospecting so the primary focus was to find gold, not to test every possible combination of settings on the Deus. With 10 program options and numerous settings that will be a longer term project. I obviously wanted to try the Gold Field program 10. After a little experimenting I settled on the GM Power program 2 as an alternate disc mode to try. Getting from program 10 to program 2 is only a couple button pushes, so I bounced back and forth between the two programs and tweaked settings higher as I found targets and could compare readings.
    Gold Field is a threshold based all metal mode with what I find to be a rather pleasant digitized buzz. That's me of course, others may differ on that point. I was able to run sensitivity full out at 99. All my work was done at 74 khz, the default highest frequency setting without trying to push it higher via the offset. I figure the coil is tuned at 74 khz and so stuck with that for now. Manual ground balance about 84.
    GM Power I got sensitivity to 94 with only minor falsing. I reduced reactivity (similar to SAT for you nugget hunters) to 0 from the default of 2 and ran the audio response (audio boost) up to 7 (max).
    Both modes exhibit just a little touch sensitivity at these high gain levels. This might be tamed with the ground notch but I have not fooled with that yet and it did not bother me at all anyway.
    ads by Amazon...

    What I found was Gold Field has a softer response in general but that my boosted version of GM Power banged hard on the little bits. Not unlike going from all metal mode on the Gold Bug 2 to the Iron Disc mode. Instead of faint threshold variations you get a strong "beep". The difference is that the Gold Bug 2 Iron Disc mode has an obvious loss in sensitivity. The Deus by comparison in this particular situation actually seemed to work better in GM Power mode, but that is mainly the boosted audio at work.
    I left the disc settings at the defaults for GM Power which worked well - low tone iron, higher tones non-ferrous. I ran the IAR (iron reject) in Gold Field at 2. This was just enough to cause ferrous to break up. Higher settings would blank most ferrous completely but getting to aggressive can also eliminate weak gold signals. The ferrous discrimination worked very well in both programs. GM Power in particular was pretty awesome in the nail pits with iron tones firing off like a machine gun. I bumped reactivity back to 2 in the dense trash.
    Anyway, this is a very preliminary report and so no point getting too deep into it as I will probably modify my opinions and settings as I get more time on the machine. Right now this is a high price option if all you need is a prospecting unit, but for a person wanting one machine to do everything XP just kicked it up a notch. If they introduce a dedicated gold unit at a lower price similar to the Depar DPR 600 it would be very competitive. For now this is an option for somebody that wants a detector for more than just gold prospecting since the Deus is a superb coin, relic, and jewelry detector.

    XP DEUS as ultimate "stuff it in a rucksack" metal detector
    The elliptical coil and rod assembly is just 1 lb 13 oz (1.8 lbs) and so a true featherweight. At 5' 11" I have to run it fully extended and at that it does flex a bit, but I did not find that bothersome at all. A solid coil cover will be good as there are too many coil edges that want to hang up on rubble and sticks. A minor quibble however as the machine is a joy to handle, especially when reaching uphill waist high and higher. A great unit for poking in and around bushes and other obstructions. The coil is hotter at the tips which also helps in poking into tight locations.
    Early days but the final word is that I am happy with how this coil performs on small gold nuggets after all the wait. Time will tell how it handles the really bad ground and how it fares directly against some of the competition as other people report in. As always giving it time and waiting for a consensus opinion from many users to develop is a wise policy with any new detector.
    ~ Steve Herschbach
    Copyright © 2017 Herschbach Enterprises
    Official XP Deus Page (U.S.)
    XP DEUS V4 Instruction Manual
    XP DEUS Color Brochure
    V4 Update Color Brochure
    XP DEUS V4 Summary / Manual Supplement
    XP DEUS Versions/Update History
    Forum Discussion of V4 Update & Coils
    Forum Threads Tagged "xp deus"
    XP Metal Detectors Forum
    XP DEUS V4 Technical Specifications* Internet Price $875 - $1565, 9" Coil w/WS4 Phones, Remote $1520 Technology Induction Balance (IB) Frequency 4, 8, 12, 18 kHz or 14, 30, 55, 80 kHz Autotune Mode(s) Multiple "Reactivity" Settings Ground Rejection Grab, Manual, Tracking Soil Adjust Beach Mode Discrimination Variable, Visual ID, Tone ID, Notch Volume Control Yes Threshold Control Yes Tone Adjust Yes Audio Boost Yes Frequency Offset Yes Pinpoint Mode Yes Audio Output 1/8" headphone socket & speaker, wireless headphones Hip Mount Yes Standard Search Coil(s) 9" DD or 11" DD Optional Search Coils 13" x 11" DD,  9.5" x 4.7" HF DD, 9" Round HF DD Battery Built In Rechargeable Operating Time 20 hours Weight 2.0 lbs Additional Technology Wireless coils, control box, headphones; firmware updates via internet Notes Perhaps the most popular detector sold in Europe *Notes on Technical Specifications - Detailed notes about the specifications listed in this chart.

  • Steve Herschbach
    The White's PulseScan TDI was released in 2008 and is still in production as the TDI SL. Prior versions have been discontinued. I was one of the original users of the TDI and still dabble with them to this day. See my story White's TDI at Moore Creek, Alaska for pictures of lots of TDI gold nugget finds. I also have extensive notes on using the TDI for coin detecting at Steve's Guide to White's TDI Coin Settings. The TDI is a unique detector and is seeing use in many applications unforeseen when it first came out.
    The TDI has been available in several versions but all are basically the same detector as far as how they work. June 2018 Note: White's has a model called the TDI SL Special Edition out now. It is available for a limited time only, so I will refer you to the White's website for availability and details. Basically it is the White's TDI SL with a different rod and coil option at a discounted price.
    I am a big fan of competition as I always want more and better detectors from the manufacturers personally, and I think competition is the best way to get better detectors. After Garrett got into the ground balancing pulse induction (GBPI) game with the Infinium people including myself were really after White's to make an entry into the field. I went so far as to visit White's Electronics personally to lobby for such a detector with suggestions on how to get there. In particular, I advised that rather than developing something from scratch, it might make more sense to license the existing Goldscan technology from Eric Foster, widely known as "the father of pulse technology" for his early work in the field.
    Eventually White's did decide to pursue the matter, and I was therefore aware early on that White's was working on a new detector, In 2007 I was sent a prototype unit to evaluate while I was on vacation in Hawaii. I was very impressed not only with the power of the detector but more importantly for me in Hawaii I was very impressed with how stable the detector was in salt water. It was also virtually immune to electromagnetic interference (EMI) issues that had dogged my use of other detectors in Hawaii.

    White's TDI SL with closeup of control panel (compare to original TDI controls below)
    My use of previous GBPI detectors, the Minelab models and the Garrett Infinium, made me familiar with how they respond to targets with various tones. Each target generates a dual tone that varies depending on whether the target is above or below the ground balance point that has been set. You will hear either a high tone followed immediately by a low tone (hi-lo), or a low tone followed immediately by a high tone (lo-hi). This dual tone system is effective for most uses but if you get into a target rich location it in effect doubles the number of audio signals coming from the detector.
    I also had an opportunity in Alaska to visit with Brent Weaver, the main engineer at Garrett responsible for the development of the Infinium. While testing a prototype Infinium I asked him about the dual tones (Garrett now refers to them as "echos") and whether they could be suppressed. He told me the dual tones were integral in how the Infinium worked and that it was not practical to produce a single tone result on the circuit they were working with.
    White's did end up working with Eric Foster on the development of the TDI. His method is one I like because instead of the dual tone responses generated by the Minelab and Garrett models (hi-lo or lo-hi) the TDI generates one of two tones, either a low tone, or a high tone. The tone depends on whether the target is above or below the current ground balance setting, and therefore there is only a tone difference when the ground balance system is engaged. The ground balance off, straight PI mode has monotone responses. Also, because the ground balance can be set manually on the TDI, this tone "breakpoint" can be shifted by the operator. This allows targets to be separated broadly into two distinct groups. On one hand there are high conductor type targets, like most coins and large steel items, that on the TDI produce a low tone response. The other group is comprised of low conductor type targets, and includes most gold items, US nickels, aluminum, and small ferrous trash. These all produce a high tone response on the TDI. There are far more high tone targets than low tone targets in most locations.
    I really liked the prototype TDI that I used in Hawaii, in particular the fact that it generated half the audio responses compared to a Garrett or a Minelab. Once again I wondered if one tone or the other could be suppressed. I sent an email to Eric Foster, and was surprised when he told me that not only could it be done, but it would be a very simple thing to implement with a basic toggle switch arrangement. This came about very late in the TDI development, and I lobbied hard for just such a feature to be added. A last second vote was taken by those involved, and probably the last major change on the TDI before it went into production was the Target Conductivity switch. There was no such switch on the tan prototype models.

    Prototype White's TDI Used by Steve Herschbach in Hawaii
    Now, I do not want to give the impression I was some kind of major player in the development of the TDI. I was just one of many voices pushing at White's for years to develop a ground balancing pulse induction (GBPI) detector. I am pretty sure though my last second inquiry and little push was what made the tipping point to getting the Target Conductivity switch included, and I think to this day it is one of the most useful and intriguing features on the TDI. It allows for a vast reduction in the number of audio responses in certain situations and in conjunction with the manual ground balance and pulse delay offers a degree of discrimination on the TDI not seen on any other pulse induction detector made today.
    This makes the TDI a pulse induction machine that can be used effectively for coin detecting, if the operator knows what they are doing and employs some smarts in site selection. I wrote an article entitled Steve's Guide to White's TDI Coin Settings on this very subject. I will not repeat the information here in the interest of keeping this page from getting too long. Suffice it to say the TDI has the ability to play tricks and discern targets far beyond what most PI detectors can achieve.
    Another major feature on the TDI is the ability for the ground balance system to be shut off. The method used to ground balance the TDI in effect subtracts the ground reading from the total readings returned by the detector. This subtractive method does actually steal some depth, which is easily shown in air tests on targets with the ground balance turned on and the ground balance turned off. The closer the target is in relation to the ground balance setting, the more depth is lost. People find this very confusing, as the whole point of ground balancing a PI is to get better depth, right?

    Original White's TDI Control Panel
    The way it works is this. In low mineral ground a PI gets maximum depth without using any ground balancing. However, as mineralization increases, depth is affected. The more mineralization, the more depth is lost. Also, ground effects increase. In low mineral ground, the coil may be raised off the ground with little response. In highly mineralized ground, raising the coil even slightly off the ground produces a false signal. Nearly all PI detectors have an audio retune circuit that slowly retunes the audio response to keep it at the set threshold level. Otherwise circuit drift and minor ground variances would require constant retuning. In high mineral ground, the ground produces a response, but the detector compensates as long as the coil is kept at an exact height over or on the ground. If the coil is raised quickly, the audio overshoots when the ground signal is removed and a false signal occurs. This can be a real problem in even ground or in the water where it is difficult to maintain a steady distance above the ground or sea bottom.
    Hot rocks or wildly varying ground mineralization present an even greater issue. Again, the detector does well as long as the conditions are constant, but when a hot rock or mineralized ground condition like a clay seam enter the picture, a false signal is heard. In areas with lots of hot rocks PI detectors that cannot ground balance are almost useless due to the overwhelming number of false signals.
    So imagine a PI with no ground balance in low mineral soil. All is well, maximum depth is achieved. Pretend we have the ability via a magic dial to turn up the ground minerals and/or hot rocks in the ground. A point is reached where performance and efficiency is greatly impacted. It becomes impossible to discern good targets from ground signals and false hot rock signals. At such a point, engaging the ground balance circuit gains back the lost performance and efficiency. It does this by eliminating the ground signal and hot rock signals.

    White's search coils for TDI (from 2018 product catalog)
    This leads to situations occurring where people use a GBPI detector in low mineral ground and decide they are no better than a VLF. That actually often is true, in that a good VLF in all metal mode will do about as well as a Ground Balancing PI in low mineral ground, if both have similar coil sizes. A GBPI does not come into its own until the ground conditions or hot rocks are such that a VLF operator wants to toss the detector in a gully in frustration.
    This has been a very long lead explanation to the TDI secret weapon. In low mineral ground, turn the ground balance off! The detector will become extremely stable with a very smooth threshold and become more resistant to electrical interference. Gain may be boosted and a great deal of extra depth achieved in situations that allow for this type of operation, and they are actually very common. This would be the preferred beach mode on most beaches, the exception being beaches with a lot of black sands. The White's TDI in pure PI mode is one of the most powerful straight PI detectors available. The tone differences between targets disappear, and sometimes the ability to differentiate targets is more important than the depth gained by shutting the ground balance system off. But do not overlook this ability to run without ground balance in situations that warrant doing just that as it can really pay dividends to the knowledgeable operator.
    ~ Steve Herschbach
    Copyright © 2010 Herschbach Enterprises
    Official White's TDI SL Page
    White's TDI SL Instruction Manual
    White's TDI Pro Instruction Manual
    White's Original TDI Instruction Manual
    White's TDI Field Manual
    Forum Threads Tagged "whites tdi"
    White's Metal Detectors Forum
    Great Post on Batteries For the TDI SL
    Excellent Review of PulseScan TDI Pro by Chris Ghoulson
    White's TDI Coin Settings
    White's TDI Technical Specifications* Internet Price TDI SL $1189 (Special Edition $1049) Technology Ground Balancing Pulse Induction (GBPI) Frequency 3250 - 3370 Pulses Per Second Autotune Mode(s) Slow Motion Ground Rejection Manual, one turn control Soil Adjust Ground Balance On or Off (two position switch) Discrimination Conductivity switch*, 10 - 25 Pulse Delay Volume Control No Threshold Control One turn control Tone Adjust No Audio Boost No Frequency Offset One turn control Pinpoint Mode No Audio Output Speaker, 1/4" headphone socket Hip Mount No Standard Search Coil(s) 12" Round Dual Field Optional Search Coils Over 100 accessory coils available Battery Rechargeable NiMH & AA Operating Time Up to 6 hours Weight TDI SL 3.5 pounds Additional Technology The TDI was designed specifically to be able to use Minelab SD/GP compatible coils. However, performance can vary and the pulse delay may have to be advanced to compensate for coil differences that result in overload readings. Notes *The TDI is unique in that it can suppress audio responses into two different classes. Targets have a high tone or low tone audio depending on how the target relates to the ground balance setting. In general high conductive targets give a low tone and low conductive targets a high tone. The TDI can be set to allow for one response or the other. See White's TDI Coin Settings for more details on this control. *Notes on Technical Specifications - Detailed notes about the specifications listed in this chart.

  • Steve Herschbach
    Where Do I Begin? by Ron Wendt
    You’ve developed an interest in prospecting for gold. A couple friends have told you how much fun they’ve had looking for gold. In this article I’ll point out the pros and cons about this activity and in the end you’ll probably have decided to what degree you want to pursue your search for gold. To begin with, it must be pointed out, there are several types of prospectors:
    1 - Those who wish to dig right in as a recreational prospector.
    2 - One who is serious about learning about the finer aspects of geology related to precious metals and would pursue possibly developing potential income from this endeavor.
    3 - A hardcore, hand miner “give me a bulldozer, I wanna gamble.” Of course mining can be a gamble and the biggest mistake some folks make is getting too serious about it. Many times most of the fun goes right out the window when it becomes serious. What happens is the deep desire for gold becomes elusive and discouragement sets in when there are no results.
    Looking for gold can be hard work with few rewards. Years ago an old timer once told me; “the fellows that got rich during the gold rush were just plain lucky!” Napoleon once said that too: “I want good generals, but I also want lucky ones!” Yes, there is a lot of luck in this business. The old timer and Napoleon were right. A lot of it is luck, but a lot of it is hard work to. You can choose to enjoy it with a little reward or to not enjoy it with little reward. The truth is the odds are you won’t get rich, but you might get lucky! We all know about luck. You can go to the gambling hall and pull on the “one armed bandit,” all day and not make a dime. Such is mining and prospecting. I’ve been lucky and I’ve been unlucky. I’ve been rich and I’ve been poor. I like rich better, and I like getting lucky.

    Shoveling gold bearing dirt into power sluices
    To be a prospector you must be willing to take a risk to a certain degree. There are those who think they can go out and simply put their shovel into the ground and there it is! They believe they’ll strike it rich. I have known some who have struck it big their first few times out. They didn’t have a clue, but were in the right place at the right time. There are several things in your character you should be aware of.
    1 - You should be the type of person not easily discouraged.
    2 - You should not be afraid of getting dirty and not afraid of hard work.
    3 - You should have a keen interest in exploring, prospecting things that are related in this field because it is all connected.
    4 - Be frugal. Don’t mortgage the farm. It doesn’t take much in the way of investment to get into this “field of study,” as I call it.
    5 - You should not be afraid to get wet, camp out, or endure the elements.
    6 - Attitude is a major in this business of mining/prospecting. This probably goes along with “don’t be easily discouraged.”
    7 - Don’t be afraid to fail. Failure is a great learning experience.
    8 - Have some curiosity about what could be over the next hill or under the next rock.
    9 - Be optimistic. If you’re not, you probably shouldn’t be in this business.
    10 - Most of all enjoy it. Enjoy it even though you don’t get rich from it. Your reward is experience and experiences many will never have the opportunity to do.
    Where do I begin? First off don’t go out and buy a bulldozer, when a gold pan can simply do the trick. In other words, start out learning the basics. Those basics are the gold pan, pick, shovel, sluice box, and perhaps a sniffer bottle to suck up gold from cracks. It would be good to go along with a veteran, not only to see how it’s done but to see if you like it. I have seen many times where folks will go out and buy a $1,500 suction dredge only to sell it the next year because they probably got discouraged, when a gold pan and hand tools would have sufficed. A big majority of prospectors I know will tell you they started out small, by that I mean, small mining tools which would include sluices, gold pans, picks and shovels. Once you decide you will make prospecting your side line, one can eventually branch out into other methods.

    Dredging for gold
    There are some who will head out into the world of nugget detecting. Here’s something to think about. When you spend $600 to $1,000 on a brand name detector, before you even make a decision to buy it, ask yourself this; “Where will I use it?” This may seem like a funny question, but in Alaska and the Yukon Territory, we may have a lot of gold scattered around up here, but is it detectable and accessible? Will I be able to drive somewhere during my time off from my regular job and spend enough time detecting nuggets? Is there a location close by where gold is detectable? Am I willing to invest this kind of money to use this machine in a proven area?
    There’s nothing worse than buying a piece of mining equipment and not be able to get into areas that are productive. For instance, the mountains behind my house generally yields mostly fine gold and some hardrock gold. For me to get any bigger gold I must travel south of my house about two hours down the highway or 5 to 10 hours to the north to get into productive ground. I am willing to spend times going to my favorite remote spots in search of gold. So you must determine how much am I willing to put into this to get results? It’s the same with going from your gold pan/sluice operation to a high banker or a suction dredge. Are you planning on a few choice trips to areas to get results, which by the way aren’t guaranteed?
    My recommendation is build up your knowledge of prospecting over 2 or 3 years before investing in bigger toys. This way once you’ve established a good, possible gold source, you might feel it’s now time to go for higher production. Large scale industrial miners work in much the same way. I have a good friend who suction dredged for a few years on a creek. After taking out numerous ounces of gold, he made a decision to go bigger. From there he bought a small D-6Cat to feed a sluice box, then eventually he added a backhoe. Today he has a D-9, a bigger backhoe and a dragline. He’s been seriously at it for over 25 years. In the off season he has another job to support his “sickness” called “gold fever.”

    Gold found by a prospector
    I’ve met a few folks who complained: “Yeah, I went out for a couple hours, and didn’t get a thing. There’s nothing out there!” He immediately was very skeptical there was any gold at all out there.” I said that was fine. There’ll be more for the rest of us! I told this fellow, a couple hours does not do the trick. You have to work at it. It won’t jump up into your pan, and no one will tell you exactly where it is because they don’t know themselves where it is exactly. We have an idea, but we can’t always pin point it. Most of the time we walk right over it. I remember an old prospector from up on the Yukon River was once asked where he kept all his gold, to which he replied; “Its in a safe place in the creek!” He knew he could dig it out anytime he wanted to, but he had to make the effort. No one would get it for him. He took out enough gold to survive on most of his life. It was his lifestyle and sole occupation.
    Finally, recapping everything, I can’t stress enough:
    1 - Start small, then gradually increase your devices to accommodate your potential production. You might advance from a sluice/gold pan to a nugget detector. You might eventually obtain all the tools of the trade, short of buying a bull dozer. The bull dozer purchase would probably indicate you’re pretty serious or you’ve got money to blow!
    2 - Enjoy this endeavor. If you don’t enjoy it, get out of the business. You probably should not have gotten into it.
    3 - There’s no room for discouragement. If you’re easily disappointed then prospecting is probably not for you.
    4 - Expect to work hard at it. Be patient. Patience is a virtue. You will put in time of no rewards, but when they come, it’s worth it all.
    5 - Don’t get greedy. If you hit it big, a few ounces here and there or bigger, consider it your much deserved reward.
    6 - Don’t mortgage the farm. Never, never do this! I’ve known miners to put all their eggs in one basket and they all cracked! Unless you like living in tents on the edge of town, never gamble with your stability.
    7 - Enjoy prospecting. Its one of the most fascinating occupations I can think of. What better way to enjoy the outdoors, splash around in cold water on hot days, explore old ghost towns, collect rocks, view big game, there are folks that would give their right arm to do this.
    A word of encouragement to those in search of gold: Practice patience, be optimistic. Always learn from your mistakes and always keep enough bug dope in your pack!
    by Ron Wendt 2005
    Note from Steve Herschbach - Ron was a dear friend who left this world too soon. He donated this article for use on the website not too long before his health finally failed. We all miss you Ron! R.I.P. Ron Wendt 1956 - 2007
    From the obituary:
    Ron Wendt was born April 24, 1956, in Fairbanks, in the Territory of Alaska. He was raised on his family’s homestead on Chena Hot Springs Road outside of Fairbanks and his father’s mining claims in the Circle gold fields. He developed an early interest in Alaska history by exploring ghost towns and mining camps and talking with old-timers from the gold rush era.
    Ron worked as a gold miner, newspaper reporter, photographer, college instructor, construction worker and custodian before starting his own publishing business, Goldstream Publications, in Wasilla. He wrote about gold rush history, modern day mining and prospecting, and many tales of Alaska. He was a member of the Alaska Miners Association, an avid baseball fan and loved to travel the roads of Alaska with his wife, Bonnie.

  • Steve Herschbach
    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.

  • Steve Herschbach
    The Minelab Equinox 800 was announced in 2017 and has really made an impression in the detecting world. Never before have so many features been packed into a lightweight metal detector at such a low cost. Key items include waterproof to 3 meters (about ten feet), genuine multifrequency operation, extremely fast recovery speed, built in wireless headphone capability, and the ability to run one of several different frequencies separately from the multifrequency mode. All this and more at the stunningly low announced price of $899.00.
    Visit the new Minelab Equinox Fan Club!
    This website tends to focus on metal detectors that have some sort of included gold prospecting capability. The Equinox 800 is of interest due to a dedicated prospecting (Gold) mode and it's ability to run at either 20 kHz or 40 kHz. The 40 kHz frequency in particular is clearly in the realm normally only available in detectors made specifically for gold prospecting.
    Minelab has actually released two Equinox models, the Equinox 800 (US$899) and the lower price (US$649) Equinox 600. Both have identical performance in the modes they share, but the Equinox 800 offers one extra mode (the Gold Mode) plus other advanced audio tuning features.

    Minelab Equinox Series Metal Detectors
    Minelab Equinox 600 basic features:
    3 Detect Modes (Park, Field, Beach)
    4 Frequency Options (5kHz, 10kHz, 15kHz, Multi)
    Wired Headphones Supplied
    Minelab Equinox 800 basic features:
    4 Detect Modes (Park, Field, Beach, Gold) 
    6 Frequency Options (5kHz, 10kHz, 15kHz, 20kHz, 40kHz, Multi)
    Bluetooth Headphones and WM 08 Wireless Module Supplied
    As can be seen the main difference is the Equinox 800 adds the ability to employ the 20 kHz and 40 kHz frequency settings separately that could enhance the ability of the detector to find very small items. These could be small jewelry items or small/thin silver hammered, cut coins, gold nuggets, or micro jewelry.
    Introducing Minelab 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.

    Minelab Multi-IQ Simultaneous Multi-Frequency Range
    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.

    Minelab Equinox 800 Controls Explained
    Note from Steve Herschbach - I have never seen a detector release that has come so close to matching up with my list of desired features. There are certain things I want in a genuine "do-it-all" metal detector. I like to hunt just about anything that can be found with a metal detector so when I think of multipurpose I really mean it. My desired detector would be waterproof and able to handle saltwater well, and that calls for multifrequency. Yet I want the detector to be hot on small gold, and that calls for a high single frequency mode. So far getting both multifrequency and a hot single frequency in a waterproof detector has not been possible. Now, in theory at least, I can use the same detector to surf detect on saltwater beaches and while looking for gold nuggets on dry land.
    Multifrequency also means highly accurate target id capability, but this has usually come at the cost of recovery speed. The Equinox promises recovery speeds as fast or faster than the competition. Long story short I have had to have multiple detectors for what I do as even todays so-called multipurpose detectors fall short in one way or another. The Minelab Equinox looks to truly be able to do it all and do it well, and as such represents a definite break with what has been available in the past, especially at the prices quoted.
    Official Minelab Equinox 800 Page
    Minelab Equinox Color Brochure
    Minelab Equinox Getting Started Guide
    Minelab Equinox Full Instruction Manual
    Equinox 600 vs Equinox 800
    Minelab Equinox Essential Information
    Forum Threads Tagged "minelab equinox"
    Minelab Equinox Forum
    Minelab Equinox 800 Technical Specifications* Internet Price $899.00 Technology Induction Balance (IB) Frequency 5, 10, 15, 20, 40 kHz plus Multifrequency Autotune Mode(s) Adjustable Detect Speed Ground Rejection Manual & Tracking Soil Adjust Four Tuned Modes (Park, Field, Beach, Gold) Discrimination Variable with Visual ID, Tone ID, Notch ID Volume Control Yes Threshold Control Yes Tone Adjust Yes - High Level Of Tone Controls Audio Boost No Frequency Offset Yes (Manual & Automatic) Pinpoint Mode Yes Audio Output 1/8" Headphone Socket, Speaker, APTX Bluetooth Wireless, Minelab WiStream (aptX LL Headphones Included) Hip Mount Shaft Mount Only Standard Search Coil(s) 11" Round DD Optional Search Coils 6" Round DD and 12" x 15" DD Battery Built In Li-Ion Rechargeable Operating Time  Up to 12 hours Weight 2.96 lbs Additional Technology Multi-IQ Technology, Screen Backlight, Minelab WiStream Low Latency Wireless Audio, Waterproof to 10 feet Notes Battery can be charged while in operation. The Equinox 800 comes with both APTX Bluetooth wireless headphones and the new Minelab WM08 WiStream low latency wireless module that may be used with any detector headphones *Notes on Technical Specifications - Detailed notes about the specifications listed in this chart.

  • Steve Herschbach
    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 / MXT 300 Instruction Manual
    White's MXT Pro Instruction Manual
    Forum Threads Tagged "whites mxt"
    White's Metal Detectors Forum
    Unofficial MXT User Support Page
    MXT Engineering Report
    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 Search 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.
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    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

  • Steve Herschbach
    The Nokta AU Gold Finder metal detector was introduced in 2016 and is still in production. The AU Gold Finder is a 56 kHz metal detector in a lightweight, weather resistant package. It fights the trend towards LCD display menu based control systems with a set of control knobs and switches.
    The Nokta AU Gold Finder is closely related to the sister company Makro Gold Racer in overall function and controls. The two detectors are so close that they can share the same search coils, and so much about how the Nokta AU Gold Finder operates and performs can be discovered by studying the information about the Gold Racer, which has been on the market longer. For all intents and purposes the Nokta AU Gold Finder is basically a Makro Gold Racer in a different housing.
    The Nokta AU Gold Finder reminds me of what a Gold Bug 3 might have been if Fisher had ever made one. Hot on tiny gold, variable disc, option to use ground tracking, ground grab, or manual ground balance - and more. There is a dual tone ferrous/non-ferrous mode, and a red LED (ferrous) green LED (non-ferrous) visual id system. The control box contains the batteries and is easily removed from the rod for belt mounting with the integrated belt loops. The Gold Finder runs off four AA batteries.


    Nokta AU Gold Finder prospecting detector
    This should really appeal to those who are not fond of all the digital menu nonsense and who prefer to flip a switch and tweak a knob. The Nokta AU Gold Finder with both 10" x 5.5" DD coil and 5" round DD coil (both with scuff covers).
    It is important to know that while Makro Gold Racer coils can be used with the Nokta AU Gold Finder, the coils for the Gold Racer do have shorter cables. They are fine for rod mount operation with the Gold Finder, but not really long enough for chest or hip mount setups. The two coils made for the Gold Finder have longer cables providing the extra amount needed for chest and hip mounting the detector control box.
    Official Nokta AU Gold Finder Page
    Nokta AU Gold Finder Color Brochure
    Nokta AU Gold Finder Instruction Manual
    Nokta Metal Detectors Forum
    Review by Kevin Hoagland
    Nokta AU Gold Finder Technical Specifications* Internet Price $799 Technology Induction Balance (IB) Frequency 56 kHz Autotune Mode(s) iSAT Intelligent Self Adjusting Threshold Ground Rejection Grab, Manual, & Tracking Soil Adjust No Discrimination LED Visual ID & Tone ID Volume Control Yes Threshold Control Yes Tone Adjust No Audio Boost Yes Frequency Offset No Pinpoint Mode Yes Audio Output 1/4" Headphone Socket & Speaker Hip Mount Yes Standard Search Coil(s) 10" x 5.5" DD, 5" round DD Optional Search Coils 5.5" x 10" concentric, 13.25" x 15.5 DD" Battery Four AA Operating Time 25 - 30 hours Weight 3.1 pounds Additional Technology iMask noise suppression technology Notes IP56 water and dust resistant. Compatible with Makro Gold Racer coils. *Notes on Technical Specifications - Detailed notes about the specifications listed in this chart.

  • Steve Herschbach
    The Minelab Gold Monster 1000 was introduced in 2017 and is still in production. The GM1000 was created as a relatively inexpensive, easy to operate, high performance metal detector. The Gold Monster 1000 is designed specifically for gold prospecting but may have applications such as micro jewelry detecting. At 45 kHz with both automatic ground tracking and automatic sensitivity settings, the Minelab Gold Monster 1000 is not only very sensitive to small gold but it is relatively easy for beginning detectorists to use.
    I am fortunate to have been involved in the testing of the new Minelab Gold Monster 1000 prior to its release. One benefit is that I have seen the questions that others have posed about the detector, and now I can answer a few of them.
    When I use new detectors I always have a goal in mind. I am not trying to pick the detector apart for what it cannot do. Instead, I believe most well designed detectors have something they excel at. My goal is to determine how to use a new detector for maximum benefit. The best way to make that happen is to use the detector in the way it was intended to be used, instead of trying to force it to be something it is not. The key is to be realistic. The Gold Monster 1000 is sold as an entry level single frequency metal detector. Expecting it to outperform detectors costing many times its price is unrealistic.
    Engineers face a very important choice when designing a single frequency metal detector, especially as regards gold prospecting. What frequency should the detector run at? That choice determines nearly everything else about the detector. In general, low frequencies below 20 kHz handle mineralized ground better, and offer good performance on larger gold nuggets. Higher frequencies over 20 kHz enhance the sensitivity to small gold nuggets, but unfortunately ground handling suffers.
    The number one question I see asked on the internet is how the Gold Monster stacks up as compared to this detector or that detector. Minelab has actually tried to answer that question directly via the following illustration:

    Minelab Gold Monster Frequency Range Compared
    The majority of the single frequency nugget detectors on the market today operate at or near 18 kHz. These detectors handle ground relatively well for non-PI detectors, and have good sensitivity on gram size and larger gold nuggets. They can detector smaller gold, but the smallest gold is not where they excel and the chart attempts to illustrate that. Other single frequency detectors running as high as 71 kHz have superb sensitivity to the smallest gold nuggets, but tend to suffer when it comes to depth on larger gold in highly mineralized ground. Again, the chart attempts to illustrate this fact.
    The Minelab Gold Monster 1000 engineers decided to concentrate on a frequency that offered the best attributes of the lower and higher frequency extremes. The goal was to design a machine that would attempt to acquire in a single pass the bulk of the gold that machines operating at either extreme could recover if operated together – and yet do it with just one detector operating as efficiently as possible.
    The catch is that the Gold Monster is still a single frequency detector and it cannot possibly capture 100% of the gold that two detectors operating separately at two vastly different frequencies can capture. If you study the illustration carefully, you will see there is still some gold the 18 kHz detector will do better on, and some gold the 71 kHz detector will do better on. Minelab is not claiming to be able to outperform every other detector under all other circumstances. The goal here is to capture as much of the obtainable gold as is possible with a single detector operating in the most efficient manner possible.

    Minelab Gold Monster 1000 nugget prospecting detector
    I have mentioned efficiency because there is more that goes into designing a gold prospecting detector than just the operating frequency. This is where Minelab is attempting to not only make a wise choice in the operating frequency, but to extend the efficiency of that frequency by optimizing the other parameters. First, electrical interference is detected and automatically rejected as much as possible when the detector is first turned on. This helps alleviate interference that could result in less than optimum performance.
    A great deal of effort has been made into designing a sensitivity control that offers the ability not only to manually tune the detector but to deliver excellent results automatically. The automatic operation is important in ground that varies dramatically from place to place in such a fashion that it becomes difficult – inefficient – to constantly be readjusting the machine manually to retain the best overall performance level. Novices in particular tend to set and forget the sensitivity, leading to a situation where the detector could be running better if the control were optimized more often.
    The crowning glory of the Minelab Gold Monster 1000 however is the automatic ground tracking system. The 45 kHz frequency is considered to be a high operating frequency, and as such it is subject to possible issues from highly mineralized ground and hot rocks. Manual tuning detectors can have great difficulty dealing with these problems… here is that word again… efficiently. The operator must be on top of and constantly adjusting the machine manually. It is very easy for the operator to be out of sync with the ground conditions and operating at less than optimum performance. At high frequencies having the proper ground balance is extremely critical.

    Manual ground balance versus automatic ground tracking
    I will admit I have always tended to distrust automatic ground tracking systems. The theory is they can track out good signals resulting in missed targets. The reality however is the risks entailed by not being properly ground balanced are even greater, especially for novices. The illustration below attempts to show what happens when the operator of a manually tuned detector falls out of sync with changing ground conditions, and then “catches up’ by retuning the machine. The automatic tracking or continuous ground balancing detector however maintains optimum conditions at all times.
    Even given this evidence in the past however I was a skeptic, and always preferred to manually adjust my detector ground balance controls. That is until I obtained first a Minelab SDC 2300 and then a GPZ 7000 detector. The SDC forced me to use automatic ground balance by offering no other option. A surprising thing happened – I liked it! It worked and it worked extremely well, so much so that when I got my GPZ 7000 it also remains in automatic ground balance mode.
    The fact is that Minelab has always been a leading developer of automatic ground balancing systems, and I do not think it is being unreasonable to state that they may have the very best ground tracking systems available. The company really has had no choice being based in Australia and developing machines for ground conditions considered to be among the worst in the world.
    Can the Minelab Gold Monster 1000 go up against the hottest high frequency detectors made and hold its own? Yes. I have personally used the Gold Monster with its 5” coil to easily find nuggets (flakes?) weighing under a grain. Not grams, grains - there are 480 grains per Troy ounce. Remember however that even Minelab in that first chart is telling you that a machine tuned specifically at a much higher frequency will have an edge on at least some tiny gold nuggets.

    Eleven small nuggets 14.9 grains total, largest 4.4 grains - Smallest at bottom 0.6 grain and 0.3 grain
    The difference and the serious advantage I believe with the Gold Monster 1000 is in the combination of the superior Minelab ground tracking system and the automatic sensitivity system, designed specifically for the GM1000. In all but the mildest ground operators will find that the Gold Monster is a much more efficient detector that allows more ground to be covered while keeping the machine tuned for the best performance possible. My advice to the old pros that get their hands on the GM1000 is that rather than try and force the machine into operating like your favorite manually tuned machine, seek out instead conditions where that machine struggles. Then trust in the Minelab automatic ground balancing system to compensate for and deliver superior performance under those conditions. Use manual more for targeting specific small areas.
    Case in point, I took the Gold Monster to a location where hot rocks had given my GPZ 7000 some difficulty. Much to my surprise the Monster was able to automatically compensate for and allow me to operate in those hot rocks and find a couple tiny nuggets too small for the GPZ 7000 to find. The machine was far smoother and I was able to cover ground far more efficiently with automatic ground balance. I followed this up with a visit to a location with wet alkali ground where a high frequency machine would normally fail. I struggled with manual sensitivity for a bit, then threw in the towel and went to the highest Auto+ sensitivity setting. The machine quieted right down and I found a nice little nugget shortly thereafter.

    Nugget embedded in lump of dirt
    If the ground allows you can certainly use manual ground balancing to get that hot edge on tiny gold nuggets. The Gold Monster 1000 lacks a standard threshold, but it is easy to set up a pseudo threshold by advancing the sensitivity to where the machine produces some light feedback from the ground. Those who like a threshold can run it this way – others may wish to back down just one notch for silent operation.
    Old timers like me rebel at the thought of running without a threshold but with the GM1000 it works. The normal reason for running a threshold is to be sure the detector does not fall out of proper ground balance. Here however you can put a superb automatic ground balance to work for you, eliminating that concern. For the very worst conditions, the automatic sensitivity system can augment the automatic ground tracking to allow for efficient ground coverage under conditions that will bring other detectors in this class to a crawl, if not a complete stop. Frankly, if you can’t get the Gold Monster to handle the ground, it is time for a Minelab PI detector or a GPZ 7000.
    To sum up, I do not want to leave you with the impression that the Gold Monster is the be all and end all of single frequency nugget detectors, and that it will under all circumstances get better performance on every single gold nugget than other single frequency detectors. That is not possible given the limitations imposed by having to choose a single operating frequency. I do believe however that the engineers at Minelab have come as close to this as is possible. The real secret to getting good results with the Minelab Gold Monster 1000 versus the competition will be in leveraging its superb ground handling capability to get the best overall gold nugget performance possible from a single frequency detector.
    ~ Steve Herschbach
    Copyright © 2017 Herschbach Enterprises
    Official Minelab Gold Monster 1000 Page
    Minelab GM1000 Color Product Brochure
    Gold Monster 1000 Getting Started Guide
    Forum Threads Tagged "minelab gold monster"
    Minelab Metal Detectors Forum
    Jonathan Porter On Mastering The Minelab Gold Monster
    Understanding The Sensitivity Control On The Gold Monster 1000
    Reports Of GM1000 5" Coil Touch Sensitivity
    My GM1000 Methodology - Manual Versus Auto Sensitivity
    Minelab Gold Monster 1000 Technical Specifications* Internet Price $799.00 Technology Induction Balance (IB) Transmit Frequency  45 kHz Autotune Mode(s) Pre-Set Slow Motion Ground Rejection Automatic Ground Tracking Soil Adjust No Discrimination Iron Reject Mode plus Visual Indicator Volume Control Yes 1 - 6 Threshold Control No Tone Adjust No Audio Boost Yes (Always On) Frequency Offset Yes - Automatic On Power Up Pinpoint Mode No Audio Output Speaker & 1/8" Headphone Socket - Headphones Included Hip Mount No Standard Search Coil(s) 10" x 5" elliptical DD & 5" round DD Optional Search Coils N/A Battery Li-Ion Rechargeable Included, 8 AA Optional Operating Time 20 Hours Weight 3.2 lbs. (with rechargeable battery and 10" coil) Additional Technology The GM1000 automatic sensitivity setting is a feature not seen before in prospecting detectors. Notes Unique rod mounting system allows use of broomstick or other items as a rod. *Notes on Technical Specifications - Detailed notes about the specifications listed in this chart.

  • Steve Herschbach
    The Fisher Gold Bug 2 was released in 1995 and is still in production over 20 years later. I had the first Gold Bug 2 in Alaska and to this day it is one of my all time favorite detectors - a true classic. Amazingly, nobody has come out with a better detector for hitting tiny gold after all these years. Quite a few models have tried to challenge the Gold Bug 2 on the tiniest gold, and while many can be said to give the "Bug" a run for its money it is debatable if any have really exceeded it. There is a specialized tool called the Falcon Gold Probe that will actually hit smaller gold than a Gold Bug 2, but it would be more properly termed a pinpointer than a normal metal detector.
    What makes the Gold Bug 2 special is the 71 kHz operating frequency. It was the highest operating frequency in a commonly available ground balancing metal detector for a long time. When paired with the 6" elliptical concentric search coil, the Gold Bug 2 easily detects small pieces of gold weighing less than 1/10th grain. There are 480 grains in an ounce so we are talking less than a 4800th of an ounce! I have a set of digital powder sales that weighs to 1/10th grain, and I regularly found single flakes of gold that will not register on the scale with the Gold Bug 2.
    Don't think such small gold is found at any depth. I get these tiny bits by literally scrubbing the small epoxy filled coil into the soil. The coil is tough and immune to false signals from being knocked around so the goal is to get that coil right down on the gold. The 6" epoxy filled concentric coil perfectly tuned to the Gold Bug 2 is no doubt part of the magic since other detectors in this class normally run DD coils. The Gold Bug 2 is a perfect detector for "scrape and detect" operations where the surface is carefully scraped away to expose more soil for detecting. It is also ideal for checking quartz for tiny gold, like when hunting around old mine dumps. The Gold Bug 2 will hit specimens with wire or sponge gold that other detectors cannot detect.
    There are only three coils for the Gold Bug 2, a 6.5" elliptical, 10" elliptical, and 14" elliptical. All three are concentric coils - there has never been a DD coil produced for the Gold Bug 2. I am a little surprised there have never been any aftermarket coils produced for the Gold Bug 2 due to its enduring popularity. I have always wanted a probe for it that would basically turn it into a Falcon Gold Probe type unit, but with more adjustment and iron discrimination. The coils are all waterproof and come with extra long seven foot cables for use when the control box is chest or hip mounted. The coils are among the best I have ever used and are immune to false signals from bumps and knocks.
    The chart below illustrates a common misperception. People often ask which coil gets the most depth, and it is assumed bigger coils go deeper. That is definitely not true. Coil size has to be matched to probable target size for best depth, and the chart clearly shows how running too large a coil can cause gold nuggets to be missed entirely. The normal 10" coil is a compromise but better depths can be obtained using not only larger coils but smaller coils. Since I normally hunted small gold with my Gold Bug 2 the small coil rarely came off it.

    Coil Size vs Depth Fisher Gold Bug 2
    Source - Field Testing the Gold Bug 2 by Gordon Zahara
    Despite the high operating frequency the Gold Bug 2 can be made to work in the worst ground conditions. I took one to Australia recently and was surprised how well it did in tough ironstone country. It has a very good iron discrimination setting intended for rejecting man made ferrous trash. This also acts as the setting of last resort for highly iron mineralized soils and hot rocks. When in iron discriminate mode common hot rocks will be ignored or at most pop and click, but they will not sound like gold. Some sensitivity is lost in iron disc mode, but the Gold Bug 2 is so sensitive to small gold it will still hit small nuggets in disc mode that other detectors would miss.
    The design is very compact and tough, and with what is getting rare these days, a removable control box. The box can be slid off the rod, and slipped on a belt with the integrated belt slots. There is plenty of extra cable, and a chest mount can easily be made with just a belt and a camera strap. This is ideal for working in deep water or heavy rain since the control box is protected and better yet creates a detector so light it can be used for very long hours with no arm strain at all.
    I usually have the Gold Bug 2 set at full volume and full sensitivity, with the mineralization switch set to low and audio boost engaged. I run this way until I can't due to hot rocks or ground, and then usually go to iron disc mode. However, if you do stay in all metal mode the proper way to deal with mineralization issues like hot rocks is to reduce the sensitivity, mineralization switch settings, or both. Disengaging the audio boost also moderates the responses generated by tough ground.
    Audio boost does just that - it boosts the audio so that faint signals are louder and more distinct. It also boosts spurious ground signals and so in some cases you may want to run the detector in Normal audio. I have found in practice I very rarely take the Gold Bug 2 out of audio boost mode.

    Fisher Gold Bug 2 nugget prospecting detector
    I should note here that the Gold Bug 2 employs VCO (voltage controlled oscillator) audio. Responses not only get louder but they increase in pitch ,producing very distinct "zippy" responses on non-ferrous targets. Large targets literally squeal. Some people think this means the Gold Bug 2 employs some sort of audio discrimination because they can tell a coin response from small trash responses due to this. All that is really happening is that strong signals sound different than weak signals, and so a deep coin will sound just like a shallower, smaller target.
    The mineralization switch adjusts the threshold auto tune rate, with the low setting being a slow auto tune and high being a very fast auto tune. This is similar to White's Variable Self Adjusting Threshold (V/SAT) control but instead of variable you get three preset selections to choose from. A fast auto tune setting dramatically impacts performance but can be an aid in very uneven ground conditions. Experiment with it to see what I mean but for me in most places it stays set in low. You can find more information on auto tune at Steve's Guide to Threshold Autotune, SAT & V/SAT. Fisher has gone this one better by also adjusting the gain (sensitivity) via these settings at the same time as the auto tune rate is adjusted. The Low Mineral setting not only slows down the auto tune rate but it boosts the gain above and beyond where the sensitivity control is set. The high mineral setting speeds up the auto tune rate and attenuates the gain.

    Fisher Gold Bug 2 control panel
    There is an undocumented trick that may or may not work on any particular Gold Bug 2 in iron disc mode. The threshold control usually has no effect when the unit is in iron disc mode. However, some units display a distinct difference in iron disc performance between the threshold being set low or being set high. This ability to "supercharge" a silent search disc mode by turning the threshold up is not unheard of in other detectors and it appears some Gold Bug 2 models have this ability. Several of us used this ability to good effect at Ganes Creek. The detector pops and clicks a lot when supercharged in this fashion but adds considerable depth on large gold nuggets. After awhile the popping and clicking is mentally tuned out as nuggets have a distinctly clearer beep.
    This ability may have been an accident on some units, as more recent Gold Bug 2 models display no change in the disc mode when the threshold control is manipulated. A simple air test between low and high threshold settings while in iron disc mode will reveal if your Gold Bug 2 has this ability to be supercharged.
    The iron discrimination on the Gold Bug 2 is unique compared to most detectors in that it is either on or off. There is no direct adjustment of the setting. In theory the Gold Bug 2 in iron discriminate mode rejects signals from ferrous man-made iron and steel targets plus many ferrous based hot rocks. It does this by simply ignoring and producing no signal on items deemed ferrous in nature. The setting is designed to be conservative, and so it does produce a signal on many ferrous items, but the audio response is choppy and more often a "click" than a "beep". Practice with a nugget and various ferrous targets will make the differences clear.
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    The more mineralized the ground, the more chance there is of gold nuggets being accidently rejected as ferrous. Borderline targets will often be rejected if swept one way and sound good if swept another way. It is therefore not a good idea to hunt directly in iron discriminate mode, as a bad call on the first sweep will cause you to miss the target and not even know it was there. It is better to hunt in all metal, then flip to iron disc to check the target. This can be an undue burden in thick trash though and sometimes it is simply more efficient to hunt directly in disc mode, but the likelihood of missing nuggets goes up dramatically.
    As noted above the threshold setting may have an effect on the responses generated in the iron disc mode. The sensitivity setting will also affect the setting, and by enhancing ferrous ground mineralization response it may also lead to more gold nuggets being identified as ferrous. the ground response overwhelms the nugget response leading to a false iron reading. Reducing sensitivity may produce more accurate iron disc readings in bad ground.
    If you are switching back and forth from all metal to iron disc mode constantly it can prematurely wear out the switch. I have seen several examples of the switch getting so loose as to be inoperable due to the nut on the backside of the control panel becoming loose or even falling off inside the control box. The control panel can be removed and the nut tightened if this is the case.
    I have found many thousands of gold nuggets with the Gold Bug 2. Granted most were small but not all. The largest I have found with the detector is a 4.95 ounce specimen at Ganes Creek, Alaska. I have numerous stories on Steve's Mining Journal that highlight the Gold Bug 2. See Detecting Small Gold at Crow Creek, Detecting Gold at Ganes Creek, Lode Gold at Hatcher Pass, Memorial Day at Ganes Creek, and Detecting Micro Nuggets at Crow Creek.
    The Gold Bug 2 is a very specialized detector usually used solely for gold nugget detecting. Recently people have taken note of its extreme sensitivity and have pressed it into service searching for very small jewelry items that others detectors normally miss. Simple post earrings and thin gold chains are difficult if not impossible to detect and the Gold Bug 2 excels at finding these small targets. Thomas Dankowski coined the term "micro-jewelry detecting" to describe this type metal detecting.
    The Gold Bug 2 does have limitations. The extreme sensitivity that makes it signal on hot rocks that other detectors would ignore. This can be very problematic in some locations, although somewhat offset by using the iron disc control in places where the hot rocks are iron based. More serious is that in highly mineralized ground the Gold Bug 2 has very poor depth on pennyweight and larger gold nuggets compared to most nugget detectors. The high frequency air tests very well but loses that depth quickly on in ground targets. Depth losses of 20-25% are not unusual with the Gold Bug 2 in highly mineralized ground when compared to detectors running in the 12-20 kHz range. The Gold Bug 2 is often best used when paired with another detector for depth on large gold while it serves as the small gold sniper.
    The Gold Bug 2 also gives a strong response on wet salt sand and so when used for micro-jewelry detecting on salt water beaches wet sand must be avoided. Despite these caveats, I consider the Gold Bug 2 to be a unique and essential detecting tool that even after 20 years is worth consideration by gold prospectors wanting the hottest metal detector possible on tiny gold.
    ~ Steve Herschbach
    Copyright © 2008 Herschbach Enterprises
    Official Fisher Gold Bug 2 Page
    Fisher Gold Bug 2 Instruction Manual
    Control Box Cover for Gold Bug 2
    Hip Mount / Chest Mount For Gold Bug 2
    Changes To GB2 Rod & Coil Design
    Forum Threads Tagged "fisher gold bug 2"
    First Texas (Fisher) Metal Detectors Forum
    Fisher Gold Bug 2 Technical Specifications* Internet Price $764.00 Technology Induction Balance (IB) Frequency 71 kHz Autotune Mode(s) Fast, Medium & Slow Autotune Rate Ground Rejection Manual - Course and Fine Tune Knobs Soil Adjust (High/Normal/Low) Three position switch Discrimination Iron Disc setting (On or Off) Volume Control One turn control Threshold Control One turn control Tone Adjust No Audio Boost Yes (On or Off) Frequency Offset No Pinpoint Mode No Audio Output 1/4" headphone socket & speaker Hip Mount Hip, chest, or shaft mount Standard Search Coil(s) Choice of 10" or 6" elliptical concentric Optional Search Coils 14" concentric accessory coil available Battery Two 9V Operating Time 25 - 35 hours Weight 2.9 pounds with 10" coil Additional Technology   Notes Extreme high frequency detector for sensitivity to the smallest gold. *Notes on Technical Specifications - Detailed notes about the specifications listed in this chart.

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