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Detector Prospector 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 White's Goldmaster 24K has just been announced for 2018 and will be available soon. The Goldmaster 24K is a White's GMT updated for the 21st century with advanced ground tracking technology and increased power.  XGB technology is a patent-pending automatic ground balance system. It is purpose-built for operating a high-frequency VLF gold nugget detector in the worst ground conditions. Traditional VLF detectors struggle to balance rapidly changing ground mineralization. Historically this has been where Pulse Induction machines fared much better.
    The White's GMK announcement is so new that there are sure to be changes and updates to this page very soon - all information and specifications are subject to change!
    With XGB technology, the Goldmaster 24k is able to track small changes in soil composition as well as longer-term shifts in both ground phase and strength. This allows it to operate in ground that traditional VLFs struggle in. Users have extended control over the range of XGB in the Goldmaster’s All-Metal mode. Simply enable Iron Cancel to expand the ground filter in moderate soils. In very challenging soil conditions, hold the Iron Cancel button and select the 2-bar setting for maximum performance in variable ground.

    White's Goldmaster 24K metal detector - new for 2018
    The new White's Goldmaster 24K also features a full backlit LCD target id screen and control suite. The potential target id is displayed on the screen whenever possible - the higher the number, the better the chance of a non-ferrous target. There is dual tone capability that reports a low tone for ferrous objects, and a high tone for all non-ferrous targets.
    White's Goldmaster 24K Features
    SENSITIVITY - Set the sensitivity at a level that does not result in false signals from the ground. Very strong ground may result in the symbol on screen and a loud sound - this means the sensitivity is too high. GROUND BALANCE - With the default setting, the detector will use XGB to automatically ground balance. Tap to lock the ground balance to the current setting. Tapping when the ground balance is locked will update the current ground setting to what is under the coil. GROUND SCAN - Hold to put the detector into Ground Scan mode. The top bar displays the ground strength and the two digit numbers display the ground type (phase). Useful for tracing paystreaks. IRON CANCEL - Tap to silence hot rocks, trash and mineral changes in both audio modes. Hold to select the Iron Cancel setting (1 bar is default). Note that this setting may decrease the detector’s sensitivity to very small gold, but is necessary in difficult ground conditions. VOLUME and THRESHOLD - Tap to adjust the volume with the up and down buttons. Hold to adjust the threshold with the up and down buttons (“th” displays on screen). Set these to a comfortable level for your hearing and preference. AUDIO MODE - With the displayed on screen, the detector is in “BEEP” audio mode (high tone = good target, low tone = bad target). The default setting (without on screen) is a traditional All-Metal audio mode with greater sensitivity to small targets. SAT - SAT can smooth out ground inconsistencies. Hold to adjust it (“Sa” displays on screen, 2 is the default setting). PINPOINT - Hold for non-motion pinpoint mode. In difficult ground this mode may be affected by mineralization. BACKLIGHT - Tap to enable the backlight (this reduces battery life). FREQUENCY SHIFT - Hold when turning the detector on to shift frequency (useful when there is EMI). Power off to save the selection. FACTORY RESET - Hold when turning the detector on to perform a factory reset. Not only does the new White's Goldmaster 24K features a new ground tracking system, but the gain has been boosted with an increase of voltage to the coil. From the Advanced Guide (link below):
    "When our engineers set out to build the GM24k, the goal was simple: improve the user’s chance to find gold without hurting their wallets. The obvious way to achieve this goal is increased sensitivity. The GM24k features a 54% increase in coil voltage over the GMT. You will see this in increased sensitivity to small nuggets. While testing this machine in Brazil, this was shown in a tiny, 0.4 grain crystalline nugget we found encased in quartz. In some cases this much power can be counter-productive if the ground is very challenging, so use it with caution! Even at lower gain settings the GM24k is an extremely “hot” machine on small gold and specimen nuggets."
    The new White's Goldmaster 24K comes with both rechargeable batteries and a holder for AA batteries. The GMK comes standard with the 6" x 10" DD search coil. The detector is also available with a two coil package - the 6" x 10" DD and a 6" round concentric.

    White's Goldmaster 24K display and controls
    Pre-sales will commence in August 2018 with general availability in September 2018.
    The White's Goldmaster 24K announcement is so new that there are sure to be changes and updates to this page very soon - all information and specifications are subject to change!
    White's Goldmaster 24K Quick Start Guide - preliminary
    White's Goldmaster 24K Advanced Guide - Preliminary, has inaccuracies (GMT references, etc.)
    White's Goldmaster 24K Technical Specifications* Internet Price MSRP $649.95 ($749.95 Dual Coil Package) Technology Induction Balance (IB) Frequency 48 kHz Autotune Mode(s) Variable Self Adjusting Threshold (V/SAT) Ground Rejection Tracking & Fixed w/Grab function, Ground Balance Offset Soil Adjust No Discrimination Visual & Audio Ferrous ID Volume Control Yes Threshold Control Yes Tone Adjust No Audio Boost No Frequency Offset Yes Pinpoint Mode Yes Audio Output 1/4" headphone socket & speaker (Headphones Included) Hip Mount Shaft Mount Only Standard Coil(s) 6" x 10" DD Coil standard; dual coil package with 6" concentric also available Optional Search Coils ??? Battery Rechargeable NiMH plus Eight AA Pack Included Operating Time 20 - 40 hours Weight 3.6 pounds Additional Technology XGB Ground Tracking Technology, Ground Scan mode for tracing black sand deposits Notes IP 54 Rain & Dust Resistant *Notes on Technical Specifications - Detailed notes about the specifications listed in this chart.

    White's Goldmaster 24K Standard Configuration

    White's Goldmaster 24K Export Configuration
  • Jim Hemmingway
    Benchtesting Rocks & Minerals with an F75 Metal Detector
    Introduction
    From the earliest time when we were aware of our surroundings, most of us looked for pretty rocks. We wondered what interesting or valuable minerals might possibly comprise them. Now as adult hobbyists, I doubt if any of us hasn’t benchtested an interesting rock from curiosity, and wondered what actually produced the signal. 
    Although a sensitive benchtest usually has little in common with how marginally conductive rocks and minerals respond to metal detectors in the field due to ground effects, we can learn and become familiar with how rocks and minerals in our respective areas respond to metal detectors in a benchtest. A sensitive metal detector’s electromagnetic field penetrates rocks, usually generating either a positive or a negative signal in response to whatever material is in the rock. We can sometimes determine whether such signals should be investigated further, or whether worthless iron minerals produced them. 
    I’d generally describe my benchtest results as worthwhile and informative, but that notwithstanding, I look forward to doing a benchtest because I think it is an intriguing study on its own merit. That said, how do you conduct a benchtest? I’ll describe my methods and hopefully we’ll see what you think about it.

    Benchtest Requirements and Techniques
    Benchtesting ideally requires a visually displayed, fully calibrated, manually adjustable ground balance that covers the entire (soil) mineral range from salt to ferrite. As a minimum, the detector should feature a threshold-based true motion all-metal mode, and preferably an additional true non-motion all-metal mode for significantly improved sensitivity to borderline samples. Visual displays in either of the true all-metal modes are essential for target ID, Fe3O4 magnetic susceptibility and GB readouts. 
    I prefer a small (concentric) coil to promote detector stability and improve sensitivity to the rock sample, to ensure uniform sample exposure to the coil, and to minimize EMI (electromagnetic interference) especially if benchtesting at home. Elevate the sensitivity control as high as possible while maintaining reasonable detector stability such that you can clearly hear changes to the threshold.
    To check for a target ID, move the sample back and forth across the coil at a distance that produces the best signal but does not overload the coil. To determine ground balance and Fe3O4 readouts, advance the sample toward the coil, back and forth to within an inch or two (depending on sample size and signal strength) of the coil’s electrical sweetspot. Ensure your hand does not come within detection range of the coil to avoid creating false signals. If you extend your fingers to hold the sample, this is not an issue when testing larger samples. If necessary use a plastic or wood food holder that can firmly grasp small samples.

    Benchtests should be conducted utilizing a minimum of two widely diverse GB control adjustments. Initially I prefer the same GB control adjustment that is typically required to keep my detector ground-balanced to the substrates in my prospecting areas. It’s a personal preference that works for me. That particular GB control point (F75 / GB86) is more likely to improve any rock or mineral sample’s signal strength compared to using a more reduced (more conductive) GB compensation point.
    The next step is to use a dramatically reduced GB control adjustment (F75 / GB45) as suggested by Fisher Research Engineering. This setting ensures that (obviously weathered) oxidized samples do not generate a positive signal from any type of non-conductive iron mineral inclusions, particularly maghemite mineralization that may be present within such rocks. It follows that this second benchtest will, if anything, slightly subtract from the sample signal strength, particularly with low grade and otherwise marginally conductive samples, compared to the first step of the benchtest at GB86. 
    As a general rule, I do not recommend the F75 / GB45 compensation point for benchtesting (non-oxidized) mafic samples that are dominated by constituents such as common magnetite or other black minerals that normally support highly (non-conductive) elevated GB readouts. Such samples can produce strong negative threshold responses at the reduced GB compensation point. It will be difficult or impossible for the signal from a marginally conductive substance to successfully compete with those negative threshold signals. For non-oxidized samples Fisher Research Engineering suggests using F75 / GB65 rather than the F75 / GB45 compensation point, since obvious iron mineral oxidation should visually be absent from such samples.
    With the above discussion in mind, extremely fine-grained, unweathered magnetite that occurs in pyroclastic material (for example volcanic ash) can drop into the GB45 range, but it is extremely rare. Unweathered volcanics do frequently drop into the GB70's due to submicron magnetite, but the recommended F75 / GB65 compensation point will eliminate those positive signals. 

    The arsenopyrite sample depicted above is a good example of a commonplace mineral that we encounter in the silverfields of northeastern Ontario. Generally field examples could be described as marginally conductive and many are low-grade. A good many react with only a mild positive signal, and sometimes not at all to a benchtest depending on which GB compensation point is used. 
    The high-grade, solidly structured sample above produces a strong positive signal in either zero discrimination or true motion all-metal mode with the ground balance control adjusted to the GB compensation point required for our moderately high mineralized soils. As noted, that’s approximately F75 / GB86, although in the field, of course, it varies somewhat depending on location and coil type / size employed. 
    The response is not as strong as a similar size and shape metalliferous sample would produce, but it does generate a surprisingly strong benchtest signal that would be readily detectable in the field. Even with the GB control dramatically reduced to more conductive values (F75 / GB45), to ensure that any positive signals produced by non-conductive iron mineral inclusions should now only produce a negative threshold signal, it is no surprise that this (non-oxidized) specimen continues to generate a strong signal. 

    For those readers unfamiliar with detector responses to such minerals, the same general response scenario described above with arsenopyrite applies to other marginally conductive minerals such as galena, pyrrhotite and to a lesser extent even iron pyrites. Ordinary iron pyrites is generally innocuous, but maghemitized pyrite, pyrrhotite, and the copper sulfide ores, particularly bornite and chalcocite, can be a real nuisance in the field due to magnetic susceptibility, magnetic viscosity, and / or electrical conductivity, just depending on what minerals are involved. 
    Such variable responses from arsenopyrite and many other mineral and metalliferous examples clearly infer that signal strength and potential target ID depends on a sample’s physical and chemical characteristics, including the quantity of material within a given rock. These factors include structure, size, shape, purity (overall grade), and magnetic susceptible strength of iron mineral inclusions. Moreover, the VLF detector’s sensitivity, the GB compensation points employed, the coil type and size, and the sample profile presented to the coil further influence benchtest target signal strength and / or potential target ID readouts. 
    Incidentally, neither of my PI units will respond to the arsenopyrite sample depicted above, even with a TDI Pro equipped with a small round 5” mono coil, the GB control turned off, and a 10 usec pulse delay to deliver its most sensitive detection capability. That result is typical of most, but certainly not all sulfides and arsenides that occur in my areas. Higher grade and solidly structured pyrrhotite, an unwelcome nuisance iron sulfide, and collectible niccolite, a nickel arsenide, are commonplace mineral occurrences here that do respond strongly to PI units, although their respective VLF target ID ranges are quite different. 
    As a related but slight diversion, the photo below depicts a handsome example of the widely occurring mineral sphalerite. It forms in both sedimentary beds, and in low temperature ore veins. It is interesting to collectors because it possesses a dodecahedral cleavage which means that it breaks smoothly in twelve directions, and it is usually triboluminescent, meaning that it gives off a flash of light when struck sharply. Like many desirable minerals lurking in prospecting country, unfortunately sphalerite doesn’t react to metal detectors. 

    A Final Word
    The foregoing is intended to illustrate that sensitive metal detectors can be utilized as a supplementary tool to assist with evaluating rocks and minerals. There is no question that the benchtest has serious limitations, particularly if trying to distinguish positive signals produced by some types of iron mineral inclusions from weak conductive signals. 
    That notwithstanding, a positive signal that persists below the F75 / GB45 compensation point cannot be confused with iron mineral negative threshold signals produced at that same compensation point. Therefore a positive signal merits further investigation. Such signals are almost certain to be generated by a marginally conductive mineral or a metalliferous substance. 
    On the more interpretive side of a benchtest, we need to point out that weak positive signals from lower-grade samples of minerals such as arsenopyrite, galena, pyrrhotite, chalcopyrite, and doubtless a few others, may disappear well before the GB control is reduced to the F75 / GB45 compensation point. We learn early that benchtests are frequently equivocal and require interpretation based on any further evidence that might support the benchtest result. Look for iron oxidation in addition to structural or other physical evidence as described above that could explain why a sample reacts as it does to a metal detector.
    Jim.
    This article was promoted to an article from a forum thread. Additional information may be found there in follow up posts.
  • Steve Herschbach
    Introducing the Makro Gold Kruzer metal detector, new for 2018. The Makro Gold Kruzer is available now from select dealers. The 61 kHz Gold Kruzer breaks new ground by being the lightest weight highest frequency waterproof detector on the market. Be sure and read the detailed review by Steve Herschbach at the bottom of this page below the specifications list.
    The Makro Gold Kruzer comes standard with an 10" x 5.5" concentric coil plus a 4" x 7.5" DD coil and has one optional coil available at launch. The Gold Kruzer has proprietary 2.4 Ghz wireless headphones included. The big announcement of note however is the very high 61 kHz operating frequency, making this one of the hottest machines available on tiny non-ferrous targets, and the only one waterproof to over 5 meters (16.4 feet).
    There are already a number of detectors on the market operating in the over 40 kHz region and the basics of this high frequency detection have been covered well for at least twenty years. In other words, if all a person wants is a detector running in a high frequency threshold based all metal mode, there are quite a few options to choose from.
    What makes the Gold Kruzer interesting is that as far as I can recall, nobody has made a detector before where the primary design intent is jewelry detecting. More to the point with the Gold Kruzer - detecting for micro jewelry. Micro jewelry has no exact definition but basically just means very small, hard to detect jewelry. Things like thin gold chains, or single post earrings. Most standard coin type detectors are weak on these sorts of small targets, if they can even detect them at all. Up until now people had to choose between coin detectors that have the features but are weak on micro jewelry targets, or use dedicated gold prospecting detectors hot on small targets, but very limited in features. What that usually means is little or no discrimination features.

    Makro Gold Kruzer for detecting jewelry, gold nuggets, and more
    Makro has gained attention as a company that listens to its customers. The new Gold Kruzer model is the perfect example of that, creating a unique machine based almost solely on feedback provided by customers in the last couple years. The Micro Mode on the new Gold Kruzer is a direct nod to those who want a detector for hunting micro jewelry and possibly even for gold prospecting, but who do not wish to give up the features available on most detectors today. In fact, Makro goes a step beyond, with the Gold Kruzer sporting features not included on many detectors today. These would include being waterproof to ten feet of more (16.4 feet with the Gold Kruzer), built in wireless headphone capability, and the ability to receive firmware updates via the internet.
    The result is a new detector with a unique feature set. There is literally no other detector made right now operating over 40 kHz that is fully submersible. Built in wireless and internet updates are frosting on the cake.
    Official Makro Gold Kruzer Page
    Makro Gold Kruzer Full Color Brochure
    Makro Gold Kruzer Instruction Manual
    Forum Threads Tagged "makro kruzer"
    Makro Metal Detectors Forum
    Makro Gold Kruzer Technical Specifications* Internet Price $749 Technology Induction Balance (IB) Frequency 61 kHz Autotune Mode(s) iSAT Intelligent Self Adjusting Threshold Ground Rejection Grab, Manual, & Tracking Soil Adjust Yes Discrimination Visual ID & Tone ID, Tone Break Adjustment Volume Control Yes Threshold Control Yes Tone Adjust Yes Audio Boost Yes Frequency Offset Yes Pinpoint Mode Yes Audio Output Speaker & Waterproof Headphone Socket Hip Mount Shaft Mount Only Standard Coil(s) 10" x 5.5" Concentric & 4" x 7.5" DD Optional Search Coils Yes Battery LiPo Rechargeable (optional external AA pack available) Operating Time Up to 19 hours Weight 3.0 pounds Additional Technology iMask noise suppression technology, backlit screen, save settings Notes Includes 2.4 Ghz wireless headphones, waterproof to 5 meters (16.4 feet) *Notes on Technical Specifications - Detailed notes about the specifications listed in this chart.
    Detailed Review Of Makro Gold Kruzer by Steve Herschbach
    I was asked to review a new gold detector in the fall of 2014 from a company I had never heard of before then – the FORS Gold by the Nokta company based in Istanbul, Turkey. I was pleasantly surprised to find the Nokta FORS Gold to be a very capable 15 kHz VLF detector that could serve well not just for nugget detecting, but almost any detecting tasks.
    The FORS Gold did have some odd design quirks, like the use of mechanical rocker switches instead of touch pads. I listed a few of these things, expecting that would just be the way it is. I was almost shocked when within a short period of time Nokta fixed or changed every item I had mentioned in my review as possibly needing improvement. This was unusual as normally once a machine has gone into production manufacturers are extremely resistant to design changes, especially changes in the physical design. It was a sign of what people have now found to be fact – that this company is serious about listening to their customers as a prime driver for product improvement.

    New Makro Gold Kruzer
    It was revealed that Nokta had a sister company called Makro, and the two officially combined forces shortly after I made my review. In other words, both Nokta and Makro now share the same ownership and management, but continue to be marketed separately under the two brand names. The detector models that each sell are unique, but there is an obvious sharing of the underlying technology between some models that the two brands sell.
    I had commented at the time that I would prefer a more standard configuration for a LCD based detector rather than the non-standard configuration as presented by the FORS Gold. By the fall of 2015 I was using the new Makro Gold Racer, which incorporated many ideas I had lobbied for over the years with detector manufacturers. I had been trying for some time to get somebody to create a metal detector that ran at nugget detecting type frequencies over 30 kHz but with a full target id system. It seems strange now but at that time nobody made such a detector.
    The Makro Gold Racer was quite unique in 2015 by offering a detector running at 56 kHz that also offered a full range LCD based target id system and dual tone based audio discrimination modes. This made it a detector useful not just for nugget detecting, but low conductor hunting in general for relics and jewelry. It is even a halfway decent coin detector for regular park type scenarios. The versatility and well thought out control scheme scored points with me, and I still have the Makro Gold Racer even after selling most of my other detectors.
    It seems that the moment the Makro Gold Racer hit the streets, that everyone else was working on similar ideas, as other detectors running over 30 kHz but with a full feature set started to appear on the market. High frequency detecting is suddenly in vogue for more than just gold nugget detecting.
    The one thing obvious now about the Makro / Nokta partnership is that they never sit still, but continue to work on and release new models at a pace that puts all the other manufacturers to shame. The companies are also big believers in seeking public feedback and then implementing the suggestions to create better products for their customers. This is readily apparent in the progression I have personally witnessed in going from that original Nokta FORS Gold to the new 61 kHz Makro Gold Kruzer just now hitting the market. In less than four years the company has gone from “catching up” to meeting or surpassing detectors made by other companies.
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    The Makro Gold Kruzer has a full suite of functions, is fully waterproof, incorporates built in wireless headphone capability, and can be firmware updated over the internet. That short feature list alone puts the Makro Gold Racer in a very select group of detectors offering those same 21st century “basic features” that were lacking in almost all detectors made in the last century.
    The Makro Gold Kruzer obviously builds on the Gold Racer feature set with the following key differences. The Gold Racer runs at 56 kHz and the Gold Kruzer at 61 kHz, one of the highest frequencies available in consumer metal detectors. This continues the focus on detecting small low conductor targets. The Gold Kruzer is waterproof to 5 meters (16.4 feet) whereas the Gold Racer is not waterproof at all. Finally, the Gold Kruzer adds a three tone hunt mode, taking things up another step from the dual tone modes available on the Gold Racer.
    Now let’s look at the Makro Gold Kruzer in detail. Makro switched things up in that the Gold Kruzer comes with two coils, a 5.5” x 10” concentric coil, and a 4” x 7.5” DD coil; both include scuff covers. The 5.5” x 10” concentric coil, which was an option offered for the Gold Racer, has been redesigned and cut from 1” thick to ¾” thick and the weight reduced to 384 grams (13.5 oz). The coil is hollow and therefore slightly buoyant, so the 25% reduction in thickness is quite welcome in reducing that buoyancy to where it is basically unnoticeable underwater.
    The little 4” x 7.5” DD coil is a solid epoxy filled coil which works extremely well in smaller coils where epoxy filling does not result in too much weight. The small DD coil weighs 368 grams or 13.0 oz. There is one accessory coil available at this time, a 5” x 9.5” epoxy filled DD. This coil weighs 14.3 oz or 404 grams. It should be noted that because of the frequency change and with the Gold Kruzer using waterproof connectors, that Makro Gold Racer coils will not work on the Gold Kruzer.
    Makro has also learned lessons as regards coil ear durability. The coil ears on the Gold Kruzer are about twice the mass of those on my older Makro Gold Racer. Taller, wider, and thicker – these extra beefy coil ears should all but eliminate breakage issues.

    4” x 7.5” DD coil showing beefed up ears
    The Makro Gold Kruzer employs a fairly standard “detector pod on an S rod” design forgoing the underarm battery box used on the Gold Racer. This confers a large advantage when it comes to waterproofing the detector in that only the pod has to be sealed. The change from AA batteries to a built in sealed LiPO rechargeable battery also aids in eliminating battery doors, which are always at risk of leaking.
    The three piece S rod itself is quite stout with no flex or wiggle. The cross hatch carbon fiber lower rod is not only strong, but lends an air of high tech quality to the look of the detector. The Gold Kruzer does not have the separate underarm battery compartment and in handle vibration mechanism featured on the Makro Gold Racer. This means the pod is totally self contained and can be removed from the handle assembly. This in turn allows for other rod options and the ability to break the detector completely down fitting in a small backpack or carry on bag.
    When the stout rod is combined with the beefed up coil construction you have a design that should survive those spills a person can take when working in the surf and there the detector ends up acting like a walking stick for support.
    It has been interesting to watch the company experiment with different handle designs. It is a thankless task because you never can please everyone. For me at least the handle / rod may be the best yet from Makro, with a molded hard rubber grip that will serve very well for a detector that may see underwater use. I personally found the Nokta Impact handle to be large for my hands and the smaller Gold Kruzer handle near perfect. Others may feel just the opposite so there you go.
    The arm cuff is a little different. It is narrower than some – good for me but maybe not so much for somebody with huge forearms. The adjustment is non-standard, with the arm cup sliding up and down the upper rod over a set of threaded holes. A small screw inserted into the top of the armrest and into one of these threaded holes secures the armrest in place.

    Kruzer upper rod showing cuff adjust holes and hand grip (control box removed)
    A unique feature on the Gold Kruzer is an optional external AA battery pack that can provide extra operating time in the field should the internal rechargeable battery go dead. The pack is designed to be held into the bottom of the detector armrest / stand by a separate plastic cover bracket that is held in place with two screws. I found the holes these screws go into will fill with sand if this bracket is left off, so I advise installing the bracket even if the external battery pack is not in use. The external battery pack with bracket is an option and so dummy screws or plugs should be installed to keep the screw holes clean and free of debris by those who down not have the bracket.
    I don’t think most people will ever need the external battery pack as long as the detector is regularly charged after use. It is a very nice touch however, especially for off grid use, as all you need is the external AA battery pack and a box of AA batteries to off grid for as long as the batteries will last. Some people may want the optional battery pack for travel into the field just in case the battery runs short on power in the middle of a hunt.
    The port where you attach the external battery pack also acts as a port to attach a USB style charger cable. The detector is charged using this cable by employing the included USB wall charger. You may also use most USB charging adapters and newer computer USB ports.
    The USB cable also allows the Makro Gold Kruzer to be attached to a computer so that updates can be made in case any bugs are found in the future. This update feature is very nice insurance that should be standard on all new detectors.
    Another item that should be standard on all new detectors is built in wireless headphone capability. Makro uses a proprietary low latency system that exhibits no discernible lag at all. A really nice thing about being proprietary is there is no pairing process. All you have to do is enable the wireless feature on the control box, turn on the headphones, and boom, you are in business. The downside is you only have one choice of headphones – the included Makro wireless headphones. These are a nice, light set of phones but they are just a bit too small to fit over most people ears. I have fairly small ears and they still rest on instead of over my ear. The sound quality is good, but like most wireless headphones they seem less “bright” than wired headphones. All in all the wireless headphones are quite good however and a pleasure to use.

    Makro wireless headphones
    The Makro Gold Kruzer does have a waterproof speaker with decent volume that can be used instead of the wireless headphones. If you prefer other headphone options, be sure and get the optional waterproof port to ¼” headphone adapter cable. This cable attaches to the same port used for charging and software updates and allows any wired headphones to be adapted to the Gold Kruzer.
    The LCD display is well laid out with a very large target id number displayed. The other setting indicators might be a little harder for those with poor eyesight to make out, but should present no issues once the layout is learned. One big change from the Gold Racer is that the four large navigation buttons, trigger switch, and rotary dial power / volume switch have all been replaced by ten small buttons on the control panel. All the buttons can be reached and controlled by the operators thumb, but the small size and closeness of the buttons may make for some navigation errors early on, and especially when trying to change settings underwater or with gloves on.

    Makro Gold Kruzer display and controls
    The Makro Gold Kruzer User Manual is available for download so I will refer you there for all the little details. What you have in the Makro Gold Kruzer is a hot 61 kHz metal detector waterproof to 5 meters (16.4 feet). The Gen (General) mode is a fairly standard VCO audio all metal gold nugget detecting circuit. The Gold Kruzer in Gen mode is very reminiscent of other hot gold nugget detectors running in the all metal prospecting mode.
    The Gen mode acts exactly like one would expect a threshold based all metal mode to function. There is a nice smooth threshold that gives feedback about the ground and reacts to hot rocks with classic nulling signals and small nuggets with that classic “zip-zip” VCO audio. Voltage Controlled Oscillator (VCO) audio increases both in volume and pitch when a target is detected, giving a distinct response very common on many gold detectors. The only thing different here is that since the Gold Kruzer has an LCD readout; you can get target id number results while running in all metal Gen mode. The audio is far more sensitive than the meter however, so do not be surprised if the deepest and smallest of targets give no target id information.
    In a break with the Gold Racer the Fast and Boost modes are not dual tone modes, but instead are silent search (no threshold) single tone modes. Items either signal audibly or not based on the current discrimination settings. The discrimination setting, like that of the Gold Racer, is a simple up and down control. Everything above the setting gives an audio signal of “beep”. Anything below the discrimination setting level is rejected or ignored with no sound at all. The Gold Kruzer has no notching capability i.e. the ability to pick and choose individual target id numbers for rejection.
    Fast mode is just what it sounds like – a fast setting for working in really dense trash. Target recovery speed has been increased at the expense of outright depth, but sheer depth is useless where target masking is the main problem. Boost mode is exactly the opposite. Boost is the deepest discrimination mode on the Gold Kruzer but due to the increased sensitivity is more suitable for less mineralized ground and sparser targets.
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    It should be obvious that the Makro Gold Kruzer is all about gold. This explains the shift from dual tone to monotone audio in the Fast and Boost. Dual tones as employed in the Makro Gold Kruzer can be problematic when hunting the smallest gold targets, especially in highly mineralized ground. It is hard for a detector to get a clean separation of ferrous and non-ferrous targets when the targets are very small.
    This is because the actual dividing line between ferrous and non-ferrous is not a line at all, but a zone. The Makro Gold Kruzer uses a fairly standard discrimination scale that ranges from 0 – 99. The range from 0 – 40 is considered to be the ferrous range, and 41 and above non-ferrous.
    Yet the discrimination default for both the Fast and Boost modes is 25. This is because if you bury small gold in highly mineralized ground or large gold extra deep in mineralized ground, the ferrous ground signal can overwhelm the very weak non-ferrous signal. It really is not about the object size. A deep large nugget is a very weak signal just the same as a shallower small nugget, and either can end up reading as a ferrous target.
    The solution is to lower the discrimination setting into the ferrous range and accept that you have to dig some ferrous items to get all the gold items. This actually applies to any metal detecting. If you dig absolutely no ferrous trash, you are almost 100% guaranteed to be passing up some non-ferrous items reading incorrectly as ferrous. This can be acceptable of course depending on what you are doing, but passing on a deep six ounce gold nugget because it reads ferrous can be an expensive mistake. The Gold Kruzer default discrimination setting for Fast and Boost is 25 instead of 40 for this very reason.
    Dual tones have issues for this same reason, with decisive results on the weakest targets difficult if not impossible to obtain. The difference is quite small, but monotone is slightly more stable and proficient at working with the tiniest and faintest of signals right at the dividing line between ferrous and non-ferrous, wherever you have set the control to tell the Gold Kruzer where that line is for your particular situation. There is no pat answer as the where to set the discrimination control. It is a judgment call based on experience, but when in doubt, use less discrimination and dig more trash. Welcome to gold detecting!

    Makro chart showing gold occurring in 0 – 40 ferrous range
    The Makro Gold Kruzer has a new control that relates to this overlap between ferrous and non-ferrous readings. The Extra Underground Depth (E.U.D.) control acts to directly impact the tipping point between ferrous and non-ferrous readings. The E.U.D. control only works in one of the three discrimination modes and when used on a suspect target that is reading ferrous may reveal by a different tone that it is actually non-ferrous. It is noted in the manual that it can reveal some targets misidentified as ferrous, but it will also give more false positives on ferrous targets.
    I was unable in the time allowed to figure out just how efficient this control is. In theory you can just set the discrimination lower, digging more ferrous but getting those missed non-ferrous items. Or set the discrimination a little higher, and now examine suspect targets individually by engaging the E.U.D. control momentarily. Finally, you can run E.U.D. on at all times. Is higher disc with E.U.D. on at all times going to get better results than just using a lower discrimination setting? Sadly, I just do not know at this time. I do know it is no magic bullet so the efficiency of employing the E.U.D. control will have to be determined over time by users around the world
    What? You say you wanted tones? Well, the Makro Gold Kruzer has you covered. The new Micro mode is a three tone mode similar to that on other company models, but running at that hot 61 khz. The 0 – 40 target id range produces a low tone. The 41 – 66 range produces a medium tone, and 67 – 99 range a high tone.
    Micro mode allows the “ferrous break point” to be adjusted. This is that magic point where you decide what is going to read as ferrous and what reads as non-ferrous. Note that unlike the Fast and Boost modes, the default ferrous breakpoint is set at 40 instead of 25. This is good for coin type detecting but again may be too high for other types of detecting. While in Micro mode you may use the Tone Break control to vary this all important setting. You could mimic the other two modes by setting the Tone Break at 25. Now 0 – 25 will be a low tone, 26 – 66 a medium tone, and 67 – 99 a high tone.
    Tone Break can only be used to set the ferrous breakpoint. The upper high tone region of 67 – 99 is preset and fixed by the factory with no adjustment possible.
    You may use the Ferrous Volume setting to control how loud the low tone response is. The medium and high tone responses are set with the main volume control.
    The discrimination control still functions in Micro mode, with a default setting of ten. Hot rocks and ground responses occur this low on the scale, and so having at least some of the low end blocked or rejected with reduce the number of low tone responses generated by the ground itself. The control can be set as high as you want and will override the other settings, blocking all targets below the desired target id setting.
    The Makro Gold Kruzer does have a tone control, but it does not allow the tones to be changed in Micro mode. Those are factory preset, with the Tone Break between ferrous and non-ferrous plus Ferrous Volume as the two adjustments you can make. The Tone setting allows the tone of the audio response and threshold to be changed in Gen, Fast, and Boost modes only.
    Micro was designed first for hunting micro jewelry. Micro jewelry is a loose term that applies to all very small jewelry items, like very thin chains, single post earrings, tie tacks, etc. Micro is perfect for hunting tot lots and beaches and focusing on the “gold range” targets represented by the mid tone reading in Micro mode. Many jewelry hunters consider digging coins a waste of time, and so ignoring high tones can save digging pocket change when the real goal is a woman’s diamond and platinum ring.
    The Makro Gold Kruzer has a nominal non-ferrous range of 41 – 99 which is a 59 point spread. Normal U.S. coin responses are 63 for a nickel, 83 for a zinc penny, 84 for a copper penny, 86 for a clad dime, and 91 for a clad quarter. The high 61 kHz operating frequency acts to push target id numbers higher and most coins will respond at 83 and higher. I was surprised a zinc penny and copper penny for all intents read the same.
    The good news is the low conductor range is expanded, which offers the ability to help discern different pull tabs and other trash items over a wider range. This in turn may help eliminate at least a few pesky trash items while hunting gold, although ignoring gold range items of any sort can be risky. Still, with a U.S. nickel reading at 63 and most women’s rings reading under the nickel, you get the 40 – 63 zone as a 23 point range where much of the most valuable jewelry will turn up. The default high tone breakpoint of 66 – 67 is clearly focusing the Gold Kruzer mid-tone on this very important gold range. Do note that large men’s rings and nearly all larger silver jewelry will read above 66 and therefore give a high tone reading.
    The Gold Kruzer has some obvious applications but there are a couple catches. First, it is running at 61 kHz, which means it is very hot on low conductors, but that it will have just adequate performance on high conductors like silver coins. Second, its extreme sensitivity to low conductors means it will not work well if at all in saltwater or on wet salt sand. Saltwater is a low conductor and will respond quite strongly on the Gold Kruzer, and getting it to not respond to saltwater gives up all the sensitivity to small gold. The Gold Kruzer will work very well around freshwater or on dry sand, it is not intended as a detector for use in or near saltwater. I would suggest the new Makro Multi Kruzer as an alternative to those who want to hunt in and around saltwater on a regular basis.

    Makro Gold Kruzer with optional 5” x 9.5” DD coil
    There are many features I could delve into but at over six pages this report is getting long, so I will again refer people to the User Manual for the details. Suffice it to say that the Makro Gold Kruzer has a full set of features like frequency shift for reducing interference, temporary audio boost for the Gen all metal mode, adjustable backlight, and the ability to save settings when the detector is powered down, and more.
    I got the Gold Kruzer prototype during a period when I was quite busy and the weather was not helping. I did have time to do a few tot lot hunts plus make a trip to the goldfields to evaluate the machine. The Gold Kruzer is well behaved in urban locations, with only a little static from electrical interference sources. I found the new Micro mode to be just the ticket for quickly blasting through a tot lot recovering prime gold range targets. I dug everything as is my practice when learning a detector, and ended up with the usual pile of aluminum foil, junk jewelry, and coins. Nothing special found but no doubt in my mind that the Gold Kruzer acts as intended in this type of setting.
    There were no surprises in the goldfields. At 61 kHz and in Gen mode the Gold Kruzer is a real pleasure to run, with all the response and nuance one expects from a great threshold based all metal circuit. Boost Mode also works very well as an alternative for small nugget detecting. I had no problem at all finding a couple little bits of gold weighing under a grain (480 grains per Troy ounce) on my first and only nugget hunt so far with the Gold Kruzer.

    Two tiny gold nuggets found with Makro Gold Kruzer
    To sum up, the new Makro Gold Kruzer once again ups the ante at Makro. It comes standard with two coils and is fully waterproof for about the same price as the Makro Gold Racer so I would have to assume the Gold Racers days are numbered. The one thing I am not sure about at this time is that the Gold Racer has a 15” x 13” DD coil option. The Makro Multi Kruzer has the 15” coil option, but no such accessory has yet been announced for the Gold Kruzer. This is probably not a concern for very many people, but it bears mentioning.
    I have no problem at all recommending that anyone interested in a detector with a focus on gold take a very serious look at the new Makro Gold Kruzer. It’s performance on low conductors of any type means that the Gold Kruzer is not just for prospectors and jewelry hunters but may also see favor with some relic hunters who focus of low conductor targets like buttons and bullets. This is a solid detector with 21st century features at a very attractive price.
    Makro Kruzer Color Brochure
    ~ Steve Herschbach
    Copyright © 2018 Herschbach Enterprises
  • Steve Herschbach
    There are a few key things to know about headphones for use with metal detectors. The most important thing is to know that some detectors operate in mono, and some in stereo. If you mismatch headphones you can end up with audio in one ear only, or none at all. In fact, this has happened to me. I took my White's DFX out to do a little detecting, and grabbed an old pair of Fisher Phones I had around, and when I got out I found the phones would not work on the DFX. So most detector phones have a stereo/mono switch, or are specially wired to work either way. Make sure your headphones match your detector for stereo or mono operation. But best case is to only use headphones that can do both so you can use them with any detector. You never know when they might get put to use on a different machine. In a situation where you are determined to use a mono headset on a stereo detector or vice-versa plug in adapters can be purchased at most electronics supply houses.
    99% of the detectors out there have a 1/4" headphone plug, but many generic headphones have a 1/8" plug. Sure, you can use an adapter, but it just adds a weak spot in the system. So get a 1/4" plug unless your detector is one of the rare 1/8" models. Again, pay attention to the mono versus stereo issue. The good news is that if you make a mistake there is almost always an adapter that will fix the problem but it is best to try and get the correct match.
    Does your detector have a volume control? Many do not. It is best to buy headphones that have their own volume controls, so you can use them with detectors that do not have a volume control. Again, you never know when you might switch detectors.
    Ohm matching can be important, and generally higher ohms is better. This is not always true however and some detectors do work better with lower ohm rated models. It is usually easy to determine what the headphone ohm is but almost impossible to know what the detector rating is. I therefore recommend that you should have your detector in hand and be trying the headphones before you buy them instead of going by specs on this point.
    Things to look for:
    1. How do they sound? Are targets sharp and clear to your ear? If not, you can now pass on this set and try another. Different headphones match up with different machine and different ears in such a way that nothing short of trying them can sort this point out. They either sound good to you personally, or they do not. It does not matter what your friend likes. Some detectors allow you to change the pitch from high to low. Try different pitches with your detector to see what sounds best. How do faint targets sound to your ear? People have different frequency responses, some like low tones and some high, and the type of speaker wired into the headphone can make this sound vary a lot. Get a set of headphones that make faint signals as clear as possible to your particular ear.
    2. Assuming they sound good, how adjustable is the volume? A good match will give you the ability to fine tune the sound with the volume control on the headphone. In other words, the volume control will have some range. If you have very high ohm headphones and use them on a high volume machine that has no volume control, the headphones may be so loud you have to set the volume on the headphone nearly off. And then tweak it within a fraction of a turn. Some headphones are too powerful for some detectors! The volume control should run from off at one end and too loud at the other, with lots of adjustment in between.
    3. How many volume controls are there? Some people like two, one for each ear. This can be great if you have poor hearing in one ear and need to compensate. I personally prefer a single control that works both ears at the same time, so I do not need to fiddle two controls. So this is a personal preference thing, but your headphones should have one or two headphone volume controls. A note on setting your headphones. Turn the detector volume all the way up, if it has a volume control. Turn your headphones all the way down, then turn on your machine and wave it over a large metal item. Turn the headphones up until the loudest sound you will get over a large item is not so loud as to damage your hearing. Now, set the threshold sound on your detector for a faint buzz. You should now be able to hear faint variations in the threshold, but going over a 55 gallon drum will not damage your hearing.

    Metal detector headphones showing 1/4" 90 degree jack, coiled cord, padded muffs, and dual volume controls
    4. How well do the phones exclude outside noises? Normally, get a set of headphones that will exclude outside noises like running water, wind in the trees, or anything else that might distract you from the detector sounds. Sometimes it may be advantageous to use phones that let you hear outside noises, like in bear or snake country. Or maybe in real hot climates bulky units get too warm. But from a pure detecting standpoint sound excluding headphones are best. Earbuds are perfectly acceptable however for quieter locations.
    5. How well do the headphones fit and feel? Imagine they are going to be on your head for 12 hours. Something that feels good initially can feel pretty bad in a few hours. Beware of headphones that are too tight or that have too little padding. I prefer phones that completely cover my ear and seal to the side of my head. I do not like the kind that squash my ear but people's preferences vary. Make sure your headphones are comfortable for long hours of use.
    6. How tough do the headphones appear to be? This can be hard to gauge sometimes, but in general avoid anything that looks to have cheap construction. The number one failure point is the cord, so make sure it is strong and well anchored so it cannot pull out. Headphones that feature a 90 degree plug are often desired to reduce strain and prevent the plug from pulling out due to a simple tug on the cord.Some top end models feature replaceable cords so you can carry a spare. I prefer to simply carry a complete spare set of headphones.
    7. Finally, be aware that the newest metal detectors are coming equipped with built in wireless headphone capability. Early versions have either been standard Bluetooth, which is too slow, or some faster proprietary method. Standard Bluetooth has a significant lag between detecting a target and the actual audio response heard in the headphone which is bothersome to most people. The problem with proprietary is that you are stuck with very limited options as to headphones. The best option currently for most people is aptX Low Latency (aptX LL) Bluetooth, which is fast enough that most people are satisfied with the speed, and options abound in the choice and style of headphones.
    To sum up, if buying headphones at Big Box Inc. at the least you'd probably want a set with a stereo/mono switch, 1/4" jack, and volume control/controls just to make sure it will work on most any detector. But remember that headphones are like tires for an expensive sports car. They are one of the only important items on a detector you can customize for optimum performance, the other being search coils. Finding the set of headphones that is just right for you can make a real difference in detecting success, so it deserves some effort in getting the right set. This is where a local dealer with a good selection who is willing to let you try them all out on your detector can really help you out.
    ~ Steve Herschbach
    Copyright © 2009 Herschbach Enterprises
  • 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
    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
    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 Forum!
    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.
    ads by Amazon...
    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 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 V3i was introduced in 2009 and is still in production. The V3i was originally released as the White's Spectra Vision or simply White's Vision. Due to a name conflict with another company the name was changed to White's Spectra V3. The original Vision and V3 models both suffered from software issues. Updates were issued and finally consolidated into the final White's Spectra V3i model which is still being manufactured today. All previous models can be updated to the latest V3i software by returning the detector to White's Electronics. Details here. This all leads to quite a bit of model confusion when buying used versions of these detector because it is not always clear if a model has been updated or not. The V3i was also later released in a feature limited model called the VX3.
    There are several things that make the White's V3i unique. One of the most obvious is the use of a very bright high contrast color screen, still ahead of its time compared to anything else on the market. The V3i takes screen customization to a level that quite frankly is unlikely to be exceeded in the near future if ever. There is a reason for that that I will explain shortly.
    The V3i was also one of the first metal detectors to incorporate a proprietary wireless headphone system designed to overcome the lag issues common in aftermarket solutions at the time. It was initially promised that the wireless system would also enable communication via a plug in dongle that would allow the V3i to be programmed via software on a PC. This ended up being one of the never realized disappointments of the White's V3i. The headphone system ended up working well enough after initial problems were ironed out but the proprietary nature of the system limits the choice of headphones to a single model.

    White's V3i multifrequency metal detector
    The V3i is the direct successor to the White's DFX, a dual frequency metal detector that could run at 3 kHz and 15 kHz, either separately or both at once. The V3i took this another step, by running at 2.5 kHz, 7.5 kHz, or 22.5 kHz, again either separately or all three at once. This is very unique on the market today. Most multifrequency detectors either let you selectively choose a single frequency to run at from several choices, or they run several frequencies at once. The V3i is unique in letting you do it either way.
    The V3i comes with a 10" round DD coil. One of the design goals was that is was to be able to use the coils already in existence for the White's DFX and MXT models, the so-called Eclipse series. The V3i did achieve this goal, but the ability to use a transmit boost function was generally limited to newer versions of those coils that are "V" rated. Coils that are not V rated may overload when transmit boost is employed. This is honestly a bit of a non-issue as there is little reason to ever employ transmit boost but it does seem to worry a lot of people that non-V rated coils might not be performing up to specs. White's coils are individually serial numbered, with the serial number stamped into on mounting ear of the coil. Serial numbers that start with "V" indicate the coil is V rated. Aftermarket coils would be especially suspect in this regard. For more information on Spectra coils some excellent information has been compiled here.

    D2 10" Round DD coil, 6" x 10" DD coil, and 4" x 6" DD "Shooter" coil
    The 10" round DD coil that comes with the V3i is a decent coil. The 6" x 10" Eclipse DD coil however is possibly the best all around prospecting coil for the V3i. The solid construction is less likely to hand up on stubble and the narrow profile is good for getting into tight locations. The 4" x 6" Shooter DD coil is great for trashy locations and small gold nuggets. 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.
    One aftermarket coil is worth mentioning, because it is one of the only reasons I own a White's V3i. A company called Applied Creativity made some coils marketed by famed White's dealer Jimmy Sierra. One of these coils was a 3" x 18" model with a special "figure 8" winding called the Bigfoot. This coil was actually made for the DFX and is an exceptionally light weight coil yet capable over covering large areas quickly and efficiently. The Bigfoot does not get a lot of depth, but for recovering shallower targets like recent coin drops and jewelry it is unmatched in performance. Unfortunately this coil is no longer made and used ones easily go for several hundred dollars if you are lucky enough to find one. Several types were made and not all will work on the V3i, only those made for the the MXT and DFX are compatible.

    Original White's Spectra Vision model from 2009 with Bigfoot Coil
    Compatible being a relative thing. The Bigfoot is not V rated and some will not work properly on the V3i. Almost any of them will exhibit highly skewed target id numbers in the 22.5 kHz range, but oddly enough this can be used to good effect for some jewelry detecting. The bottom line is I had a Big Foot for my DFX and kept it for use on my V3i. The Big Foot / V3i combo is my number one dry land jewelry detector. White's V3i - My Third Try.
    The White's V3i does have a 22.5 kHz Prospecting Mode and other features that in theory make it a proficient prospecting detector. The machine is hot on small gold in the 22.5 kHz mode. When the original Vision came out I did some bench tests on it versus the MXT sing a 0.7 grain test nugget (480 grains per Troy ounce). An MXT with a 4" x 6" Shooter coil at max Gain would barely signal on the nugget within 1/4" of the coil.
    The same Shooter coil was used on the Vision in Prospecting Mode (22.5 kHz only), with no tweaks except max RX Gain. The threshold a bit ratty but no worse than MXT at max Gain. The Vision got a good hit at 2" and whisper at 3". I then engaged the TX (transmit) Boost, raising voltage to the coil from 10V to 30V. I then got a good hit at 3" and whisper at 4". That is a 50% increase on a tiny nugget by engaging TX Boost. This is easily better than MXT performance and actually closer to what I'd expect from a GMT.
    This was an air test and ground conditions are unlikely to allow running at full gain with TX Boost engaged but it would work in milder ground. In fact Transmit Boost will work against you in bad ground and it also cuts battery life dramatically. Still, this test shows there can be benefits on small gold items in particular. Of interest also is that the test was done with an old coil from my MXT, proving that not all coils need to be V rated to work properly.

    0.7 Grain (480 grains per Troy Oz) Gold Test Nugget
    There have been some good gold nugget finds made with the V3i in the mild ground at Ganes Creek, Alaska. My friend Marko used the V3i there for at least two visits and reported to me that he thought the V3i was unexcelled at identifying deep ferrous junk versus gold nuggets in the relatively mild ground at Ganes Creek. He had quite a few ounces of gold to prove it! He used the stock Prospecting mode exclusively.
    The bottom line is that the V3i is first and foremost a detector designed for coin and jewelry detecting, and I would not recommend it specifically for somebody looking for a gold nugget prospecting detector. Other machines like White's own GMT or MXT can be had for half as much money that are far more practical as nugget detectors. However, if you do own a White's V3i, rest assured it can be used to find gold nuggets. It would in particular be useful in milder ground with copious amounts of ferrous trash where its advanced discrimination capabilities can be put to good use. In more mineralized ground the V3i the V3i may struggle however because it's ground balancing system is not up to tracking in bad ground and manual adjustments can be difficult to make due to the way the ground balance system is controlled. The tracking must be "locked" and the only manual adjustment that can be made from that point forward are small offsets to the locked setting. Don't worry about this for regular metal detecting - I am specifically talking about gold prospecting in highly mineralized ground. If the V3i has a weak spot this is it.
    ads by Amazon...
    I said earlier in this article that the V3i takes customization to a level unlikely to be exceeded now or in the future. The V3i is very much metal detector engineers dream detector, with direct access to many machine functions that are hidden in other detectors. This in theory allows the user to create almost any detector they want with the right degree of programming. What has been revealed in actual use however is that the number of functions and their interactions create layers of complexity that overwhelm most people. The V3i can be operated quite well with its factory preset programs and a bit of tweaking, but at the end of the day it represents feature overkill. It is a great detector for people who love to fiddle with the detector itself, but for most metal detecting the average users prefer something simpler that just gets the job done. The VX3 was a response to this by offering similar functionality in a more feature limited way. I think the V3i will be a high water mark when it comes to this type of feature overload and it is unlikely anyone will in the future try to outdo it, for the simple reason doing so is not the sure way to sales success.
    For me personally the V3i is one of the most capable jewelry detectors ever made, especially when coupled with the Bigfoot coil. The ability to customize both the screen and audio responses combined with expanded target VDI ranges on jewelry type targets at higher frequency ranges makes the White's V3i a jewelry hunters dream machine. That said, similar results can be had by people with simpler and less expensive detectors. The V3i is just a machine for the true detector nerd, and I have to say I guess that is what I am!
    Official White's V3i Page
    White's V3i Instruction Manual
    White's Advanced User's Guides
    White's V3i & VX3 Master Reset
    Selectable Frequency And Multiple Frequency
    Forum Threads Tagged "whites v3i"
    White's Metal Detector Forum
    White's Spectra V3i Technical Specifications* Internet Price V3i $1349.00     w/Wireless Phones $1555.00 Technology Induction Balance (IB) Frequency 2.5, 7.5, & 22.5 kHz, together or separately Autotune Mode(s) Varied Motion Settings Ground Rejection Tracking, Fixed & Manual Soil Adjust Beach Mode Discrimination Visual, Tone, Notch - Ultimate Customization Volume Control Yes Threshold Control Yes Tone Adjust Yes Audio Boost Yes Frequency Offset Yes Pinpoint Mode Yes Audio Output 1/4" headphone socket & speaker Hip Mount Shaft Mount Only Standard Coil(s) 10" Round DD Optional Search Coils Over 15 accessory coils available Battery Eight AA Operating Time 8 - 10 hours Weight 4.5 pounds Additional Technology Wireless headphones, exceptional color screen, ultimate in programmability Notes A machine for true "detector nerds"! *Notes on Technical Specifications - Detailed notes about the specifications listed in this chart.
    V3i example screens - click image for larger version

  • Steve Herschbach
    Resurrection Creek Gold Panning Area
    The second discovery of gold on the Kenai Peninsula was on Resurrection Creek in about 1888. The creek has produced an estimated 30,000 to 40,000 oz. of gold since 1895. Below Palmer Creek, Resurrection Creek flows through a 1,000 foot-wide alluvial flood plain. Creek gravels rest on a tan to yellow clay hard-pan with streaks of blue clay present. Bench gravels are exposed on both sides of the creek. Gold is disseminated throughout the gravel, but is concentrated on clay and bedrock.

    Resurrection Creek south of Anchorage on the Kenai Peninsula
    A half-mile stretch of Resurrection Creek lies within a withdrawal and is available for recreational gold panning. This area is a favorite site for recreational mining. Suction dredges (4-inch or smaller) are allowed from May 15 to July 15 with a free ADF&G permit and a ADEC permit ($25 annual fee). You can access this area via the Resurrection Creek Road out of Hope. The mining area begins at the Resurrection Pass Trail footbridge, 4.5 miles from Hope, and continues upstream for 0.5 miles to a patented (private land) claim (Forest Order No. 10-04-30-05-01). The claim boundary is marked with a gate.
    Fine gold can be panned from gravels all along the creek. Try for fine, flat gold near the campsite 0.25 mile above the footbridge and along the creek bank near the recreational mining information sign. Bedrock is exposed on the east canyon wall just above the campsite and just below the private lands. Both spots are good bets for gold. Rounded boulders piled along the creek are tailings from old hydraulic operations. Much of the road has been built on these tailings.

    Resurrection Creek Public Mining Site
     Here are a few simple rules and guidelines that all recreational gold panners must know:
    Recreational gold panning on the Chugach National Forest consists of the use of hand tools, panning, sluicing, and suction dredging with a 4-inch or smaller intake hose. You must follow all National Forest rules, such as camping limits, discharge of firearms, and use of trails. You can find regulations in Title 36 Code of Federal Regulations (CFR), with general prohibitions in part 261. Review these regulations before you go gold panning. You can find copies of these regulations on the Internet and at Chugach National Forest offices in Anchorage, Girdwood, Seward, and Moose Pass. You can use gold pans and hand tools-fed sluice boxes year round in the streams listed in this booklet. No hydraulic mining or use of earth-moving equipment is allowed. Work only the active stream channel or unvegetated gravel bars. Do not dig in stream banks! You are not allowed to build structures, cut trees or dig up archaeological, historical, or paleontological objects, nor are you allowed to obstruct others in their recreational pursuits. If you find those objects, please report them to the Chugach National Forest. Suction dredges (4-inch nozzles or smaller) are permitted from May 15 to July 15 only. Remember that permits are required. The Kenai Peninsula is home to brown and black bears. Stay alert and avoid bears whenever possible. For more information, get Bear Facts from the U.S. Forest Service or Alaska Public Lands Information Centers. The water is cold and you can expect to get wet— after all, the gold is in the water. Wear insulated waterproof boots and gloves. Wool clothing can keep you warm even when wet. Bring extra clothing and dress in layers. Keep Alaska green, do not trash or litter. Many places have a $1,000 fine for littering. Follow Leave No Trace principles. Good luck and good prospecting!
    Resurrection Creek, Alaska in 2014

    Most of the information above was derived from GOLD PANNING, Guide to Recreational Gold Panning on the Kenai Peninsula, Chugach National Forest, Alaska (2018) found here - See the full text for more information and details.
  • 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.
    July 2018 - Deus Version 5 Software announced and new X35 search coils announced.
    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
    July 2018 - Deus Version 5 Software announced and new X35 search coils announced.
    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 Coil(s) 9" round DD or 11" round 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
    What is metal detector “autotune” or automatic tuning? Not automatic ground balancing or automatic ground tracking. Autotune is something so common now it is taken for granted, but it is a key feature when considering how detectors work, especially those designed to work with a faint threshold sound, like most nugget detectors.
    Prior to the 1980's most detectors had to be ''tuned''. You held them at a fixed height over the ground and manipulated a ''tuner'' until you got a bare threshold sound. A very faint sound you could barely hear. An increase in this sound meant you had a target. You could hold the detector over the target when you found it, and the increase in sound held steady. When the detector was moved off the target, the sound went away. No motion was required to get a signal, and so this mode of detecting is referred to as the ''non-motion mode''.
    There were two problems. First, the detectors of that day ''drifted''. The faint sound you set would either get louder or fainter. As the machines adjusted to temperature differences, or as the batteries ran down, the threshold changed. It did so rather rapidly, and so you constantly had to adjust the faint threshold setting manually to keep it on that vital edge.
    Also, the machines of the day could not ground balance. So if you raised the coil you got a false signal. If you lowered it the detector ''detuned'' and the threshold went away. Faint targets were lost. This was mostly an issue with small depressions in the ground. If you had the detector tuned to a fine edge, going over even the slightest depression gave a false positive signal. What I did myself was hold the detector an inch over the ground, tune it, and then lower it to the ground. This slightly detuned the detector and gave up the fine edge, but eliminated false signals from small depressions in the ground.

    Early 1970s "Mineral - Metal" ttuner control
    The first solution to this issue was push-button retune. If the faint threshold you had set got too loud or went away for any reason you just pushed a button, and you went right back to the original threshold setting. It was a great advance in its day, as pushing a button was much easier than turning a knob to get back the correct threshold. The detector “remembered” where you set the threshold, and a push of the button instantly returned it to where you had previously set it. This also made for better pinpointing of targets, as you could get close to the target, hit the button to detune the detector, and then zero in on the sharpest signal. Some detectors today still feature this form of ''non-motion pinpointing''.
    The next advance was electronic. The detector took note of the threshold you set, and circuits attempted to maintain the same threshold level. Since the original idea was to ''tune'' your detector, autotune was born. The detector automatically tuned the threshold. But a side effect was that if you held the detector steady over a target it was ''tuned out'', as the machine sought to return to the ideal threshold level. You had to keep the coil moving over the target to hear it, and so the “motion mode” was born.
    The original Gold Bug is the best example of all this. If set in the ''non-motion'' mode you can hold the detector over a target and get a louder sound that does not fade away. The closer you are to the target, the louder the sound. Great for pinpointing. But if you set the Gold Bug in this mode, it drifts. The threshold sound tends to get louder and louder. A button is provided to retune the Gold Bug to the original threshold sound. You must hit it about once a minute.
    The Gold Bug also has an ''autotune'' mode. This is the mode you would normally use. The detector now reads the threshold setting and keeps it steady. The side effect is that if a target is held steady under the coil, it is ''tuned out'' rapidly. The coil must be kept in motion over the target to get a signal, otherwise the autotune circuitry adjusts it out. It does not matter what causes the threshold to vary. The circuitry just attempts to keep it steady. Nothing is being tuned other than the threshold sound.

    Fisher Gold Bug controls, with autotune in lower left
    Various detectors were introduced with this feature. What varied was the rate at which they retuned. A slow retune meant that the detector would not adjust as rapidly to variations in the threshold sound. The slow retune had less of a tendency to ''tune out'' small targets or very deep targets. A fast retune was more forgiving of variations in the way the detector was operated, in particular as regarding the distance of the coil over the ground and false signals, but is more prone to tuning out very small or very deep targets. Whatever retune rate is chosen, it is a compromise. And what works well in one location does not work so well in another.
    When nugget detecting became popular a new variable was introduced. Ground mineralization, and more importantly, variations in ground mineralization, was something coin hunters rarely had to deal with. It was something a nugget hunter commonly encountered.
    Detectors at this time developed the ability to ground balance, or adjust out the ground effect that caused early detectors to give a false signal if the distance over the ground varied. Depth of detection dramatically increased. The ground balance control initially was a manual control, and so could be set for a certain ground condition. Any change in the ground mineralization tended to produce false signals.
    Autotune once again came to the rescue, as evidenced by its use in the original Gold Bug model. Units with a slow autotune had fewer tendencies to tune out small gold nuggets, or very deep gold nuggets. The downside is they had to be operated very slowly to allow the autotune to keep up with ground variations. Units with a fast autotune could handle variations in the ground conditions better, but had more of a tendency to tune out small or deep targets. Overall depth was usually decreased with faster autotuning but ease of operation increased.
    Another split in the technology came along. Many detectors, especially coin detectors, opted for a “silent search” mode. This mode eliminates the threshold sound entirely, very much like taking a detector with a threshold control and turning the threshold down until it cannot be heard. This makes for a quiet machine and became the preferred mode for many coin detectors. But it gives up a fine edge and so top performing units continued to offer a threshold control. Detectors that are silent search units do not need an autotune circuit.
    You can test a detectors autotune rate on detectors that have a threshold setting by holding a coin under the coil, and noting how fast the threshold adjusts back to its original level. This can vary from a couple seconds to almost an almost instant adjustment.
    An interesting side effect of autotune is ''overshoot''. If the detector is swept to one side and encounters a target, it attempts to ''tune into'' the target. If the target is a ''positive'' target, in other words the threshold increases, then the autotune circuitry immediately reads the increase and attempts to adjust lower. As the coil passes the target, there is a brief moment of silence as the autotune now has to turn around and increase the threshold back to its original level.
    In practice, you normally do not hear this. You hear the increase in tone, but not the decrease that follows. The target goes ''beep-beep'' as you swing back and forth over it. The ''beep'' is centered over the target. Move the coin back and forth under the coil and you will hear the sound. Now hold the coin under the coil until the threshold steadies, then remove the coin. The machine will go silent for a short period, again depending on how fast the autotune circuit is.
    However, if the target is an iron mineralized rock, most commonly a rock with a high magnetite content, then the threshold ''detunes''. The threshold is reduced and goes silent. So as you pass over the hot rock the threshold sound goes silent. The autotune circuit attempts to adjust by raising the threshold sound. But at this point you have passed over the ''negative'' target. A distinctive ''boing'' sound results since the threshold sound is now too high, and the autotune immediately attempts to adjust back down. The ''boing'' sounds occur to each side of the target as you sweep back and forth over it. The quiet spot, or ''null'' at the point between the opposing boings indicates the actual location of the target.
    To reiterate, autotune creates two types of signals. A beep-beep signal with the beep centered as the coil sweeps over it in both directions. Or a boing-boing signal, with the apparent target dancing back and forth as the coil sweeps over it. The null between the two boings is the actual location of the target, usually a hot rock.
    When White's introduced the Goldmaster V/SAT it featured "Variable Self Adjusting Threshold" or V/SAT. Self Adjusting Threshold is White's term for autotune. It is a more appropriate term as it explains what is really happening. People tend to confuse autotune with automatic ground balance. Unfortunately, White's fondness for acronyms is such that most people do not know what SAT or V/SAT stands for. The latest acronym is iSAT by Nokta/Makro for "Intelligent Self Adjusting Threshold".

    White's GMT Variable SAT Control
    The Goldmasters are the only nugget detectors that allow you to vary the rate at which the threshold readjusts itself via a knob - anything from very fast to very slow. This allows for more control in varying situations. In general, use the lowest SAT setting that allows for smooth operation. As ground variations increase, setting a higher self adjusting threshold can be beneficial. At low settings, the coil can be swept slower. High settings demand a faster sweep rate.
    The Gold Bug 2 has a “High”, “Normal”, and “Low” mineral modes. These are actually three preset autotune adjustments, with Low being the slow autotune and High being the fastest. Normal of course is in the middle.
    With the vast majority of the nugget detectors you have no ability to vary the autotune rate. A few programmable coin detectors offer the adjustment but usually relate it more to sweep speed so the detectors can be set for a slow sweep speed or a fast sweep speed.
    To sum up, it is very important to know how fast your detector is autotuning. If it has a fast autotune and you move the coil too slowly, you will lose very small and very deep targets as the machine tunes out the faint signal before you hear it. Conversely, if your detector has a very slow autotune rate (rare these days, but common on old detectors like the Compass Gold Scanners) then moving the coil too quickly will also cause very small or very deep targets to be lost.
    The best way to observe this is to bury a target, and sweep the coil over it. Go real slow, go real fast, and try something in between. You will find a certain speed will produce the loudest and sharpest signal. Going much faster or much slower will muffle the target. Detector engineers try to shoot for a normal sweep speed, and newer detectors are much more forgiving than older units. But sweep speed does impact the performance on many detectors. One thing that sets the pro apart from the novice is that the pro keeps the coil moving at the optimum rate that produces the best signal. When autotune is combined with auto ground tracking, this awareness of optimum sweep speed is even more critical.
    As a rule single frequency machine can handle faster sweep speeds. Multi-frequency and pulse induction (PI) detectors benefit from slower sweep speeds. People used to one type of detector often have a hard time adjusting. It is very common for operators of single frequency fast sweep detectors to swing PI detectors far faster than they should, resulting in significant lost performance. Do not be one of those people. Experiment with your detector to find the optimum sweep speed, and in the case of the few machines that allow for adjustments, experiment to see how slower and faster settings affect the performance. It can make all the difference between finding that gold nugget and missing it.
    ~ Steve Herschbach
    Copyright © 2010 Herschbach Enterprises
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