The Minelab GPX 4500 detector was released in the spring of 2008, and discontinued in 2020. The Minelab series of pulse induction (PI) metal detectors starting with the SD 2000 are widely acknowledged as being some of the most powerful gold nugget prospecting detectors currently available. The GPX 5000 is the latest and most refined in the series but the GPX 4500 is only just a step behind it in features and performance. See Steve's Guide to Differences of Minelab SD, GP, & GPX for details.

The GPX 4500 created a page in gold rush history by being singled out as the detector of choice in Africa for some time. Many large nugget finds were made there with the new GPX 4500 and starting around 2009 demand far exceeded supply as African prospectors were willing to pay any price to get what they believed was the only detector capable of possibly making them rich. Buyers in the U.S. drove prices far over retail due to extreme demand and these units were resold in Africa for prices well exceeding $10,000 per machine. This amazing demand was almost single-handedly responsible for driving Minelab sales and stock prices to all time highs.

When the GPX 4800 and GPX 5000 were introduced Minelab stopped selling the GPX 4500 in the U.S. and Australia but demand was such that it continued to be sold in Africa. Finally, in 2015 the GPX 4500 was reintroduced for sale again in those countries as an entry level pulse induction model (for Minelab) priced at less than half what the GPX 5000 sells for. This makes the GPX 4500 an exceptional value at this time.

Minelab GPX 4500 Pulse Induction (PI) metal detector for gold prospecting and more

I got my own GPX 4500 in 2008 and saw many others in use at my old mine at Moore Creek, Alaska. The GPX 4500 made the ground light up like it had never been hunted with many nuggets found in already detected locations. Here is my report at the time about what I observed at Moore Creek:

"I have run a little pay-to-mine operation at Moore Creek for four years now. We have old tailing piles that have nuggets in them. Some piles produced quite a few nuggets, and so everyone and their brother has been over them hoping for just one more. For instance, Dean's Hill. Dean found a 6.54 oz nugget a mile below camp on a pile. Rich Lampright found I think about 6 more ounces of smaller specimens on the same pile. Anyway, well over a pound came off this one pile.

Now, these piles are small hills. You might be talking 300 feet long by 100 feet wide by 40 feet tall. Big but not something a person can't cover every square inch of. There have been probably 50 people hunt Dean's Hill using everything from the SD2200 on up to the GP3500 and probably a GPX-4000 or two last summer. There are other hills with similar reputations, including Bud's Island right near camp. Over 100 people have hunted it since it is so near camp.

So the guys show up this year with the GPX-4500. A determination was made almost immediately that all ground should be treated as virgin again, and sure enough nuggets started coming out of Dean's Hill and Bud's Island and other places that were well and truly "hunted out". It was simply way too many nuggets to chalk up to anything other than the GPX-4500 being able to hear nuggets previous units could not hear at Moore Creek.

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I attribute this to two things. Previous SD/GP units had a tendency to sound very faintly on hot rocks at Moore Creek. So you got to where you usually ignored those sounds as they were almost always rocks and listened for something just enough different to indicate a real target. It is possible with the GPX to completely and absolutely tune out those faint hot rocks, allowing whisper faint nuggets to be detected. They might not actually be deeper per se, it is just that you could not discern them before. Same difference as far as I'm concerned.

Plus, with the Gain and extra timings you can crank the GPX up for some insane performance. Steve F got his biggy by running the GPX up to the point where the ground was super noisy. You'd not normally hunt that way but he was focused on one spot, and it did allow him to get an exceptionally deep target.

The bottom line is I am absolutely convinced the GPX is doing stuff that could not be done before. It was too many people getting too many nuggets out of too many hard hit spots to be anything else. There is no doubt in my mind that money spent on a GPX-4500 is money well spent. Remember, though, it can't make the gold. We had a couple GPX users who simply could not seem to get over nuggets.

Anyway, hopefully Rob and Glenn and Steve and other Moore Creek visitors will chime in here with some of the settings they were using at Moore Creek to help little old me out. I am headed back up to Moore Creek August 8th to prep ground for next season but plan on firing my new GPX up for the first time finally. I gave away everything I found in June so it would be nice to have at least one nugget to call my own this summer!! Any tips would be most welcome.

Steve Herschbach
Moore Creek Mining LLC
July 25, 2008"

Gold found with Minelab GPX 4500 at Moore Creek, Alaska in 2008 - largest nugget 3.5 ounces

The was a period of time after the GPX 4500 was discontinued in the United States that the GPX 4800 and GPX 5000 were the only two PI models available from Minelab. Garrett introduced their new Garrett ATX at less than half the price of those detectors. It was a bargain at $2120 compared to almost $6000 for the GPX 5000. I do not know this for a fact but I believe that Garrett had something to do with the GPX 4500 being reintroduced for sale. The GPX 4500 at $2699 with two coils was close enough to the $2120 ATX with one coil, that it pretty much stopped the ATX dead in its tracks as a prospecting detector. Up until that point I had been recommending the Garrett ATX as a bang-for-the-buck alternative to the much higher priced GPX uits. Given the extra power and versatility of the GPX 4500 at the new lower price, and the GPX 4500 is now my recommendation for anyone wanting a "bang-for-the-buck" new full warranty high power PI for gold prospecting and possibly even beach or relic detecting.

Official Minelab GPX 4500 Page

Minelab GPX 4500 Instruction Manual

Minelab GPX 4500 Product Brochure

Minelab GPX 4000-5000 Timings Charts

Difference Between Minelab SD, GP, and GPX Models

Forum Threads Tagged "minelab gpx"

Minelab Metal Detectors Forum

*Notes on Technical Specifications - Detailed notes about the specifications listed in this chart.

The Garrett ATX was introduced by Garrett Electronics in 2013 and is still in production. It is a pulse induction metal detector waterproof to ten feet. It is unique in that it is one of the few metal detectors retailed to the general public in a housing developed for military applications. Garrett makes a military land mine detector called the Recon Pro AML-1000. It was developed and marketed after the Garrett Infinium, the only underwater ground balancing pulse induction (GBPI) metal detector made by a major manufacturer at the time. The Recon is notable for the waterproof telescoping compact design with hidden coil cables. The new ATX is a highly refined detector combining the best of the Garrett Infinium and Garrett Recon AML-1000 into a single package. The actual housing is almost identical to that used by the AML-1000. The electronics has attributes from both detectors. It is a considerable improvement over the much older Infinium electronically and folds into a remarkably small package without disassembly.

I was one of the first individuals to obtain a Garrett ATX when they came out as I had been waiting for a new waterproof ground balancing pulse induction metal detector ever since the Infinium came out over ten years ago. I honestly was a bit surprised Garrett came out with a second generation waterproof GBPI before the competition has released any at all. Ground balancing PI detectors have the ability to work in a combination of salt water and black sand/hot rock environments in unique ways. VLF and even standard non-ground balancing PI detectors suffer under these extreme conditions. The Infinium showed me what might be possible in Hawaii but it suffered from issues common in first generation detectors. There was room for improvement, and I am hoping the ATX addresses the electromagnetic interference (EMI) and salt water instability problems that plagued the Infinium.

My first impressions were positive, with my first detailed report at Gold and Silver with the New Garrett ATX. I have a separate article on prospecting with the ATX at Gold Nugget Detecting with the Garrett ATX. The ATX is a versatile detector and will see use prospecting, relic hunting, jewelry detecting (above water and under) and even coin detecting. I have two beach detecting articles on the ATX - Beach Detecting in Hawaii With The ATX and Garrett ATX Return To Hawaii.

Garrett ATX waterproof pulse induction (PI) metal detector with 10" x 12" coil

The Garrett ATX is uniquely versatile in its physical aspects. It can be extended longer than most people need yet can collapse into a very short diver configuration due to the three piece lower rod design.

Garrett ATX collapsed for diving use

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

Garrett ATX folded for storage or backpacking

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

Garrett ATX Control Panel

Quick Guide to Garrett ATX controls from Owner's Guide  - Click image for larger version

The Garrett ATX comes standard with a 10" x 12" DD search coil. Optional 8" round and 15" x 20" mono coils with integrated lower rods are also available. New for 2017 are 11" x 13" enclosed coil options in both mono and DD designs.

The ATX does have a built in waterproof speaker and so does not require headphones. It does come with land headphones that use a waterproof connector, the same connector that Garrett uses on the Infinium and AT Pro/AT Gold models. The same waterproof headphones available for those models work on the ATX and are required if it is desired to put the headphones underwater. The included headphones have a waterproof cable that can be submerged but the headphones themselves must be kept dry. A short adapter dongle is also available to convert the ATX waterproof headphone connector to the standard 1/4" female receptacle so standard metal detector headphones may be used.

See the Garrett ATX Accessory Page for details on headphones, search coils, and other accessory items available for the Garrett ATX. There is information there on using Garrett Infinium coils on the ATX, and notes on how to chest mount or even backpack mount the ATX control box.

Finally, the ATX runs off eight standard AA batteries, eliminating any shipping or airline issues that can be a problem with some PI detectors. The detector comes complete with both alkaline and NiMH rechargeable batteries plus a 110V and 12V charger system. The detector runs approximately 10-12 hours on a charge when using headphones, less if running off the speaker. The best method is to use the rechargeable batteries and carry the alkaline set as backup.

Garrett ATX search coil options

I have had the Garrett ATX now since the fall of 2013 and so have had a solid year with the detector. It really does take about a year for me to settle down my thoughts about a detector. I tend to be all giddy with the new toy at first, having fun, and discovering new things. The strong points and weak points are revealed with use over time, and now I think I can offer up a fair summary of the detector.

The ATX is a bit difficult in that Garrett started with the premise of using an existing housing designed to military specifications, and then decided to put a detector in it for consumer retail sales. On one hand this is really great as we get this very unique detector design that would never have been developed just for consumer sales. On the other hand it means for some uses the ATX is just not a very good fit. For other uses it works pretty well.

It just so happens I am an avid prospector and an avid beach hunter. I do not beach hunt as much as I like but when I do it I really go after it. Because of this the ATX hits a particular sweet spot for me personally. I really do need a good pulse induction metal detector that can be submerged in saltwater. I would keep the ATX for that purpose alone. I am very happy with its performance as a beach detector especially on beaches where there is black sand mineralization or volcanic rock to deal with. The fact it also does very well as a prospecting PI is almost a bonus for me.

From a straight up prospecting perspective Garrett also scores though nobody needs a seven pound detector waterproof to 10 feet while desert prospecting. However, if all I had was a couple thousand dollars to invest in a brand new, full warranty PI for gold prospecting it would be a Garrett ATX. I believe the ATX is superior to the White's alternatives in overall performance and it is far less money than a new Minelab PI detector. I will not speak for the Australians but in the U.S. the ATX holds its own for PI performance and I feel quite comfortable using it gold prospecting. I could wish for a lighter package but the fact is it works and a person who puts in the effort should do just fine with the ATX. I know I can.

The ATX does well for relic hunting applications and I have even found I can cherry pick coins halfway well with it. I have always been partial to pulse induction detectors and Garrett has won me over with the ATX. I enjoy using the detector and I can make good finds with it, and that is all I can ask of any detector.

Some of Steve's finds with the Garrett ATX in the first year of use

In retrospect I have actually done remarkably well with the ATX since I got it, considering it is only one of several detectors I have been using and not the one with the most hours on it. I have found about 3 ounces of gold and platinum jewelry with the Garrett ATX plus about two ounces of gold nuggets with it. I have found gold nuggets in Alaska, Arizona, California, and Nevada with the ATX under sunny skies and in pouring rain. My ATX has spent a couple weeks of days underwater in rough surf and is none the worse for wear. Many thanks and a hat's off to Garrett for producing my all time favorite Garrett detector.

~ Steve Herschbach
Copyright © 2015 Herschbach Enterprises

Official Garrett ATX Page

Garrett ATX Instruction Manual

Garrett ATX Color Brochure

How To Disassemble and Clean the ATX Coil Shaft & Camlocks

Garrett ATX Accessory Page

Report on new 11" x 13" Search Coils

Forum Threads Tagged "garrett atx"

Garrett Metal Detectors Forum

Garrett ATX vs Minelab GPX 5000

*Notes on Technical Specifications - Detailed notes about the specifications listed in this chart.

The White's PulseScan TDI was released in 2008 and is still in production as the TDI SL. Prior versions have been discontinued. I was one of the original users of the TDI and still dabble with them to this day. See my story White's TDI at Moore Creek, Alaska for pictures of lots of TDI gold nugget finds. I also have extensive notes on using the TDI for coin detecting at Steve's Guide to White's TDI Coin Settings. The TDI is a unique detector and is seeing use in many applications unforeseen when it first came out.

The TDI has been available in several versions but all are basically the same detector as far as how they work. October 2019 Note: White's has a model called the TDI Hi-Q, which is a TDI SL with straight rod, new coil, and tan or camo paint job. See the details here.

I am a big fan of competition as I always want more and better detectors from the manufacturers personally, and I think competition is the best way to get better detectors. After Garrett got into the ground balancing pulse induction (GBPI) game with the Infinium people including myself were really after White's to make an entry into the field. I went so far as to visit White's Electronics personally to lobby for such a detector with suggestions on how to get there. Alan Holcomb, the CEO at that time, flew me down at White's expense for discussions on how to proceed with such a project. In particular, I advised that rather than developing something from scratch, it might make more sense to license the existing Goldscan technology from Eric Foster, widely known as "the father of pulse technology" for his early work in the field.

Eventually White's did decide to pursue the matter, and I was therefore aware early on that White's was working on a new detector, In 2007 I was sent a prototype unit to evaluate while I was on vacation in Hawaii. I was very impressed not only with the power of the detector but more importantly for me in Hawaii I was very impressed with how stable the detector was in salt water. It was also virtually immune to electromagnetic interference (EMI) issues that had dogged my use of other detectors in Hawaii.

White's TDI SL with closeup of control panel (compare to original TDI controls below)

My use of previous GBPI detectors, the Minelab models and the Garrett Infinium, made me familiar with how they respond to targets with various tones. Each target generates a dual tone that varies depending on whether the target is above or below the ground balance point that has been set. You will hear either a high tone followed immediately by a low tone (hi-lo), or a low tone followed immediately by a high tone (lo-hi). This dual tone system is effective for most uses but if you get into a target rich location it in effect doubles the number of audio signals coming from the detector.

I also had an opportunity in Alaska to visit with Brent Weaver, the main engineer at Garrett responsible for the development of the Infinium. While testing a prototype Infinium I asked him about the dual tones (Garrett now refers to them as "echos") and whether they could be suppressed. He told me the dual tones were integral in how the Infinium worked and that it was not practical to produce a single tone result on the circuit they were working with.

White's did end up working with Eric Foster on the development of the TDI. His method is one I like because instead of the dual tone responses generated by the Minelab and Garrett models (hi-lo or lo-hi) the TDI generates one of two tones, either a low tone, or a high tone. The tone depends on whether the target is above or below the current ground balance setting, and therefore there is only a tone difference when the ground balance system is engaged. The ground balance off, straight PI mode has monotone responses. Also, because the ground balance can be set manually on the TDI, this tone "breakpoint" can be shifted by the operator. This allows targets to be separated broadly into two distinct groups. On one hand there are high conductor type targets, like most coins and large steel items, that on the TDI produce a low tone response. The other group is comprised of low conductor type targets, and includes most gold items, US nickels, aluminum, and small ferrous trash. These all produce a high tone response on the TDI. There are far more high tone targets than low tone targets in most locations.

I really liked the prototype TDI that I used in Hawaii, in particular the fact that it generated half the audio responses compared to a Garrett or a Minelab. Once again I wondered if one tone or the other could be suppressed. I sent an email to Eric Foster, and was surprised when he told me that not only could it be done, but it would be a very simple thing to implement with a basic toggle switch arrangement. This came about very late in the TDI development, and I lobbied hard for just such a feature to be added. A last second vote was taken by those involved, and probably the last major change on the TDI before it went into production was the Target Conductivity switch. There was no such switch on the tan prototype models.

Prototype White's TDI Used by Steve Herschbach in Hawaii

Now, I do not want to give the impression I was some kind of major player in the development of the TDI. I was just one of many voices pushing at White's for years to develop a ground balancing pulse induction (GBPI) detector. I am pretty sure though my last second inquiry and little push was what made the tipping point to getting the Target Conductivity switch included, and I think to this day it is one of the most useful and intriguing features on the TDI. It allows for a vast reduction in the number of audio responses in certain situations and in conjunction with the manual ground balance and pulse delay offers a degree of discrimination on the TDI not seen on any other pulse induction detector made today.

This makes the TDI a pulse induction machine that can be used effectively for coin detecting, if the operator knows what they are doing and employs some smarts in site selection. I wrote an article entitled Steve's Guide to White's TDI Coin Settings on this very subject. I will not repeat the information here in the interest of keeping this page from getting too long so check out the link. Suffice it to say the TDI has the ability to play tricks and discern targets far beyond what most PI detectors can achieve.

Another major feature on the TDI is the ability for the ground balance system to be shut off. The method used to ground balance the TDI in effect subtracts the ground reading from the total readings returned by the detector. This subtractive method does actually steal some depth, which is easily shown in air tests on targets with the ground balance turned on and the ground balance turned off. The closer the target is in relation to the ground balance setting, the more depth is lost. People find this very confusing, as the whole point of ground balancing a PI is to get better depth, right?

Original White's TDI Control Panel

The way it works is this. In low mineral ground a PI gets maximum depth without using any ground balancing. However, as mineralization increases, depth is affected. The more mineralization, the more depth is lost. Also, ground effects increase. In low mineral ground, the coil may be raised off the ground with little response. In highly mineralized ground, raising the coil even slightly off the ground produces a false signal. Nearly all PI detectors have an audio retune circuit that slowly retunes the audio response to keep it at the set threshold level. Otherwise circuit drift and minor ground variances would require constant retuning. In high mineral ground, the ground produces a response, but the detector compensates as long as the coil is kept at an exact height over or on the ground. If the coil is raised quickly, the audio overshoots when the ground signal is removed and a false signal occurs. This can be a real problem in even ground or in the water where it is difficult to maintain a steady distance above the ground or sea bottom.

Hot rocks or wildly varying ground mineralization present an even greater issue. Again, the detector does well as long as the conditions are constant, but when a hot rock or mineralized ground condition like a clay seam enter the picture, a false signal is heard. In areas with lots of hot rocks PI detectors that cannot ground balance are almost useless due to the overwhelming number of false signals.

So imagine a PI with no ground balance in low mineral soil. All is well, maximum depth is achieved. Pretend we have the ability via a magic dial to turn up the ground minerals and/or hot rocks in the ground. A point is reached where performance and efficiency is greatly impacted. It becomes impossible to discern good targets from ground signals and false hot rock signals. At such a point, engaging the ground balance circuit gains back the lost performance and efficiency. It does this by eliminating the ground signal and hot rock signals.

White's search coils for TDI (from 2018 product catalog)

This leads to situations occurring where people use a GBPI detector in low mineral ground and decide they are no better than a VLF. That actually often is true, in that a good VLF in all metal mode will do about as well as a Ground Balancing PI in low mineral ground, if both have similar coil sizes. A GBPI does not come into its own until the ground conditions or hot rocks are such that a VLF operator wants to toss the detector in a gully in frustration.

This has been a very long lead explanation to the TDI secret weapon. In low mineral ground, turn the ground balance off! The detector will become extremely stable with a very smooth threshold and become more resistant to electrical interference. Gain may be boosted and a great deal of extra depth achieved in situations that allow for this type of operation, and they are actually very common. This would be the preferred beach mode on most beaches, the exception being beaches with a lot of black sands. The White's TDI in pure PI mode is one of the most powerful straight PI detectors available. The tone differences between targets disappear, and sometimes the ability to differentiate targets is more important than the depth gained by shutting the ground balance system off. But do not overlook this ability to run without ground balance in situations that warrant doing just that as it can really pay dividends to the knowledgeable operator.

In 2018 White's responded to long standing demand from customers and released a version of the TDI that is waterproof to 25 feet - the TDI Beachhunter. This is basically a TDI SL in a Beachhunter ID control box. The model weighs more at 5.2 lbs for obvious reasons. The TDI Beachhunter has all the same controls as the TDI SL with the exception of the conductivity switch. This means the TDI Beachhunter signals on all targets, but the dual tone scheme remains to allow the operator to differentiate targets by the sounds. In order to help insure waterproof integrity the coil on the TDI Beachhunter (12" Dual Field coil) has been hardwired into the control box. Forum thread with more information on TDI Beachhunter.

White's Electronics TDI Beachhunter - new for 2018

~ Steve Herschbach
Copyright © 2010 Herschbach Enterprises

Official White's TDI SL Page

White's TDI SL Data & Reviews

White's TDI SL Instruction Manual

White's TDI SL Special Edition Data & Reviews

White's TDI BeachHunter Data & Reviews

White's TDI Pro Instruction Manual

White's Original TDI Instruction Manual

White's TDI Field Manual

Forum Threads Tagged "whites tdi"

White's Metal Detector Forum

Great Post on Batteries For the TDI SL

White's TDI Coin Settings

Some Commentary On TDI Tuning & Discrimination

*Notes on Technical Specifications - Detailed notes about the specifications listed in this chart.

White's TDI SL High-Q Tan metal detector

The White's MXT was released in 2002 and had a great run, but is no longer in production due to the demise of White's Electronics in 2021. I helped popularize the use of this detector for searching tailing piles for large gold nuggets. Hundreds of ounces of gold have been found at Ganes Creek, Alaska alone by people using the White's MXT. My own largest gold find, a 6.85 ounce specimen, was with the MXT at Ganes Creek. I have a couple stories on Steve's Mining Journal that highlight the MXT. See Infinium & MXT at Ganes Creek and GP 3000 & MXT Get Fortymile Gold. My most recent find of note with the MXT Pro was a 267 AD Roman coin found while on a trip to the UK in 2010. See Metal Detecting Ancient Coins at Colchester, UK

The MXT is extremely popular because it does almost everything very well; coin, relic, jewelry, and nugget detecting. Despite being so versatile the MXT is also a bargain priced detector with performance rivaling much more expensive detectors. It is remarkably easy to operate, with a condensed operating guide actually printed on the bottom of the control box. Three knobs and three switches are all the controls you need. The controls have specially marked settings so that if you do not know what the controls do, just set everything at the little triangle marker and you are off and running.

A major feature on the MXT is the LCD screen that gives you visual information about the items detected as well as battery readings. White's employs a numeric target identification system that runs from -95 to +95, with ferrous targets reading as negative numbers and non-ferrous targets reading as positive numbers. White's calls these "Visual Discrimination Indicator" numbers usually referred to as VDI numbers.

The MXT also comes with one of the best manuals and DVDs of operating tips that I have ever seen come with any detector. The MXT is almost perfectly balanced due to the control box being slung back under the elbow. One simple thing about the MXT also pleases me - it does not fall over on its side like nearly all the other detectors I use when I set them down! The control box is very water resistant. I have used the MXT in the rain all day long with no adverse effects.

White's MXT All Pro metal detector for coins, jewelry, relics, and gold nuggets

There have been several MXT models. There is the original MXT which comes with a 9.5" round concentric "950" coil. This version of the MXT was discontinued in 2017 and is essentially the same detector as originally released in 2002. The was also an MXT 300, also no longer in production, which was the same detector with a 300 mm (12") search coil and a matte black paint job for $100.00 more. The MXT 300 was replaced by the MXT Pro for the same $899.95 price. The MXT Pro added multi-tones and a meter backlight plus a redesigned pod with a touch pad.

The new features do not really add anything needed from a nugget detecting perspective but are popular with coin and jewelry hunters. There is a "Ground Grab" that is nice for nugget detecting but just for convenience. Instead of switching to ground tracking for a minute and back to fixed it is possible to just remain in fixed and hit the grab button to update the ground balance setting.

A very good way to compare the MXT and the MXT Pro is to download and read both operating manuals linked to below. You can also find a quick comparison reference chart at Jeff Foster's website here.

The target reference in the MXT display above is replaced by three touch pads on the MXT All Pro. An audio pad controls various audio options, the "Ground Grab" button resets the ground balance, and there is a pad to toggle the display backlight on and off.

MXT vs MXT All Pro display pod showing new touch pad buttons

The MXT came with the 9.5" round concentric coil and the MXT All Pro is offered with either the 9.5" concentric coil or 10" round DD coil. My personal preference is for the MXT All Pro as I do like tone id for general detecting and the Ground Grab button alone is worth the extra money as far as I am concerned. I prefer to leave automatic ground tracking off most of the time and update via the grab function. The ground grab button alone is enough to make me prefer the MXT All Pro for gold prospecting. It is also a little known fact that the MXT was designed to work best with DD coils.

Here is a post by Dave Johnson (one of the engineers of the MXT) on the TreasureNet forums 2/3/2013:

"Back in the late 1990's and very early 20th century, the MXT was developed around the 10x6 elliptical DD. When you're used to that searchcoil, stick a 950 on and the 950 feels downright clumsy with its muddy response and bad masking characteristics. Downright insufferable. The 950 searchcoil geometry was designed for completely different platforms.

But, if you ask "does the 950 work?", well, yeah, it does. Wrong question.

I ain't gonna knock the MXT, it may be an old platform but it still works good. More than 10 years after, if you demand "ground tracking" (not that I say you should demand that), the GMT/MXT have the best in the industry. Not even Minelab (!) denies that! And as far as I know, the MXT/GMT are the only VLF-IB machines on the market with active transmitter regulation that makes it possible to work (with reduced performance) in heavy magnetite black sand, a circumstance otherwise left up to PI's. We're talking very good machines here. They may be a bit old in the tooth, but this is an industry that takes time to weed the turnips out of the beet patch. Ain't like celfonz where in 6 months the whole world has decided what kyckes and what szux. It takes time to deliver good beep verdict.

MXT. 10x6DD is the foundation. Everything else is an accessory. I am telling you this because if you are a White's loyalist, I want you to spend that extra buck, the folks in Sweet Home are my friends!"

Having noted that commentary, many users prefer the concentric coil options for beach use or low mineral parks where bottle caps are common. Concentric coils generally identify flat ferrous targets more reliably than DD coils.

The large 12" concentric coil and even the 9.5" concentric coil do not handle extreme ground mineralization very well, and the 12" is too large for many other tasks, like coin detecting trashy locations. The 6" x 10" Eclipse DD coil is possibly the best all around prospecting coil for the MXT for those that do not already have the 10" round DD coil and want to add a DD to the MXT. The solid construction is less likely to hand up on stubble and the narrow profile is good for getting into tight locations. However, if you have an All Pro and already have the 10" round DD coil it is a less useful upgrade. In that case I would tend to recommend the 4" x 6" Shooter DD coil for trashy locations and small gold nuggets.

To sum up, I recommend using either the 10" round or 6" x 10" elliptical DD coils for hunting heavily mineralized ground. To get the best performance on small gold, use the 4" x 6" elliptical DD (Shooter) search coil. The 9.5" concentric 950 coil and 12" concentric are best used for hunting tailing piles, beach detecting, or coin detecting in parks. The little 6" round concentric (Eclipse 5.3) is a good little coil for almost any use, including gold prospecting for small nuggets in low mineral ground.

The MXT is blessed with a large number of aftermarket coil options due to its popularity. There are so many in fact it is impossible to keep up with them so I will leave that for the reader to discover via Google.

White's MXT DD search coil options

White's MXT concentric search coil options

The MXT Pro does have an undocumented feature it is worth knowing about. The MXT in Coin & Jewelry Mode has a "Pull Tab Notch" feature when the trigger switch is locked forward. Meter readings of VDI +28 to +49 are silenced, knocking out common pull tab responses while still allowing US nickels to signal. The MXT Pro eliminated this function (trigger switch forward locks the pinpoint mode) and instead added the seven tone audio identification used by the White's M6 detector.

The intent was to have the option for different tones for preset VDI ranges while in the Coin & Jewelry Mode. The multi-tone feature was not intended for the Relic or Prospecting Modes. However, through a bug that is not documented in the owner's manual you can activate the multi-tone mode by getting your MXT all set up in Coin & Jewelry Mode and then selecting multi-tone by pressing the "Musical Note" button. Now flip the toggle switch to either Relic Mode or Prospecting Mode and the multi-tone function will remain engaged. However, if you touch any of the control pads at any time now the multi-tone function will shut off. White's decided this "bug" might actually be useful so has left it as is for you to experiment with.

There is a book written about the MXT that has no equal - The MXT Edge by Jeff Foster. If you have an MXT do not hesitate to get a copy. An interesting note is that the White's GMT and the MXT share a common heritage - see the MXT Engineering report below.

Official White's MXT Page

White's MXT 950 Owner's Manual

White's MXT 300 Owner's Manual

White's MXT Pro Owner's Manual

Forum Threads Tagged "whites mxt"

White's Metal Detectors Forum

Unofficial MXT User Support Page

MXT Engineering Guide

Steve's Guide to White's Electronics GMT versus MXT

*Notes on Technical Specifications - Detailed notes about the specifications listed in this chart.

Here are a few nugget detecting tips for the MXT. I highly recommend that if you are new to detecting you seek out a sandy location like a freshwater beach or volleyball court or the woodchip area around playground equipment to practice and learn your new MXT. The goal is to set up the detector as if you are nugget detecting and to dig everything that signals. It does not matter what it is, the goal is to learn. You should be trying to find the smallest items possible, and attempting to learn how to separate ferrous from non-ferrous signals.

It is always best to dig all targets when nugget detecting, but some areas are so full of ferrous trash that it is something that must be tuned out to some degree. Aluminum is a very common find, and that is good. Aluminum and gold respond identically on a metal detector, and the smaller and/or deeper the aluminum is, the better your detecting skills. Concentrate on the faintest signals. Hours spent practicing like this will save many more hours wasted time and frustration in the field.

Normally when looking for gold it only makes sense to use the MXT Prospecting Mode. This pretty much turns the MXT into a GMT although a bit less sensitive to very small gold. Start with the Gain at the preset (small triangle) setting. The Threshold should be set as low as it can go while still being audible. You want to be able to hear variations in the threshold sound but you do not want it so loud as to be annoying when listening to it for hours on end. Set the Trac switch to "Ground" and pump the coil over the ground until the sound caused by this pumping action dissipates. the MXT is now ground balanced, so flip the switch to the "Lock" position. This locks in the current ground balance setting.

The "Dual Control" while in Prospecting Mode is not acting as a discrimination control. The inner "SAT" section becomes active and a good starting place is the small preset triangle at the "5" setting. SAT stands for self-adjusting threshold. The threshold sound constantly varies and this circuit smooth's the threshold response. The higher the setting, the more aggressive the smoothing effect. Low settings are more sensitive to faint responses but can allow ground variations to also become to evident. Settings that are too high eliminate faint ground responses but can also cause faint signals from gold to become to faint to hear. In general less mineralized ground calls for lowest SAT settings and higher mineralization call for higher SAT settings.

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The Gain when increased does make the detector more sensitive to gold but also more sensitive to ground feedback and so-called hot rocks. The trick is to run the Gain as high as possible while retaining stable operation. Finally, in low mineral ground a locked Trac setting works best, but in ground that varies constantly running the MXT in the Ground tracking mode will result in smoother operation. Novice may want to stay in Ground Trac mode while learning the machine as it is the safe setting that keeps the machine properly ground balanced.

In theory the MXT is most sensitive with the SAT set low, the Gain maxed out, and the Trac setting locked. The reality is that increased Gain settings may also call for increased SAT settings. The goal is to seek the most sensitive balance of settings possible while while keeping the MXT stable and smooth. A small test nugget of small piece of lead can be essential for determining what setting most eliminates ground responses while most enhancing nugget responses. In general leave the SAT control at the preset, Trac in locked, and set the Gain as high as you can while still getting stable operation. If need be, switch the Trac setting to ground for smoother operation. In the worst mineralization advancing the SAT control into the Hyper SAT mode will put the MXT into a very smooth mode able to deal with extreme mineralization while still reporting small gold nuggets.

Remember, the key is to seek a smooth, stable threshold sound. It is this stable sound, when it varies, that indicates very deep or very small targets.

There are a very few detectors that can be run in what is referred to as "mixed mode". These units have the ability to run in all metal and discriminate at the same time. I am not sure who first came up with this feature but Nautilus has for a long time offered units that put the all metal signal in one ear of your headphones and the disc signal in the other ear. The advantage to this is that pure all metal modes detect deeper than discrimination modes. Hunting in regular all metal requires lots of switching back and forth to check targets. Mixed mode gives you both at once.

The White's MXT has the Relic Mode, which is a mixed mode. I wonder how many people use relic mode but really do not understand it. Good targets give a high pitched chirp. Junk targets honk. The split between high chirp and low honk is determined by the setting of the discrimination knob. This should be set to just cause iron and steel items , like a small nail, to honk, generally at a setting of 2 or less. Do not set the discrimination too high! Now here is the important part - there is a third, more subtle audio signal that indicates a target is there but the detector cannot identify it because it is too deep. This is the all metal signal. The meter will be blank. When nugget detecting, you want to hear these, and dig down until the target identification kicks in. I think many people focus so much on the other two audio responses that they ignore the fainter deep all metal signal. It is easy to fall into a habit of just digging only those high pitch targets. Not good.

The key to mixed mode is simple. Those targets in a good location that are so deep you get no indication on the discrimination channel are the ones you really want to think about. If the area has produced good finds but is now near to being worked out, these deep signals are the ones anyone running in a normal discrimination mode is going to totally miss. Sure, it could be trash. But really deep targets are often the best, and so digging some of these on occasion can produce some really good finds.

Steve with MXT and 6.85 ounce gold specimen found with it at Ganes Creek, Alaska in 2002

Unlike most dedicated nugget detectors it has a LCD based visual discrimination indicator (VDI) system. This is for the MXT coin and relic modes in particular. It turns out that for certain nugget detecting tasks the MXT has extra capabilities due to the visual target identification system.

Alaska has huge areas of old mining tailings that provide great opportunities for nugget detecting. The nature of the old operations was such that many of the very largest nuggets were lost into the tailing piles. Unfortunately there is a huge catch. Some of these tailing piles contain incredible amounts of iron junk, and at any depth. Some creeks were mined many times, and old campsites and dumps were churned up and mixed in with the tailings. This junk can be anything from rusted flakes and slivers of steel on up to cans, bolts, washers and nuts, and finally even 55 gallon drums, and various large steel plates, pipes, boilers, or even larger items.

Ganes Creek, Alaska is possibly the best known of these locations. New visitors from areas in the western US where the Minelab SD/GP/GPX detectors have reigned supreme have a hard time adjusting to the concept that there is such a thing as too much power when coupled to a poor discrimination system.

If you run a Minelab at Ganes Creek here is a likely scenario. You are in a field of fist-sized and larger cobbles. You get a nice little signal and no iron blanking. You start to dig, as best you can in a pile of rocks. After a great deal of effort you are at two feet, signal is louder, but no target. You pull out another cobble and half the hole falls in. You pull all those rocks out, and get another six inches down. Forty-five minutes has passed. You pull out another rock and the hole caves in again. Fifteen minutes later you are at 3 feet again and really tired. Over an hour has passed since you started this hole. The signal is very loud now...too loud really. You dig down a bit more, then some more, and the whole thing caves in again.

You walk away in disgust. Or you keep digging and finally find an old quart-sized can.

How deep can you hit a large can with a Minelab GP 3000? How about a 2'x 2' steel plate? How about a 55 gallon drum? There answer is very deep indeed, and they are all there waiting! Normally you would just figure it is junk past a certain depth, but the big question always must be how deep could you hit the 35 oz or 80 oz pieces found at Ganes Creek with metal detectors, or the 122 oz chunk found by the commercial miners at Ganes?

Because of this huge junk problem VLF detectors have generally been the way to go at Ganes. The low mineral conditions mean they keep you from wasting huge amounts of time going after junk targets. Most any good VLF machine works well for this, but the MXT gives you some extra capability once you learn its tricks.

There are four things to know. 1. VDI numbers increase as the nugget size increases. So a 1/4 oz nugget may read around 25 whereas a 1 oz nugget may read around 40 and a 2 oz nugget may read around 50 on the meter. 2. The larger a nugget, the deeper you can detect it. 3. Certain steel items can give positive VDI numbers and 4. VDI numbers are pulled down the deeper the nugget is buried. A 1/4 oz nugget near the surface will read 25, but at depth might read 10, and at max depth may finally read at 0 or lower and actually be identified as iron.

This last point is very important, for if you run a Fisher Gold Bug 2, or Tesoro Lobo, or Troy X5 in disc mode to tune out iron, as is common for many people at Ganes Creek, deep nuggets may read as iron. If they are, the machines will reject them; you will get no signal, and walk past the nugget. You will never know it is there. Or at best you have to search in all metal mode, then constantly switch to the discriminate mode to check the target. With the MXT, there is no switching and you hunt completely by ear.

With the MXT I like to run the detector in relic mode, with the disc set precisely at 2. Non-ferrous items will give a high tone, and ferrous junk a low tone. If you get a faint low tone, the first thing you do is kick and inch or two off the surface until you get a honk or a chirp. Now dig a little deeper. If the VDI number rises, keep digging. Targets that read iron initially and rise will often turn into non-ferrous readings, hopefully gold. If the VDI number stays the same or goes even lower, you have an iron target. Once again, be careful to listen for audio signals that give no reading on the meter - these are items being detected by the all metal channel at depths beyond what will cause the meter to react with a numeric id.

Where the MXT really shines are on 1/4 oz to 1/2 oz nuggets. Let’s say you get a reading of 24. OK, that is about a 1/4 oz nugget. Now, we know that you can hit a nugget this size at 10-12 inches. You dig a foot, and no nugget. A large, deep iron item of a certain type can also give a 24 reading, but these large items can be detected much deeper than a 1/4 oz nugget. Dig them up if you wish, but once you go past that depth at which it is reasonable to find a nugget corresponding to a certain VDI number you are wasting your time. This method eliminates digging those false positive signals from deep items like steel plates. With the other VLF units the lack of VDI number means you have no way to judge the potential nugget size and so you end up digging deep for what may be a very large nugget when with a MXT you would know the VDI number corresponds to a smaller nugget. For the many smaller nuggets that are found at Ganes this method is pretty foolproof once you get the hang of it.

Finally, certain non-ferrous items can be found in quantity, particularly things like .22 shell casings. If you get into a bunch of these, they are usually very shallow. You can easily determine the VDI number of these multiple identical targets and then simply ignore them. You would miss a nugget with an identical VDI reading, but chances are a nugget will vary enough to make it stand out. There is no way to do this with a non-VDI unit.

The MXT is a very versatile detector, but I do not think anyone anticipated just how much gold it would end up finding in Alaska. I know one prospector alone who has found over 100 ounces of gold with the MXT.

~ Steve Herschbach
Copyright © 2004 Herschbach Enterprises

The Nokta AU Gold Finder metal detector was introduced in 2016 and is still in production. The AU Gold Finder is a 56 kHz metal detector in a lightweight, weather resistant package. It fights the trend towards LCD display menu based control systems with a set of control knobs and switches.

The Nokta AU Gold Finder is closely related to the Makro Gold Racer in overall function and controls. A lot about how the Nokta AU Gold Finder operates and performs can be discovered by studying the information about the Gold Racer, which has been on the market longer. For all intents and purposes the Nokta AU Gold Finder is basically a Makro Gold Racer in a different housing. Note however that coils are not compatible between the two models.

The Nokta AU Gold Finder reminds me of what a Gold Bug 3 might have been if Fisher had ever made one. Hot on tiny gold, variable disc, option to use ground tracking, ground grab, or manual ground balance - and more. There is a dual tone ferrous/non-ferrous mode, and a red LED (ferrous) green LED (non-ferrous) visual id system. The control box contains the batteries and is easily removed from the rod for belt mounting with the integrated belt loops. The Gold Finder runs off four AA batteries.

Nokta AU Gold Finder prospecting detector

This should really appeal to those who are not fond of all the digital menu nonsense and who prefer to flip a switch and tweak a knob. The Nokta AU Gold Finder with both 10" x 5.5" DD coil and 5" round DD coil (both with scuff covers).

Official Nokta AU Gold Finder Page

AU Gold Finder Introduction

Nokta AU Gold Finder Instruction Manual

Nokta Metal Detectors Forum

Review by Kevin Hoagland

*Notes on Technical Specifications - Detailed notes about the specifications listed in this chart.

The Minelab Gold Monster 1000 was introduced in 2017 and is still in production. The GM1000 was created as a relatively inexpensive, easy to operate, high performance metal detector. The Gold Monster 1000 is designed specifically for gold prospecting but may have applications such as micro jewelry detecting. At 45 kHz with both automatic ground tracking and automatic sensitivity settings, the Minelab Gold Monster 1000 is not only very sensitive to small gold but it is relatively easy for beginning detectorists to use.

I am fortunate to have been involved in the testing of the new Minelab Gold Monster 1000 prior to its release. One benefit is that I have seen the questions that others have posed about the detector, and now I can answer a few of them.

When I use new detectors I always have a goal in mind. I am not trying to pick the detector apart for what it cannot do. Instead, I believe most well designed detectors have something they excel at. My goal is to determine how to use a new detector for maximum benefit. The best way to make that happen is to use the detector in the way it was intended to be used, instead of trying to force it to be something it is not. The key is to be realistic. The Gold Monster 1000 is sold as an entry level single frequency metal detector. Expecting it to outperform detectors costing many times its price is unrealistic.

Engineers face a very important choice when designing a single frequency metal detector, especially as regards gold prospecting. What frequency should the detector run at? That choice determines nearly everything else about the detector. In general, low frequencies below 20 kHz handle mineralized ground better, and offer good performance on larger gold nuggets. Higher frequencies over 20 kHz enhance the sensitivity to small gold nuggets, but unfortunately ground handling suffers.

The number one question I see asked on the internet is how the Gold Monster stacks up as compared to this detector or that detector. Minelab has actually tried to answer that question directly via the following illustration:

Minelab Gold Monster Frequency Range Compared

The majority of the single frequency nugget detectors on the market today operate at or near 18 kHz. These detectors handle ground relatively well for non-PI detectors, and have good sensitivity on gram size and larger gold nuggets. They can detector smaller gold, but the smallest gold is not where they excel and the chart attempts to illustrate that. Other single frequency detectors running as high as 71 kHz have superb sensitivity to the smallest gold nuggets, but tend to suffer when it comes to depth on larger gold in highly mineralized ground. Again, the chart attempts to illustrate this fact.

The Minelab Gold Monster 1000 engineers decided to concentrate on a frequency that offered the best attributes of the lower and higher frequency extremes. The goal was to design a machine that would attempt to acquire in a single pass the bulk of the gold that machines operating at either extreme could recover if operated together – and yet do it with just one detector operating as efficiently as possible.

The catch is that the Gold Monster is still a single frequency detector and it cannot possibly capture 100% of the gold that two detectors operating separately at two vastly different frequencies can capture. If you study the illustration carefully, you will see there is still some gold the 18 kHz detector will do better on, and some gold the 71 kHz detector will do better on. Minelab is not claiming to be able to outperform every other detector under all other circumstances. The goal here is to capture as much of the obtainable gold as is possible with a single detector operating in the most efficient manner possible.

Minelab Gold Monster 1000 nugget prospecting detector

I have mentioned efficiency because there is more that goes into designing a gold prospecting detector than just the operating frequency. This is where Minelab is attempting to not only make a wise choice in the operating frequency, but to extend the efficiency of that frequency by optimizing the other parameters. First, electrical interference is detected and automatically rejected as much as possible when the detector is first turned on. This helps alleviate interference that could result in less than optimum performance.

A great deal of effort has been made into designing a sensitivity control that offers the ability not only to manually tune the detector but to deliver excellent results automatically. The automatic operation is important in ground that varies dramatically from place to place in such a fashion that it becomes difficult – inefficient – to constantly be readjusting the machine manually to retain the best overall performance level. Novices in particular tend to set and forget the sensitivity, leading to a situation where the detector could be running better if the control were optimized more often.

The crowning glory of the Minelab Gold Monster 1000 however is the automatic ground tracking system. The 45 kHz frequency is considered to be a high operating frequency, and as such it is subject to possible issues from highly mineralized ground and hot rocks. Manual tuning detectors can have great difficulty dealing with these problems… here is that word again… efficiently. The operator must be on top of and constantly adjusting the machine manually. It is very easy for the operator to be out of sync with the ground conditions and operating at less than optimum performance. At high frequencies having the proper ground balance is extremely critical.

Manual ground balance versus automatic ground tracking

I will admit I have always tended to distrust automatic ground tracking systems. The theory is they can track out good signals resulting in missed targets. The reality however is the risks entailed by not being properly ground balanced are even greater, especially for novices. The illustration below attempts to show what happens when the operator of a manually tuned detector falls out of sync with changing ground conditions, and then “catches up’ by retuning the machine. The automatic tracking or continuous ground balancing detector however maintains optimum conditions at all times.

Even given this evidence in the past however I was a skeptic, and always preferred to manually adjust my detector ground balance controls. That is until I obtained first a Minelab SDC 2300 and then a GPZ 7000 detector. The SDC forced me to use automatic ground balance by offering no other option. A surprising thing happened – I liked it! It worked and it worked extremely well, so much so that when I got my GPZ 7000 it also remains in automatic ground balance mode.

The fact is that Minelab has always been a leading developer of automatic ground balancing systems, and I do not think it is being unreasonable to state that they may have the very best ground tracking systems available. The company really has had no choice being based in Australia and developing machines for ground conditions considered to be among the worst in the world.

Can the Minelab Gold Monster 1000 go up against the hottest high frequency detectors made and hold its own? Yes. I have personally used the Gold Monster with its 5” coil to easily find nuggets (flakes?) weighing under a grain. Not grams, grains - there are 480 grains per Troy ounce. Remember however that even Minelab in that first chart is telling you that a machine tuned specifically at a much higher frequency will have an edge on at least some tiny gold nuggets.

Eleven small nuggets 14.9 grains total, largest 4.4 grains - Smallest at bottom 0.6 grain and 0.3 grain

The difference and the serious advantage I believe with the Gold Monster 1000 is in the combination of the superior Minelab ground tracking system and the automatic sensitivity system, designed specifically for the GM1000. In all but the mildest ground operators will find that the Gold Monster is a much more efficient detector that allows more ground to be covered while keeping the machine tuned for the best performance possible. My advice to the old pros that get their hands on the GM1000 is that rather than try and force the machine into operating like your favorite manually tuned machine, seek out instead conditions where that machine struggles. Then trust in the Minelab automatic ground balancing system to compensate for and deliver superior performance under those conditions. Use manual more for targeting specific small areas.

Case in point, I took the Gold Monster to a location where hot rocks had given my GPZ 7000 some difficulty. Much to my surprise the Monster was able to automatically compensate for and allow me to operate in those hot rocks and find a couple tiny nuggets too small for the GPZ 7000 to find. The machine was far smoother and I was able to cover ground far more efficiently with automatic ground balance. I followed this up with a visit to a location with wet alkali ground where a high frequency machine would normally fail. I struggled with manual sensitivity for a bit, then threw in the towel and went to the highest Auto+ sensitivity setting. The machine quieted right down and I found a nice little nugget shortly thereafter.

Nugget embedded in lump of dirt

If the ground allows you can certainly use manual ground balancing to get that hot edge on tiny gold nuggets. The Gold Monster 1000 lacks a standard threshold, but it is easy to set up a pseudo threshold by advancing the sensitivity to where the machine produces some light feedback from the ground. Those who like a threshold can run it this way – others may wish to back down just one notch for silent operation.

Old timers like me rebel at the thought of running without a threshold but with the GM1000 it works. The normal reason for running a threshold is to be sure the detector does not fall out of proper ground balance. Here however you can put a superb automatic ground balance to work for you, eliminating that concern. For the very worst conditions, the automatic sensitivity system can augment the automatic ground tracking to allow for efficient ground coverage under conditions that will bring other detectors in this class to a crawl, if not a complete stop. Frankly, if you can’t get the Gold Monster to handle the ground, it is time for a Minelab PI detector or a GPZ 7000.

To sum up, I do not want to leave you with the impression that the Gold Monster is the be all and end all of single frequency nugget detectors, and that it will under all circumstances get better performance on every single gold nugget than other single frequency detectors. That is not possible given the limitations imposed by having to choose a single operating frequency. I do believe however that the engineers at Minelab have come as close to this as is possible. The real secret to getting good results with the Minelab Gold Monster 1000 versus the competition will be in leveraging its superb ground handling capability to get the best overall gold nugget performance possible from a single frequency detector.

~ Steve Herschbach
Copyright © 2017 Herschbach Enterprises

Official Minelab Gold Monster 1000 Page

Minelab GM1000 Color Product Brochure

Gold Monster 1000 Getting Started Guide

Forum Threads Tagged "minelab gold monster"

Minelab Metal Detectors Forum

Jonathan Porter On Mastering The Minelab Gold Monster

Understanding The Sensitivity Control On The Gold Monster 1000

Reports Of GM1000 5" Coil Touch Sensitivity

My GM1000 Methodology - Manual Versus Auto Sensitivity

*Notes on Technical Specifications - Detailed notes about the specifications listed in this chart.

The Fisher Gold Bug 2 was released in 1995 and is still in production over 20 years later. I had the first Gold Bug 2 in Alaska and to this day it is one of my all time favorite detectors - a true classic. Amazingly, nobody has come out with a better detector for hitting tiny gold after all these years. Quite a few models have tried to challenge the Gold Bug 2 on the tiniest gold, and while many can be said to give the "Bug" a run for its money it is debatable if any have really exceeded it. There is a specialized tool called the Falcon Gold Probe that will actually hit smaller gold than a Gold Bug 2, but it would be more properly termed a pinpointer than a normal metal detector.

What makes the Gold Bug 2 special is the 71 kHz operating frequency. It was the highest operating frequency in a commonly available ground balancing metal detector for a long time. When paired with the 6" elliptical concentric search coil, the Gold Bug 2 easily detects small pieces of gold weighing less than 1/10th grain. There are 480 grains in an ounce so we are talking less than a 4800th of an ounce! I have a set of digital powder sales that weighs to 1/10th grain, and I regularly found single flakes of gold that will not register on the scale with the Gold Bug 2.

Don't think such small gold is found at any depth. I get these tiny bits by literally scrubbing the small epoxy filled coil into the soil. The coil is tough and immune to false signals from being knocked around so the goal is to get that coil right down on the gold. The 6" epoxy filled concentric coil perfectly tuned to the Gold Bug 2 is no doubt part of the magic since other detectors in this class normally run DD coils. The Gold Bug 2 is a perfect detector for "scrape and detect" operations where the surface is carefully scraped away to expose more soil for detecting. It is also ideal for checking quartz for tiny gold, like when hunting around old mine dumps. The Gold Bug 2 will hit specimens with wire or sponge gold that other detectors cannot detect.

There are only three coils for the Gold Bug 2, a 6.5" elliptical, 10" elliptical, and 14" elliptical. All three are concentric coils - there has never been a DD coil produced for the Gold Bug 2. I am a little surprised there have never been any aftermarket coils produced for the Gold Bug 2 due to its enduring popularity. I have always wanted a probe for it that would basically turn it into a Falcon Gold Probe type unit, but with more adjustment and iron discrimination. The coils are all waterproof and come with extra long seven foot cables for use when the control box is chest or hip mounted. The coils are among the best I have ever used and are immune to false signals from bumps and knocks.

The chart below illustrates a common misperception. People often ask which coil gets the most depth, and it is assumed bigger coils go deeper. That is definitely not true. Coil size has to be matched to probable target size for best depth, and the chart clearly shows how running too large a coil can cause gold nuggets to be missed entirely. The normal 10" coil is a compromise but better depths can be obtained using not only larger coils but smaller coils. Since I normally hunted small gold with my Gold Bug 2 the small coil rarely came off it.

Coil Size vs Depth Fisher Gold Bug 2
Source - Field Testing the Gold Bug 2 by Gordon Zahara

Despite the high operating frequency the Gold Bug 2 can be made to work in the worst ground conditions. I took one to Australia recently and was surprised how well it did in tough ironstone country. It has a very good iron discrimination setting intended for rejecting man made ferrous trash. This also acts as the setting of last resort for highly iron mineralized soils and hot rocks. When in iron discriminate mode common hot rocks will be ignored or at most pop and click, but they will not sound like gold. Some sensitivity is lost in iron disc mode, but the Gold Bug 2 is so sensitive to small gold it will still hit small nuggets in disc mode that other detectors would miss.

The design is very compact and tough, and with what is getting rare these days, a removable control box. The box can be slid off the rod, and slipped on a belt with the integrated belt slots. There is plenty of extra cable, and a chest mount can easily be made with just a belt and a camera strap. This is ideal for working in deep water or heavy rain since the control box is protected and better yet creates a detector so light it can be used for very long hours with no arm strain at all.

I usually have the Gold Bug 2 set at full volume and full sensitivity, with the mineralization switch set to low and audio boost engaged. I run this way until I can't due to hot rocks or ground, and then usually go to iron disc mode. However, if you do stay in all metal mode the proper way to deal with mineralization issues like hot rocks is to reduce the sensitivity, mineralization switch settings, or both. Disengaging the audio boost also moderates the responses generated by tough ground.

Audio boost does just that - it boosts the audio so that faint signals are louder and more distinct. It also boosts spurious ground signals and so in some cases you may want to run the detector in Normal audio. I have found in practice I very rarely take the Gold Bug 2 out of audio boost mode.

Fisher Gold Bug 2 nugget prospecting detector

I should note here that the Gold Bug 2 employs VCO (voltage controlled oscillator) audio. Responses not only get louder but they increase in pitch ,producing very distinct "zippy" responses on non-ferrous targets. Large targets literally squeal. Some people think this means the Gold Bug 2 employs some sort of audio discrimination because they can tell a coin response from small trash responses due to this. All that is really happening is that strong signals sound different than weak signals, and so a deep coin will sound just like a shallower, smaller target.

The mineralization switch adjusts the threshold auto tune rate, with the low setting being a slow auto tune and high being a very fast auto tune. This is similar to White's Variable Self Adjusting Threshold (V/SAT) control but instead of variable you get three preset selections to choose from. A fast auto tune setting dramatically impacts performance but can be an aid in very uneven ground conditions. Experiment with it to see what I mean but for me in most places it stays set in low. You can find more information on auto tune at Steve's Guide to Threshold Autotune, SAT & V/SAT. Fisher has gone this one better by also adjusting the gain (sensitivity) via these settings at the same time as the auto tune rate is adjusted. The Low Mineral setting not only slows down the auto tune rate but it boosts the gain above and beyond where the sensitivity control is set. The high mineral setting speeds up the auto tune rate and attenuates the gain.

Fisher Gold Bug 2 control panel

There is an undocumented trick that may or may not work on any particular Gold Bug 2 in iron disc mode. The threshold control usually has no effect when the unit is in iron disc mode. However, some units display a distinct difference in iron disc performance between the threshold being set low or being set high. This ability to "supercharge" a silent search disc mode by turning the threshold up is not unheard of in other detectors and it appears some Gold Bug 2 models have this ability. Several of us used this ability to good effect at Ganes Creek. The detector pops and clicks a lot when supercharged in this fashion but adds considerable depth on large gold nuggets. After awhile the popping and clicking is mentally tuned out as nuggets have a distinctly clearer beep.

This ability may have been an accident on some units, as more recent Gold Bug 2 models display no change in the disc mode when the threshold control is manipulated. A simple air test between low and high threshold settings while in iron disc mode will reveal if your Gold Bug 2 has this ability to be supercharged.

The iron discrimination on the Gold Bug 2 is unique compared to most detectors in that it is either on or off. There is no direct adjustment of the setting. In theory the Gold Bug 2 in iron discriminate mode rejects signals from ferrous man-made iron and steel targets plus many ferrous based hot rocks. It does this by simply ignoring and producing no signal on items deemed ferrous in nature. The setting is designed to be conservative, and so it does produce a signal on many ferrous items, but the audio response is choppy and more often a "click" than a "beep". Practice with a nugget and various ferrous targets will make the differences clear.

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The more mineralized the ground, the more chance there is of gold nuggets being accidently rejected as ferrous. Borderline targets will often be rejected if swept one way and sound good if swept another way. It is therefore not a good idea to hunt directly in iron discriminate mode, as a bad call on the first sweep will cause you to miss the target and not even know it was there. It is better to hunt in all metal, then flip to iron disc to check the target. This can be an undue burden in thick trash though and sometimes it is simply more efficient to hunt directly in disc mode, but the likelihood of missing nuggets goes up dramatically.

As noted above the threshold setting may have an effect on the responses generated in the iron disc mode. The sensitivity setting will also affect the setting, and by enhancing ferrous ground mineralization response it may also lead to more gold nuggets being identified as ferrous. the ground response overwhelms the nugget response leading to a false iron reading. Reducing sensitivity may produce more accurate iron disc readings in bad ground.

If you are switching back and forth from all metal to iron disc mode constantly it can prematurely wear out the switch. I have seen several examples of the switch getting so loose as to be inoperable due to the nut on the backside of the control panel becoming loose or even falling off inside the control box. The control panel can be removed and the nut tightened if this is the case.

I have found many thousands of gold nuggets with the Gold Bug 2. Granted most were small but not all. The largest I have found with the detector is a 4.95 ounce specimen at Ganes Creek, Alaska. I have numerous stories on Steve's Mining Journal that highlight the Gold Bug 2. See Detecting Small Gold at Crow Creek, Detecting Gold at Ganes Creek, Lode Gold at Hatcher Pass, Memorial Day at Ganes Creek, and Detecting Micro Nuggets at Crow Creek.

The Gold Bug 2 is a very specialized detector usually used solely for gold nugget detecting. Recently people have taken note of its extreme sensitivity and have pressed it into service searching for very small jewelry items that others detectors normally miss. Simple post earrings and thin gold chains are difficult if not impossible to detect and the Gold Bug 2 excels at finding these small targets. Thomas Dankowski coined the term "micro-jewelry detecting" to describe this type metal detecting.

The Gold Bug 2 does have limitations. The extreme sensitivity that makes it signal on hot rocks that other detectors would ignore. This can be very problematic in some locations, although somewhat offset by using the iron disc control in places where the hot rocks are iron based. More serious is that in highly mineralized ground the Gold Bug 2 has very poor depth on pennyweight and larger gold nuggets compared to most nugget detectors. The high frequency air tests very well but loses that depth quickly on in ground targets. Depth losses of 20-25% are not unusual with the Gold Bug 2 in highly mineralized ground when compared to detectors running in the 12-20 kHz range. The Gold Bug 2 is often best used when paired with another detector for depth on large gold while it serves as the small gold sniper.

The Gold Bug 2 also gives a strong response on wet salt sand and so when used for micro-jewelry detecting on salt water beaches wet sand must be avoided. Despite these caveats, I consider the Gold Bug 2 to be a unique and essential detecting tool that even after 20 years is worth consideration by gold prospectors wanting the hottest metal detector possible on tiny gold.

~ Steve Herschbach
Copyright © 2008 Herschbach Enterprises

Official Fisher Gold Bug 2 Page

Fisher Gold Bug 2 Instruction Manual

Control Box Cover for Gold Bug 2

Hip Mount / Chest Mount For Gold Bug 2

Changes To GB2 Rod & Coil Design

Forum Threads Tagged "fisher gold bug 2"

First Texas (Fisher) Metal Detectors Forum

*Notes on Technical Specifications - Detailed notes about the specifications listed in this chart.

The White's GMT was released in 2000 and is still in production. The GMT has been the best-selling dedicated nugget detector in Alaska for many years. The combination of small gold finding ability, excellent depth on larger gold, and ease of use at a bargain price make it a hard unit to beat. I have used the GMT and its predecessor Goldmaster models to find thousands of gold nuggets in Alaska. See Thirty Years with White's Metal Detectors, White's Goldmaster GMT Rebuild and First Gold Nuggets Found with White's GMT for more information on my use of the GMT. See also Steve's Guide to White's Electronics GMT versus MXT. The GMT is one of only a few detectors available operating at more than 40 kHz (the GMT runs at 48 kHz), making it exceptionally sensitive to small gold nuggets.

The GMT is the latest in the new Goldmaster line of detectors that White's introduced in the early 1990's. The Goldmaster name is an old one, and White's produced many old BFO and IB/TR versions of the Goldmaster in the 60's and 70's. The early Goldmasters were old technology and did not ground balance, a key breakthrough in detector technology. These old models usually had large blue control boxes. If you see one of these for sale cheap do not confuse them with newer Goldmasters, all of which come in black boxes.

Note that in late 2018 White's introduced the 48 khz Goldmaster 24K. The GMT also remains in the lineup for now, but it is possible that the 24K will eventually replace the GMT.

The Goldmaster II was a serious breakthrough detector when it was introduced, operating at 50 kHz, far in excess of other ground balancing nugget detectors at the time, which commonly ran at 15-20 kHz. The Goldmaster II was quickly followed by the Goldmaster V/SAT, and these two models I credit with igniting a metal detector "gold rush" in Alaska. I got the ball rolling by finding thousands of gold nuggets at Crow Creek Mine south of Anchorage, and widely publicizing my discoveries. Crow Creek had produced few nuggets with detectors prior to the Goldmaster release, but the new 50 kHz design crossed a threshold where all of the sudden thousands of nuggets were large enough to be detected that were too small for previous detectors. White's simply could not build the new Goldmasters fast enough.

The Goldmaster V/SAT was followed by the Goldmaster 3 and raised the price from $499.95 to $599.95. White's then shifted gears and with the Goldmaster 4/B switched to using the control box design used by its coin machines. They also raised the price again to $699.95. This was not well received, and when Fisher introduced the Gold Bug 2 at about the same time for $775.00 Goldmaster sales plummeted.

White's GMT 48 kHz gold nugget prospecting detector

The Goldmasters were all analog designs but a shift to digital began with the Goldmaster 4/B. White's started a project for a brand new detector design by hiring Dave Johnson, a well known engineer specializing in gold nugget designs, the ended up as the White's MXT. The GMT was as early spinoff of that project released a couple years before the MXT hit the market. The MXT Engineering guide linked to below tells the story in detail. A key design goal was to have automatic ground tracking, and so the Gold Master Tracker (GMT) was born. The new model also sported a new retail price of $799.95.

The GMT is a totally new design from the prior Goldmasters  but seems very similar due to the goal of wanting it to be compatible with existing Goldmaster coils. In order to prevent "crosstalk" interference with existing Goldmaster models a 48 kHz operating frequency was chosen, which was still close enough to 50 kHz for old coils to work. However, the GMT was designed with DD coils in mind. Older Goldmasters all used concentric coils but the GMT shipped with a new 6" x 10" elliptical DD coil. One thing all the Goldmasters seriously lacked was a small coil option, and finally after the GMT was released White's came out with a small 4" x 6" coil, commonly referred to as the "Shooter". Much later yet, the concentric 8" x 14" Jimmy Sierra Gold Max coils were converted from concentric to DD. The concentric 8" x 14" coils were white and the newer DD versions are black.

White's is currently shipping only the new DD 4" x 6" Shooter, 6" x 10", and 8" x 14" Gold Max coils but until recently the only concentric coils available were the 6" x 10" and 8" x 14" coils on the used marketplace. White's in 2017 introduced a new round concentric coil for the GMT. The old concentric Gold Max coils are easy to identify - they have a white plastic housing whereas the new DD version is black. Concentric 6" x 10" coils are white plastic just like the new DD version, what differs is the decal. Any 6" x 10" Goldmaster coil not sporting the "Twin D" label is a concentric. The early decals came in red and black and later gold and variously were called the Long Scan, Gold Master II, Gold Master, and GM 3 coil. Beware of any round coils marked for use for the Goldmaster series. The only round coil ever produced that is compatible with the newer Goldmaster series is the 12" round Hot Shot coil pictured below. Any other round coils would be for the old "blue box" Goldmasters and will not work on the 48-50 kHz series.

4"x6" Shooter DD coil, 6" round concentric, stock 6" x 10" DD coil for GMT, and 8" x 14" Sierra Gold Max DD coil

Old version 6" x 10" concentric and 8" x 14" concentric coils

The GMT currently has no aftermarket coils available. Jimmy Sierra used to market a couple coils that may be found on the used market. The Hot Shot was a round 12" concentric coil that in mild ground may have been the deepest coil made for the GMT but it suffered in mineralized ground due to the concentric design. Jimmy Sierra also marketed the 2.5" x 9" Hot Foot coil, a unique rectangular DD design. These coils were made by Jim Karbowski of Applied Creativity and marketed by Jimmy Sierra. Unfortunately Jim has passed away in 2007 and the manufacture of his coils with him.

Applied Creativity Hot Shot and Hot Foot coils for GMT

As always, when designs shift from analog based to digital, there are always some who regard the analog designs as better in some way. A lot of people nostalgically remember the Goldmaster 3 as the best Goldmaster made. I do myself miss the old control box that could be converted to a hip or chest mount. However, the benefits of the GMT far outweigh any perceived faults. It was for a long time the only VLF nugget detector that allowed the operator to choose between automatic ground tracking and manual ground balance. The "Grab" button was an innovation only now being seen in other detector models over ten years later. The "follow the black sand" feature was also a unique though underutilized feature. The innovative "iron probability" ferrous identification system was unique for many years but has recently been copied by a couple other manufacturers.

GMT meter pod and typical meter readings

The ground balancing options on the GMT are as good as they get. The unit can automatically track ground conditions and keep the machine as near optimum settings as possible. The GMT has what is regarded as one of the best ground tracking systems available. It has superior resolution, tracks faster, "jumps" into new ground more quickly, has greater resistance to tracking into targets, and tracks over a wider range of soil conditions. This is an obvious advantage for beginners who often have difficulty with manual ground balancing systems. It also benefits experts in locations where the ground varies constantly. This requires constant monitoring and adjustment on a manual system. It can place an undue burden on the operator and if ignored leads to the detector not being optimally tuned for the ground conditions. Simply set the ground balance toggle switch to "Fast AutoTrac®" and let the GMT handle the ground balancing chores. The GMT will automatically track and display the ground balance setting under the "Ground Balance (Mineral Type)" heading on the meter.

Ground balance tracking systems can "track into" a faint signal produced by a very small or very deep gold nugget and cause it to fade out as if it is a ground signal. This is especially likely if the operator hovers over the target after it is heard on the initial pass. For this reason the GMT trigger switch has a dual function. It engages the iron discrimination system but more importantly it temporarily locks out the ground tracking system. Whenever a faint target is encountered, squeeze and hold the trigger switch while working the target to insure the tracking system does not cause it to fade away.

While automatic ground tracking offers many benefits it can impede finding the very faintest targets. In extreme ground conditions the fact that the machine is constantly adjusting for ground conditions can actually impede a savvy operators ability to discern ground and target signals. Professional operators like having the option of using manual ground balance and the GMT accommodates this is a couple ways. There is the standard ability to toggle the ground balance switch to manual ground balance and then adjust the setting up or down via the plus and minus touch pads. One major benefit of manual ground balance is the ability to purposefully set the ground balance slightly off of the supposed perfect neutral ground balance setting. Many prospectors will set the ground balance slightly positive, or in other words such that the detector signals very slightly when the coil approaches the ground. This tends to prime the system to react more quickly to the faintest targets.

The GMT goes one step farther with the introduction of the ground "Grab" button. This unique GMT feature was long overlooked but is now being added as a feature on many other detectors. While in manual ground balance mode the tracking system continues to work in the background. Simply touching the Grab button on the meter touchpad instantly updates the ground balance to what the tracking software thinks is the best setting at that point in time. Pressing and holding the button engages the tracking system momentarily. This offers the best of both worlds in that a prospector can hunt in manual ground balance yet take advantage of the software to instantly update the setting instead of manipulating the plus and minus pads. The Grab button acts like an instant "Coarse Tune" control, which can then be tweaked slightly with the manual touch pad if desired. This is how I prefer to run my GMT most of the time. Run in manual, update with Grab when needed, and tweak if desired.

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The ferrous discrimination on the GMT is far more nuanced than on most detectors, with the meter giving an "iron probability" reading. A LCD bar graph reading starts on the left and builds to the right hand side of the readout and indicates the relative probability that the target is ferrous. A real plus on this system is it always reminds the operator that the ferrous indication is never 100% - there is always a chance that ferrous reading is a gold nugget. The system will never give a reading of higher than 90% or less than 10% ferrous probability. Most systems tend to lull the operator into thinking they are more accurate than they really are, causing gold nuggets to be erroneously identified as ferrous. The GMT forces the operator to analyze the target more thoroughly and when there is any doubt, to dig it. The meter also helps identify iron based "hot rocks".

In other words, most ferrous target systems are audio based, with a setting that may or may not be adjustable. Targets deemed ferrous on a single pass are ignored and the operator does not even know the target existed. The GMT alerts the operator to every target to make sure it is thoroughly checked out as a detector is often wrong about a target on a single off-center pass. The downside is that where targets are thick this constant analysis can place more of a burden on the operator than a system that can be set to silently ignore most trash targets.

Running the GMT with the trigger switch in the locked forward position engages an audio discrimination circuit that gives an audio "grunt" whenever the iron probability exceeds 85%. This can quickly identify likely iron target without having to refer to the meter. This is a momentary indication that resets on each sweep of the target. It is normal for an operator to approach the target with a slightly different angle and speed on each sweep and so the iron probability indication will vary on each pass. The operator works the target and takes note of the reading on each pass to make a dig or no dig decision.

Squeezing the trigger activates a target analysis mode that automates this task for the operator. Each target response is accumulated and averaged building a more consistent response than that generated by the trigger forward setting. Targets will tend to consolidate and build either higher or lower probabilities with multiple passes. This does not mean the final reading is any more accurate however. A small nugget in highly mineralized soil will tend to read as ferrous, and relying on the analyze feature will give a false sense that the GMT is more confident in that erroneous ferrous response by accumulating and averaging many of them.

The fact is all ferrous identification systems suffer from the reality that some gold nuggets will read as ferrous if small enough or deep enough. High gain levels also increase the possibilities of inaccurate results. Some gold is actually in magnetite instead of quartz and can be picked up with a magnet! Nuggets of this type have a strong possibility of being identified as ferrous. Whenever possible a prospector should dig all targets. However, with practice a skilled operator of the GMT has a far more informative ferrous identification system at their disposal that if used properly will result if fewer gold nuggets being left behind as trash targets. Even if the GMT says the target is 90% probable ferrous it is still telling you it is a 10% chance it is gold. How lucky are you feeling?

1.89 Oz nugget found with White's GMT chest mount conversion

The meter itself opens up many features lacking in detectors without a meter. The battery check reads out on the probability meter indicating the percent battery strength when the momentary toggle switch is activated. If the batteries are not fresh, audio loudness on big targets will not be as great, but there will be no loss of sensitivity or performance because the GMT is voltage regulated to run properly at less that peak battery voltage. You can rest assured the detector is working properly until the meter reads out "SORRY, LOW BATT". Be sure to have backup batteries ready to change out when this occurs.

From the MXT Engineering Report referenced below "The GMT's circuitry broke a lot of new ground. It uses a reactive impedance transformation network to boost transmitter voltage for higher sensitivity. It uses an active transmitter regulator to keep transmitter voltage constant even when the search coil is moved over black sand that would blow an unregulated machine off the air." What this means is many detectors can actually go completely non-functional when operated over extremely mineralized ground and the operator will not even be aware of it. The GMT is very resistant to this occurring, but if it does the detector will give a loud audio "squawk" and the meter will read "BAD GROUND REDUCE GAIN". The GMT literally tells you your gain is set too high for the ground condition. Set the control lower until this message goes away for optimum performance.

The GMT can also overload on shallow oversize targets in which case the meter will display "METAL TOO CLOSE LIFT SEARCH COIL". The overload condition will correct itself when the coil is moved away from direct proximity to the large metal item. There actually are gold nuggets large enough to overload a GMT so find out what the item is!

The GMT constantly displays the ground balance setting, typically in the 70-80 range. This number is telling you what type of mineralization is affecting the GMT and is very much akin to the target VDI number displayed on coin detectors except that here it is a ground reading. The GMT goes one step father and also displays the amount of the mineral being detected. This is called the "Follow Black Sand" reading because it can be used to trace shallow black sand deposits that in turn can be used to locate gold deposits. A reference number in the upper right portion of the display shows this value. The number grows as the coil is pumped up and down over concentrations of black sand. The readings are relative so the idea is to take readings at various locations across a dry wash for example, and then to focus on the highest readings as being the probable location of a black sand deposit.

White's GMT control panel

When White's introduced the Goldmaster V/SAT it featured "Variable Self Adjusting Threshold" or V/SAT. The Goldmasters were the only nugget detectors for many years that allowed you to vary the rate at which the threshold readjusts itself via a variable control - 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 without responses being overly smoothed out. High settings demand a faster sweep rate as the detector adjusts rapidly to bring the threshold back to the level set by the threshold control knob. See Steve's Guide to Threshold Autotune, SAT & V/SAT for more details.

Finally, the GMT offers an optional Audio Boost setting that amplifies the audio by up to four times. This makes faint signals louder but in bad ground can also amplify ground noise. Still, this is an extremely useful function for eking faint targets out of the ground.

All these features added up to the GMT being vastly more popular than the Goldmaster 4/B that preceded it. The GMT remains a best seller to this day. The bottom line is the GMT bears serious consideration for anyone wanting a detector solely for gold nugget detecting. Although the GMT is intended solely as a prospecting unit, it is very popular with meteorite hunters, and it is also one of the best micro-jewelry detectors on the market.

Official White's GMT Page

White's GMT Instruction Manual

GMT Videos and Tuning Tricks

Forum Threads Tagged "whites goldmasters-gmt"

White's Metal Detector Forum

Read the MXT Engineering Report - Features some important notes on GMT design

*Notes on Technical Specifications - Detailed notes about the specifications listed in this chart.

The Makro Gold Racer metal detector was introduced in 2016 and is still in production. I very much anticipated the Gold Racer as something unique on the market at the time - a 56 kHz high frequency gold prospecting detector with all the extra discrimination and other features to make it versatile enough for other uses. What follows is a basic description with a very detailed review starting below the specifications chart. Note that Makro has introduced the 61 kHz Makro Gold Kruzer in 2018 and there is a possibility the Gold Racer will be discontinued soon in favor of this new model.

The Makro Gold Racer comes standard with an 10" x 5.5" DD coil and has optional 5" round DD, 10" x 5.5" concentric, and 15.5" x 13.25" DD coils. The Gold Racer has been changed slightly from the original Racer design to make the handle grip more comfortable based on customer feedback. The original Bluetooth dongle and wireless headphones have been replaced by a proprietary 2.4 Ghz design to help reduce the audio lag that was occurring with the regular Bluetooth design. The main item of note however is the very high 56 kHz operating frequency, making this one of the hottest machines available on tiny non-ferrous targets.

The Makro Gold Racer shares many features with the original Racer plus has added many more. The new iSAT control from the Nokta FORS Gold+ is visible as is another new feature called iMask. The Gold Racer adds a Tone Break feature often requested by Racer and FORS owners and the Gold Racer has the ability to save its settings when shut off, unlike the Racer. The layout of the control panel has also been simplified making what features are available in what modes much more obvious.

Makro Gold Racer metal detector

Makro is fast gaining attention as a company that listens to its customers. The new Gold Racer model is the perfect example of that, creating a unique machine based almost solely on feedback provided by customers in the prior year.

Official Makro Gold Racer Page

Gold Racer Color Brochure

Makro Gold Racer Instruction Manual

Ray Mills (TrinityAU) Makro Gold Racer Review

Makro Gold Racer vs Racer 2

Forum Threads Tagged "makro gold racer"

Makro Metal Detectors Forum

*Notes on Technical Specifications - Detailed notes about the specifications listed in this chart.

Detailed Review Of Makro Gold Racer by Steve Herschbach

Makro Gold Racer finds small Nevada gold

The Makro Gold Racer has been one of my most anticipated new VLF metal detectors in years. This completely new model represents something I have wanted for a very long time – a high frequency VLF metal detector that does not skimp for features, in particular as regards discrimination options.

A little background. First, I have been testing prototypes of the Makro Gold Racer, and this review is based on those prototypes. The final version due soon has a completely new LCD display layout, audio boost, refinements to other settings, and physical refinements like a change in the handle angle, etc. That being the case this review should be considered preliminary and final specifications are subject to change, as well as details you may see in my photos regarding the physical design of the detector.

Second, what is the intended market for the Makro Gold Racer? The machine looks deceptively like many other detectors aimed at general purpose metal detecting. I want to emphasize that first and foremost this is a gold prospecting detector. There are only a few other detectors that directly compare to the Gold Racer which is running at a very high frequency of 56 kHz. Comparable detectors would be the White’s GMT at 48 kHz, the Minelab Eureka Gold running in its 60 kHz setting, and the Fisher Gold Bug 2 at 71 kHz.

The intent with very high frequency detectors is to sharpen the response on extremely small metal targets. High frequency detectors are in a niche all their own when it comes to finding the tiniest of gold nuggets. This sensitivity does come at a cost however, in that the detectors are also responsive to ground mineralization and hot rocks that less sensitive, lower frequency detectors might ignore completely. There is no free lunch in detecting, and I want to caution anyone thinking that the Makro Gold Racer is going to be a magical solution to all their detecting desires to be realistic about things. Inevitably when new detectors come out people fall victim to wishful thinking, and I would like to try and avoid that here.

When it comes to reviewing detectors I do the best I can to describe detectors to help people decide if they might be interested in them or not. Do realize again however that this review is based on preliminary information. Also, I honestly do not want people buying new metal detectors based solely on my reviews. There will be some of who want the latest and greatest right now, and I appreciate that, but being a first adopter does have its risks. My normal advice to people is to never buy anything based on a single review, but to wait for more of a consensus opinion to emerge.

I have used the Gold Racer in the field, and I have found gold with it. Right now though if it is just a matter of you wanting to know if the Makro Gold Racer can find gold then I refer you to the excellent field review with photos posted by Ray Mills at the Detector Prospector Forum.

In outward appearance the Makro Gold Racer resembles its immediate predecessor, the Makro Racer, but this really is a new detector, not just a Racer running at a higher frequency. Feedback on the original Racer has been incorporated as well as extensive testing and commentary from prospectors around the world. Besides the obvious color difference, major physical changes include completely redesigning the layout of the LCD display to better differentiate what are all metal functions and what are discrimination functions. All metal functions are on the left, and discrimination functions are on the right. I think the new display is more intuitive and better accommodates the extra functions implemented on the Gold Racer.

The angle of the bend in the S rod handle grip has been relaxed based on feedback from Racer owners. The vibration mode was eliminated, shaving a tiny amount of weight and freeing up room on the display menu. The Gold Racer with stock 10” x 5.5” DD coil and NiMH batteries installed weighs in on my postal scales at exactly three pounds.

Coils available at launch are the 10” x 5.5” DD that is stock on the detector. Optional coils include a 10” x 5.5” concentric coil, 5” round DD coil, and a lightweight 15.5” x 13” DD coil.

Makro Gold Racer with 5" round DD coil

Let’s take a look at the functions. Under All Metal on the left side of the meter are the functions that apply only to the All Metal mode. On the right are the functions for the two Discrimination modes. The settings are independent in each mode, and once set can be saved when the detector is powered down. This simple and intuitive setup is also part of the power of the Makro Gold Racer. It is incredibly easy once each mode has been customized to flip quickly between the three modes, cross checking target responses to make a dig/no-dig decision.

All Metal is the heart and soul of nugget detecting, and the Makro Gold Racer has an extremely powerful, smooth, and sensitive threshold based all metal mode. The Sensitivity setting is familiar to anyone who has used a metal detector, except that there are three base levels of sensitivity or gain. Significant boosts occur between 39 - 40 and again between 69 - 70. Most detectors max out at what is a setting of 69 on the Gold Racer. Settings of 70 and above are a type of hyper gain setting that takes the machine above and beyond, but in extreme ground overload signals may occur. Overload signals are indicated by a “warning siren” audio and the machine is telling you that there is either a large metal object under the coil, or that you are encountering extreme mineralization. In the case of mineralization, either raise the coil slightly while scanning, lower the sensitivity setting, or both. Overloads occurring at 70 will almost always be eliminated by dropping to 69.

Rest assured very little is lost by lowering sensitivity to 69 or below, again, because many detectors cannot be set as hot as the Gold Racer even at their maximum setting. Do you ever run detectors and have the distinct feeling some performance has been left on the table, because the detector can always be run at maximum settings? Makro has given you that extra power for where it can be used, but in doing so they expect you will lower settings in places where that extra power works against you. Luckily, the audio alert makes it easy to know when this is. Most people do not know it but many detectors simply shut down and quit working under similar conditions with no indication at all to the operator, a situation referred to as “silent masking”.

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The threshold setting is the normal control that sets the volume of the slight audio tone that is key to any experienced nugget hunter finding the tiniest or deepest gold nuggets. The most minute variations in the threshold tone can indicate a gold nugget, and the ability to read the threshold is what sets most really good nugget hunters apart from everyone else. Makro has added a feature to the Gold Racer called iSAT, for “Intelligent Self Adjusting Threshold”. This setting consists of several levels of adjustment that vary the rate at which the threshold tone steadies itself. Higher levels of iSAT smooth the threshold more aggressively which aids in maintaining a smooth threshold in rapidly varying ground. Lower levels allow for faint variations to be heard more clearly in milder ground for extra depth and sensitivity.

The Gold Racer can be ground balanced three ways. Holding the trigger switch under the control pod in the forward position activates an instant automatic ground balance. Just pump the coil over the ground a couple times, release the trigger, and you are done. There is a short delay when you release the trigger, and during this delay you may manually adjust the ground balance setting. The instant ground balance is neutral to slightly negative. Those that like a slightly positive ground balance need only perform the instant balance, then tap the right hand control button three of four times.

The Tracking function on the control panel engages and disengages automatic ground tracking. This is most useful where the ground conditions vary wildly, a perfect example being mixed cobble piles or river bars. The tracking is very quick yet resists tracking out genuine gold signals as much as possible. This can also be an aid to anyone new to ground balancing detectors as it makes the process entirely automatic.

The Backlight setting adjusts the illumination level of the backlit screen. The FD/Save setting allows adjustments to be saved when the detector is powered off, while the FD function resets Factory Defaults. There is also a Frequency Shift setting to help eliminate outside electrical interference from power lines, or another Gold Racer being operated nearby. This is set through a combination of control buttons but not visible on the menu. Finally, although this is a true threshold based all metal mode, the meter acts independently in discrimination mode at all times and indicates target id information when the signal strength is sufficient to do so.

Easy to read well designed screen

Under the Discrimination menu are settings that are completely separate from the All Metal settings and also saved or reset separately. Disc 1 is a standard two tone mode with low tone ferrous and higher tone non-ferrous. Disc 2 is a similar but deeper, more powerful mode. Quick switching between these two modes, each with fully independent settings, creates a many layered and subtle approach to target discrimination. Both discrimination modes are silent search, no threshold based systems. However, new to Makro models is the ability to set the point at which low tones flip, or “break” over into being higher tones. Typically 39 and lower target id will cause a low tone, and 40 and above a higher tone. This ability somewhat replaces the three tone mode on the original Racer because by increasing the Tone Break setting it is possible to create various coin detecting scenarios. For instance, all targets with an id number below copper penny could register low tone, and therefore copper pennies, dimes, quarters, and dollar coins a higher tone.

Conversely, lowering the Tone Break setting would create a more conservative approach for nugget detecting by accepting a little more ferrous digging in return for possibly finding another nugget or two.

The Sensitivity control on the Disc menu is the same as but independent of the All Metal setting of the same name. ID Filter is a variable discrimination control, with higher settings eliminating or blanking out id numbers lower than the current setting. This setting is independent for each Disc mode, and again flipping back and forth can create some interesting scenarios for comparing targets at completely different sensitivity and ID Filter levels. This quick mode switching between All Metal, Disc1, and Disc2, all with independent settings, is a very powerful tool once you get used to it.

Also new with the Gold Racer is the iMask setting. I noted at the start of this review that all metal detector designs involve making trades of some sort. Extreme high frequency sensitivity to small metal targets does increase chatty false responses in extreme ground when in the discrimination modes. iMask attenuates or suppresses weaker target responses in the discrimination modes and provides a secondary level of adjustment separate from and in addition to the Sensitivity and ID Filter settings. If the detector is producing lots of quick, spurious signals in the discrimination modes, reducing sensitivity or increasing ID Filter settings or both is the first line of attack. If this does not work, go back to the original settings on those functions, and try increasing the iMask setting. If this does not work, again lower sensitivity or increase the ID Filter or both on top of the current iMask setting. iMask acts as a pre-filter giving an extra level of control to help deal with extremely bad ground conditions. Finally, Disc1 is a less aggressive mode than Disc2, so using Disc1 offers even another level of possible options when dealing with bad ground in the discrimination modes.

The Backlight setting is independent for the discrimination modes, as is the Factory Default/Save Settings function. I think it goes without saying that there has never been a high frequency metal detector ever produced with this level of options and control. There are a lot of variables to play with here, and I would not be truthful at all if I said I have this machine all figured out. In fact, I think part of the fun with the Makro Gold Racer is we are entering uncharted territory. Until the final version of the machine is released, and until quite a few people get their hands on it and experiment, it is very difficult to say just what applications creative detectorists may find for the Gold Racer. It is a very powerful VLF gold prospecting detector, I can vouch for that. Applications also may be found for jewelry detecting and relic hunting in particular, and even coin detecting, due to the unique combination of features the Makro Gold Racer offers.

OK, finally – some notes on real world use! Again, this is all based on prototype models and so I can only speak in generalities for this report. However, there is no doubt in my mind that even the prototype detectors rival anything currently available in a VLF detector for finding tiny gold nuggets. I can easily locate flakes of gold weighing under one tenth grain with the Gold Racer and the stock 10” x 5.5” DD coil. In fact, the machine is so hot with the stock coil I thought using a smaller coil offered minimal if any benefit, mostly because of lost ground coverage and possibly lost depth on larger nuggets. I would only use the smaller coil myself for nooks and crannies where the stock coil can’t fit, but otherwise the stock coil really is the way to go in my opinion. Keep in mind I did say grain not gram. There are 480 grains per Troy ounce and in my opinion I can find flakes all day long with the Gold Racer that weigh less than 1/10^th grain, or less than 1/4800^th ounce.

Smallest nugget unweighable, largest 2.4 grams

In trashy locations I generally preferred running in all metal and just checking the meter for ferrous targets, which tend to lock in hard at 21 or 22 on the numbers. In theory anything under 40 is ferrous, but to be safe I might investigate items as low as 35 or even 30 depending on the situation and amount of trash. However, as I noted most ferrous locks in hard around 20 leaving no doubt what the target is. In All Metal mode very tiny or very deep targets beyond discrimination range give no target id at all, automatically meaning they need investigation. The main reason I prefer to always hunt in All metal is the extra depth and sensitivity it affords, and checking targets visually is very quick and more efficient than toggling back and forth to a Disc mode under normal circumstances.

For areas with too much trash where meter watching might get to be a bit too much, I normally use one of the disc modes set for two tone ferrous/non-ferrous. Iron targets just burp away, while non-ferrous target pop out with a beep. If even that got to be too much for some people, increasing the ID Filter to eliminate most ferrous responses completely can make for a quieter experience in really trashy locations. As always, I must include the warning that the more discrimination applied, the more risk of missing a good target. Use no more discrimination than needed to preserve your sanity!

I used the Gold Racer to hunt a couple trashy areas where I just could not go with my big dollar all metal machine, and easily located nuggets in the midst of trash. For me personally the Makro Gold Racer fills in two areas where the high price big gun detectors come up short. The ability to find the tiniest, most dispersed gold possible, both in flake form or enclosed in specimen rock. And the ability to deal with really trashy areas where good discrimination is needed.

Perhaps the biggest surprise for me was when I decided to give the 15.5” x 13” DD coil a try. Honestly, I did not expect much from it. You normally do not see a coil this large for high frequency machines because the ground feedback usually overwhelms them, negating any gains that can be had regarding depth. Instead, the Gold Racer seemed to be even better behaved with the larger coil than with the smaller coils. I hunted some cobble piles with it and it ran smooth as can be at higher sensitivity levels. I then wandered into some moderately hot ground with it, still with no problems, and was actually surprised when I came up with a couple small gold nuggets with it. The first was only 0.8 grams which I thought was pretty fantastic. So I put a little more effort into it, and found a 0.3 gram nugget. With a 15.5” x 13” DD coil on a VLF? That is really kind of unheard of, and I was thoroughly impressed. I am not sure what is going on there but I do know the Makro detectors can sense what coil is on the detector. Something different going on with that big coil? I don’t know, but the results and performance surprised me. Also surprising was that for such a large coil it actually was not bad swinging it for half a day. That could be from my using large, heavy detectors all summer however. Still, it was an eye opener all around and changed how I think my Gold Racer might get used in the future. It looks to have more use for covering very large areas blue sky prospecting than I would have imagined.

The 15" x 13" DD coil is unique for detectors running in this frequency range

I would be remiss if I did not include at least a note on the versatility possible with the Gold Racer. I recently took it to a local park. Now, my ground in Reno is screaming hot, full of magnetite. The mineral percentage graph on the Gold Racer and similar machines all come up one bar short of maxed, and ground balance numbers run around 88-90. A magnet dropped in this stuff comes up with a lump of magnetite. As a result getting accurate target id numbers with even the best coin detectors past 5” is a chore. I know that sounds crazy but it is the truth. I ran the 5” DD coil and even then had to back the sensitivity down to 69 to prevent overloads in the worst areas.

One thing about the Racer detectors that I have heard people complain about, and that is that they tend to up average target numbers in bad soil. For me this is a good thing. Many detectors will see target id number average lower in bad ground, and so fringe targets are more likely to get identified as ferrous when they are in reality non-ferrous. This is obviously not a good thing for nugget detecting. The Racer and the Gold Racer both tend to up average, and so targets like lead sinkers or aluminum that you would expect to give lower numbers often give coin like responses with the Racers. It is odd to see in practice. I got a good high signal reading near 80 at about 5” that when dug up turned out to be a common round lead fishing sinker. Out of the hole the target id promptly dropped to about 45. This effect whether by design or by accident is common with European detectors. I think it is by design because first and foremost these machines are made to pull non-ferrous targets out of ferrous trash. Improperly identifying a non-ferrous item as ferrous is the worst possible result, and so up averaging helps insure that non-ferrous items will not be missed. However, it also means these types of detectors are not as efficient at cherry picking coins as common coin detectors are. You get the coins for sure, but you dig more trash doing it.

Still, I experimented a few hours and if you are content to live with the limitation I just described you can actually make some good finds with the Gold Racer under almost any conditions. The ID Filter works very well, and by just running it all the way to 79 it was easy for me to cherry pick a few coins though larger aluminum items like screw caps or big pull tabs often came up in the 80s also. I do think this is a result dependent on ground conditions to some degree, but really the Gold Racer is best suited for people like me who want to recover all non-ferrous targets. I prefer to hunt jewelry rather than coins myself, as one gold ring makes up for a pile of coins. And to hunt jewelry you have to dig aluminum, no two ways about that. The Gold Racer will suit me well hunting jewelry, especially micro jewelry like ear rings and fine chains.

This report is very long, and yet I really am just skimming over the features and possibilities inherent in the Makro Gold Racer. I will close by once again noting that while everything regarding the Gold Racer is pretty much set in stone at this point, last second changes are possible. Look for more soon when the factory production models hit the street. I also get frustrated when people want information on new units, but then turn right around and characterize reports trying to provide that information as hype or a sales pitch. I have tried my best here to just present what facts I can without leading anyone to think that the Gold Racer is anything other than what it is. And that, in my opinion, is a very interesting, unique, and capable metal detector. I look forward to hearing for myself in the future what people think about it and the applications and tricks they come up with, because you pretty much need to toss anything you think you know out the door when approaching this machine.

Many thanks to the folks at Makro and in particular Dilek Gonulay for providing me with the opportunity to be one of the first to use the Gold Racer. I admit that VLF detectors were beginning to bore me, and the Gold Racer has reignited my interest in seeing what they can do for me.

~ Steve Herschbach
Copyright © 2015 Herschbach Enterprises

Nokta Detectors is a new name to most people in the United States. Nokta Engineering is a company based in Istanbul, Turkey since 2001. The FORS Gold+ is an update of the earlier FORS Gold and is aimed at the prospecting market. The Nokta FORS Gold+ was introduced in 2015 and was discontinued in late 2018. The Nokta FORS Gold+ has been replaced by the Nokta Anfibio 19, new for 2018.

The main changes in the FORS Gold+ include boosting the frequency from 15 kHz to 19 kHz which should enhance the sensitivity to small gold. The stock coil has been changed to the 10" x 5.5" DD coil popular with gold prospectors and a 5" round DD coil is also included. The smaller coil is good for working nooks and crannies and will provide the best sensitivity on the smaller gold nuggets. Optional coils include a 10" x 5.5" concentric and 13.3" x 15.5" DD. The concentric is new for Nokta and offers extra performance in mild ground combined with more accurate ferrous identification properties for trashy locations.

A very new feature is what Nokta is calling the iSAT control. This allows a person to customize the threshold retune rate for ground conditions. A fast threshold retune smooth's ground responses but can also smooth faint gold signals. A slow retune rate can enhance faint signals but also enhance false ground responses. The amount needed varies with ground conditions and the type of gold being found. This setting is preset in most detectors and so by including it Nokta is offering a degree of control not possible on many prospecting detectors.

Finally, the three tone "coin mode" on the original FORS Gold has been replaced by a Fast retune two tone discrimination mode suited for hunting bad ground. This is in addition to the already existing Boost discrimination mode for work in milder ground.

The Nokta FORS Gold+ comes with two coils - 5.5" x 10" DD and 5" round DD

Here are some details in the three modes offered on the FORS Gold+. There is a true threshold based all metal mode that has no discrimination control. There is no variable discrimination in this mode but the on screen target id does kick in for targets in discrimination range. Because all metal reaches deeper than discrimination modes the deeper targets will give an audio signal but no on screen target id number. This is how you locate deep targets beyond what a discrimination mode can detect.

Then you have preset two tone discrimination modes. In two tone mode it is low tone ferrous and high tone non-ferrous. These discrimination modes are "silent search" with no threshold sound.

In both the disc modes you have a variable control called ID Mask. It is just like the control on a single knob disc machine, up and down with anything below the setting rejected. This is on top of and in addition to the tones. However, ID Mask is not like on most detectors where it starts at iron and goes up from there. The control starts all the way down in the ground range and goes up from there. This is important because many detectors cannot be set for a true "zero disc" mode but always have a little iron discrimination built in even at minimal settings. The FORS are like other Euro machines that let you fine tune the ferrous responses for extracting targets out of thick ferrous trash. This combined with the small coil makes it deadly in ferrous trash.

Nokta FORS Gold+ 19 kHz gold nugget detector

ALL modes always have an active on screen visual VDI number. If you want you can run ID Mask very high to eliminate foil or aluminum or whatever on the high end, but like other machines you will lose nickels if you go too high. There is no notch function. Run ID Mask up to just below nickel range. Now you get no signal on targets that fall below nickel, nickel on up will produce a high tone.

My FORS reads 56 on a nickel. If I turn the ID Mask up to 56 it still accepts the nickel. If I turn it to 57 nickel breaks up badly. At 58 nickel is gone.

There is no threshold in the disc modes so no threshold nulling. The rejected targets are simply gone, and nothing pops up on screen for VDI. So on screen VDI is not 100% independent of settings.

If you turn the ID Mask up to 99 nothing goes beep so the control operates over the entire discrimination range unlike many detectors that do not allow the control to run into the coin range. The ID Mask control has exceptional range all the way from ground on one end up to silver coins and above on the other end.

I like the out-of-box thinking Nokta is displaying in the design of their detectors. The FORS Gold+ has a small LED flashlight built into the handle to illuminate the work area in low light conditions or to just use as a flashlight when you get back to your vehicle in the dark. The two coils, both manual and automatic ground tracking, 19 khz, new iSAT control, dual discriminate modes, and more all add up to a metal detector worth very serious consideration. The new discounted price of $578 with two coils makes this a real bang-for-the-buck option for those wanting a full featured nugget detector at a great price.

Nokta FORS Gold+ Color Brochure

Nokta FORS Gold+ Instruction Manual

Nokta FORS Gold+ Photo Tour

Forum Threads Tagged "nokta fors"

Nokta Metal Detectors Forum

*Notes on Technical Specifications - Detailed notes about the specifications listed in this chart.

The Tesoro Lobo SuperTRAQ detector was released in 1997 and was discontinued in 2019. It is also referred to as the Lobo ST. I have had some experience with the Lobo over the years and have seen a lot of gold found with it. See Detecting for Gold with the Tesoro Lobo and Metal Detecting for Gold at Ganes Creek, Alaska at Steve's Mining Journal.

The Tesoro Lobo SuperTRAQ replaced the earlier Tesoro Lobo, which was produced from 1989 - 1997. The main difference between the two units is that the earlier model lacked automatic ground balancing, the SuperTRAQ signature feature. Be aware that coils for the earlier Lobo do not work on the newer model. The The old coils had a female coil connection and the new coils have a male pin connector. The original Lobo is listed at running "at approx. 20 kHz" while the Lobo ST runs at 17.8 kHz. Note: The Lobo ST is also quoted widely as running at 17.5 kHz. The latest spec posted on the Tesoro website is 17.8 kHz.

Another change in the old Lobo versus the new SuperTRAQ is that when the old model was manually ground balanced, the ground balance carried over in both all metal and discriminate modes. The new SuperTRAQ automatically tracks ground conditions while in all metal mode. When switched into discriminate mode, the automatic ground tracking is disabled and the unit uses a factory pre-set ground rejection. This is a less than desirable situation. In all metal nugget hunting mode it is impossible to disengage the automatic ground balancing system. Very small or very deep nuggets that generate a minimal signal are at great risk of being tracked out. Conversely, in discriminate mode there is no ground balance at all except what the factory has chosen for you.

Tesoro Lobo SuperTRAQ metal detector

Despite the lack of flexibility in ground balancing there is no doubt about one thing - the Lobo is one of the easiest detectors for a novice nugget hunter to learn. The lack of manual ground balance contributes greatly to the machine being very easy to operate, and this is a important feature in itself. The Lobo is a very forgiving metal detector.

My main experience with the SuperTRAQ came with my involvement with Moore Creek Mine in Interior Alaska. The mine produced a lot of large gold nuggets but also had hot rocks in the form of highly magnetic basalt cobbles. After trying just about every VLF detector made we decided the Lobo SuperTRAQ handled the ground as well or better than any other VLFs available at the time. The automatic ground balance smoothed the hot rock responses and in a worst case scenario the unit could be put in discrimination mode. Dialing in a discrimination setting of 1.5 eliminated the hot rocks and nearly all ferrous trash responses while still responding well to larger gold. The SuperTRAQ produced a lot of gold at Moore Creek over the years we operated the mine.

The Tesoro Lobo SuperTRAQ is getting somewhat dated in that most of the competition offers target id meters but it is still a very versatile detector. It is very easy to operate. It also is one of the few nugget detectors still produced that allow the control box to be hip or chest mounted, a very desirable feature for those working in and around water. It also has a very good coil selection, including the rare ability to run a 3" x 18" sweeper coil (Tesoro Clean Sweep).

Official Tesoro Lobo SuperTRAQ Page

Tesoro Lobo SuperTRAQ Instruction Manual

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Tesoro Metal Detector Forum

*Notes on Technical Specifications - Detailed notes about the specifications listed in this chart.

The Garrett AT Gold was released in 2011 and is still in production. It is a variation of the excellent Garrett AT Pro metal detector, but modified slightly to make it a better detector for prospecting. Garrett really raised the bar in the detecting world with the AT models. These detectors are waterproof to ten feet yet give up none of the features one would normally expect in an above water detector. They even have an external speaker for use above water which can be submerged without harm. Best of all you pay no penalty in either weight or price. The Garrett AT models provide exceptional value in metal detecting.

The AT Pro is a 15 kHz detector that features full notch discrimination. The lower frequency means that it can be used in salt water. It also allows for custom discrimination, such as tuning out coins to concentrate on likely jewelry targets. The AT Pro lacks a true threshold based all metal mode and so is less suitable for nugget detecting, although it can and will find gold nuggets.

The AT Gold runs at a slightly hotter 18 kHz and has a true threshold based all metal mode. This makes it a better nugget detector than the AT Pro. However, it is too hot to run on wet salt sand or in salt water. It also has only a couple preset discrimination patterns and so lacks the custom discrimination ability the the AT Pro has.

The AT Pro and AT Gold both have three search modes. The first is a discrimination mode preset to accept all items with an audio beep in different tones and a visual target id. Pretty much everything goes beep, but you can adjust the level at which iron/steel is rejected completely, and this is saved when the detector shuts off. The mode is preset and only the iron rejection level may be modified.

Garrett AT Gold metal detector for gold prospecting and more

The second mode is a preset discrimination mode with light foil and pull tabs set to audibly ignored. A so-called coin pattern that eliminates common trash but beep on common coins. Again, only the iron rejection level may be set and saved. The rest of the pattern is preset and cannot be adjusted.

The AT Pro has a third discrimination mode, a fully adjustable notch mode. Notch refers to the ability to set certain non-ferrous items to be accepted or rejected in ranges or "bins". The non-ferrous discrimination range is split up into sections or "notches". For example, all foil items may fall into a range of 0-20 on a scale of 0-99 and so would be said to fall in the 0-20 section/range/notch/bin. That 0-99 range can be split up into several notches and this varies by model. On the AT units you get 12 non-ferrous notches.

Garrett AT Gold with 5" "sniper coil"

An independent adjustable notch system lets you decide what sections get accepted and what get rejected. For instance, you could decide you are looking for something that reads like a nickel and set only the nickel range to beep, all other ranges get ignored. All nickels and items that read like nickels would go beep, and that is it. Or, you can set all non-ferrous items EXCEPT the nickel range to go beep, and ignore the nickel range. The AT Pro in the third search mode allows you to create a custom notch program and save it.

Again, both units treat ferrous items the same. You can adjust how the ferrous targets respond and save the setting. It is only in how non-ferrous targets are treated that the units differ.

The third search mode on the AT Gold is a pure unfiltered all metal mode. All items are detected, with significantly more depth. The all metal mode has an adjustable "iron audio" feature that will identify strong ferrous targets with a low or broken tone. The all metal mode also features a unique ground balance "window" that can expand beyond the normal area spanned by a ground balance control in order to eliminate some types of hot rocks.

Gold nuggets found with Garrett AT Gold

So on the AT Pro the third mode is an adjustable notch discrimination mode, on the AT Gold it is an unfiltered all metal mode. Finally, the AT Pro comes with an 8.5" x 11" DD coil whereas the AT Gold comes with a smaller 5" x 8" DD coil.

I think the Garrett AT Gold is an exceptional detector and for anyone wanting to use a VLF detector in and around water it is an obvious choice. Do note that while the detector itself is submersible the headphones that come with it are not. To actually use the unit face in water with mask and snorkel requires optional fully submersible headphones.

The depth of detection, sensitivity, and ground handling are on par with other 18 kHz nugget detectors. However, if the waterproof feature is never going to be needed (desert detecting?) then the special lubricated O-ring connectors for the headphones and coils add service issues that can be avoided with a normal dry land model. Therefore I think the decision to get a Garrett AT Gold depends in large part on whether the waterproof design is actually needed or not.

Official Garrett AT Gold Page

Garrett AT Gold Instruction Manual

Forum Threads Tagged "garrett at"

Garrett Metal Detectors Forum

*Notes on Technical Specifications - Detailed notes about the specifications listed in this chart.

The Fisher Gold Bug Pro was released in 2010 and is still in production. It is the final version of a series of new digital Gold Bug releases intended to replace the older analog Gold Bug models. The easiest way to tell the new Gold Bugs from the old Gold Bugs is that the new models sport a prominent digital readout. The model is also marketed separately by First Texas, Fisher's parent company, as the Teknetics G2. The G2 has a different rod and handle assembly and comes standard with the 11" elliptical DD coil for slightly more money. The Gold Bug Pro comes standard in three versions - with a 5" round DD coil (actually 4.7" diameter), or with the 7" x 11" elliptical DD in which case it is called the Fisher Gold Bug Pro DP. Finally, there is a dual coil package the includes both the 5" round DD coil and the 5" x 10" DD coil. In addition to the three coils mentioned here DeTech markets the 13" Ultimate DD coil for the G2 that will work on the Gold Bug Pro. For more information see the Guide to Different Versions of the Fisher Gold Bug.

I have come to rely on the Gold Bug Pro as my general purpose prospecting detector for when I want a unit that can handle trashy areas. I appreciate its light weight and simplicity in getting the job done. I prefer to run the detector in all metal mode for the best depth and sensitivity. The nice thing is that the meter always displays possible target ID information to help make digging decisions without having to switch or toggle to another mode. This is far more efficient in the field not to mention wear and tear on switches. I prefer the 5" x 10" DD coil for general use - it is too bad Fisher does not sell the Gold Bug Pro with that as the stock coil. The only way you can get it is as a package deal or as a separate accessory item.

The only thing I wish was that instead of displaying the ground phase as a large number while in all metal mode the Gold Bug Pro instead displayed the possible target ID number. The target ID is displayed on a small "racetrack" display above the ground phase number. I rarely if ever need to know what the ground phase is but I constantly refer to the target ID. Hopefully this will be addressed in future versions.

Fisher Gold Bug Pro - Gold Bug DP variant (7" x 11" DD coil)

I normally hunt in all metal. The detector hits all targets with the same audio signal except the stronger the target, the stronger the signal. There is a little "speedometer" target id readout in all metal above the big ground phase reading and so after hearing target I work it and eyeball the reading. If you get no target id it is target deeper than disc can hit (all metal prospect mode goes deeper than discriminate mode) so dig until you get target id or target.

You need to decide on what target id to dig and what to pass. In theory all 40 and above is non-ferrous so in theory just dig all 40 and higher. Reality is small gold or very deep gold can read iron. I usually opt for digging some iron, and so depending on types of ferrous trash and ground mineralization the actual number I choose may be 35-39, usually 38.

Then, and this is key, work the target. If the number bounces even once to or above your chosen break point, dig. The numbers bounce around, and if they consistently read at or below your chosen reject number, for example 38, if the number is always 38 or lower pass it up. If it bounces even once to 39 or higher dig it. Again, number picked depends on actual ground conditions. Start lower, maybe 35, then adjust upwards after digging targets. As long as you are not digging too much ferrous stay put but is too much digging adjust higher. VLF discrimination can and will lie on small or deep gold so better conservative and digging at least some ferrous than leaving gold.

Fisher Gold Bug Pro with 5" x 10" elliptical DD coil

Ok, let's assume too much trash, to many signals to analyze each one. Go to disc mode. Immediate depth loss! But now we can set target id audio break point. The unique tone disc system has three tones, mid tone, low tone, and no tone (target rejected). You can move range but it is not totally adjustable. The low tone area compresses as the disc is set higher. If you set low tone cutoff at 30 all target below 30 make no sound at all and all passed up. You never know they are there. 30 to about 55 will be low tone, meaning most gold and small ferrous, 56 and above will be mid tone, usually brass but maybe big nuggets. There is no high tone on the GBP.

You can adjust this potential gold tone range to a certain extent. Set at 35 and nothing below 35 reports, 35 to maybe 60 (doing this from memory so may be off a bit on the numbers) will be low tone, above 60 mid tone. Or if trash really is bugging you set at 39 so only 40 and above beeps.

But because some targets read mostly ferrous but bounce non-ferrous at times it is a fuzzy choice. If you set for 40 and above and small nugget reads 38 on first pass, you miss it and never know it was there. At the end of the day it depends on trash level and how much target analyzing you want to do in the fuzzy zone. Most small nuggets actually read around 50 but again all depends on gold size, shape, purity, ground mineralization and other factors.

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Lots of nuance in what is a deceptively simple detector. The more I use it the more I appreciate it. In all metal with 11" x 7" DD it approaches PI depths on most average size gold in moderate to mild ground. I very much like having the dual ability of hunting in all metal while having visual target id. No toggling back and forth.

I not only use the Gold Bug Pro for prospecting but for jewelry detecting. It is a not the best coin detector in the world but does well, especially in trashy areas with the little 5" coil. All in all a great little machine, one I can swing high and low all day long with little fear of arm strain. I highly recommend the Gold Bug Pro for anyone looking for their first nugget detector or for old pros like myself wanting something light, simple, and effective.

Official Fisher Gold Bug Pro Page

Download the Fisher Gold Bug Pro Instruction Manual Here

Guide to Different Versions of the Fisher Gold Bug

Forum Threads Tagged "fisher gold bug"

First Texas (Fisher) Metal Detectors Forum

*Notes on Technical Specifications - Detailed notes about the specifications listed in this chart.

Two basic technologies are described here; Induction Balance (IB) and Pulse Induction (PI). Induction balance is often referred to as VLF, or very low frequency. This is a misnomer, as some gold nugget detectors and some coin detectors are not very low frequency units as normally defined. VF = Voice Frequency = 300 Hz - 3 kHz, VLF = Very Low Frequency = 3 - 30 kHz, LF = Low Frequency = 30 - 300 kHz. Most IB gold detectors operate in the Low Frequency Range and quite a few coin detectors operate as low as the Voice Frequency range. Pulse Induction (PI) detectors operate over hundreds of frequencies employing a totally different technology than IB detectors but can be best imagined from an operational standpoint as Low Frequency detectors

Internet Price - Manufacturer's often publish manufacturer suggested retail prices (MSRP) intended to set the full value of an item. In the United States they also will often set a minimum advertised price (MAP) that determines the lowest price that can be used for advertising purposes. Note that this is not the lowest price an item can be sold for but instead is what you will normally see in print ads or online as the lowest advertised (sale) prices. The Internet Price in the chart is the normal advertised sale price as commonly found on the internet as of the date listed. Dealers will often try and sweeten the deal by including "free" items in the advertised prices. You can often negotiate a lower price by contacting the dealer requesting a lowest price for the item without all the "free" package items.

Technology - The basic operating technology a detector uses has a huge impact on how it behaves. Early consumer 1960's model detectors commonly employed a method referred to as Beat Frequency Oscillator (BFO). This simple design can be built by a school child with a handful of components. The search coil or loop was literally a coil or loop of wire. They are noted for making a distinctive "putt-putt-putt" continuous beat. The beat increases as a target is detected and the BFO responds to both conductive metals and magnetic minerals. The early 1970's saw the appearance of the Induction Balance (IB) detector. The IB detector employs two coils, a transmit and a receive coil, that are kept in electronic balance. They were therefore also commonly referred to as Transmitter/Receiver (TR) and that term saw more popular use. The TR produces a steady tone that increases in volume and the early TR models, like the BFO, responded to both conductive metals and magnetic minerals.

The BFO and TR were both very limited because their ability to detect magnetic minerals interfered with their ability to detect conductive metals. An IB or TR variant was developed that allowed the detectors to not only eliminate the signal from ground minerals but to discriminate between various metals. These detectors ran at lower frequencies than the TR models and referred to as Very Low Frequency (VLF) detectors. Dual mode models existed, the VLF/TR, but the TR modes were so limited they were eventually dropped in favor of pure VLF operating modes. Almost all such detectors are referred to as VLF detectors today, but VLF is actually a misnomer. In electronics, VLF refers to the 3 kHz - 30 kHz frequency spectrum. There are detectors operating at under 3 kHz, and so technically they are Voice Frequency (VF) detectors. There are also many models operating over 30 kHz which are technically Low Frequency (LF) detectors, although because they are operating at higher than VLF frequencies many people refer to the as "high frequency" detectors. Therefore on this website the more technically correct term Induction Balance (IB) will be used.

This is important because IB detectors are dramatically different than the other major technology employed at this time, the Pulse Induction, or PI detector. The IB detector requires two coils or loops that continuously transmit and receive in electronic balance. The PI detector requires only one coil but may use two. Rather than transmit and receive continuously, the PI detector transmits, pauses, then receives, which can be done with a single coil. The PI detector is able to ignore salt water and mineralized ground that an IB has difficulty with. This makes PI detectors particularly well suited for salt water diving applications, and that is where most consumer models have been aimed over the years.

Simple PI detectors are often advertised as having "automatic ground rejection" but that is not strictly true. A normal PI will ignore common ground conditions, but they still are affected by highly mineralized ground and hot rocks, and so are not suitable for most prospecting applications. A company in Australia recognized the potential however, and developed PI detectors aimed specifically at the prospecting market. These detectors do actually ground balance, or tune out the effects of highly mineralized ground and hot rocks, and so along with other models now on the market represent a subset of the PI detectors, the Ground Balancing Pulse Induction (GBPI) detector.

Frequency - Induction Balance (IB) detectors as radio devices normally operate on one of more frequencies that govern certain operating characteristics. The transmit frequencies are often quoted but what is most important is the frequencies the detector receives and actually processes. Most detectors receive and process a single frequency but a few detectors receive and compare the results of two or more frequencies. The focus on frequency has lead some marketing people to advertise multiple transmit frequencies in ways that are a bit misleading because people assume more is better. The reality is single frequency detectors excel at some tasks and multi-frequency detectors at others. Single frequency detectors can be better honed for specific tasks, such as nugget detecting. Multiple frequency detectors are better able to handle salt water environments and generally excel at target discrimination. In general, the higher the frequency, the more sensitive the unit is to small gold, but also more affected by mineralized ground and rocks. Lower frequencies penetrate mineralized ground better but are less sensitive to small nuggets. Multiple frequency detectors have historically acted like lower frequency detectors but newer models are so sensitive as to be practical for gold nugget detecting. Frequency article

Pulse Induction (PI) detectors are sometimes advertised as using huge numbers of frequencies, which is technically true, but again is the marketing people going to work. Operating frequencies on IB detectors do not really equate with PI detectors which operate on a different principle. The closest specification in a PI detector that has some bearing on the operating characteristics is the Pulse Frequency which is the number of times the transmitter pulse is repeated every second. It is usually quoted at Pulses Per Second (PPS). The pulse frequency affects the response time (slower PPS call for slower sweep speed), power consumption (higher PPS uses more power) and interference rejection (adjustable PPS helps adjust out electromagnetic interference).

Pulse Induction (PI) detectors again are a special case, and the sensitivity to small items and ground minerals is more affected by the Pulse Delay than the Pulse Frequency. The Pulse Delay is the wait time between the transmit mode and receive mode. The shorter the delay, the more sensitive the detector is to small items and hot rocks. In theory a PI can be just as sensitive as an IB detector by operating at extremely short delay times, but then it would suffer the same problems as an IB detector. PI detectors designed to hunt gold often have a pulse delay of about 10uS (microseconds). Salt water however signals at 10uS so salt water PI detectors often run about 15uS. Some PI detectors can have an adjustable pulse delay that commonly runs from 10uS to 25uS.

Autotune Modes - Almost all modern detectors require the search coil to be in motion over the target to get a response. Nugget detectors employ automatic threshold tuning, which acts to help keep the threshold tone even in variable ground. The circuit seeks to return the threshold to a level preset by the threshold control. The retune rate can vary from slow to fast and in some cases can be adjusted by the operator. Holding the coil stationary over the target causes the target to disappear as the autotune circuitry brings the threshold back to the preset level. Detailed article

Ground Rejection - Ground rejection or ground balance can be set at the factory (Pre-Set), manually set by the user (Manual) or automatically track ground conditions (Tracking). Fixed refers to units that lock in whatever setting the automatic system has at any moment but which cannot be manually adjusted. Manual adjustment allows a unit to be purposefully adjusted to specific conditions that cannot normally be attained through manual or fixed settings. The preferred option is to have both tracking and manual ground balance systems. A compromise between manual ground balance and ground tracking is an automatic "Grab" function. This allows the unit to be ground balanced by pressing a button. The ground balance setting is obtained instantly or with a few pumps of the coil over the ground.

Soil Adjust - This refers to a control that allows the operator to adjust the unit for basic ground conditions. Common settings are Normal, High Mineral, Low Mineral (Sensitive), Salt (for salt water beaches or salt flats) or a variable setting. The technology employed may vary. The unit will compensate for difficult conditions by basically lowering the overall sensitivity of the detector in various ways so as to not detect the item or items causing problems. The sensitivity to desired items almost always suffers as a result.

Discrimination (Disc) - Most detectors offer all metal detection, all metal with ferrous (man made iron or steel) rejection, possibly adjustable, and fully adjustable discrimination that can actually identify different non-ferrous targets one form the other. The method may be audio only, via a visual display, or both. A control that allows for only ferrous items to be rejected to a varying degree is commonly referred to as "Iron Mask".

Volume Control - Detectors with volume controls usually have a built in speaker and this way you can adjust the speaker output. Detectors without volume controls operate at full volume at all times. Be sure and purchase headphones that have an adjustable volume for these detectors or the headphones will be too loud to use.

Tone Adjust - This allows for a change of tone in the speaker output, to the sound that best suits the user's ears. Some people hear high tones better and some people better hear low tones.

Audio Boost - Boosts the audio volume on small, faint targets, making them easier to hear. It may also boost ground and hot rock signals in some areas and so is usually offered as an option.

Frequency Offset - Two detectors operating on the same frequency close together will "cross-talk" or cause some kind of false signals in both nearby detectors. A frequency offset or adjust allows for a small change in frequency so detectors are less prone to interfere with each other. The control may also alleviate interference from outside sources like power lines or cell phone towers, referred to as EMI (Electro-Magnetic Interference).

Pinpoint Mode - Common in coin detectors, rare in gold nugget detectors. The pinpoint mode is usually a variation on the all metal non-motion mode (see Search Modes above) that allows the detector to be held steady over a target as an aid to locating the exact position of the target. This may be of some benefit in some "silent search" that lack a threshold tone and which only make a sound when passing over a target. The mode is usually activated via a momentary push button or trigger switch.

Audio Output - Nearly all detectors have a built in speaker and a 1/4" headphone jack. Others vary from the norm and are so noted. Also, be aware that some detectors have a mono output and some have stereo output. This is noted when known but it is best always to have headphones that can operate in either mode. Headphone notes

Hip Mount - Some models allow the control box to be put on a belt or chest harness. A very desirable feature, as even a lighter detector can cause arm soreness, or even injury, if used for long periods of time. New detectors are so light this is now a rare feature more often seen on older models. An exception are the Minelab SD/GP detectors in that they are heavy, but through the use of an ingenious harness and bungee system they actually impose less arm strain in level ground than most detectors. Similar harness/bungee systems can be obtained for use on most detectors from aftermarket sources. Chest mounts however are still a valuable option for those thinking of using their detector in deep water.

Standard Search Coil(s) - The search coil or coils that come that come with the detector. Also referred to as loops. IB detectors have concentric or double D (DD) options. PI detectors have mono or double D (DD) options. Concentric or mono coils are usually more sensitive but more affected by ground mineralization. Double D coils handle ground mineralization better but at some loss of maximum depth in low mineral conditions. Concentric or mono coils have an inverted cone detection pattern with maximum depth dead center that fades off in all directions. DD coils have an elongated inverted canoe pattern that covers the ground more thoroughly but lacks the maximum depth dead center that concentric or mono coils offer. Large coils get more depth and cover more ground than small coils, but lack sensitivity to small targets. Small coils lack overall depth but enhance sensitivity to small targets and have better target separation by not "seeing" two targets under the coil at once. Large coils are more affected by the overall ground mineralization, small coils are more affected by hot rocks. Suffice it to say that the more coil options one has, the better. Coil compatibility

Optional Search Coils - See the note above. The more, the better.

Battery - Options are usually disposable batteries, rechargeable systems, or both. Common battery types are AA batteries and 9V batteries. Disposable batteries tend to fade away slowly as they lose power. Rechargeable batteries maintain a more even power output then go dead very rapidly. Rechargeable are preferred by heavy users and a backup battery is a necessity.

Operating Time - Normal battery life in operation with standard battery. Note that the use of headphones will significantly extend operating times.

Weight - Weight of unit on arm with a few noted exceptions.

Additional Technology - Features offered by this detector not normally seen on other models.

Notes - Anything else of interest about the model in question.

The Minelab X-Terra 705 was released in 2009 and is still in production. It is a feature packed detector available for under $500 and weighing less than 3 pounds. Quite a remarkable detector for the price, the X-Terra 705 can run at any one of three separate frequencies by changing to various custom tuned "smart" coils.

Unlike some detectors that select between frequencies while using a single coil, the X-Terra 705 insures optimum performance by using coils specifically tuned for each operating frequency. The coils contain a chip that tells the detector what frequency it is designed to run at, and the detector automatically switches to match the coil. You can choose between 3 kHz, 7.5 kHz, and 18.75 kHz.

The original X-Terra 705 comes stock with the 9" round concentric coil, which is great for general purpose detecting. The X-Terra 705 Gold comes with the 10" x 5" 18.75 kHz DD coil deemed best as an all around prospecting coil.

The X-Terra 705 has a full complement of ground balancing options - a simple "Ground Grab" automatic push button option, full adjustable manual ground balance, and automatic ground tracking, making it one of the few prospecting detectors that offer all three methods. There are several tone id options to choose from, all the way from a simple mono tone to a full multi tone mode. The X-Terra 705 features full programmable notch discrimination with memory to save all your settings when turned off.

Minelab X-Terra 705 Gold multipurpose metal detector

Most importantly, the X-Terra 705 Gold has a very powerful threshold based all metal mode, one of the best available. The all metal mode "Prospect Mode" has an adjustable "iron mask" which allows shallow ferrous trash to be identified and rejected even while in the all metal Prospect Mode.

The Beach setting along with the optional alternate frequency coils makes the Minelab X-Terra 705 a worthy contender for those seeking a single powerful "do-it-all" detector in an affordable and lightweight package. At one time this was a $700 detector and it was a good value then - at $499 it is a true bargain.

Official Minelab X-Terra Gold Page

Minelab X-Terra 705 Instruction Manual

Minelab X-Terra 705 Gold Start Guide

Understanding Your X-Terra by Randy Horton

Minelab X-Terra Coil Brochure

X-Terra 70 & 705 On Gold Nuggets

Forum Threads Tagged "minelab x-terra"

Minelab Metal Detectors Forum

*Notes on Technical Specifications - Detailed notes about the specifications listed in this chart.