Advantages and Disadvantages of the MXT

The MXT is powerful, easy to learn, moderately priced, and that has made it one of the most popular detectors in years. However, in the development of any detector, there are trade-offs. This is especially true for a general use machine with high gain like the MXT. I think it is worthwhile to have a discussion of the advantages and disadvantages of the MXT.
PLEASE NOTE: These comments, especially the comparisons, represent my opinions, and mine alone. They are developed upon experience and due consideration, but there are folks out there who may disagree with them, which is just fine with me.

High Gain – The MXT has a greater gain (amplification of the signal seen by the receive coil) than most general use detectors. Most of the MXT's ability to get deep items or small gold nuggets is due to this higher than normal gain (and the circuitry to handle that higher gain). While this does give the MXT increased detection depth, the trade off is increased chatter and noise.  The higher gain, the fact it does not average passes over targets, the greater operating Khz of the MXT, and the analysis software which wants to keep marginal targets all combine to make the detector notably more chattery than most. It is most noticeable in areas with high mineralization, or trash. Although the satisfaction rate of MXT buyers is extremely high, the noise issue is probably the most commonly cited problem by the few who do not like it. However, this is an issue that can be dealt with. There are a number of practical techniques to cut down on the background noise including use of the relic mode, using of double D coils rather than the standard 950 concentric, and turning down the gain. Although turning down the gain will cut down on the noise significantly, it will also significantly reduce depth and sensitivity. In order to get those deep coins others have missed, or to pick up those small nuggets, the gain needs to be up at +2 or +3. So to get the full performance from the MXT, one needs to learn to get used to some chatter and learn to pick out those good targets from the background noise. With practice and a little tweaking, one can find the best balance of coil and other adjustments to make the targets as distinct as possible from the background chatter. See the FAQ section for further information and suggestions on minimizing background noise and chatter.

Moderate Operating Frequency - The operating frequency of the transmit coil significantly affects how various targets respond. Lower frequencies detect deeper, are better at discrimination, and respond a bit better to high conductivity targets. Higher frequencies detect small objects better and are a bit more sensitive to low conductivity targets. The MXT operates at 13.889 kHz. Most coin oriented machines operate at a lower frequency in the 3 to 6 range, while most gold only VLF units operate in the 50 to 65 range. So the MXT is a bit high for a coin machine, and a bit low for a gold machine. As a result, the MXT detects bigger gold deeper, and has better discrimination than gold only machines, but will not detect the tiniest gold particles, less than about a third of a grain (as a reference, a one third grain particle contains about 44 cents worth of gold at $625/oz). For coins / jewelry hunting, the MXT has extra sensitivity to deep gold jewelry and small jewelry like earrings and chains. It is also more sensitive to low conductivity targets like nickels. However the MXT has slightly less sensitivity to deep silver (though this is made up for by the high gain).

Automatic Ground Balance Engine - For most folks, having the machine take care of the ground balance makes things much easier. This is especially true for beginners. So most MXT owners are very happy with the automatic ground balance engine, but there are a few times where it would be an advantage to create a slightly positive ground balance, to heighten the sensitivity to small nuggets, which is an option which is available on the GMT and other high frequency gold detectors.

Target Computer Analysis Engine - The analysis of the signals obtained by the receiver coil is done by a microprocessor software program in the MXT. This is as opposed to the hardwire electronics used to evaluate targets in most older detectors. For the most part this works very well, and is not subject to the drift in the electronics caused by heating and cooling. The software in the MXT which looks at the signals obtained by the receiver coil is designed to keep marginal targets. In one sense this is good in that it can help to find targets which are at the limits of the detectors ability. The tradeoff is that it also contributes to increased background noise.

Simple to Use - The MXT is intentionally designed to be simple to use. Many buyers dislike the multi-menu approach used to program many detectors and really appreciate the simple "turn the knob and go" method of adjusting the MXT. This really does a lot to reduce learning time it takes to master the MXT. The flip side of this coin is that adjustable features that are appreciated on some other machines just are not there. Some MXT users have wished for the flexibility of things like an optional manual ground balance adjustment, lighted display, multi tone ID, adjustable notch discrimination, selectable operating frequencies, separate output volume controls and other features. Unfortunately, the addition of multiple adjustable features adds difficulty and requires special programming - it is just not possible to be BOTH very simple and offer a rich list of adjustable features. So as a sacrifice to ease of use, the MXT lacks ability to make some detailed adjustments. Most users however, find it is plenty flexible enough to meet their needs in a wide variety of environments.

As a coin/jewelry detector: - The MXT is tops for deep jewelry detection. It also detects deep, and many operators report finding deep coins in areas previously thought as hunted out. Because the operating frequency is higher than most coin orented detectors, it is most sensitive to lower conductivity targets, not higher conductivity targets like silver. The opeating frequency loss for silver is more or less cancelled by its higher gain, depending on your soil. In most cases, it will detect silver as deeply as the best coin oriented machines. It will generally out perform them for lower conductivity targets like gold jewelry or nickels.   

As a gold prospecting detector: - Able to detect small gold, but will not contest with either the GMT or the Gold Bug II for the title of "King of the Specs". The high frequency units do detect the smallest nuggets better. However, the MXT has a better discrimination system than either of these, and will detect larger gold slightly deeper than the high frequency gold detectors. Because of its target ID system and lower frequency, the MXT is better than the high frequency VLF nugget detectors in iron junk or hot rock infested areas.

As a relic hunter: - Because of its sensitivity to low conductivity objects, the MXT is more sensitive to deep iron and lead objects than most other VLF detectors. Maximum gain is necessary to achieve the deepest detection depths.

A number of folks considering a detector purchase want to compare the MXT and the DFX. Other than the fact that they share coils, the MXT and DFX are really quite different. Comparing the MXT and the DFX is really an apples and oranges kind of comparison. One is simple to use and sensitive to small and deep targets; The other is feature rich and extremely flexible.

The programmable DFX has a huge number of adjustable features. It can be customized into a wide number of configurations. There are 10 basic and an additional 34 detailed adjustable features on the DFX. Although some love this level of flexibility, it is that same dizzying array of features that frustrates a large number of users. Many users often wonder if they have their units correctly programmed to get the most out of their DFX. The XLT has fewer adjustable features than the DFX, but is still frustrating to some users. It is not avoidable: the addition of multiple adjustable features adds difficulty. It is just not possible to be BOTH very simple and offer a rich list of adjustable features. So as a sacrifice to ease of use (and because of its nugget detector heritage), the MXT lacks ability to make some detailed adjustments. Folks who like the DFX appreciate the many adjustable features it offers. Most MXT users however, find it is plenty flexible enough to meet their needs in a wide variety of environments. It is because of its simplicity of operation that the MXT is often recommended to new detector users. 

Most of the MXT's ability to get deep items or small gold nuggets is due to its higher than normal gain (and the circuitry to handle that higher gain). This higher gain, and the "two filter" design does make it more chattery than most. Luckily, there are a number of techniques that can help reduce the MXT background noise. However, the increased sensitivity of the MXT is one option that neither the DFX or the XLT can offer. Although I do not own a DFX or XLT, I have seen many posts in which various folks have tested these against the MXT and shown the MXT clearly detects deeper at the highest gain settings. An MXT setting of 9 on the gain (the factory recommended setting) is roughly equal to the max gain on the DFX or XLT (the DFX does have slightly higher gain that the XLT). Gains of +2 or +3 will detect deep and small targets the DFX or the XLT will simply miss. Most experienced users who choose the MXT appreciate it because of gain - this givies the MXT its ability to get deep coins or small nuggets.

If you don’t need or want the extra depth of detection the MXT can achieve – you are missing a big part of what the MXT offers. If you never intend to use the MXT to hunt for gold nuggets or small gold jewelry like earrings, you are missing another big part of what the MXT was designed to do. If you are not interested in the simplicity of use that the MXT offers, you are missing the other big advantage of the MXT. On the other hand, if you just can’t stand that chatter that the MXT makes, and you need adjustable features the MXT does not offer, it is simply not the detector for you.

The bottom line is that both the DFX and the XLT are fine detectors and some will prefer them to the MXT, depending on how they want to use their detectors. There is no clear "one best" choice among them. When making a choice in a detector, its important to match the features offered to your personal preferences and find the one that would be best for you. To help with that, I have made this short comparison chart:

MXT Advantages

DFX Advantages

1. Detects deeper and smaller targets.
2. Good for small nugget shooting.
3. Fast target response.
4. Simple to use.

1. Extremely flexible in adjustments.
2. Can be specially configured for a wide variety of detecting conditions.
3. Muti-Frequency detection option.

MXT Disadvantages

DFX Disadvantages

1. More background noise than other detectors.
2. Lacks some adjustable features commonly found on other detectors.

1. Programming the detector is intimidating to some users.

SPECIAL TOPIC II : Comparing the MXT and Pulse Induction Units for Prospecting

A number of folks considering a detector purchase want to compare the MXT and and various Pulse Induction detectors. The MXT is a VLF type unit, and the pulse induction types are a different technology - they really are quite different. I am going to cover some of the pros and cons of each, and the advantages and dis-advantages. Each has advantages that can allow them to shine under different circumstances. Many dedicated nugget prospectors choose to own both technologies, to allow themselves the maximum amount of flexibility. If you have no problem with the money, having both is the way to go.

As far as advantages, PI units don't do as well on small specimen gold, wire gold and crystalline nuggets. These are the types of gold you might commonly find on an old hard rock mine dump. VLF detectors like the MXT are better on these types of gold than PI units. On the other hand, with larger nuggets, where the gold is more solid (nuggets say of around half a dwt.), the PI units will detect deeper, and the difference is significant.  In extremely trashy areas, PI units also have problems because they don't have an effective discrimination system - you basically dig everything. So if there is loads of trash, you'll be digging all of it. This makes PI units unsuitable for general coin shooting and multiple use like the MXT. On the other hand, in areas with loads of hot rocks and iron mineralization, VLF units can have fits. However, in general, there are many areas in the California, Nevada and Arizona gold fields where the mineralization is   moderate, so that they can can be hunted with VLF technology. PI detectors are far less impacted by this and can completely ignore some levels of mineralization. Because of the PI's insensitivity to iron mineralization, it is possible to use large coils that would just not be possible with a VLF like the MXT.  So in places where depth is critical, or covering a large area with a large coil makes the difference, the PI technology has a very definite advantage. Typically the Desert areas in Nevada and Arizona are most commonly hunted with PI units - This is because: 1) the well known areas have been heavily worked and most of the remaining targets are deep, and 2) because there are areas where hot rocks make using VLFs difficult; 3) because the coverage of a larger coil can allow the user to look at more ground. VLF detectors, including the MXT, are best for very shallow gold (ie, shallow bedrock) or otherwise gold near the surface. VLFs are also best in trashy places with small or wiry gold such as may commonly be found on old gold mine dumps.

Many of the folks who are very active in this part of the hobby and are often out detecting for gold nuggets have made the move to purchase a pulse based nugget detector. However, I know one guy who spent the money to buy a PI unit, and after digging a considerable quantity of iron junk, decided to switch back to a VLF, because, as he said, he was "tired of digging 2 foot deep holes to find bits of iron nails". In spite of this, it is common that most serious nugget hunters own both a VLF and a PI unit for maximum flexibility. I myself own a Minelab GP Extreme in addition to my MXT, and while the Minelab is simply not a detector for trashy areas, it does penetrate highly mineralized areas better than VLFs, and I can use very large coils - I own a 20 inch diameter round coil for my GP Extreme.

Another important factor is the cost. There is no question that PI detectors can cost significantly more than VLF types. The final decision is up to the user, but should be based on a number of factors, including the overall intended uses of the detector and how often one will be out detecting for gold nuggets. Making a good decision as to which detector to purchase partly involves knowing what types of areas you will be working. The best suggestion I can give is to get the best detector you can afford, even if you have to save up for a while in order to make your purchase.

MXT Advantages

Pulse Detector Advantages

1. Detects smaller targets.
2. Good discrimination for use in trashy locations.
3. Fast target response.
4. Simple to use. 

1. Detects larger gold deeper in mineralized ground.
2. Can handle variety of detecting conditions, including high mineral and plentiful hot rock situations.
3. Fantastic array of optional coils available.

MXT Disadvantages

Pulse Detector Disadvantages

1. More sensitive to mineralization and hot rocks than pulse "PI" detectors.
2. Lacks some adjustable features commonly found on other detectors.
3. Will not detect as deeply in high mineral conditions.

1. Too heavy for some users.
2. Poor and unreliable discrimination ability.
3. High cost of purchase.

Nevada Outback Gems