By Andy Sabisch
From Page 37
January, 2003 issue of Lost Treasure
Whites Electronics has been a leading manufacturer in the metal detecting industry for more than 55 years and over that time, has developed the reputation of a company producing quality detectors making impressive finds around the world. Recently theyve introduced several new models, and I was looking forward to giving the MXT a try when I was told one was enroute.
The MXT is a departure from some of the standard design specifications found in other Whites detectors. While it does not appear much different from the outside, the electronics make the MXT a totally new detector. The engineers opted not to use the typical 6.592 kHz operating frequency found on most Whites units over the past 20-plus years and selected 14 kHz based on its increased sensitivity to low conductive targets. A point current Whites users should be aware of with this change is that coils from other Whites detectors cant be used on the MXT - there are 2 optional Double-D coils designed specifically for the MXT.
The MXT is controlled by three knobs and two toggle switches on the housing and a three-position trigger on the handgrip. The internal software has been pre-programmed to provide three distinctly different settings for three different types of treasure huntingcoin and jewelry, relics and prospecting. Selecting the desired type of hunting is as simple as moving a toggle switch to appropriate setting. The remaining toggle switch controls the ground balance circuitry and has three positions, ground, lock and salt. In ground, the MXT will automatically track and compensate for changes in ground mineralization. If mineralization changes rapidly, more stable operation will be achieved in lock which fixes the ground balance. Salt is optimized for saltwater beaches or alkali ground often found prospecting for gold. The knobs are labeled gain (sensitivity), dual control (either discrimination or SAT depending on search mode) and threshold.
The LCD meter display provides a wealth of digital information and what is displayed changes depending on what search mode has been selected. In all three modes, a unique VDI (visual discrimination indication) number will be displayed that can be used to accurately identify targets before recovery. In the Coin and Jewelry and Relic modes, in addition to the VDI number a target ID label is displayed. These labels are tied to the displayed VDI number and were selected to match U.S. coinage, common trash, some jewelry and Civil War relics. The relic mode has only four possible target ID labels (iron, button, bullet or buckle); however, most avid relic hunters will tend to focus on the VDI number rather than the label when determining if a target is worth recovering. In addition, the relic mode operates with a mixed-mode audio signal in which a low tone is produced for rejected targets and a high tone for accepted targets. This means that all targets under the coil produce a signal; however, unwanted targets can be ignored based on tone and/or meter indication. Both the coin and jewelry and relic modes have 16 LCD segments that appear beneath the VDI number and target ID label. These segments allow the user to check the target ID independently by using the chart below the LCD screen. The size of the block also provides additional information to help the user. If the block is full height, the MXT is fairly certain of the target ID. A half-block means that the circuitry is not 100% certain but is indicating what it might be. A quarter block means the MXT is more than likely guessing what the target is based on very little information being available to analyze.
The prospecting mode provides two unique pieces of information in addition to the VDI number. The first is iron target which shows up as a percentage value. It indicates the likelihood that the target is iron. Whites recommends that any target reading 50% or less should be recovered when searching for gold with the MXT. The other piece of information provided is GND which gives users a way to measure ground mineralization underneath the coil. This data can be used effectively to locate concentrations of black sand (and hence pockets of flake and flour gold) that would otherwise have been undetectable. The manual contains an excellent description of how this information can best be used when using the MXT for electronic prospecting. [Hyper SAT feature?]
The trigger on the handgrip also serves different functions depending on what search mode is selected. The center position is the normal search mode while pulling & holding the trigger switches to the depth-reading, non-motion mode. In the coin and jewelry mode, pushing the trigger forward activates the Pull Tab Notched Out software which automatically rejects pulltabs while still accepting nickels. In the relic mode, the forward trigger position activates the Disc Suppress Rejects software. Targets below the Disc setting will not produce any audio signal. If the Disc control is set to 0, all targets under the coil will produce an audio signal with ferrous targets producing a lower pitched tone than non-ferrous targets. This is useful when trying to locate a camp or skirmish site and the presence of ferrous targets may be the first indication relic hunters will receive when they are getting close. In the prospecting mode, the Without Iron Grunt software is activated which eliminates the tell-tale grunt audio signal produced when a target above 80% iron content is detected; however, audio and meter indication will still respond to a target. There may be a few applications where one might not want the Iron Grunt feature active; however, it will allow much of the common iron trash to be effectively eliminated through the audio response it produces.
The MXT uses the standard Whites drop-in battery pack which uses 8 AA batteries. The new circuitry produces almost 40 hours of use from alkaline batteries. The optional Whites rechargeable pack can be used with no impact on performance and is the same one used on most Whites detectors.
The typical Whites Feel-of-Quality was immediately evident upon picking up the assembled MXT. Over the years I have always been impressed at the solid, well-built construction of Whites detectors.
The first site I took the MXT to was an old middle school closed for years that had been converted to apartments in a nearby town. The school was on a main thoroughfare and virtually every treasure hunter in the area had probably spent time searching the site over the last 25 years. In my last three trips to the school, I had come up empty handed so I felt that this would be an acid-test of the MXTs performance.
Opting for the coin and jewelry search mode, I set both the gain and disc controls to their preset marks, pumped the coil up & down a few times to set the ground balance and started hunting. Almost immediately I recognized the familiar chatter from highly mineralized ground. Coal has been used for heating in the northeast for more than 100 years and the mineralized cinders that remain raise havoc with most detectors when hunting these sites. Switching the trac control to lock all but eliminated the chattering as I continued searching the side of the school. I was somewhat concerned that using the lock setting would reduce the detection depth of the MXT; however, the next few signals would dispel my concerns. Near the road I received a repeatable signal that registered +78 on the VDI scale and a half-block appeared above the 1c/10c segment of the target ID label. Pulling the trigger to switch to check the targets depth, the MXT indicated it was 6 inches deep. Cutting a plug and removing the loose dirt revealed the edge of a silver coin at the bottom of the hole. Pulling a 1935 Mercury dime in XF condition brought a smile to my facethis was the first piece of silver I had found here in more than a year. Over the next hour I added two wheat cents, a small metal button and a pencil eraser to my pouch. Even though some rejected targets produced occasional chirps, their lack of repeatability and inconsistent meter indications made it quite obvious that they were not worth recovering.
The next site I hit was my mother-in-laws yard located in a small coal-mining town near Hazleton, Pennsylvania. The first 30 minutes hunting close to the house turned up a few recently lost coins and a pull-tab. Heading towards the back of the property, I hoped my luck would improve. Parts of the lot had been used to dump coal cinders and an old house had been torn down years earlier. Trash was plentiful and it became increasingly difficult to hunt the area due to the false signals and erratic meter indications that the MXT produced with each sweep even with max discrimination. Opting to switch to the 5x10 elliptical coil, I headed back to the troublesome area and continued hunting. The target separation afforded by the new coil allowed me to hunt with much better results. A slightly slower sweep speed provided clear responses from targets that fell in the accept range and rejected targets were easily discernible and ignored. Hunting a section of the back forty turned up a few keepers including an Indian Head penny (with the date long gone), a skeleton key, an engraved suspender clip with an 1892 patent date and a small ladies gold-plated compact. While these finds demonstrated the MXTs ability to successfully ferret out keepers from amongst a high concentration of trash, there was one memorable find that really stood out. As I was washing off the finds, my mother-in-law grabbed a blob of melted aluminum and started laughing. It turned out to be all that was left of a cooking pot that my wife Rosanne had left unattended on a stove when she was growing up. It had been thrown out years ago and will hold a spot in one of our shadow boxes as an interesting conversation piece (and one Rosanne had wished stayed buried).
Wanting to give the relic mode a try, I took the MXT to a series of old foundations from a long-abandoned coal mine near Wilkes Barre. I had previously obtained permission from the landowners and was anxious to see what might come to light. Setting the gain and disc knobs to the preset marks and the trac toggle to ground, I pumped the coil a few times to ground balance the MXT and started hunting near the front of a large foundation. There were fewer targets than I had expected so I pushed the trigger into the forward position and turned the disc control to minimum. Distinguishing between the ferrous & non-ferrous targets was simple based on the audio response and meter indication. The first good target registered 50 on the VDI scale and read bullets. At just over six inches, I found a large button with the initials of either a coal company or rail line. While the VDI and depth reading was accurate, the label was not, but as I mentioned previously, most relic hunters will focus on learning what targets correspond to specific VDI numbers rather than rely on the four labels. Over the next few hours I found a number of interesting items such a key, tools, a license plate, buttons and the usual collection of unidentifiable items at above average depths. In a few areas I had to switch to the 5x10 elliptical coil due the concentration of trash; however, the 9.5 coil worked fine in most areas I searched.
The new MXT offers a number of innovative features in an easy-to-use package. Its use in well-hunted areas produced a fair number of keepers obviously missed by previous hunters and very few adjustments were required to make these recoveries. To effectively search trashy sites and minimize falsing and chattering from multiple targets, one of the optional elliptical coils is highly recommended. A point to consider when using the Double-D coils is that while target separation and operation in mineralized ground is improved, some loss of detection depth will be noted. The MXT has obviously been designed with input from end-users and deserves a serious look if you are looking for a new, high-end detector.
The MXT lists for $799.95 and comes with the standard two-year Whites transferable warranty. Optional coilsa 5x10 & 3x6 elliptical, along with a rechargeable battery system are also available to enhance the versatility of this new addition to the Whites line.
For more information on the MXT or any of their other models, contact the factory at (800) 547-6911 or visit their web site at www.whiteselectronics.com.