User manual WHITES ELECTRONICS GOLDMASTER GMT

[. . . ] GMT Table of Contents NOTE: Due to Acrobat PDF limitations the Introductory page is on page 29 GMT Table of Contents Chapter 1 Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Assembly Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Chapter 2 Batteries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Standard Battery Holder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ] This technique makes the very tiniest nuggets (flakes of gold) visible to the detector. You may have to return to "perfect" GROUND BALANCE ( where there is no change in the sound of threshold when the search coil is pumped up and down ) if small red hot rocks (positive mineralization) become a problem in the search area. The new GMT introduces digital microprocessor control with a much higher 4000:1 resolution for manually adjusting GROUND BALANCE. Each tap (fine adjustment) of the plus (+) or minus(-) pads on the display pod is equal to 1/4000 of the total range. To quickly make a large change (coarse adjustment) in the GROUND BALANCE value, just touch and hold the pad. 15 Chapter 5 GMT Searching Searching Pinpoint Technique Due to the wide scan nature of elliptical searchcoils it can be difficult to locate small targets under the physical center of the loop. Use an "X" marks the spot technique as shown in the diagram to identify the portion of ground the nugget is in. Because most nuggets are too small to isolate to an exact location as in coin or relic hunting, remove the soil under the center of the "X" until the target is no longer in the hole, but in your pile of dirt. Techniques for examining the pile of dirt are discussed later in the manual. (page 20) Again, the procedure is to sweep over the target from side to side noting the side to side center. Then turn 90 degrees and sweep the coil side to side noting the center from this new direction. You can practice with a small pieces of lead or gold on top of the ground to become acquainted with the technique. It's a good idea to have a magnet handy, preferably in the handle of your digging pick, to pull iron out of the dirt pile. It will work on small almost invisible hot rocks too. 16 Chapter 5 GMT Searching Headphones The headphone jack on the GMT is located on the control box near the plug for the search coil. There is a dust cover on the headphone jack that needs to be removed before the stereo plug from the headphone is inserted. Most prospectors prefer high quality stereo headphones so White's has chosen to wire the headphone jack for stereo. If you have a mono headphone, you can purchase an adapter that will allow sound in both earpieces. In choosing headphones, make sure they have a VOLUME CONTROL as there is no target volume control on the GMT. Remember that you want the faintest THRESHOLD "hum" possible but a strong comfortable target signal. With headphones you will be able to work with a lower THRESHOLD "hum", hear fainter target signals, avoid bothering others with a "beeping" box, and save on battery life. Many high quality headphones from full ear enclosure to lightweight summer models that offer a bit more safety in snake and bear country are available on the market. Higher impedence headphones ( 60 Ohms or greater) give the most sensitivity and are better for hearing the tiny targets most likely to be heard while prospecting. Properly balanced impedence is important as well as low distortion. 17 Chapter 5 GMT Searching Chapter 4 GMT Searching Field Use & Tuning Tips Putting it all together: Once you have achieved the initial ground balance, you are ready to start searching. [. . . ] The new GMT is the culmination of a series of Goldmasters, refined and improved over the years. With the addition of Fast Ground Tracking the GMT is the ultimate Goldmaster. The reason the Goldmaster stands above all other detectors in finding gold nuggets is the care taken to accommodate the particular conditions encountered while gold prospecting. Since gold is most often found in highly mineralized soil, it was necessary to design a ground balance circuit which had the range to cancel out both extremes (+) and (-) mineralization. [. . . ]