[html] En test fra en bruker i USA<br /><br />Coin Shooting with the X-Terra 70 <br /><br />Several months ago, I wrote an article entitled Coin Shooting with the X-Terra. This article was designed to jump-start hobbyists detecting with either the Minelab X-Terra 30 or the X-Terra 50. My intentions were to immediately follow that article up with one on the X-Terra 70. But, as many of those using it can attest to, the more I use it the more I learn. So much that it has taken me nearly a year to come up with an article that logically explains some of the ways I use the X-70. So let´s cut to the chase….. <br /><br />If you haven´t read my article on the X-30 and X-50, you may want to do so before trying to fully understand the X-70. Basically, they all work the same. They are all lightweight and well balanced. And all three models offer a large “easy to read" LCD, low power consumption, notch discrimination, all-metal mode, pinpoint mode with visual indicator, target depth indicator, low battery audio and variable audio tones. But, just as the X-50 has features not found on the X-30, the X-70 has several features unique to it. Among those features are: Adjustable Threshold tone; Automatic or manually adjusted (5 channel) Noise Cancel; Adjustable Audio Response that allows the use of a single tone, 2 tones, 3 tones, 4 tones or 99 tones; Ground Balance modes: Manual GB with settings from 1-90 Automatic GB, Tracking mode and Beach mode (which compensates for salt water, ferrous targets and some low conductivity targets); 3 adjustable Notch Discrimination Patterns allowing the user to accept or reject 28 two-digit segments; All-Metal (zero discrimination) mode with shortcut button; Target ID Stabilizer for highly mineralized ground; Prospecting mode with an adjustable Iron Mask feature and a variable threshold tone; Three Coil frequencies: Mid-frequency 7.5 kHz for general metal detecting, Low Frequency 3 kHz for larger targets, deeper targets and higher conductive targets and the High Frequency 18.75 kHz for smaller targets, shallow targets and low conductive targets. And, there is a 10.5-inch DD coil designed for those hunting in sites with above "average" mineralization. <br /><br />I will address each of these items, as well as tell you how I set X-70 for coin hunting. In addition, I will address a couple settings that all three models have in common. <br /><br />Threshold <br />I like to run my X-70 with a faint threshold hum in the background. When hunting in a Pattern mode, if you are running with a slight threshold sound, you will not only hear a louder response when you pass over a target that registers within an accepted range. But you will also lose that threshold sound when you pass over a target that falls within the rejected range. This is called Target Blanking. Target blanking indicates that you are passing the coil over targets that register in a notch segment that you have set to reject. And, if you listen closely, you will learn as much about the site you are hunting by target blanking as you will by what does produce tones. For example, if you are hunting in an open area, such as a farmstead, target blanking will tell you when you are passing the coil over rejected targets. And, that concentration of nails might just be where the house was torn down or the barn burned 100 years ago? If you are using the all-metal mode (zero discrimination), and have set the X-70 for more than one tone, you will hear a low tone on ferrous targets. <br /><br />Sensitivity <br />I like to think of the Sensitivity, Threshold and Ground Balance working hand in hand. If you have the Sensitivity set too high, you will not likely obtain the optimum GB setting. In addition, your Threshold will become instable, creating false signals as you scan over varying mineralization. If you hear this unstable sound, you need to evaluate your current settings. As mentioned in my X-30 and X-50 article, I recommend setting the sensitivity at a single digit level, until after I have set the GB. After I have achieved the proper Ground Balance, I turn the Sensitivity up as high as I can, without causing false signals when I sweep. <br /><br />Ground Balance <br />I consider Ground Balance to be another form of discrimination. Before you can find the targets you are looking for, you have to reject the mineralization of the ground they are buried in. But you have to be careful to not set the GB too high as it will provide the same results as if you set your discrimination too high. You will reject the targets you are after! Proper GB allows you to maximize your sensitivity setting, improves target ID accuracy and allows the X-70 to operate more stable. The X-70 offers two types of Ground Balance and several ways to set each of them. In a nutshell, Normal GB is used for inland hunting and Beach GB is used when hunting in the wet sand of salt water areas. A small Beach umbrella icon will appear in the top right corner of the LCD when the Beach mode has been selected. <br />The quickest way to ground balance the X-70 is by using the Auto GB feature. Place your X-70in the all metal mode, find an area that is clear of an metallic targets, hold the coil about 4 inches off of the surface, select Ground Balance, Press Mode AUTO to activate the automatic GB program, lower the coil toward the ground and raise it back up to the 4-inch level. Continue to raise and lower the coil as the letters AU appear, and a progress bar indicates the status of the process. Once the setting has been chosen, I usually check that setting to see if I can “fine tune“ the Auto Setting. To do this (continue to raise and lower the coil to that level, about 4 inches above the ground. Don´t let it touch the ground. Keep listening for that GB tone. You will see the current GB setting on your LCD. Your objective is to lock in the setting that represents a merging of the lower tone and higher tone. If the tone is predominantly low, press the + keypad. If it is high, press the - keypad. Again, you probably won´t get the tone to go silent. You should strive for a minimum variation in volume and tone. <br />To manually adjust the Ground Balance of the X-70, set the detector to the all-metal mode and find an area of ground that is clear of any metal. Before making any adjustment to the ground balance, temporarily adjust the sensitivity down to a level in the single digits. Sensitivity is the detector´s level of response to a target, the ground or outside interference, and we will increase that level after we have properly ground balanced the X-70. After lowering the sensitivity to a “single digit" level, hold the coil steady and about 4-inches above the surface and press the Ground Balance pad. You should now hear a constant hum known as the Ground Balance Tone. Lower and raise the coil repeatedly, without touching the ground. As you do this, you will hear a fluttering tone that is either high in pitch, or low in pitch. If the tone is low, you will need to press the + key until the high tone is heard. If the tone starts out high, you will need to press the - key until the low tone is heard. Your objective is to get the high tone and low tone to "meet in the middle". I seldom find it possible to completely eliminate or nullify either tone. I usually set mine at a point where neither tone is dominant and the two tones blend together. And, as I mentioned earlier, after I have achieved optimum ground balance, I boost the sensitivity up to maximize the detector's potential, without causing false signals, chatter or erroneous TID. <br /><br />Tracking Ground Balance constantly monitors the mineralization and automatically updates the GB setting of your X-70. But be careful using it. It might rebalance itself over a target, if you repeatedly pass your coil over it. Especially if you are merely wiggling the coil over the suspected target. If I am using the tracking mode, I turn off the Tracking Ground Balance when I am “X"ing over a target. To turn it off, simply press the TRACK keypad. To turn it back on, simply press the TRACK key again. Tracking is automatically deactivated when you manually adjust the GB while in Tracking mode. When Tracking is activated, a tracking icon will appear on the LCD and the current GB setting will also be displayed. If I am not using Tracking, I try to check my GB every 15 or 20 minutes. Depending on the site, you might be surprised how the mineralization can vary during that timeframe. <br /><br />Tracking at the beach <br />Not living near a beach, my comments here are based more on theory and what I have learned from visiting with others. Briefly, the Tracking mode will work in All Metal mode, Discrimination patterns or Prospecting mode. But, in my opinion, whether or not you use Tracking mode at a salt water beach will depend a lot on the specific site and the coil you are using. Wet sand - dry sand - trashy site - clean site - varying mineralization - stable mineralization - Concentric or DD. Typically, you can run with a higher sensitivity in dry sand versus wet sand. Minelab recommends using the normal GB mode in dry sand and the Beach GB when detecting on wet sand. I attribute this to the Beach mode having an expanded GB range. Running Beach mode in the wet sand will allow you to set your sensitivity a bit higher than in normal mode. If you do experience interference, adjust the Noise Cancel to see if that helps before lowering the sensitivity. Tracking automatically recognizes the ground mineralization and continuously adjusts the X-70 to compensate for it. This is to help maximize your depth of detection while hunting, and is a big plus when hunting sites with mineralization levels that change quickly. From some of the reports I have read, the tracking speed is much faster while hunting in the Beach mode as compared to the normal GB mode. Although this is normally a good thing, it could cause you to null out a target if you sweep across it too many times. (or don't move the coil far enough away between passes) To avoid blanking out a target, switch off the Track mode while X-ing over the target. A fast and easy way to temporarily disable the Tracking mode is to simply press the Pinpoint button while X-ing over the target. When you disable the Pinpoint mode, Tracking mode automatically resumes. If you are hunting a beach that has a lot of trash, the tracking mode might not "keep up" with your sweep speed and number of targets, causing the X-70 to perform less than desired. In trashy areas and dry sand, Minelab recommends using the manual GB mode. <br /><br /><br />Noise Cancel <br />The X-70 allows the user to automatically set the Noise Cancel to best suit the specific site. Although you can adjust the settings yourself when you experience interference, you have the capability to let the X-70 do it for you. Simply press Menu Select and chose Noise Cancel. Press Mode Auto and the letters AU will appear on the LCD. A progress bar will appear and after 15 seconds, the X-70 will have chosen the quietest channel for that site. You can override this or make a manual change by selecting Noise Cancel in the Menu mode and press the + and - buttons to select your channel. <br /><br />Audio Target Response <br />The X-70 allows the user to select a variety of target tones. For those who prefer a detector that only makes one sound when it locates a target, there is the One tone setting at 450 Hz. For those who prefer to have one tone for ferrous targets and another for non-ferrous targets, there is the Two tone setting of 130 Hz and 700 Hz. For those who prefer even more separation, with ferrous targets at a low tone and the conductive targets having two distinctly different tones (separated about halfway into the conductivity range), there is the Three tone setting. This three tone setting is similar to the X-30, and incorporates the single tone 450 Hz tone in between the 130 Hz and 700 Hz found in the Two tone mode. The Four tone setting is similar to the X-50 and offers the same low and mid tones of the Three tone setting, but changes the upper four conductive notches to a 900 Hz tone. This allows the user to differentiate dimes and quarters, by sound. <br />And finally, we have the Multiple 99 tone mode. This setting varies the pitch of the target response from 130 Hz to 950 Hz, with 99 different tones. Honestly, I can´t differentiate between that many tones. I can easily hear somewhere between 15 and 18 different tones. So, for the sake of simplicity, I chose either the 3 tone mode or the 4 tone mode. <br /><br />Pinpointing <br />Although I seldom use the Pinpoint mode, I felt it was important to briefly explain how it works. If you are hunting in a discrimination Pattern, when you press the Pinpoint / Detect pad, the X-Terra temporarily disengages the discrimination mode and becomes an all-metal, non-motion detector. You will hear a constant audio response that is both tone and volume modulated. This means that the closer you get the center of the coil to the target, the louder it gets and the higher pitch it makes. By Xing over the target, you will be able to determine where the target is buried. You will notice that the X-70 updates both the TID and depth reading while Pinpointing in the Coin and Treasure mode. (Pattern) To resume hunting, simply press the Pinpoint / Detect button again. <br /><br /><br /><br />Discrimination values <br />I have a theory about discrimination values. Most people look at discrimination levels as a straight line, running from the least amount possible, to the highest. I consider discrimination levels to be circular instead of linear. For example, a circle is comprised of 360 degrees, with 0 being the same as 360. If you think of discrimination being circular instead of linear, you will find that the highest discrimination level setting is adjacent to the lowest level setting. To support this theory, I found that a piece of ferrite would read both -8 and + 48 in the all metal mode of my X-70. These two readings represent the maximum possible reading at each end of the spectrum. +48 being the highest and -8 being the lowest. (Circular discrimination values?) And, when I switched to a discrimination Pattern with all notches accepted, it only read the -8. Why??? I believe it is because the X-70 was only accepting segments of targets and not accepting all possible metallic targets, as when I was in the all metal mode. In other words, while in a Pattern mode, the detector was set up to accept those targets that fell into a specific notch segment, or segments. In all metal mode, it accepted all ferrous and non-ferrous materials. Some folks say that the X-Terra all metal mode is actually a zero discriminate mode. Not being part of the design team or an engineer, I don't know for sure. But this ferrite test indicates to me that the all metal mode is capable of detecting virtually any level of ferrous material that you can put in front of it. And, as a coin shooter, that is enough for me. <br /><br /><br />Notch Discrimination / Coin and Treasure Mode <br />As you already know, target signals contain ferrous and conductivity information. On the X-70, target ID (TID) numbers range from -8 to +48. Negative numbers represent ferrous targets and positive numbers represent non-ferrous targets. The more negative the number, the more ferrous the target. And, the more positive the number, the less ferrous AND more conductive the target. When hunting with the X-70, the TID of the last target detected remains on the LCD until another target is detected. If the coil passes over a target that has been set as a rejected target, the LCD will display two dashes instead of a number. In addition to the TID number, targets will appear as a particular segment on a linear scale at the bottom of the LCD. Use this scale as a reference when accepting or rejecting notch segments. Rejected segments appear as black indicators on the linear scale. Accepted segments do not appear on the scale. The combination of these accepted and rejected segments are referred to as Discrimination Patterns. The X-Terra 70 offers an All Metal mode and three preset Discrimination Pattern modes. (it also offers an iron mask mode, which I will discuss later in this article). The X-70 has 28 notch segments, representing all target categories. These 28 notch segments run in sequence, from -8 to +48, in two digit increments. Each notch segment can be set as either accepted or rejected. Turn on the segment to reject the target and turn off the segment to accept it. The All Metal mode is preset to accept all 28 notch segments. That means All Metal mode has zero discrimination. Although you can change the presets on the three Pattern Modes, they come preset as follows: Pattern 1 rejects ferrous objects and hot rocks. These are indicated by notch segments -8, -6, -4, -2 and +48. All other notch segments are accepted. Pattern 2 rejects the same notch segments as Pattern 1 PLUS a few lower conductive segments (+2, 4,6) and seven notch segments that indicate most aluminum foil and pull tabs (14, 16, 18 20, 22, 24, 26). Be careful when rejecting these segments. As you may know, gold jewelry and some older copper coins will be found within these segments. I have dug Indian Cents with readings as low as 24. Pattern 3 is preset to reject some ferrous targets, hot rocks and a few non-ferrous targets. (-8, -2, +2, 4, 48 ) Again, be careful when rejecting notch segments that represent those targets that you may want to accept. Personally, I run my X-70 in the All Metal mode, and let my ears and brain sort out the audio tones generated by the keepers. More about that later. <br /><br /><br /><br />Target ID Stabilizer <br />Although the X-70 has an excellent discrimination scale, you may encounter some instability when hunting in heavily mineralized areas. This effect is not exclusive to the X-Terra 70. But, the manner it is compensated for is unique. The X-70 incorporates a Target ID Stabilizer that uses a special filter designed for high mineralization. This allows the X-70 to better analyze the target and provide more accurate information as to what that target actually is. Although the TID will become more stable, make note that the audio tone may not always match the stabilized Target ID. <br />To activate the Target ID Stability while hunting, press and hold the MODE AUTO for three seconds. A + icon will appear on the LCD, indicating that Target ID Stability is activated. To turn off the Target ID Stability, simple press that same MODE AUTO pad again, and it will be deactivated. You will also notice that the + icon disappears when deactivated. <br />Unless you are having high mineralization problems while hunting in a normal mode, it is not recommended that you use the Target ID Stability. This feature is designed for hunting in extremely high mineralization. Know that Target ID Stabilizer not only stabilizes the signals from good targets. It will also stabilize the ID of trash targets. <br /><br /><br /><br />Prospecting Mode <br />The Prospecting mode was designed to be used when hunting for gold nuggets and relics. It is very effective in highly mineralized soils in that it is very sensitive to small target signals. While in the Prospecting mode, you can toggle back and forth to the all-metal mode by simply pressing the All Metal keypad. In Prospecting mode, targets are identified by audio only. The audio response of Prospecting mode is an abrupt change in both volume and pitch. This makes it easy to hear faint signals and at the same time, monitor your threshold level. The TID number is not related to the target. They are indicative of the value set for Iron Mask. The Iron Mask level and the first 20 segments of the Iron Mask Discrimination Scale are used to identify the amount of iron targets being rejected by the X-70. By increasing the Iron Mask Level, you are rejecting more iron signals. So, in essence, having an adjustable Iron Mask feature allows you to expand the ferrous discrimination range on a scale of 0 - 20. When you set the Iron Mask at 0, most gold nuggets will be accepted. But you will also accept some ferrous trash. The higher toward 20 you set the Iron Mask, the more ferrous targets you will reject. But you risk rejecting some nuggets as well. For the most part, you should keep the Iron Mask set low to avoid missing valuable targets. <br /><br />I don´t have any first hand experience Prospecting for gold. Fortunately, most of the folks you meet in this hobby are good about answering questions and sharing information. With that said, I have emailed a couple fellow detectorists that have provided me some tips on using the X-70 in search of gold nuggets. The three most common responses I got involved proper GB, Sensitivity settings and Sweep Speed. If you recall, I mentioned earlier that Ground Balance can be thought of as another discrimination mode. That is particularly apparent when using the Prospecting mode. In the Prospecting mode, think of the having a proper GB setting as maintaining a steady, balanced threshold. What you are hearing in the headphones is exactly what the coil is reading in the ground. If your GB gets out of whack in a Pattern or All Metal mode, the X-70 won´t tell you. That is why I said earlier to check it every so often, and re-GB if necessary. However, if your GB gets out of whack in the Prospecting mode, the threshold will become unstable and you won´t be able to hear those faint targets. So check the GB regularly and keep that threshold steady. I recommend that you don´t use Tracking with the Prospecting mode. Many of the places that folks hunt for gold will be very mineralized. And those highly mineralized sites may cause the tracking mode to provide less than desirable GB results. <br /><br />Just as with coin shooting in a normal mode, it is very important to set your sensitivity properly. If you set it too high, you will encounter a lot of false signals and ground noise. This will cause you to not hear those faint signals that might represent the find of your life. On the other hand, setting it too low will result in missed targets due to your not achieving the depth you may need. So, my recommendation for Prospecting mode is just the same as for coin shooters and relic hunters. Set the Sensitivity as high as you can, while maintaining a steady threshold tone and a minimal amount of false signaling. <br /><br />Although I enjoy a fairly rapid sweep speed while coin shooting with the X-Terra, it is important to slow that sweep speed down while in the Prospecting mode. Too fast of sweep will not allow the X-70 sufficient time to analyze the soil and produce a good signal. The reason is that, again, many of the places you will be prospecting will have highly mineralized soil conditions. And even though the X-Terra is state of the art, it must analyze everything that passes under the coil, and process that information as you sweep. Sweeping too quickly will cause you to miss targets that are being masked by an adjacent target, and will create false signals. <br /><br />A tip that was passed on to me involves where to search for those gold nuggets. It was suggested to press the GB key while hunting in the Prospecting mode. Then, he leaves the GB reading displayed on the LCD. As he swings the coil in his search, he is able to detect changes in the mineralization levels within the site. Lower GB numbers represent higher mineralization. And, according to him, higher mineralization is a good indication that there may be some gold. Although reading that GB number won´t indicate gold. Knowing the mineralization in a specific area may improve your odds. <br /><br />Although I am primarily a coin shooter, I was curious as to how the Prospecting mode would benefit my efforts. What I have found is that it can be an excellent tool for both target sizing and pinpointing. Granted, the X-Terra series has a separate Pinpointing Mode. But I prefer to simply “X" over the targets in my normal hunt mode. However, by pressing the Prospecting pad, I can re-sweep over the target, and get a very accurate idea as to its size and exact location. Remember, the audio response of Prospecting mode is an abrupt change in both volume and pitch. I simply listen for the loudest sound and the highest pitch, and the center of the coil will tell you where to dig. If that high pitched, loud sound is wider than a coin, then you can bet the target is not a coin. As an example, many of you have probably dug more old crushed aluminum cans in your local park than you care to remember. I have found that by switching to the Prospecting mode, I can pretty well determine the size of the target I have located. Even if the TID indicates a good coin number, the Prospecting mode will tell me if it is larger than a coin. This technique is more of an art than a science. So practice at home, in your own yard! <br /><br /><br /><br />Consistency. Let´s find those old coins! <br />Since the X-70 allows for setting the audio in many different configurations, I won´t go into detail about which tone is present for each target. You need to find the number of tones that work for you and remember which tones represent which targets. Although the X-Terra 70 offers excellent discrimination “Patterns“, I prefer to coin-hunt in the all-metal mode with 3 or 4 tones, and allow the audio tones, target location and target ID numbers to help identify each target. When hunting for coins, I generally ignore all low tones. Low tones represent ferrous targets, which will not be produced by US coins. I concentrate on listening for medium-low, medium high and high tones. On my X-Terra 70, nickels register a target ID of 12 on the LCD. I have found a couple V nickels that read a solid 10, and will add that 40% silver nickels come in at 12, 14 or 16, depending upon how worn they are and the soil conditions you find them. If I am wanting to find nickels, I dig all the targets from 10 - 16. A small copper cent will register either 24, 26, 28, 30 or 32 on the X-70. As with nickels, the visual display of a copper cent will depend on the metallic content of that particular coin. I´ve scanned hundreds of IH cents and only have a few that register under 28. But, if I had not dug those 24´s and 26´s, I would have fewer IH cents. A dime will produce a visual ID of 36, 38 or an occasional 40, depending on the metallic composition and depth of detection. I will mention that the only 40 I have found with the X-70 belonged to a silver Roosevelt at less than 3inches. A quarter will usually indicate 42 on the LCD. I do have one old worn Seated Liberty Quarter that reads a solid 40. I don´t know if the lower reading has more to do with the wear or the metallic content of that specific year. Half dollars will read a solid 44 and silver dollars will read a 46. A quarter ounce $5 gold coin reads 26. A half-ounce $10 gold coin reads a 34. And an ounce $20 gold coin reads a 38. Now, before you try to memorize these numbers, let me remind you that soil conditions, target masking, depth of target and angle that it is buried will have an effect on what any specific coin will read. And, you may have noticed that some of the coins had multiple numbers? Let me explain. When I first got my X-70, just as with the X-30 and X-50, I passed more than 100 Seated Liberty, Barber, Mercury and Roosevelt dimes under the coil. I was surprised to find that some dimes produced a different visual target ID than others. At first I thought it might be the amount of wear or the specific issue of coin. Then I realized that three Mercury dimes, in similar physical condition, each gave a different reading. One was 36, one was 38 and another was a 40. However, I also noticed that if a specific dime read 36 on the initial pass, it would always read 36. If it read 38 on the initial pass, it would always read 38. And, those that read 40 on the initial pass would always read 40. Notice the consistency of the readings on any one specific coin. Each coin always “locked on" a specific number, with every pass under the coil. (Exception: soil conditions, target masking, depth of target and angle that it is buried will have an effect on what any specific coin will read.) Visual target ID is a good tool. But it should only be one of the tools you use to determine when to dig. <br /><br />Consistency <br />The X-Terra 70 offers several options for setting the number of audio tones you can listen for. As I said, I like to run mine at either 3 tone or 4 tone, depending on the site I am hunting. When I hear a tone other than a low tone, I pass the coil back and forth over that location from several directions. And, I slow my sweep speed down when I am confirming targets. If the tone remains “consistent" from a variety of directions, there is a good chance it will be a coin. By consistent, I mean a tone that is sharp, clear and provides one single tone. If you hear more than one tone being produced by the same target, it will not likely be a US coin. If the tone is consistent, I make a mental note where the center of the coil produces the loudest sound. It may be “marked" by a blade of grass, a clump of dirt or a leaf. (Although the X-Terra has an excellent pinpointing mode, I prefer to remain in the all-metal motion mode use an “X-ing" method) As I pass the coil back and forth over the target area, I look for target location consistency. In other words, is the loudest tone coming from the exact location with each pass of the coil? Does that sound stay in the same location when I sweep from various directions? If not, then it will not likely be a coin. If the location is not consistent with each direction of the sweep, I go on to the next target. If the target audio tone is generated from the same location (consistent) as I sweep the coil over the spot I have made a mental note of, I look to the numeric display for target confirmation. For example, if I hear a solid tone coming from a consistent location, I look to see if the LCD is displaying a number 24 or greater. (24 represents the lowest reading I have found on a copper cent) While looking at the LCD, I make sure the target ID number is consistent. It is permissible for the number to change by one notch in either direction. But, if it jumps by more than two notches, it won´t likely be a US coin. (Never say never). But, I have not yet dug a coin whose reading varies by more than two notches in either direction, prior to being exposed. In fact, I have dug very few coins that had readings that varied by more than one notch. I have dug dimes that may bounce between 36 and 38. And I have dug dimes that bounced between 38 and 40. But I have never dug a dime that bounced between 36 and 40. I have dug IH cents that bounced from 28 to 30. And I have dug Lincoln cents that bounced from 34 to 36. But, I have never dug a copper cent that bounced between 28 and 32 or between 32 and 36. Separation by more than one notch has not yielded many coins with my X-70. And, those that were dug always had multiple targets in the immediate area. My rule of thumb has become, if the visual target ID number bounces by more than two notch segments, I don´t dig it. You may chose to dig some “inconsistent" signals until you feel confident you can differentiate coins and trash. When the tone, location and visual display are consistent or within one notch, dig the coin. When I locate a target that provides a solid “coin" number from one direction, and a 20, 22 or 24 from another direction, it will usually be a pull-tab, screw cap or can slaw. With hundreds of varieties of pull tabs and screw caps having been produced, you need to confirm the target ID of those lost in your area. Jewelry hunters need to keep in mind that ignoring non-ferrous trash items may result in missing some nice finds. Again, this article is for coin-shooting. Know the numeric readings of the types of items you want to recover and look for consistency. The important thing for those hunting coins to remember is, if the numbers bounce more than one notch in either direction, it won‘t likely be a coin. For the sake of argument, I have dug more than my share of pull tabs trying to get a grasp on just where they would read. As most of you have found out with other detectors, there is no consistency between various manufacturers and types of pull tabs. However, as general rule, I have found smashed screw caps read around 30. Whole screw caps read 28. Unbroken pull tabs read 16 or 18. Pop top rings read 16. Square tabs with one hole read 24. Square tabs with 2 holes read 26. And those large pop top rings read 20. So, as you can see, most of these targets fall within the range of jewelry and some coins. I guess you really never know until you dig it. <br /><br />Search Coils <br />The X-70 offers the user the capability of using any of three frequencies of coils. They come in 3 kHz, 7.5 kHz and 18.75 kHz. As a rule of thumb, the higher the frequency, the better it responds to lower conductive targets. The lower the frequency, the better it responds to higher conductive targets. So, theory has it that the 3 kHz coil will be the best on silver and copper coins, whereas the 18.75 should prove to be the jewelry hunter´s choice. Right in the middle is the one I use the most if I am hunting an area with modern trash. The 9-inch concentric “stock" coil, operating at 7.5 kHz. The 7.5 kHz series is considered to offer the best discrimination characteristics in trash infested environments. Kind of an “all-round" coil for coin shooters. I have used the lower and higher frequency coils and found the higher frequency coil to be a bit more sensitive. But, this required me to lower the sensitivity setting on the X-70. As a coin shooter, I had to ask myself, “If I have to lower the sensitivity of the detector to accommodate the higher sensitivity of a coil, what is the point?" Again, it is suppose to be an excellent choice for jewelry hunters, beach hunters and nugget hunters. I haven't found that I need to diminish the sensitivity as much when I use the 10.5 DD coil at 18.75. I know the windings of a DD coil are designed to cancel much of the interference that might affect concentric designs. But, the additional weight of the 10.5 DD does seem to be a bit more awkward to swing for any period of time. I have a couple sites that the 3 kHz concentric has been good to me, finding old silver on each outing. In fact when I hunt in areas with little or no modern trash, the 3 kHz coil is the one I like the best. Like when I am hunting amongst those nasty old square cut nails. It seems to me that the 3 kHz coil does a better job of providing a solid low tone on the ferrous objects, allowing me to concentrate on those higher signals. But, as with this entire article, that is just my opinion. <br /><br />So, there you have it, a condensed version of many pages of notes, taken over the past year, using my X-70. My advice to each of you is to get to know your detector, regardless of the make or model. Build yourself a coin garden and work at better understanding your machine. Understand what each adjustment provides as well as how to compensate for “less than perfect" hunting conditions. Learn to set your Threshold, Sensitivity and Ground Balance properly. Set your discrimination to accept and reject only those targets you intend to accept or reject. Don´t over discriminate. Listen to what your detector is telling you. Recognize that smooth tone a coin makes as opposed to the snap, crackle or pop of those annoying trash targets. Watch for those mixed numeric readings. Look for consistency in location, audio and TID. Don´t be afraid to experiment with target blanking or target sizing via the Prospecting mode. And, as always, enjoy the hunt. HH Randy <br /> [/html]
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