Yesterday I spent most of my day listening to the subtle differences in tones and tweaking the accept/reject notches for various targets. I have listened to the tones long enough now that I don't find myself looking at the meter very often, let alone watching it like I did the first couple days. When setting the accept notches for coins, the tones that are steady and clear have proven to be good targets. Trashy items tend to "cluck" when you sweep over them from various directions. Sometimes targets sound good from one direction and break up in another. I don't even stop and dig those now because all of them I have dug over the past several days were trash. If the sound was consistent and stable, I would look at the meter for visual confirmation. In the areas I have been hunting, when the meter would give a good target ID one direction and number "21" or "27" would sneak in from the other direction, it was aluminum. I have found when I heard a solid medium-high or high tone and the LCD reading was consistent from every direction swept, it has been a good target. Maybe not always a coin. But the metallic content has been within the accepted range. (like those #%#*# little pieces of copper wire that someone scattered across that field!) I setup today detecting in preference one. When I would get a target that turned out to be bad (like 21 or 27), I would notch it out. I know that I risked missing some good stuff, but this is a field test and I wanted to see how many notches I could reject. Besides, this was in an isolated location that I will continue to hunt. Anyway, I ended up blacking out all of them except 9, 12, 18, 33, 36, 39 and 42. The reason these were not notched out is either because they represented a good find, or I just never hit anything with that number. Notching out 3 and 6 FINALLY got rid of those pesky 22 calibur casings. Those little things have plagued me in this site for 25 years. Once I determined that it was always a 22 casing that bounced the 3's and 6's, I accepted both groups so I would not reject stable readings that may represent a valuable target.
Changing the accept / reject notches on this is very simple. You can pass the coil over an item to be rejected and simply press the reject / accept button. OR, you can scroll the number display with the + and - arrows, and push the reject / accept button when it displays the number representing the target you want to change. If the target represented by the number on the LCD is rejected, it has an X below it. Accepted numbers do not have that X. It takes just a few seconds to change the status of any notch level. You may have noticed that I notched out 45. This represents half dollars and silver dollars. I found out early on that it also represents smashed aluminum cans. By mid-day, I had turned 45 back to accept. I have become familiar enough with the pinpoint sound to determine size and somewhat the shape of an item. If you consider the depth and you can tell if it is a can or a half.
From the testing that I have done over the past few days, most of the notched out targets give me a partial or broken response, similar to a detector with standard discrimination circuitry. But, there is more to it than that. I have found that when I slow down my sweep speed, and make a concious effort to keep the coil about an inch off of the ground, the notches pretty well blank out the bad stuff completely. When I get sweeping a little to fast, or scrub the ground with the coil, the notches let some of the audio of trash bleed through. Kind of like falsing, but only when the coil is over the target. In either regard, they don't repeat with any consistency. Numbers or tones. The 4-tone audio does sound different with a trash target because it will generally give a mix of two distinct tones. I'll probably catch some flack for saying this, but it reminds me of how the FBS units sound. By looking at the meter, you will see that the LCD also bounces around with different target IDs. The wider the separation of those numbers, the more separation of tone is heard. Some of the mixed tones I got, say with one particular type of pull tab, gave me readings of 15 and 21. Each of these numbers is represented by a separate tone, so it was easy to tell the item was a pull tab, simply by listening to those mixed tones and confirming the numbers. On those 22 calibur cartridge casings that I hate to dig, the tone would be more steady, like a coin, but the numbers would bounce around from 18 to 33, with a 3 or a 6 tossed in the mix. I don't know if that was due to the metallic content being rejected or the way it was laying in the ground. It is tough to tell on something cylindrical,that small and in the dirt. But, when I saw the 3 or 6 flying by on the display, I knew it was going to be one of those copper/?/brass 22 cartridge casings. No more digging those darn things! Whatever the science is behind the circuitry, it didn't take me long to recognize the sounds associated with trash. The single-solid tone of "keepers" vs. the mixed tone of "trash", made the "dig or not to dig" decision quite easy. Add that difference in sound to the accuracy of the numeric display and the depth indicator, and you will find that you can make some very accurate predictions as to what is buried under that coil. I am still not able to determine some of the signals coming in at 30 and 33, without digging them. But the list is getting shorter!
Every day I take the X-Terra to the field, I learn a little bit more and it continues to impress me. Lightweight, well balanced, great depth of detection, good target separation, very-VERY sensitive to small targets and the current set of 4 AA batteries have been in for over 18 hours, and they still show full charge on the display. Great detector!! HH Randy
Changing the accept / reject notches on this is very simple. You can pass the coil over an item to be rejected and simply press the reject / accept button. OR, you can scroll the number display with the + and - arrows, and push the reject / accept button when it displays the number representing the target you want to change. If the target represented by the number on the LCD is rejected, it has an X below it. Accepted numbers do not have that X. It takes just a few seconds to change the status of any notch level. You may have noticed that I notched out 45. This represents half dollars and silver dollars. I found out early on that it also represents smashed aluminum cans. By mid-day, I had turned 45 back to accept. I have become familiar enough with the pinpoint sound to determine size and somewhat the shape of an item. If you consider the depth and you can tell if it is a can or a half.
From the testing that I have done over the past few days, most of the notched out targets give me a partial or broken response, similar to a detector with standard discrimination circuitry. But, there is more to it than that. I have found that when I slow down my sweep speed, and make a concious effort to keep the coil about an inch off of the ground, the notches pretty well blank out the bad stuff completely. When I get sweeping a little to fast, or scrub the ground with the coil, the notches let some of the audio of trash bleed through. Kind of like falsing, but only when the coil is over the target. In either regard, they don't repeat with any consistency. Numbers or tones. The 4-tone audio does sound different with a trash target because it will generally give a mix of two distinct tones. I'll probably catch some flack for saying this, but it reminds me of how the FBS units sound. By looking at the meter, you will see that the LCD also bounces around with different target IDs. The wider the separation of those numbers, the more separation of tone is heard. Some of the mixed tones I got, say with one particular type of pull tab, gave me readings of 15 and 21. Each of these numbers is represented by a separate tone, so it was easy to tell the item was a pull tab, simply by listening to those mixed tones and confirming the numbers. On those 22 calibur cartridge casings that I hate to dig, the tone would be more steady, like a coin, but the numbers would bounce around from 18 to 33, with a 3 or a 6 tossed in the mix. I don't know if that was due to the metallic content being rejected or the way it was laying in the ground. It is tough to tell on something cylindrical,that small and in the dirt. But, when I saw the 3 or 6 flying by on the display, I knew it was going to be one of those copper/?/brass 22 cartridge casings. No more digging those darn things! Whatever the science is behind the circuitry, it didn't take me long to recognize the sounds associated with trash. The single-solid tone of "keepers" vs. the mixed tone of "trash", made the "dig or not to dig" decision quite easy. Add that difference in sound to the accuracy of the numeric display and the depth indicator, and you will find that you can make some very accurate predictions as to what is buried under that coil. I am still not able to determine some of the signals coming in at 30 and 33, without digging them. But the list is getting shorter!
Every day I take the X-Terra to the field, I learn a little bit more and it continues to impress me. Lightweight, well balanced, great depth of detection, good target separation, very-VERY sensitive to small targets and the current set of 4 AA batteries have been in for over 18 hours, and they still show full charge on the display. Great detector!! HH Randy