Critterhunter
New member
Recently several threads have sort of converged onto the same topic at once, that being proper sensitivity settings to achieve best depth. My contribution spawned out of my suspicions that I wasn't producing any coins at a very large known deep coin spot. I've got skunked there twice so far in my attempts to pull what I know have to be deeper coins from this spot. It contains very powdery black top soil with no known clay or rock sub layer in site that would stop or slow coins down in their descent to the depths. New state quarters are already 3 or 4" deep and Rosies, Mercs, and wheats start at about 6 or 7" and go deeper. This site spans a large amount of years as evidence by the barbers, seateds, and even an 1840's bank half cent.
We've worked this spot for years with many machines, all of which pretty much bottom out at around 7 to 8" in depth on a silver dime. A friend had used an Etrac there for a short few hours before he sold it and I witnessed him dig two separate targets at about 9 1/2", one being I think a Rosie and the other a Merc. That jives with what I've always thought about this place, that there are many more coins to be found at further depths than the about 8" or so we've scoured the others out at. I'd be confident in my GT with the stock 10" coil getting this deep and even much deeper because I've already dug my two deepest coins on any machine by using the GT and the 10" at one site. Those were an indian and a v-nickel that I can't exactly remember the depth on, but I know they were well over 9" and judging by the length of my digger which I now know is 11" long they might well have been that because I remember sticking it down in the hole pretty much to the top of the handle.
Either way, along comes the 15x12 SEF coil so I never really have had a chance to work the above other deep coin spot with the 10", but I've been even more excited about using the SEF there anyway because I feel this coil is deeper, both based on what I've read about it's performance in the field by others and also by how deep I've dug non-coin targets (even tiny ones) with it. It's done very well for me and found me silver in trash or on edge that I might otherwise have missed, but as of yet I've still not popped what I would consider to be real deep coins with it. That being coins say 9" to 11" or even deeper. Anything past 9" is a step above just about anything on the market with a few exceptions, so I'd be happy with anything even approaching 12" which I've heard others say they've popped coin at with the Sovereign and other coils. I'm talking on land here. I know beach hunters report depths well into the teens for coins. Not that I haven't read and seen some "teen" depth on land with the SEF, just that I have to see and do it for myself to have that kind of confidence.
Anyway, now that the ground work has been re-hashed again I've been highly suspicious of why I'm not popping the deep coins thus far with it. Most of the time I'm able to max out sensitivity as I find this coil I think to be even more stable than the 10", and that's saying a lot because the 10" is a great coil. I'd say at roughly 80% of my sites thus far full sensitivity is the norm for me with a seemingly stable threshold. Sure, I get the occasional "null" that one would expect to be iron. Even if this drop out of the threshold might be due to a bit too much sensitivity most guys will put up with that in order to max out the depth on any machine, right? Not so fast, because that's been my experience with every machine I've ever owned too with the exception of the Explorer, in that a slightly unstable threshold would still produce maximum coin depths so long as you can deal with the slight falsing. That's the way I've been running my GT, and that's probably been WHY I haven't dug any real deep ones yet with it...
I just came back from a short hunt at a site that I've dug some nice coins from in the past. Not many, as the RF noise due to nearby high power lines (BIG Ones!) and the heavy clay with high mineralization causes any machine to have major problems with stability. Still, I would hunt that spot with the above "slightly unstable on the verge" type of sensitivity setting and did manage to come away in the past with a Canadian half dime, large cent, a few indians, and I think a Merc or two along with maybe a barber dime thrown in from memory. These coins weren't deep, maybe 4 or 5" max, and still yet they didn't give me 100% perfect coin signals. I just knew to dig them at a site like this because they were "just about there" in terms of being perfect. More like a junky screw cap or bottle cap signal than a good coin signal, but good enough at at spot like this one.
I figured here's the perfect spot to begin my investigation on this sensitivity thing. Yea, I want to test my method at non-mineralized/non-RF noise sites as well because it probably will be very informative to see what gives at those kinds of sites as well, but regardless I figured I'd start at one of the worst spots you can imagine. It's not heavy with iron or other trash, but the minerals and noise would provide obstacles to overcome in their own way and are more directly related to sensitivity as far as I'm concerned.
So, onto the test...I throw the machine into auto and find a spot where no trash or anything else causing the threshold to null out was present. Now I want to be sure that there is nothing present deeper that auto can't detect, so I throw it into manual and slowly raise it as I sweep over this spot. Still clean, but then the threshold started dropping out and the ID became erratic once I got around 3/4ths max sensitivity (or about the 11 O'Clock position). Backed it down to "Noon" and it seems stable now with no jumpy ID or erratic threshold that tells me it's picking up too much noise or ground mineralization. Spot looks clean to me. Good, so I dig a hole 7 1/2" deep and stick a silver Rosie at the bottom laying flat. Fill the hole back up and pack it good to try to keep the air out, which worked nicely because the ground was rather wet and mushy.
Threw sensitivity into Auto first and swept over the spot. No change in audio and no threshold null, like it wasn't even there. I've got coins at almost 8" in auto with this coil before but I'm guessing the nearby power lines is kicking it much further down at this spot, so that wasn't surprising. Turn it to lowest manual and sweep over it. No change. Move it up to about between the 4 and 3 O'Clock position and now I'm getting a null over the target but nothing else. Move it up a tiny bit at a time and right at about the 2 O'Clock position I'm still getting the null but with an occasional "chirp" thrown in that tells me the target is now trying to break through. Move it slightly up between 2 and 1 O'Clock and it's back to being a null! Move it to 1 O'Clock, Null! Move it to Noon, Null! Move it past noon and it's still Null City, and now I'm starting to get the erratic threshold and ID.
Move it back down to lowest manual and begin doing the slow creeping up of sensitivity again, just a tad at a time and then sweeping, and once again find all of the above to be the same. Null at around 3 to 4 O'Clock on the dial, slight "chirp" break through at about 2, and back to being a null with any higher sensitivity than 2. Tried the target from every direction, fast Sovereign "Wiggle", slow sweep. Same results.
OK, that's getting interesting....Now for the added test. Crank it up to about noon and sweep around. Of course the target is still a null, but I want to see what general sweeping around the area is doing. Machine is what I would consider stable. Not even really leaning on the edge of being unstable to me. Once I get up to like 10 or 11 O'Clock is when I would consider that I'm riding on the verge of unstability, the way I usually always hunt. But, like said, at many of my sites I'm finding even max stability to not even be on the "edge" of stability like I like to hunt. Smooth as silk and wouldn't even consider myself pushing the machine as I would at 10 or 11 O'Clock at this particular site.
So, what does all this mean? What it means to me is that there is in fact a point of adjustment, somewhere lower than the edge of stability that most people would hunt at, and EVEN LOWER than REAL stable by just about anybody's standards, where max depth is going to be achieved, and it's MUCH lower than what I would have ever guessed! It's very early in my testing and I need to conduct the same tests at various sites of differing soils to confirm all this to hold true for those conditions as well, but if things pan out the way it looks then here's my conclusion...
I won't be following the manual's suggestions for sensitivity. After all, a "stable" threshold doesn't mean it's getting best depth. It might very well null over your target like it was iron if you have it set at something that high. My normal "riding the edge of stability" method doesn't work for this machine, as it didn't for the Explorers I've owned. It might be true for a lot of other machines out there. At least I always found that to be the case with your typical VLF machine, but these FBS and BBS machines are for the exception to the rule. What about the pump method? Don't know yet, but I have high hopes that it will calibrate sensitivity to the proper level. What I plan to do is set it like I did above on a buried silver dime and then try the pump method to re-adjust sensitivity from scratch again. If the dial falls about where the buried dime told me to set it then I'll be a happy camper, because anything other than having to dig a hole and stick a dime in the ground at each new site would be a lot easier...
But, if nothing else will suffice then it looks like I'm starting each new hunt by digging a hole, sticking a dime in the ground, and slowly adjusting sensitivity up to (and past) the point where I get the best response. I want to see where it begins and ends. Probably so long as it keeps sounding off at even much higher sensitivity levels than where you first start hitting it then that's OK to set it as high as that will let you. But, I feel the most precise method is going to be to dig up the coin and stick it another 2 or 3" in the ground and do it all over again. I'm going to want to find that tight spot where too little sensitivity causes a null or no response, and too high of sensitivity only produces a null or no longer gives a good audio and ID. I figure 6" is a good starting point in heavy mineralized soil. As shown above anything deeper might not give a good response on a freshly buried target. Of course with healed ground and a good coin halo of an undug target you'd expect something deeper, but I'm talking really bad ground here. In better ground 8, 9, or even 10 or 11" might be the depth needed to find that "sweet" spot, where anything higher or lower loses the target or destroys the response. Hope the method to my madness makes some kind of since here, as I'm not sure I'm explaining it as clearly as I should, but I think you get the idea.
So think again if you think you know what is stable, what is not, and what is the deepest. Those "nulls" you think are iron might not be iron at all, but rather a nice silver coin that the machine is overloading on and nulling out because you've got the sensitivity TOO HIGH for maximum depth!
Look forward to hearing differing opinions, others methods, or any other insight on how you guys like to set sensitivity for maximum depth...
We've worked this spot for years with many machines, all of which pretty much bottom out at around 7 to 8" in depth on a silver dime. A friend had used an Etrac there for a short few hours before he sold it and I witnessed him dig two separate targets at about 9 1/2", one being I think a Rosie and the other a Merc. That jives with what I've always thought about this place, that there are many more coins to be found at further depths than the about 8" or so we've scoured the others out at. I'd be confident in my GT with the stock 10" coil getting this deep and even much deeper because I've already dug my two deepest coins on any machine by using the GT and the 10" at one site. Those were an indian and a v-nickel that I can't exactly remember the depth on, but I know they were well over 9" and judging by the length of my digger which I now know is 11" long they might well have been that because I remember sticking it down in the hole pretty much to the top of the handle.
Either way, along comes the 15x12 SEF coil so I never really have had a chance to work the above other deep coin spot with the 10", but I've been even more excited about using the SEF there anyway because I feel this coil is deeper, both based on what I've read about it's performance in the field by others and also by how deep I've dug non-coin targets (even tiny ones) with it. It's done very well for me and found me silver in trash or on edge that I might otherwise have missed, but as of yet I've still not popped what I would consider to be real deep coins with it. That being coins say 9" to 11" or even deeper. Anything past 9" is a step above just about anything on the market with a few exceptions, so I'd be happy with anything even approaching 12" which I've heard others say they've popped coin at with the Sovereign and other coils. I'm talking on land here. I know beach hunters report depths well into the teens for coins. Not that I haven't read and seen some "teen" depth on land with the SEF, just that I have to see and do it for myself to have that kind of confidence.
Anyway, now that the ground work has been re-hashed again I've been highly suspicious of why I'm not popping the deep coins thus far with it. Most of the time I'm able to max out sensitivity as I find this coil I think to be even more stable than the 10", and that's saying a lot because the 10" is a great coil. I'd say at roughly 80% of my sites thus far full sensitivity is the norm for me with a seemingly stable threshold. Sure, I get the occasional "null" that one would expect to be iron. Even if this drop out of the threshold might be due to a bit too much sensitivity most guys will put up with that in order to max out the depth on any machine, right? Not so fast, because that's been my experience with every machine I've ever owned too with the exception of the Explorer, in that a slightly unstable threshold would still produce maximum coin depths so long as you can deal with the slight falsing. That's the way I've been running my GT, and that's probably been WHY I haven't dug any real deep ones yet with it...
I just came back from a short hunt at a site that I've dug some nice coins from in the past. Not many, as the RF noise due to nearby high power lines (BIG Ones!) and the heavy clay with high mineralization causes any machine to have major problems with stability. Still, I would hunt that spot with the above "slightly unstable on the verge" type of sensitivity setting and did manage to come away in the past with a Canadian half dime, large cent, a few indians, and I think a Merc or two along with maybe a barber dime thrown in from memory. These coins weren't deep, maybe 4 or 5" max, and still yet they didn't give me 100% perfect coin signals. I just knew to dig them at a site like this because they were "just about there" in terms of being perfect. More like a junky screw cap or bottle cap signal than a good coin signal, but good enough at at spot like this one.
I figured here's the perfect spot to begin my investigation on this sensitivity thing. Yea, I want to test my method at non-mineralized/non-RF noise sites as well because it probably will be very informative to see what gives at those kinds of sites as well, but regardless I figured I'd start at one of the worst spots you can imagine. It's not heavy with iron or other trash, but the minerals and noise would provide obstacles to overcome in their own way and are more directly related to sensitivity as far as I'm concerned.
So, onto the test...I throw the machine into auto and find a spot where no trash or anything else causing the threshold to null out was present. Now I want to be sure that there is nothing present deeper that auto can't detect, so I throw it into manual and slowly raise it as I sweep over this spot. Still clean, but then the threshold started dropping out and the ID became erratic once I got around 3/4ths max sensitivity (or about the 11 O'Clock position). Backed it down to "Noon" and it seems stable now with no jumpy ID or erratic threshold that tells me it's picking up too much noise or ground mineralization. Spot looks clean to me. Good, so I dig a hole 7 1/2" deep and stick a silver Rosie at the bottom laying flat. Fill the hole back up and pack it good to try to keep the air out, which worked nicely because the ground was rather wet and mushy.
Threw sensitivity into Auto first and swept over the spot. No change in audio and no threshold null, like it wasn't even there. I've got coins at almost 8" in auto with this coil before but I'm guessing the nearby power lines is kicking it much further down at this spot, so that wasn't surprising. Turn it to lowest manual and sweep over it. No change. Move it up to about between the 4 and 3 O'Clock position and now I'm getting a null over the target but nothing else. Move it up a tiny bit at a time and right at about the 2 O'Clock position I'm still getting the null but with an occasional "chirp" thrown in that tells me the target is now trying to break through. Move it slightly up between 2 and 1 O'Clock and it's back to being a null! Move it to 1 O'Clock, Null! Move it to Noon, Null! Move it past noon and it's still Null City, and now I'm starting to get the erratic threshold and ID.
Move it back down to lowest manual and begin doing the slow creeping up of sensitivity again, just a tad at a time and then sweeping, and once again find all of the above to be the same. Null at around 3 to 4 O'Clock on the dial, slight "chirp" break through at about 2, and back to being a null with any higher sensitivity than 2. Tried the target from every direction, fast Sovereign "Wiggle", slow sweep. Same results.
OK, that's getting interesting....Now for the added test. Crank it up to about noon and sweep around. Of course the target is still a null, but I want to see what general sweeping around the area is doing. Machine is what I would consider stable. Not even really leaning on the edge of being unstable to me. Once I get up to like 10 or 11 O'Clock is when I would consider that I'm riding on the verge of unstability, the way I usually always hunt. But, like said, at many of my sites I'm finding even max stability to not even be on the "edge" of stability like I like to hunt. Smooth as silk and wouldn't even consider myself pushing the machine as I would at 10 or 11 O'Clock at this particular site.
So, what does all this mean? What it means to me is that there is in fact a point of adjustment, somewhere lower than the edge of stability that most people would hunt at, and EVEN LOWER than REAL stable by just about anybody's standards, where max depth is going to be achieved, and it's MUCH lower than what I would have ever guessed! It's very early in my testing and I need to conduct the same tests at various sites of differing soils to confirm all this to hold true for those conditions as well, but if things pan out the way it looks then here's my conclusion...
I won't be following the manual's suggestions for sensitivity. After all, a "stable" threshold doesn't mean it's getting best depth. It might very well null over your target like it was iron if you have it set at something that high. My normal "riding the edge of stability" method doesn't work for this machine, as it didn't for the Explorers I've owned. It might be true for a lot of other machines out there. At least I always found that to be the case with your typical VLF machine, but these FBS and BBS machines are for the exception to the rule. What about the pump method? Don't know yet, but I have high hopes that it will calibrate sensitivity to the proper level. What I plan to do is set it like I did above on a buried silver dime and then try the pump method to re-adjust sensitivity from scratch again. If the dial falls about where the buried dime told me to set it then I'll be a happy camper, because anything other than having to dig a hole and stick a dime in the ground at each new site would be a lot easier...
But, if nothing else will suffice then it looks like I'm starting each new hunt by digging a hole, sticking a dime in the ground, and slowly adjusting sensitivity up to (and past) the point where I get the best response. I want to see where it begins and ends. Probably so long as it keeps sounding off at even much higher sensitivity levels than where you first start hitting it then that's OK to set it as high as that will let you. But, I feel the most precise method is going to be to dig up the coin and stick it another 2 or 3" in the ground and do it all over again. I'm going to want to find that tight spot where too little sensitivity causes a null or no response, and too high of sensitivity only produces a null or no longer gives a good audio and ID. I figure 6" is a good starting point in heavy mineralized soil. As shown above anything deeper might not give a good response on a freshly buried target. Of course with healed ground and a good coin halo of an undug target you'd expect something deeper, but I'm talking really bad ground here. In better ground 8, 9, or even 10 or 11" might be the depth needed to find that "sweet" spot, where anything higher or lower loses the target or destroys the response. Hope the method to my madness makes some kind of since here, as I'm not sure I'm explaining it as clearly as I should, but I think you get the idea.
So think again if you think you know what is stable, what is not, and what is the deepest. Those "nulls" you think are iron might not be iron at all, but rather a nice silver coin that the machine is overloading on and nulling out because you've got the sensitivity TOO HIGH for maximum depth!
Look forward to hearing differing opinions, others methods, or any other insight on how you guys like to set sensitivity for maximum depth...
First, not sure I made it clear but the Explorer was the only machine I found to also have targets vanish if ran at too high of sensitivity, even if things appears in every respect to be perfectly stable.
