Has anyone ever compared both of these coils for stability and depth, and all around performance ? ... I'm sure folks have one or the other and probably both like these coils , but I'm looking for someone who has tried BOTH of these coils and made a comparison ... Inquiring minds want to know ......Thanks, Jim
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Coiltek WOT 15 vs 12 x 15 SEF ?
- Thread starter synthnut
- Start date
Critterhunter
New member
The 15x12 is lighter than the WOT. Take off the coil cover and the 15x12 is lighter than the 10" stock coil with it's cover still on. I sprayed bed liner on mine and it feels no heavier than the 10", but then again I'm running it on a light weight setup I built. The WOT is the heaviest coil out there for the Sovereign. Read threw a bunch of old threads on the web before buying my 15x12 and found that most said they liked it better than the WOT. Otherwise I would have bought the WOT. Just be careful. I have a feeling that if your ground has real high minerals then the 12x10 might be a better option as the 15x12 might be seeing too much ground. Haven't proven that for myself one way or the other yet. By all rights and reviews the 15x12 is said to get deeper on dime sized coins or bigger than the 12x10, but again that might change in really bad ground where something smaller might get deeper. As for the WOT, the two biggest perks I heard most about the 15x12 was easier to pinpoint with and much more stable with less falsing. Third would probably be being able to hit on smaller targets better. Fourth would probably be better depth. It's also cheaper new than the WOT.
Thenks for the info guys ....I appreciate it .....
Kered,
It's good to know that you have had both and went with the SEF .....That means a lot ....Thanks
Critter ,
I have read most all of your threads over coffee ....Last I looked I think I went thru 10 lbs of coffee !!!.....
..... I did read you debate on the 10x12 vs the 12 x 15 SEF ...... Since the stock coil is so close in size to the 10x15 , I would have to opt for the 12 x 15 ..... I listenned to my buddies setup on the E Trac and even on the beach and on the wet sand , it was really very stable and very quiet ....More so than the Pro Coil ..... The SEF comes with the cover too which is nice ..... I just figured that if the Coiltek was lighter , and more powerful , I would go that route , but it dose not appear that way .... You can run the sensitivity up higher on the SEF too which might work in certain applications .....I do realized though that you have found that running the sensitivity too high has not really helped you , but the fact still remains that the SEF coil is more quiet and more stable and DOES cover more ground ..... That's important around here where when you hit the treasure lane, and there are at least 6 or so other detectorists running on the same beach at the same time .....The early bird get's the worm .....
Keep the threads coming .......I'll get more coffee !!!.............Jim
Kered,
It's good to know that you have had both and went with the SEF .....That means a lot ....Thanks
Critter ,
I have read most all of your threads over coffee ....Last I looked I think I went thru 10 lbs of coffee !!!.....
..... I did read you debate on the 10x12 vs the 12 x 15 SEF ...... Since the stock coil is so close in size to the 10x15 , I would have to opt for the 12 x 15 ..... I listenned to my buddies setup on the E Trac and even on the beach and on the wet sand , it was really very stable and very quiet ....More so than the Pro Coil ..... The SEF comes with the cover too which is nice ..... I just figured that if the Coiltek was lighter , and more powerful , I would go that route , but it dose not appear that way .... You can run the sensitivity up higher on the SEF too which might work in certain applications .....I do realized though that you have found that running the sensitivity too high has not really helped you , but the fact still remains that the SEF coil is more quiet and more stable and DOES cover more ground ..... That's important around here where when you hit the treasure lane, and there are at least 6 or so other detectorists running on the same beach at the same time .....The early bird get's the worm .....Keep the threads coming .......I'll get more coffee !!!.......
......Jimrajae2006r
New member
Hello .
Thank you to all the information that is precious to me too because I want a powerful
drive for my Sov-GT
that goes looking for the jewels to 20 inches this winter
Rajae, Bordeaux - France.
Thank you to all the information that is precious to me too because I want a powerful
drive for my Sov-GT
that goes looking for the jewels to 20 inches this winterRajae, Bordeaux - France.
Critterhunter
New member
I liked the joke about the coffee. Actually I probably help their sales because you have to keep yourself awake to make it through my long posts too. 
Yes, I find that the machine can run higher than the 10" coil in sensitivity at a lot of sites, but also as said that isn't going to mean better depth. It means less depth, in fact. On the other hand, at a lower mineral site (like good black topsoil or sand with lower minerals) I bet max stable sensitivity would be best for depth because the machine isn't losing the target in the ground matrix. In other words, in low mineral areas the highest possible sensitivity setting probably would give the best depth just like on any other machine for the most part. Most of my sites are medium to high in minerals so I'm finding max stable sensitivity is giving me less depth on targets. They'll degrade in quality or even null out if I max out sensitivity.
But, since I think the 15x12 is even more stable than the 10" coil, that means you could run at a higher sensitivity setting in low mineral sites where that might give best depth. Reverse of that is it might be than in medium to high minerals the 15x12 is past the point of return in terms of size to depth even with my "best" calibration of the sensitivity buy sticking a dime in the ground. In that case the 12x10, 10", or even an 8" coil might be deeper than the others. Still haven't proven that one way or the other yet with the 15x12. Need much more field time on it with my new found calibration method. When I start popping coins deeper than the 10" coil (about 11" on land is the deepest I've dug them with that coil), like at least 11" deep or deeper then I'll know the 15x12 is deeper. Then again, I'll have to note the mineral content of the soil. If it's low in minerals I'll still have my suspicions that the 10" is deeper in higher minerals.
Anybody who has hunted a really bad high mineral site with other machines (much more easier to see the effects of minerals on non-Minelab machines) has probably been surprised to find that something like a 6" coil gave them better depth and cleaner target IDs than say a 9 or 10" coil. That's due to the smaller coil seeing less ground and thus having less trouble separating the target from the ground matrix. It's less important on a Minelab due to how they handle the ground signal but I bet it's still an issue once the size of the coil and the mineral content of the ground goes past a certain point. In those cases bigger isn't going to be better, but again this is all pure speculation and this 15x12 might be deeper than any smaller coil on coins even if the mineral content is real high. Just have to see what gives by actual field use and will report back on that when I have evidence one way or the other.
Yep, the 12x10 isn't much different in size than the 10". In fact, if you lay the 10" over the 15x12 they don't look nearly as different in size as you would think in your mind. But, first and foremost to me is max depth and whatever coil that turns out to be in my soil will be the one I use like the 12x10 say. One of many things I keep repeating is that the 15x12 is not nearly as big or as heavy in your hand as you probably imagined. As I also keep saying, the 10" coil will feel like an 8" coil when you go back to it now. I almost can't stand using the 10" coil on land. Just feels like I'm missing too much unless I'm real careful with my sweeping. In the water it's great, though. The only way I'll ever use the 10" coil on land again is if I find out it's deeper than the 15x12. No other reason other than that to go back to it as the separation feels better on the SEF and it pinpoints better for me. If I do find out the 15x12 isn't as deep due to my high minerals you can bet I'll be giving the 12x10 a try before resorting back to the 10" for land use. It's not that the stock 10" coil isn't a great coil. It's one of the best coils I've ever used on any machine, maybe the best. It's that the SEF is SO much better in all respects to the 10" coil. Because of that, only depth performance will make me use the 10" again once I sort that out.
Yes, I find that the machine can run higher than the 10" coil in sensitivity at a lot of sites, but also as said that isn't going to mean better depth. It means less depth, in fact. On the other hand, at a lower mineral site (like good black topsoil or sand with lower minerals) I bet max stable sensitivity would be best for depth because the machine isn't losing the target in the ground matrix. In other words, in low mineral areas the highest possible sensitivity setting probably would give the best depth just like on any other machine for the most part. Most of my sites are medium to high in minerals so I'm finding max stable sensitivity is giving me less depth on targets. They'll degrade in quality or even null out if I max out sensitivity.But, since I think the 15x12 is even more stable than the 10" coil, that means you could run at a higher sensitivity setting in low mineral sites where that might give best depth. Reverse of that is it might be than in medium to high minerals the 15x12 is past the point of return in terms of size to depth even with my "best" calibration of the sensitivity buy sticking a dime in the ground. In that case the 12x10, 10", or even an 8" coil might be deeper than the others. Still haven't proven that one way or the other yet with the 15x12. Need much more field time on it with my new found calibration method. When I start popping coins deeper than the 10" coil (about 11" on land is the deepest I've dug them with that coil), like at least 11" deep or deeper then I'll know the 15x12 is deeper. Then again, I'll have to note the mineral content of the soil. If it's low in minerals I'll still have my suspicions that the 10" is deeper in higher minerals.
Anybody who has hunted a really bad high mineral site with other machines (much more easier to see the effects of minerals on non-Minelab machines) has probably been surprised to find that something like a 6" coil gave them better depth and cleaner target IDs than say a 9 or 10" coil. That's due to the smaller coil seeing less ground and thus having less trouble separating the target from the ground matrix. It's less important on a Minelab due to how they handle the ground signal but I bet it's still an issue once the size of the coil and the mineral content of the ground goes past a certain point. In those cases bigger isn't going to be better, but again this is all pure speculation and this 15x12 might be deeper than any smaller coil on coins even if the mineral content is real high. Just have to see what gives by actual field use and will report back on that when I have evidence one way or the other.
Yep, the 12x10 isn't much different in size than the 10". In fact, if you lay the 10" over the 15x12 they don't look nearly as different in size as you would think in your mind. But, first and foremost to me is max depth and whatever coil that turns out to be in my soil will be the one I use like the 12x10 say. One of many things I keep repeating is that the 15x12 is not nearly as big or as heavy in your hand as you probably imagined. As I also keep saying, the 10" coil will feel like an 8" coil when you go back to it now. I almost can't stand using the 10" coil on land. Just feels like I'm missing too much unless I'm real careful with my sweeping. In the water it's great, though. The only way I'll ever use the 10" coil on land again is if I find out it's deeper than the 15x12. No other reason other than that to go back to it as the separation feels better on the SEF and it pinpoints better for me. If I do find out the 15x12 isn't as deep due to my high minerals you can bet I'll be giving the 12x10 a try before resorting back to the 10" for land use. It's not that the stock 10" coil isn't a great coil. It's one of the best coils I've ever used on any machine, maybe the best. It's that the SEF is SO much better in all respects to the 10" coil. Because of that, only depth performance will make me use the 10" again once I sort that out.
Critter,
Thanks for your reply .....The thing that confuses me about the SEF 12 X 15 is that it is more quiet than the stock coil .....I agree that the stock coil happens to be a great coil in it's own right , but the 12 x 15 coil is more stable and runs more quiet than the stock Pro Coil ......To me , the only thing that would make sense of this is the design of the coil and the parts that went into this coil .... I personally have not spent time with this coil , but hunt side by side with my buddy who owns it ..... Today we were at the beach and his coil running the same program with the same settings was much more quiet than my machine running the stock coil .... This still amazes me ......
You say that you think that the smaller coils may go deeper than the stock coil ......Are you sure that you're not confusing depth with say the better seperation and clarity that you get wtih the smaller coil , and hearing the targets better ? ...... My 5" Sunray does not go deeper than my stock coil , HOWEVER , when in higher mineralized soil , or when in a trashy park , I can hear MUCH better using the smaller Sunray coil to the point where I can go over the same area with the same targets and pick each one out better with the Sunray than I can with the stock Pro Coil ..... This is not better depth , this is just plain being able to hear my targets better ..... Iffy targets now become a lot more clear running the smaller coil ....Less coil area , less ground noise ( this is what amazes me with the 12 X 15 SEF coil ....it defies this logic ) ...... What also cool about the smaller coil is the fact that you can bring your sensitivity up if need be ....... Raising the sensitivity in dry sand is a GAS !!..... I'll bet if you raise the sensitivity on the the SEF coil in dry sand , you would have to learn how to speak Chineese you will dig so deep !!!...... Jim
Thanks for your reply .....The thing that confuses me about the SEF 12 X 15 is that it is more quiet than the stock coil .....I agree that the stock coil happens to be a great coil in it's own right , but the 12 x 15 coil is more stable and runs more quiet than the stock Pro Coil ......To me , the only thing that would make sense of this is the design of the coil and the parts that went into this coil .... I personally have not spent time with this coil , but hunt side by side with my buddy who owns it ..... Today we were at the beach and his coil running the same program with the same settings was much more quiet than my machine running the stock coil .... This still amazes me ......
You say that you think that the smaller coils may go deeper than the stock coil ......Are you sure that you're not confusing depth with say the better seperation and clarity that you get wtih the smaller coil , and hearing the targets better ? ...... My 5" Sunray does not go deeper than my stock coil , HOWEVER , when in higher mineralized soil , or when in a trashy park , I can hear MUCH better using the smaller Sunray coil to the point where I can go over the same area with the same targets and pick each one out better with the Sunray than I can with the stock Pro Coil ..... This is not better depth , this is just plain being able to hear my targets better ..... Iffy targets now become a lot more clear running the smaller coil ....Less coil area , less ground noise ( this is what amazes me with the 12 X 15 SEF coil ....it defies this logic ) ...... What also cool about the smaller coil is the fact that you can bring your sensitivity up if need be ....... Raising the sensitivity in dry sand is a GAS !!..... I'll bet if you raise the sensitivity on the the SEF coil in dry sand , you would have to learn how to speak Chineese you will dig so deep !!!...... Jim
Tony in FL
Member
Hi. Can anyone comment on how the Sun Ray INTRUDER S-12 compares to the WOT and 12 x 15 SEF? It sounds like the Sun Ray is the lightest of the bunch. Also I have heard the stock coil for the GT is pretty darn good. Do these after market coils really provide noticeably more depth or is it more of a matter of larger coil = easier to cover large sections of a beach / field?
Critterhunter
New member
No, I'm not talking about target masking by nearby trash due to using a larger coil. Of course that's the main reason why a smaller coil will find things that larger ones have missed, but I'm talking about the limits the machine can handle in terms of the ground signal and being able to identify a target signal that's mixed in with it. There reaches a point in size of the coil due to heavy ground mineral content where bigger is no longer deeper. I'm not saying the 15x12 isn't as deep even in high minerals. I am saying I have yet to prove that either way for myself. Based on the tiny targets I've dug real deep with this coil I'm inclined to believe that it will get coins deeper than the 10" coil, but I won't say that's a fact until I do it. I've also dug a small sinker standing on end at 11" with the 15x12 that sounded and ID'd perfectly as a coin just as it should. Since that sinker presented less surface area than even a dime I'd expect to get coins that deep and deeper.
One interesting thing I've heard is that larger coils seem to find more coins standing on end than smaller coils. The theory is that this is due to the angle of the coil's eddy currents. On a larger coil the eddy currents are at less of an angle due to the larger magnetic field. Not sure if that's true or not, but I have dug more coins on end with this coil. They don't even have to be deep, well with in the range of any coil for the most part, yet for one reason or another the SEF got them when I know other coils didn't in areas I've pounded in the past.
One interesting thing I've heard is that larger coils seem to find more coins standing on end than smaller coils. The theory is that this is due to the angle of the coil's eddy currents. On a larger coil the eddy currents are at less of an angle due to the larger magnetic field. Not sure if that's true or not, but I have dug more coins on end with this coil. They don't even have to be deep, well with in the range of any coil for the most part, yet for one reason or another the SEF got them when I know other coils didn't in areas I've pounded in the past.
Finderskeeper
Active member
Is the 12 x 15 SEF a good choice for a die hard water hunter with an Excalibur II 1000? I hunt salt water in the winter (Florida) and fresh water in the Summer. (Ohio)
I also do a lot of land hunting (parks, school yards and large open areas) so I know that a larger coil will cover more ground quickly. But is the SEF a wise choice. I have a WOT and it is nice....but I would really like to try the SEF on an Excalibur II.
I also do a lot of land hunting (parks, school yards and large open areas) so I know that a larger coil will cover more ground quickly. But is the SEF a wise choice. I have a WOT and it is nice....but I would really like to try the SEF on an Excalibur II.
Critter,
I understand what you're saying now ..... If your 12 x 15 SEF coil still runs more quiet on land as in parks and such then the stock coil , then I would have to say that the Sovereign can handle the information that the 12 x 15 is sending to it ..... Of course , you are going to have a problem if the ground is trashy , in which case a 12 x 15 coil will sound like fireworks going off even if it runs more quiet than the stock coil just by virtue of the area that it covers .....Jim
I understand what you're saying now ..... If your 12 x 15 SEF coil still runs more quiet on land as in parks and such then the stock coil , then I would have to say that the Sovereign can handle the information that the 12 x 15 is sending to it ..... Of course , you are going to have a problem if the ground is trashy , in which case a 12 x 15 coil will sound like fireworks going off even if it runs more quiet than the stock coil just by virtue of the area that it covers .....Jim
Finderskeeper,
Are you sure you want to be swinging a 12 x 15 coill in the water ? ...... Water detecting is hard enough without having to deal with a coil of this size .....I would proebably opt for something like a SunRay S-12 for the largest coil that I would want to go into the water with .... I'm not saying that the 12 x 15 would be impossible , but I sure wouldn't want to be the guy on the other end of it ....The least amount of weight the better not to mention, I can picure myself tripping over a 12 x 15 coil in the water ....Coils seem to grow once you hit the water !!......Jim
Are you sure you want to be swinging a 12 x 15 coill in the water ? ...... Water detecting is hard enough without having to deal with a coil of this size .....I would proebably opt for something like a SunRay S-12 for the largest coil that I would want to go into the water with .... I'm not saying that the 12 x 15 would be impossible , but I sure wouldn't want to be the guy on the other end of it ....The least amount of weight the better not to mention, I can picure myself tripping over a 12 x 15 coil in the water ....Coils seem to grow once you hit the water !!......Jim
Critterhunter
New member
I used my 15x12 in the water and it was fine. In fact, it was easier to pinpoint with because I used the tail of the coil to find the target. Move the coil back and fourth as you advance it until you just lose the target. Now stick your big toe in the "V" that the coil forms here. It's an upside down V of course at the tail. The target is right there. On land I use the tip of the coil and the "V". The last moment you hear the target it will be exactly at the base of that V. It's more precise than the 10" coil for me. It even pinpoints better than smaller coils on other machines I've used like the 9.5" Whites.
But, the drag of the 15x12 in water is a little too much for me and wears my arm out faster. A comfortable sweep speed will be real slow and at about the speed that most people say you should swing a Sovereign, so I guess that's OK. I, on the other hand, find the Sovereign to give best depth by using around a medium sweep speed with the way I calibrate sensitivity for max depth. Trying to move the 15x12 through water at this speed that I prefer is possible, but it for sure wears your arm out faster. If you are content with the very slow sweep speed most Sovereign users think they are supposed to use then the 15x12 will be fine in the water for them. But, I found the 10" coil to have much less drag for the somewhat faster sweep speed I like to use. Really, I bet the 12x10 would be no more drag that you could tell than the 10", so if I was going to be a coil just for water use it'd either be the 12x10 or the Sun Ray S-12. It seems most water hunters who use a larger coil use the S-12, so I bet it's no worse in drag than the 10". I don't own a 12x10 yet so I can't say for sure that it's drag would be no worse than the 10" or S-12 but I bet it would be fine. All I know is the 10" coil feels like a sniper coil to me now after using the 15x12. I'm content to use the 10" in the water but I'd probably rather have the 12x10 or S-12 for more coverage.
I've said it a hundred times already but the 15x12 is my land coil all the time. I honestly feel it separates BETTER than the 10", and that's saying a lot since the 10" is one of the best coils I've ever used. I'm not talking from tip to toe because obviously this coil is pretty long, but from left to right this thing almost feelts like an 8" coil in how good it separates targets side by side. I have no problem using this coil in heavy trash and have found silver in heavy trash with it that wasn't even deep, meaning other coils that are smaller have missed those coins for whatever reason. I believe there are three reasons for this- One, it separates from left to right better than even some much smaller coils because the detection line width on it is very tight (which is a good thing). Two, being a hybrid coil that is part concentric (in the very center) but mostly double D, I believe the unique coil field dynamics of this coil cause it to hit on coins in trash better than other coils in certain situations. I also feel it is better at hitting coins on edge than convention DD or concentric coils. I feel no more issues hunting in trash with this coil than I do with the 10". It's smooth as silk and I can't believe how well it separates and pinpoints.
No, I'm not saying the 15x12 might not be deeper due to trash. I'm saying that it might not be deeper than say the 10" or 12x10 if the mineral content is high. Even if the coil is running smooth that means nothing. The machine still has to be able to separate the target signal from all that ground matrix it is also seeing, meaning minerals not multiple targets. Think of it this way- If you look at an entire page of text at once can you pick out the meaning of it? No, it's going to be hard to arrive at the conclusion to what that page says. If, on the other hand, you look at a few sentences at a time then things start to become more clear. That's what I mean, that I have a feeling that at least in high minerals the Sovereign might not be able to pull the target signal out of all the ground signal that it's being washed in. Turning down the sensitivity much lower than what is stable DOES give both the 10" coil and this coil more depth, but whether or not that will compensate enough on the 15x12 to still get more depth than the 10" is still up for grabs for me. I've only recently figured out that the machine gets less depth if you max sensitivity out to the edge of stabilitiy. Like I've also said a billion times before, even if say 8 O'clock on the dial is still very stable I'm finding that 2PM on the dial can give more depth and target ID than something much higher. That's true with any coil on this machine, though, not just the 15x12. All the reports I've read say the 15x12 is deeper than the 12x10 on dime size targets or bigger. The 12x10 is a half inch deeper on something a bit smaller than a half dime. However, it may be that in high mineral sites the 12x10 is deeper due to it seeing less ground, or even the 10" might be deeper than either one of them due to it seeing even less ground. The balance here is coil size, sensitivity, and the amount of minerals. Any one of these factors might make one coil deeper than the others. For instance, in low minerals I bet the 15x12 is for sure deeper than them and you can probably run the sensitivity at max for best depth. In moderate minerals it might still be deeper but the sensitivity might need to be at half or less. In higher minerals it might be that this size coil can no longer provide best depth and the the 12x10 or 10" will.
I'm finding at many of my sites that the 15x12 can be run at higher sensitivity settings than the 10". Even at full blast on the dial at many sites where say the 10" couldn't run that high. BUT, as I've said over and over to the point where even I'm getting sick of saying it, max stable sensitivity does NOT mean it's the deepest. Something like 2 or 3PM on the dial might provide more depth and better target IDs. I really wish more people would try this. Stick a silver dime in the ground at like 7". Play with the sensitivity and wiggle over the target. You'll often find that say 2PM is the best depth with the easiest target ID. Noon might still give a good target ID but you'll see that it's much harder work to get it to do that. 10PM will be even worse or even NULL out the target. Same deal with too low of sensitivity. So, long story even longer (man I need a smoke right now), just because a certain coil is more stable at higher sensitivity settings like the SEF that does NOT mean you will get more depth with it. Stability has a lot to do with the way the windings are matched up to each other inside a coil. It isn't all about sensitivity. I have a feeling these SEF coils have very tight tolerances with the coil windings (they must mirror each other to balance the signal out) and that's why it's so smooth. One more time- It's proper sensitivity setting, size of the coil, and mineral content. Any one of those things can mean a smaller coil can be deeper in say a high mineral site, or a larger coil might be at least in lower minerals. There is a point of deminishing returns where size starts costing you depth, otherwise we'd all be hunting with coils that were 5 feet in diameter. It isn't all about separation, it's about how much ground the machine is taking in.
OK, now I am going out for a smoke. That was long even for me but that's my theory take it or leave it.
But, the drag of the 15x12 in water is a little too much for me and wears my arm out faster. A comfortable sweep speed will be real slow and at about the speed that most people say you should swing a Sovereign, so I guess that's OK. I, on the other hand, find the Sovereign to give best depth by using around a medium sweep speed with the way I calibrate sensitivity for max depth. Trying to move the 15x12 through water at this speed that I prefer is possible, but it for sure wears your arm out faster. If you are content with the very slow sweep speed most Sovereign users think they are supposed to use then the 15x12 will be fine in the water for them. But, I found the 10" coil to have much less drag for the somewhat faster sweep speed I like to use. Really, I bet the 12x10 would be no more drag that you could tell than the 10", so if I was going to be a coil just for water use it'd either be the 12x10 or the Sun Ray S-12. It seems most water hunters who use a larger coil use the S-12, so I bet it's no worse in drag than the 10". I don't own a 12x10 yet so I can't say for sure that it's drag would be no worse than the 10" or S-12 but I bet it would be fine. All I know is the 10" coil feels like a sniper coil to me now after using the 15x12. I'm content to use the 10" in the water but I'd probably rather have the 12x10 or S-12 for more coverage.
I've said it a hundred times already but the 15x12 is my land coil all the time. I honestly feel it separates BETTER than the 10", and that's saying a lot since the 10" is one of the best coils I've ever used. I'm not talking from tip to toe because obviously this coil is pretty long, but from left to right this thing almost feelts like an 8" coil in how good it separates targets side by side. I have no problem using this coil in heavy trash and have found silver in heavy trash with it that wasn't even deep, meaning other coils that are smaller have missed those coins for whatever reason. I believe there are three reasons for this- One, it separates from left to right better than even some much smaller coils because the detection line width on it is very tight (which is a good thing). Two, being a hybrid coil that is part concentric (in the very center) but mostly double D, I believe the unique coil field dynamics of this coil cause it to hit on coins in trash better than other coils in certain situations. I also feel it is better at hitting coins on edge than convention DD or concentric coils. I feel no more issues hunting in trash with this coil than I do with the 10". It's smooth as silk and I can't believe how well it separates and pinpoints.
No, I'm not saying the 15x12 might not be deeper due to trash. I'm saying that it might not be deeper than say the 10" or 12x10 if the mineral content is high. Even if the coil is running smooth that means nothing. The machine still has to be able to separate the target signal from all that ground matrix it is also seeing, meaning minerals not multiple targets. Think of it this way- If you look at an entire page of text at once can you pick out the meaning of it? No, it's going to be hard to arrive at the conclusion to what that page says. If, on the other hand, you look at a few sentences at a time then things start to become more clear. That's what I mean, that I have a feeling that at least in high minerals the Sovereign might not be able to pull the target signal out of all the ground signal that it's being washed in. Turning down the sensitivity much lower than what is stable DOES give both the 10" coil and this coil more depth, but whether or not that will compensate enough on the 15x12 to still get more depth than the 10" is still up for grabs for me. I've only recently figured out that the machine gets less depth if you max sensitivity out to the edge of stabilitiy. Like I've also said a billion times before, even if say 8 O'clock on the dial is still very stable I'm finding that 2PM on the dial can give more depth and target ID than something much higher. That's true with any coil on this machine, though, not just the 15x12. All the reports I've read say the 15x12 is deeper than the 12x10 on dime size targets or bigger. The 12x10 is a half inch deeper on something a bit smaller than a half dime. However, it may be that in high mineral sites the 12x10 is deeper due to it seeing less ground, or even the 10" might be deeper than either one of them due to it seeing even less ground. The balance here is coil size, sensitivity, and the amount of minerals. Any one of these factors might make one coil deeper than the others. For instance, in low minerals I bet the 15x12 is for sure deeper than them and you can probably run the sensitivity at max for best depth. In moderate minerals it might still be deeper but the sensitivity might need to be at half or less. In higher minerals it might be that this size coil can no longer provide best depth and the the 12x10 or 10" will.
I'm finding at many of my sites that the 15x12 can be run at higher sensitivity settings than the 10". Even at full blast on the dial at many sites where say the 10" couldn't run that high. BUT, as I've said over and over to the point where even I'm getting sick of saying it, max stable sensitivity does NOT mean it's the deepest. Something like 2 or 3PM on the dial might provide more depth and better target IDs. I really wish more people would try this. Stick a silver dime in the ground at like 7". Play with the sensitivity and wiggle over the target. You'll often find that say 2PM is the best depth with the easiest target ID. Noon might still give a good target ID but you'll see that it's much harder work to get it to do that. 10PM will be even worse or even NULL out the target. Same deal with too low of sensitivity. So, long story even longer (man I need a smoke right now), just because a certain coil is more stable at higher sensitivity settings like the SEF that does NOT mean you will get more depth with it. Stability has a lot to do with the way the windings are matched up to each other inside a coil. It isn't all about sensitivity. I have a feeling these SEF coils have very tight tolerances with the coil windings (they must mirror each other to balance the signal out) and that's why it's so smooth. One more time- It's proper sensitivity setting, size of the coil, and mineral content. Any one of those things can mean a smaller coil can be deeper in say a high mineral site, or a larger coil might be at least in lower minerals. There is a point of deminishing returns where size starts costing you depth, otherwise we'd all be hunting with coils that were 5 feet in diameter. It isn't all about separation, it's about how much ground the machine is taking in.
OK, now I am going out for a smoke. That was long even for me but that's my theory take it or leave it.
Finderskeeper
Active member
I can swing the WOT with no trouble in the water. The SEF does not seem to be that much larger.
In the water, it is not the size overall but the width of the edge that gives resistance to a swing.
Maybe it is too big. I don't have trouble with the WOT and it is heavier than the 15 x 12 SEF and the WOT is just a tad smaller than the SEF.
I have not heard much on the 15 x 12 on the Excalibur II 1000. Anyone have any experience with the 15 x 12 SEF on an Excalibur II and use it in the water?
In the water, it is not the size overall but the width of the edge that gives resistance to a swing.
Maybe it is too big. I don't have trouble with the WOT and it is heavier than the 15 x 12 SEF and the WOT is just a tad smaller than the SEF.
I have not heard much on the 15 x 12 on the Excalibur II 1000. Anyone have any experience with the 15 x 12 SEF on an Excalibur II and use it in the water?
Critterhunter
New member
I think it's more the length of the coil from tip to toe that causes drag, but like you said it's thickness probably as well matters. The width (left to right size) of the coil probably doesn't matter at all.
I used my 15x12 in the water and it was fine. In fact, it was easier to pinpoint with because I used the tail of the coil to find the target. Move the coil back and fourth as you advance it until you just lose the target. Now stick your big toe in the "V" that the coil forms here. It's an upside down V of course at the tail. The target is right there. On land I use the tip of the coil and the "V". The last moment you hear the target it will be exactly at the base of that V. It's more precise than the 10" coil for me. It even pinpoints better than smaller coils on other machines I've used like the 9.5" Whites.
But, the drag of the 15x12 in water is a little too much for me and wears my arm out faster. A comfortable sweep speed will be real slow and at about the speed that most people say you should swing a Sovereign, so I guess that's OK. I, on the other hand, find the Sovereign to give best depth by using around a medium sweep speed with the way I calibrate sensitivity for max depth. Trying to move the 15x12 through water at this speed that I prefer is possible, but it for sure wears your arm out faster. If you are content with the very slow sweep speed most Sovereign users think they are supposed to use then the 15x12 will be fine in the water for them. But, I found the 10" coil to have much less drag for the somewhat faster sweep speed I like to use. Really, I bet the 12x10 would be no more drag that you could tell than the 10", so if I was going to be a coil just for water use it'd either be the 12x10 or the Sun Ray S-12. It seems most water hunters who use a larger coil use the S-12, so I bet it's no worse in drag than the 10". I don't own a 12x10 yet so I can't say for sure that it's drag would be no worse than the 10" or S-12 but I bet it would be fine. All I know is the 10" coil feels like a sniper coil to me now after using the 15x12. I'm content to use the 10" in the water but I'd probably rather have the 12x10 or S-12 for more coverage.
I've said it a hundred times already but the 15x12 is my land coil all the time. I honestly feel it separates BETTER than the 10", and that's saying a lot since the 10" is one of the best coils I've ever used. I'm not talking from tip to toe because obviously this coil is pretty long, but from left to right this thing almost feelts like an 8" coil in how good it separates targets side by side. I have no problem using this coil in heavy trash and have found silver in heavy trash with it that wasn't even deep, meaning other coils that are smaller have missed those coins for whatever reason. I believe there are three reasons for this- One, it separates from left to right better than even some much smaller coils because the detection line width on it is very tight (which is a good thing). Two, being a hybrid coil that is part concentric (in the very center) but mostly double D, I believe the unique coil field dynamics of this coil cause it to hit on coins in trash better than other coils in certain situations. I also feel it is better at hitting coins on edge than convention DD or concentric coils. I feel no more issues hunting in trash with this coil than I do with the 10". It's smooth as silk and I can't believe how well it separates and pinpoints.
No, I'm not saying the 15x12 might not be deeper due to trash. I'm saying that it might not be deeper than say the 10" or 12x10 if the mineral content is high. Even if the coil is running smooth that means nothing. The machine still has to be able to separate the target signal from all that ground matrix it is also seeing, meaning minerals not multiple targets. Think of it this way- If you look at an entire page of text at once can you pick out the meaning of it? No, it's going to be hard to arrive at the conclusion to what that page says. If, on the other hand, you look at a few sentences at a time then things start to become more clear. That's what I mean, that I have a feeling that at least in high minerals the Sovereign might not be able to pull the target signal out of all the ground signal that it's being washed in. Turning down the sensitivity much lower than what is stable DOES give both the 10" coil and this coil more depth, but whether or not that will compensate enough on the 15x12 to still get more depth than the 10" is still up for grabs for me. I've only recently figured out that the machine gets less depth if you max sensitivity out to the edge of stabilitiy. Like I've also said a billion times before, even if say 8 O'clock on the dial is still very stable I'm finding that 2PM on the dial can give more depth and target ID than something much higher. That's true with any coil on this machine, though, not just the 15x12. All the reports I've read say the 15x12 is deeper than the 12x10 on dime size targets or bigger. The 12x10 is a half inch deeper on something a bit smaller than a half dime. However, it may be that in high mineral sites the 12x10 is deeper due to it seeing less ground, or even the 10" might be deeper than either one of them due to it seeing even less ground. The balance here is coil size, sensitivity, and the amount of minerals. Any one of these factors might make one coil deeper than the others. For instance, in low minerals I bet the 15x12 is for sure deeper than them and you can probably run the sensitivity at max for best depth. In moderate minerals it might still be deeper but the sensitivity might need to be at half or less. In higher minerals it might be that this size coil can no longer provide best depth and the the 12x10 or 10" will.
I'm finding at many of my sites that the 15x12 can be run at higher sensitivity settings than the 10". Even at full blast on the dial at many sites where say the 10" couldn't run that high. BUT, as I've said over and over to the point where even I'm getting sick of saying it, max stable sensitivity does NOT mean it's the deepest. Something like 2 or 3PM on the dial might provide more depth and better target IDs. I really wish more people would try this. Stick a silver dime in the ground at like 7". Play with the sensitivity and wiggle over the target. You'll often find that say 2PM is the best depth with the easiest target ID. Noon might still give a good target ID but you'll see that it's much harder work to get it to do that. 10PM will be even worse or even NULL out the target. Same deal with too low of sensitivity. So, long story even longer (man I need a smoke right now), just because a certain coil is more stable at higher sensitivity settings like the SEF that does NOT mean you will get more depth with it. Stability has a lot to do with the way the windings are matched up to each other inside a coil. It isn't all about sensitivity. I have a feeling these SEF coils have very tight tolerances with the coil windings (they must mirror each other to balance the signal out) and that's why it's so smooth. One more time- It's proper sensitivity setting, size of the coil, and mineral content. Any one of those things can mean a smaller coil can be deeper in say a high mineral site, or a larger coil might be at least in lower minerals. There is a point of deminishing returns where size starts costing you depth, otherwise we'd all be hunting with coils that were 5 feet in diameter. It isn't all about separation, it's about how much ground the machine is taking in.
OK, now I am going out for a smoke. That was long even for me but that's my theory take it or leave it.
Critter,
I have to say that I think these theories are some of your best yet ..... I do believe that all the factors that you mention play a HUGE role in how your sensitivity should be adjusted ...... I agree with you until you get to the statement that 2pm is the highest the sensitivity needs to go for the ultimate depth ....... Perhaps in the soil that you are dealing with , 2 pm is the best setting for you ...... My thoughts are like yours in the respect that mineralization will at some point stop a coil from reading targets .....I picture it like this .....I picture my coil as a headlight .....and I picture mineralization as fog .....The bigger the headlight , and the more fog there is , the less I'm gonna see ......Give me the same amount of fog , and give me a smaller headlight , and I will see better than I can with the larger headlight , but still not all that good ..... Now if I turn down the power to that headlight ( sensitivity ) there will be a time when I will be able to better see thru the fog ...... My thoughts are that you have turned the sensitivity down to a certain point ( 2 pm ) for your ground conditions , and it is the optimal setting for your ground with it's mineralization what it is ....... NOW ( follow me here ) If I take away the fog ( mineralization ) and turn my headlights on high beams ( higher sensitivity ) I think that I will be able to see further ( deeper ) ......You will loose depth if you turn your sensitivy all the way down , so you would have to agree that you need a certain amount of sensitivity to gain some sort of depth ....I am in total agreement with all your theories , and also agree that it's all a matter of balance .....Coil size, sensitivity , mineralization , and even coil design .... Look at how well the SEF coil reads coins on edge ....Probably because of how it was designed ......I can read a LOT deeper at the beach in dry sand if I stay away from the wet sand .....Why ? ....Because there are far less minerals in it .....I have already had some iffy signals at the beach and have raised my sensitiviy up higher , and brought them in loud and clear .....Would I be able to do that with higher mineralization ? .....NO !!!.... I would not be able to do that at the local park because of the make up of the soil .... I will say one thing for sure that the 2 pm works great for you , and I'm glad it does .....THat number will always stick in my head ..... When I go out hunting , 2 pm is going to be my starting point ..... Thanks again for your theories .....I look forward to your findings on the smaller 10 x 12 SEF ......Do they make a 10 x 12 SEF for the Sovereign ? >......I'm not sure if they do ....Thanks again , Jim
BTW .....Please quit smoking ....It's killing you !!!.....We need you on this forum for a long time to come !!.....Thanks, Jim
But, the drag of the 15x12 in water is a little too much for me and wears my arm out faster. A comfortable sweep speed will be real slow and at about the speed that most people say you should swing a Sovereign, so I guess that's OK. I, on the other hand, find the Sovereign to give best depth by using around a medium sweep speed with the way I calibrate sensitivity for max depth. Trying to move the 15x12 through water at this speed that I prefer is possible, but it for sure wears your arm out faster. If you are content with the very slow sweep speed most Sovereign users think they are supposed to use then the 15x12 will be fine in the water for them. But, I found the 10" coil to have much less drag for the somewhat faster sweep speed I like to use. Really, I bet the 12x10 would be no more drag that you could tell than the 10", so if I was going to be a coil just for water use it'd either be the 12x10 or the Sun Ray S-12. It seems most water hunters who use a larger coil use the S-12, so I bet it's no worse in drag than the 10". I don't own a 12x10 yet so I can't say for sure that it's drag would be no worse than the 10" or S-12 but I bet it would be fine. All I know is the 10" coil feels like a sniper coil to me now after using the 15x12. I'm content to use the 10" in the water but I'd probably rather have the 12x10 or S-12 for more coverage.
I've said it a hundred times already but the 15x12 is my land coil all the time. I honestly feel it separates BETTER than the 10", and that's saying a lot since the 10" is one of the best coils I've ever used. I'm not talking from tip to toe because obviously this coil is pretty long, but from left to right this thing almost feelts like an 8" coil in how good it separates targets side by side. I have no problem using this coil in heavy trash and have found silver in heavy trash with it that wasn't even deep, meaning other coils that are smaller have missed those coins for whatever reason. I believe there are three reasons for this- One, it separates from left to right better than even some much smaller coils because the detection line width on it is very tight (which is a good thing). Two, being a hybrid coil that is part concentric (in the very center) but mostly double D, I believe the unique coil field dynamics of this coil cause it to hit on coins in trash better than other coils in certain situations. I also feel it is better at hitting coins on edge than convention DD or concentric coils. I feel no more issues hunting in trash with this coil than I do with the 10". It's smooth as silk and I can't believe how well it separates and pinpoints.
No, I'm not saying the 15x12 might not be deeper due to trash. I'm saying that it might not be deeper than say the 10" or 12x10 if the mineral content is high. Even if the coil is running smooth that means nothing. The machine still has to be able to separate the target signal from all that ground matrix it is also seeing, meaning minerals not multiple targets. Think of it this way- If you look at an entire page of text at once can you pick out the meaning of it? No, it's going to be hard to arrive at the conclusion to what that page says. If, on the other hand, you look at a few sentences at a time then things start to become more clear. That's what I mean, that I have a feeling that at least in high minerals the Sovereign might not be able to pull the target signal out of all the ground signal that it's being washed in. Turning down the sensitivity much lower than what is stable DOES give both the 10" coil and this coil more depth, but whether or not that will compensate enough on the 15x12 to still get more depth than the 10" is still up for grabs for me. I've only recently figured out that the machine gets less depth if you max sensitivity out to the edge of stabilitiy. Like I've also said a billion times before, even if say 8 O'clock on the dial is still very stable I'm finding that 2PM on the dial can give more depth and target ID than something much higher. That's true with any coil on this machine, though, not just the 15x12. All the reports I've read say the 15x12 is deeper than the 12x10 on dime size targets or bigger. The 12x10 is a half inch deeper on something a bit smaller than a half dime. However, it may be that in high mineral sites the 12x10 is deeper due to it seeing less ground, or even the 10" might be deeper than either one of them due to it seeing even less ground. The balance here is coil size, sensitivity, and the amount of minerals. Any one of these factors might make one coil deeper than the others. For instance, in low minerals I bet the 15x12 is for sure deeper than them and you can probably run the sensitivity at max for best depth. In moderate minerals it might still be deeper but the sensitivity might need to be at half or less. In higher minerals it might be that this size coil can no longer provide best depth and the the 12x10 or 10" will.
I'm finding at many of my sites that the 15x12 can be run at higher sensitivity settings than the 10". Even at full blast on the dial at many sites where say the 10" couldn't run that high. BUT, as I've said over and over to the point where even I'm getting sick of saying it, max stable sensitivity does NOT mean it's the deepest. Something like 2 or 3PM on the dial might provide more depth and better target IDs. I really wish more people would try this. Stick a silver dime in the ground at like 7". Play with the sensitivity and wiggle over the target. You'll often find that say 2PM is the best depth with the easiest target ID. Noon might still give a good target ID but you'll see that it's much harder work to get it to do that. 10PM will be even worse or even NULL out the target. Same deal with too low of sensitivity. So, long story even longer (man I need a smoke right now), just because a certain coil is more stable at higher sensitivity settings like the SEF that does NOT mean you will get more depth with it. Stability has a lot to do with the way the windings are matched up to each other inside a coil. It isn't all about sensitivity. I have a feeling these SEF coils have very tight tolerances with the coil windings (they must mirror each other to balance the signal out) and that's why it's so smooth. One more time- It's proper sensitivity setting, size of the coil, and mineral content. Any one of those things can mean a smaller coil can be deeper in say a high mineral site, or a larger coil might be at least in lower minerals. There is a point of deminishing returns where size starts costing you depth, otherwise we'd all be hunting with coils that were 5 feet in diameter. It isn't all about separation, it's about how much ground the machine is taking in.
OK, now I am going out for a smoke. That was long even for me but that's my theory take it or leave it.
Critter,
I have to say that I think these theories are some of your best yet ..... I do believe that all the factors that you mention play a HUGE role in how your sensitivity should be adjusted ...... I agree with you until you get to the statement that 2pm is the highest the sensitivity needs to go for the ultimate depth ....... Perhaps in the soil that you are dealing with , 2 pm is the best setting for you ...... My thoughts are like yours in the respect that mineralization will at some point stop a coil from reading targets .....I picture it like this .....I picture my coil as a headlight .....and I picture mineralization as fog .....The bigger the headlight , and the more fog there is , the less I'm gonna see ......Give me the same amount of fog , and give me a smaller headlight , and I will see better than I can with the larger headlight , but still not all that good ..... Now if I turn down the power to that headlight ( sensitivity ) there will be a time when I will be able to better see thru the fog ...... My thoughts are that you have turned the sensitivity down to a certain point ( 2 pm ) for your ground conditions , and it is the optimal setting for your ground with it's mineralization what it is ....... NOW ( follow me here ) If I take away the fog ( mineralization ) and turn my headlights on high beams ( higher sensitivity ) I think that I will be able to see further ( deeper ) ......You will loose depth if you turn your sensitivy all the way down , so you would have to agree that you need a certain amount of sensitivity to gain some sort of depth ....I am in total agreement with all your theories , and also agree that it's all a matter of balance .....Coil size, sensitivity , mineralization , and even coil design .... Look at how well the SEF coil reads coins on edge ....Probably because of how it was designed ......I can read a LOT deeper at the beach in dry sand if I stay away from the wet sand .....Why ? ....Because there are far less minerals in it .....I have already had some iffy signals at the beach and have raised my sensitiviy up higher , and brought them in loud and clear .....Would I be able to do that with higher mineralization ? .....NO !!!.... I would not be able to do that at the local park because of the make up of the soil .... I will say one thing for sure that the 2 pm works great for you , and I'm glad it does .....THat number will always stick in my head ..... When I go out hunting , 2 pm is going to be my starting point ..... Thanks again for your theories .....I look forward to your findings on the smaller 10 x 12 SEF ......Do they make a 10 x 12 SEF for the Sovereign ? >......I'm not sure if they do ....Thanks again , Jim
BTW .....Please quit smoking ....It's killing you !!!.....We need you on this forum for a long time to come !!.....Thanks, Jim
jerseydigger
New member
Just where would one purchase a 12 x 15 SEF, and who makes them? Thanks!
jerseydigger
New member
is this the kelloco coil?( sef 12x15?)
Critterhunter
New member
Yea, looks like you understand the theory I am trying to get acrossed. Depending on how high the mineral content is (or even the amount of tiny little hot rocks or other obstacles in the soil) a smaller coil can go deeper in certain situations. The sensitivity adjustment can compensate for this to an extent so there is some overlap. A large coil adjusted down in sensitivity lower than a smaller coil might be able to see deeper in this type of soil, but there reaches a point when sensitivity can't compensate and so a smaller coil run at a higher sensitivity setting will penetrate the soil better. When a detector is looking at the ground matrix it's constantly trying to separate a target signal from the ground load. On a typical detector when you ground balance it you are setting up a filter for the ground load that the machine then ignores and looks for anything (meaning a target) that spikes up and out of that buffer (ground balance). Minelabs do this somewhat differently (thus not needing you to set a ground balance) and that's why high mineral content doesn't effect FBS and BBS machines as much as it does any other brand. Still, depending on coil size, sensitivity, and the amount of minerals in the soil even Minelabs can lose depth or degrade target identity, it just takes much more of that to happen for them to have problems compared to other machines.
The balance between coil size, sensitivity, and mineral content is what is going to determine which coil goes deepest. The 15x12 in high minerals might still go deeper because you can lower the sensitivity, but I'm sure that there comes a point when that won't compensate and so you are now trading depth for coverage. In that case the 12x10, 10" Tornado, or even an 8" coil (in REALLY bad ground) might be the coil which can see targets deeper than the larger ones. Despite any of the above, I still say that it's very important to calibrate the sensitivity by sticking a coin in the ground. Keep sticking it deeper and deeper until you come to a point where only a very narrow setting of the dial produces the best or easiest target ID. You'll find that anything higher or lower will either degrade the signal, null it out, or at least make it much harder to get the proper ID. I calibrate mine doing the Sovereign wiggle where you hold the coil as tightly over the coin as possible while wiggling it as fast as possible. I must have made it sound like 2PM is the best choice and didn't mean that. What I meant was that I'm finding in my soil that most of the time 2PM produces the deepest response when doing the buried dime test. At some sites this setting is higher, and at some it's lower. The lowest I think I've had to go was 3PM to produce the best response/most depth, and I think the highest I've gone has been at like 10 or 11PM on the dial in soils with lower minerals.
I also like to calibrate the meter when doing this because I feel it will make the meter give the most true response to a target that's in the soil. A coin on the surface might read 180, but 7" down due to iron or other soil content it might make the ID sag down a digit or two. And, as I've said before, I'll try to set the meter so that the silver dime I buried produces a 181 number about every 4th or 5th sweep (wiggle) over the target. The ID degrading on targets due to depth or soil conditions isn't as much of a problem on Minelabs as it is on other machines, but just the same I still feel it's a good ID to set the meter on a buried target and not on top of the ground.
The other thing I hope I've made clear is that in real low minerals such as good black top soil I think the sweet spot for sensitivity gets very close to the same setting you'd use when you max sensitivity right to the edge of threshold stability. That's the typical way most people set up a machine but most of the time I find that will null or severely degrade the target on a Sovereign or an Explorer. If it's stable at say 7PM on the dial (or just out of Auto) and the soil is very low in minerals then there is a good chance that that is also the best setting for max depth, but the only way to tell is to bury a dime. Keep sticking it deeper and deeper until the range of sensitivity narrows down to a very tight spot. Notice how easy it is to achieve the proper ID and audio. Move the sensitivity up and down while doing the wiggle several times to confirm that one specific spot is where it's giving the best ID at depth. So far I have not found any location where this setting also ended up being right at the edge of stability of the machine. It's normally much lower than that and as said usually around 2PM on the dial. I think there has only been one spot at a beach where my buried dime test ended up having the sensitivity being set at a point where the machine would null out it's threshold a little here and there- in other words ride on the edge of being unstable.
The headlights in a fog thing is very true. Here's a small example: There is one site I hunt at an old park where the soil contains a lot of black sand or I guess you could call them tiny hot rocks. On my QXT Pro the 9.5" coil would produce junky coin IDs and never a perfect one. Switching over to the 5.3" coil it not only cleaned up the coin signals to where they were much better, but as a result I also was digging them deeper than I did with the larger coil. I have yet to see this happen with the Sovereign since it's so much better at ignoring minerals, but they theory still stands and that's where coil size, sensitivity setting, and mineral content is going to determine which coil is going to give you the best depth. So far the 10" Tornado has given me the most depth, but now that I know to not run my sensitivity at max stability I'm betting on the fact that the 15x12 will get deeper, at least if the minerals aren't super heavy at a location.
The balance between coil size, sensitivity, and mineral content is what is going to determine which coil goes deepest. The 15x12 in high minerals might still go deeper because you can lower the sensitivity, but I'm sure that there comes a point when that won't compensate and so you are now trading depth for coverage. In that case the 12x10, 10" Tornado, or even an 8" coil (in REALLY bad ground) might be the coil which can see targets deeper than the larger ones. Despite any of the above, I still say that it's very important to calibrate the sensitivity by sticking a coin in the ground. Keep sticking it deeper and deeper until you come to a point where only a very narrow setting of the dial produces the best or easiest target ID. You'll find that anything higher or lower will either degrade the signal, null it out, or at least make it much harder to get the proper ID. I calibrate mine doing the Sovereign wiggle where you hold the coil as tightly over the coin as possible while wiggling it as fast as possible. I must have made it sound like 2PM is the best choice and didn't mean that. What I meant was that I'm finding in my soil that most of the time 2PM produces the deepest response when doing the buried dime test. At some sites this setting is higher, and at some it's lower. The lowest I think I've had to go was 3PM to produce the best response/most depth, and I think the highest I've gone has been at like 10 or 11PM on the dial in soils with lower minerals.
I also like to calibrate the meter when doing this because I feel it will make the meter give the most true response to a target that's in the soil. A coin on the surface might read 180, but 7" down due to iron or other soil content it might make the ID sag down a digit or two. And, as I've said before, I'll try to set the meter so that the silver dime I buried produces a 181 number about every 4th or 5th sweep (wiggle) over the target. The ID degrading on targets due to depth or soil conditions isn't as much of a problem on Minelabs as it is on other machines, but just the same I still feel it's a good ID to set the meter on a buried target and not on top of the ground.
The other thing I hope I've made clear is that in real low minerals such as good black top soil I think the sweet spot for sensitivity gets very close to the same setting you'd use when you max sensitivity right to the edge of threshold stability. That's the typical way most people set up a machine but most of the time I find that will null or severely degrade the target on a Sovereign or an Explorer. If it's stable at say 7PM on the dial (or just out of Auto) and the soil is very low in minerals then there is a good chance that that is also the best setting for max depth, but the only way to tell is to bury a dime. Keep sticking it deeper and deeper until the range of sensitivity narrows down to a very tight spot. Notice how easy it is to achieve the proper ID and audio. Move the sensitivity up and down while doing the wiggle several times to confirm that one specific spot is where it's giving the best ID at depth. So far I have not found any location where this setting also ended up being right at the edge of stability of the machine. It's normally much lower than that and as said usually around 2PM on the dial. I think there has only been one spot at a beach where my buried dime test ended up having the sensitivity being set at a point where the machine would null out it's threshold a little here and there- in other words ride on the edge of being unstable.
The headlights in a fog thing is very true. Here's a small example: There is one site I hunt at an old park where the soil contains a lot of black sand or I guess you could call them tiny hot rocks. On my QXT Pro the 9.5" coil would produce junky coin IDs and never a perfect one. Switching over to the 5.3" coil it not only cleaned up the coin signals to where they were much better, but as a result I also was digging them deeper than I did with the larger coil. I have yet to see this happen with the Sovereign since it's so much better at ignoring minerals, but they theory still stands and that's where coil size, sensitivity setting, and mineral content is going to determine which coil is going to give you the best depth. So far the 10" Tornado has given me the most depth, but now that I know to not run my sensitivity at max stability I'm betting on the fact that the 15x12 will get deeper, at least if the minerals aren't super heavy at a location.