What is the benefit from this type of coil? Do they really give significantly better depth? How do they do as far as target masking? Any difference between them and original equipment DD coil as far as target masking? How about ground balancing or stability? They're kind of novel looking, but how's the performance? What do they offer vs. detector manufacturer's DD coils or Detech's Excellerator coils?
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Need Info on SEF Butterf;ly Coils
- Thread starter Cliff KS
- Start date
SEF coils are made in Bulgaria. KellyCo carries this coil as well as a number of other brands. Go to the Soveriegn GT/Excalibur forum and there is a lot of information on thr SEF coils. The Explorer forum has the most detailed field test on numerous different coils. Bryce Brown has went to great lengths doing test on various coils. You should get all the information you need about coils. Hope this helps you. HH 
Critterhunter
New member
These SEF coils are better designs, more like a mostly DD but morphed with some concentric traits. They are more stable, separate better, pinpoint real well, provide better audio, quiet falsing or iron hits, seem to hit coins on edge or masked in certain ways better than standard DD or concentric designs. They are great coils. Most say the 15x12 is the deepest on coins but the 12x10 will hit a half inch deeper on tiny little targets such as a cut quarter penny (smaller than a half dime). Both are said to be deeper than the stock 10" Sovereign or Etrac 11" pro coils and are better in all respects than them. I'd only caution that in my medium to high mineral soil the 15x12 got less depth than my stock 10" coil, but otherwise was better in every other respect. I'm trading it this week for a 12x10 because I have a theory that the 15x12 is past the point of no return in terms of getting more depth on coins due to my higher minerals. Even though it will run stable at higher sensitivity settings than the stock 10" coil it hasn't go me coins as deep and I feel that's because the target is getting lost in the extra ground matrix the machine is taking in. I'm betting on the fact that the 12x10 will give me more depth than the stock coil without going past the point of no return in terms of seeing too much ground matrix. The 15x12 was a good 2 or 3" deeper on my fresh water beaches, though, and those are mineralized so I can't understand why it never seemed to go as deep as the stock coil on land but does better on the beach.
Great coils. Better than convention DD round designs I think in many respects. Audio also seems to improve. Most like the 15x12 better than the WOT coil as well. If you have high minerals then I'd lean towards the 12x10 for probably best depth. If your minerals are low or you do a lot of wide open beach areas or fields then I'd lean towards the 15x12. Even though it didn't seem as deep on coins to me than the 10" Tornado on land I loved this coil in every other respect. It's separation is something to behold. Use the tip of tail of the coil to sort out targets and it feels like it's got the separation of an 8 or 9" coil. The tip or tail of the "V" also is great for pinpointing. Despite the fact that I didn't dig deeper coins on land with it, I have dug tiny little pieces of metal like shoe lace holes at 8 to 11" deep. Max coin depth in my high mineral land sites was about 9", but the stock 10" coil has got me coins at 11" deep with more to give based on how well they hunt. My primary hunting is old parks for deep coins so I'm hoping the 12x10 will show greater depth than the stock coil. If I was strictly a beach or large field hunter I would have kept the 15x12. In fact, down the road I'll probably buy another just for my beach hunting the dry sand. Tried it in the water and it's too much drag. Stick with the 12x10, stock 10" coil, or S-12 on the Sovereign for water.
Great coils. Better than convention DD round designs I think in many respects. Audio also seems to improve. Most like the 15x12 better than the WOT coil as well. If you have high minerals then I'd lean towards the 12x10 for probably best depth. If your minerals are low or you do a lot of wide open beach areas or fields then I'd lean towards the 15x12. Even though it didn't seem as deep on coins to me than the 10" Tornado on land I loved this coil in every other respect. It's separation is something to behold. Use the tip of tail of the coil to sort out targets and it feels like it's got the separation of an 8 or 9" coil. The tip or tail of the "V" also is great for pinpointing. Despite the fact that I didn't dig deeper coins on land with it, I have dug tiny little pieces of metal like shoe lace holes at 8 to 11" deep. Max coin depth in my high mineral land sites was about 9", but the stock 10" coil has got me coins at 11" deep with more to give based on how well they hunt. My primary hunting is old parks for deep coins so I'm hoping the 12x10 will show greater depth than the stock coil. If I was strictly a beach or large field hunter I would have kept the 15x12. In fact, down the road I'll probably buy another just for my beach hunting the dry sand. Tried it in the water and it's too much drag. Stick with the 12x10, stock 10" coil, or S-12 on the Sovereign for water.
As a recent Etrac owner, I had all of the S.E.F. coils available [6x8, 10x12, 12x15 and 15x18] along with the standard 11" pro coil. The last month or two that I owned that machine, the only coils I used were the 11" stock coil and 6x8" S.E.F.
In my soil, the Pro-coil was better at depth, pin-pointing, and separation than all of the other coils in my arsenal. The only exception being the 6x8" S.E.F being only slightly better with separation. I found the 15 x 18" S.E.F the most disappointing of the bunch with a lack of depth to coin sized objects and it was really really heavy.
Now that I've been swinging the F75 ltd for the last six months, I can say that the 9x11" Biaxial coil is as good or better in all categories from the before mention coils. I may give the Pro Coil a slight edge in pin-pointing, but that could just be the diff. in machines and not the coils.
A lot of people would think that the fewer coil options for the F75 is a hindrance, personally I like it. With the Etrac, I was always second guessing myself when hunting a certain area, wondering if I chose the right coil for the task. With the F75 ltd, I own the 5" DD and Stock 9x11" only and I usually have a good idea which of the two coils will perform the best in a given area.
In my opinion, there is no better combination for hunting in iron than the F75 with the 5" coil. I also get much better depth with the 5" coil than I did using the 6x8" S.E.F.
When hunting relatively clean areas, I know that I can cover an area really fast and deep with the biaxial coil. I'm going over areas that I had hunted with all of the bigger S.E.F. coils and picking targets that I know I went right over with S.E.Fs.
I realize that my coil comparisons are apples to oranges (Etrac vs. F75 ltd), so take my assessment with a grain of salt.
In summary, the 6x8" and 10x12" coils were the best of the S.E.F coils for me. The bigger coils were just not as deep as advertised.
Now, if Fisher unveils a slightly larger Bi-axial Coil, I'm sure I'll be the first in line. So apparently I haven't learned anything afterall.....
In my soil, the Pro-coil was better at depth, pin-pointing, and separation than all of the other coils in my arsenal. The only exception being the 6x8" S.E.F being only slightly better with separation. I found the 15 x 18" S.E.F the most disappointing of the bunch with a lack of depth to coin sized objects and it was really really heavy.
Now that I've been swinging the F75 ltd for the last six months, I can say that the 9x11" Biaxial coil is as good or better in all categories from the before mention coils. I may give the Pro Coil a slight edge in pin-pointing, but that could just be the diff. in machines and not the coils.
A lot of people would think that the fewer coil options for the F75 is a hindrance, personally I like it. With the Etrac, I was always second guessing myself when hunting a certain area, wondering if I chose the right coil for the task. With the F75 ltd, I own the 5" DD and Stock 9x11" only and I usually have a good idea which of the two coils will perform the best in a given area.
In my opinion, there is no better combination for hunting in iron than the F75 with the 5" coil. I also get much better depth with the 5" coil than I did using the 6x8" S.E.F.
When hunting relatively clean areas, I know that I can cover an area really fast and deep with the biaxial coil. I'm going over areas that I had hunted with all of the bigger S.E.F. coils and picking targets that I know I went right over with S.E.Fs.
I realize that my coil comparisons are apples to oranges (Etrac vs. F75 ltd), so take my assessment with a grain of salt.
In summary, the 6x8" and 10x12" coils were the best of the S.E.F coils for me. The bigger coils were just not as deep as advertised.
Now, if Fisher unveils a slightly larger Bi-axial Coil, I'm sure I'll be the first in line. So apparently I haven't learned anything afterall.....
Interesting! Right now I have an X-terra 70, but was thinking about getting an E-trac or an Omega. When checking the E-trac forum the other day, it seemed that a lot of E-trac owners are trying the SEF coils, so I wanted to find out more about them.
It seems that the Omega is very popular, but I had a bad experience with build quality and coils on an early F75 that left a bad taste in my mouth and would make it very hard for me to pull the trigger on another First Texas purchase, although they seem to have very hot electronics. Glad you got a good one and are doing well with yours.
It seems that the Omega is very popular, but I had a bad experience with build quality and coils on an early F75 that left a bad taste in my mouth and would make it very hard for me to pull the trigger on another First Texas purchase, although they seem to have very hot electronics. Glad you got a good one and are doing well with yours.
Critterhunter
New member
Opinions are opinions but most people who own Explorers or Etracs found the 12x10 to be slightly deeper and better in all respects than the 11" Pro Coil. The only plus to the Pro Coil was it's lighter and is slightly more sensitive to tiny targets. The minus side of the Pro Coil is that people find it more noisy and also that they tend to dig phantom silver signals with it. I've read just about every post on all these coils on here and acrossed the net and the vast majority of Explorer, Etrac, or Sovereign users prefer the 12x10 over the stock 10" or 11" coils.
I've owned the 15x12 and it's an awesome coil, but in my medium to high mineral ground it didn't show me greater depths than the stock 10" Tornado. In every other respect is was better, though. I've got a 12x10 on the way because I feel it will see less ground content and thus should show improved depth over the stock coil unlike the 15x12 which I feel was past the point of no return in size to depth ratio concerning my mineralized ground. On the beach the 15x12 was a good 2 or 3" deeper than the stock coil, though, and the odd thing is my beaches are mineralized so I don't know why it didn't do the same on my mineralized land sites.
Anything bigger than the 15x12 is NOT meant for coin sized targets. Coils of that size and larger are meant to find bigger items at greater depths such as caches. As a rule of thumb roughly 10 to 12" in size is about as big as you can get in a concentric and still be sensitive to coin sized targets. Since DD's see less ground (and thus are less prone to losing the target in the ground minerals) the general rule of thumb in max coil size for them on coins is roughly 12 to 14". Anything bigger will not see coins deeper as they are less sensitive to coin sized targets. Also, as said, the amount of minerals in your ground also can lower the max coil size. While others report better depths with the 15x12, in my soil it's just seeing to much ground (even though it runs stable at higher sensitivity settings) to show me improved depth.
In the "official" field tests of these coils the 15x12 and 12x10 were equal in depth on coin sized targets but the 15x12 was a bit deeper on something say as big of a silver dollar or bigger roughly. On the other hand, the 12x10 was a half inch deeper on tiny half dime sized coins. The coins in between (dimes, pennies, quarters, etc) both coils are for the most part even on PROVIDED your soil isn't mineralized. In that case expect the 12x10 to get better depths.
I've owned the 15x12 and it's an awesome coil, but in my medium to high mineral ground it didn't show me greater depths than the stock 10" Tornado. In every other respect is was better, though. I've got a 12x10 on the way because I feel it will see less ground content and thus should show improved depth over the stock coil unlike the 15x12 which I feel was past the point of no return in size to depth ratio concerning my mineralized ground. On the beach the 15x12 was a good 2 or 3" deeper than the stock coil, though, and the odd thing is my beaches are mineralized so I don't know why it didn't do the same on my mineralized land sites.
Anything bigger than the 15x12 is NOT meant for coin sized targets. Coils of that size and larger are meant to find bigger items at greater depths such as caches. As a rule of thumb roughly 10 to 12" in size is about as big as you can get in a concentric and still be sensitive to coin sized targets. Since DD's see less ground (and thus are less prone to losing the target in the ground minerals) the general rule of thumb in max coil size for them on coins is roughly 12 to 14". Anything bigger will not see coins deeper as they are less sensitive to coin sized targets. Also, as said, the amount of minerals in your ground also can lower the max coil size. While others report better depths with the 15x12, in my soil it's just seeing to much ground (even though it runs stable at higher sensitivity settings) to show me improved depth.
In the "official" field tests of these coils the 15x12 and 12x10 were equal in depth on coin sized targets but the 15x12 was a bit deeper on something say as big of a silver dollar or bigger roughly. On the other hand, the 12x10 was a half inch deeper on tiny half dime sized coins. The coins in between (dimes, pennies, quarters, etc) both coils are for the most part even on PROVIDED your soil isn't mineralized. In that case expect the 12x10 to get better depths.
montanagold
New member
I didn't notice any advantages on my E-trac from the stock coil. But the X-12 now that's a different story.
montanagold
New member
The x 12 is lighter, deeper and sepreates way better. I don't even use a smaller coil in trashy areas I trust the 12 completely in all conditions.
Critterhunter
New member
I have yet to test an S-12 for the GT. Somebody recently told me in a test they did on it compared to the 12x10 that the S-12 would not pick up as small of targets. Since this person is a jewelery hunter on the beach they got rid of the S-12 (two I think). Regardless, the S-12 I hear is a very good coil and also the lightest of them all in the 10" or bigger size range of coils, but even my 15x12 was lighter than the stock 10" Tornado coil once I got rid of the coil cover and sprayed the bottom with spray on bed liner. It's already been done to my new (used) 12x10 to save weight, and I'll be weighing it on a digital scale to see just where it's at. Based on a few comparisons I believe the FBS (Explorer/Etrac) versions of these coils are heavier than the BBS versions (Sovereign/Excal).
Also, there are many good comparisons/field reports of the 12x10 versus the 11" Pro Coil and the 10" Explorer/Sovereign coils across the web if you do enough looking. In the Explorer forum here on Findmall you might also want to read the thread in which a guy compared the Pro Coil and 12x10 on both an SE and an Etrac. He used both coils on one machine, then both on the other, and marked undug targets in the field with them. Results were the 12x10 saw more good targets that the Pro Coil couldn't, and the Pro Coil didn't find any targets that the 12x10 wasn't able to hit fine or better on. Some of these were at depth and on edge. Both machines showed the same results with both coils. That says a lot.
I'm planning on doing extensive testing of the 12x10 compared to the 10" stock Tornado coil and the 15x12 in the Sovereign forum over the next few months.
Also, there are many good comparisons/field reports of the 12x10 versus the 11" Pro Coil and the 10" Explorer/Sovereign coils across the web if you do enough looking. In the Explorer forum here on Findmall you might also want to read the thread in which a guy compared the Pro Coil and 12x10 on both an SE and an Etrac. He used both coils on one machine, then both on the other, and marked undug targets in the field with them. Results were the 12x10 saw more good targets that the Pro Coil couldn't, and the Pro Coil didn't find any targets that the 12x10 wasn't able to hit fine or better on. Some of these were at depth and on edge. Both machines showed the same results with both coils. That says a lot.
I'm planning on doing extensive testing of the 12x10 compared to the 10" stock Tornado coil and the 15x12 in the Sovereign forum over the next few months.