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The White 10x12 SEF (old link)
Posted by: Rob (IL)
Date: November 15, 2014 09:57PM
Optimized (White) 10x12 SEF Coil
SEF stands for (Symmetric Electromagnetic Field). The SEF coil is a modified DD where the two loops overlap each other in the middle. When testing the prototype V3i I experienced less ground noise, slightly better depth and better coverage with the non V rated 12X10 SEF coil that I was using at the time. The canceled ground noise is probably what allows you to hear deeper targets better. The 10X12 is two inches longer than the D2 coil which gives more coverage per swing. They are made in Bulgaria and Kellyco is the only place you can get them in the USA.
The original black coils had some drawbacks and were not optimized for the V3i and VX3. My old (black) SEF, which was suitable for Whites DFX, MXT and M6, did not allow me to get the best efficiency with my Spectra. This was due to the nulling which is not optimized for the 3 frequencies the Spectra uses. It was possible to use the old SEF with a single frequency 2.5 kHz or 7.5 kHz but in multi-frequency and single frequency 22.5 kHz I had to decrease the sensibility considerably. The use of Boost Mode was out of the question. The black coil always overloaded. Many of the coils would be limited to RX 9. Also, the VDI numbers were off on low conductive targets. A nickel would read as a 25 VDI rather than the usual VDI 19.
The white-colored Detech SEF coil is optimized for use with the V3i and VX3. Of course the first thing I noticed was its white color. The white colored coil does not absorb ultra-violet rays as much as black colored coils and subsequently the coil runs at a lower temperature. This reduces the internal coils induction balance drifts which are caused by exposure to direct sunlight. This gives a better stability to the metal detector.

My white 10x12 SEF weighted less than my D2. The coil is center mounted so it has excellent balance. Here are the two coils, my D2 and 10x12. Both have no cover and have the lower shaft attached. My white 10x12 is lighter.



The white SEF solved the null problem and allows high RX settings. My White 10x12 is a good one but still does not have as good a null as my V rated coils. The white SEF doesn't run as low a signal% as my D2 but it is not that much higher My SEF however will not overload at RX15 with boost on. Some non V rated Whites coils and black SEF coils, by luck, can run boost. I have my doubts about the White SEF tolerances and don’t know if the problems have finally been solved. Here are two sets of readings, one with boost and one with boost off. The area that I took the readings at was a high EMI area. I just wanted to show the coil can handle high settings.



So, let’s see. Greater ground coverage then my stock coils at no extra weight that I can feel. The coil allows the ability to run high RX settings and TX boost mode at Signal% readings comparable to my D2. It is a coil that can handle bad ground, has about an inch more depth and the same great side by side discrimination as the black SEF. Oh, I almost forgot It ID's nickels correctly. This looks like a winner to me.
One more thing, some people don’t actually measure the depth of their finds. The D2 readings are accurate but depending on what coil choice the V3i is set to, the 10x12 can give an inaccurate deeper depth reading. For the guys that are running the black coil, I think if you will check you will see you are running higher signal loss at lower RX settings than the D2.



"Everyone has an opinion, but mine is free":devil:
"You might very well think that; I couldn't possibly comment..."



Edited 1 time(s). Last edit at 04/01/2015 04:47PM by Rob (IL).


Re: The White 10x12 SEF (old link)
Posted by: sweeper60
Date: March 05, 2015 12:55PM
The worst thing about SEF Coils are they Do Not have a Uniform search Patten and No 2 coils are/were the same, Which is Important when searching for Small Items, For Hunting bigger things Like Relics they are OK

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Re: The White 10x12 SEF (old link)
Posted by: Rob (IL)
Date: March 05, 2015 02:25PM
Sweeper would you explain more in detail. I've found no problem and use a SEF most of the time for coins.



"Everyone has an opinion, but mine is free":devil:
"You might very well think that; I couldn't possibly comment..."

Re: The White 10x12 SEF (old link)
Posted by: sweeper60
Date: March 05, 2015 02:41PM
A few years back After I Bought about some of their Coils After reading the Rave reviews and their Alleged Results Did not match my findings so I bought 8 Coils and tested them for Quite a few months and then I Gave them to An Electronic Wizard I Know and he found the Same issues, as I did, On Coin Sized Targets you will hardly notice the difference, But for small Items There are much better Options out there for you to choose from,
If you make up some small test pieces you can Map their detection field out and see the difference,

Re: The White 10x12 SEF (old link)
Posted by: sweeper60
Date: March 05, 2015 03:14PM
Sorry about the back ground but I am doing this on my Phone, This picture is the shape of the detection field of the 10x12 I got and as you can see the loss of coverage at the front of the coil, and it was not as sensitive at the front as it was at the back, Hopefully they have done better with these newer coils but seeing as Whites Nor Minelab have Give them the Tuning Specs of their Machines I would not discount your Whites Coils just yet, And Just enjoy them for what they are and don't go into it too Deeply.

Re: The White 10x12 SEF (old link)
Posted by: sweeper60
Date: March 05, 2015 03:16PM
something is wrong here because I up load the picture and then it tells me I have not up loaded it, I tried 5 times, So that's it.

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Re: The White 10x12 SEF (old link)
Posted by: Rob (IL)
Date: March 05, 2015 03:17PM
There is no photo.



"Everyone has an opinion, but mine is free":devil:
"You might very well think that; I couldn't possibly comment..."

Re: The White 10x12 SEF (old link)
Posted by: sweeper60
Date: March 05, 2015 03:19PM
Quote
Rob (IL)
There is no photo.

I will try again, ok

Re: The White 10x12 SEF (old link)
Posted by: sweeper60
Date: March 05, 2015 03:25PM
Sorry the file was too big, Try this,




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