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View Full Version : Interesting Coil Comparison Test...

Jim Hemmingway
06-04-2011, 09:58 AM
A test by our good buddy Keith Southern...


06-06-2011, 05:51 AM
Jim- I'm not real familiar with the S.E.F coils.What are the main advantages to the coil? I have a 14x8 Sierra Gold Max coil for my GMT, it produced similar results to the S.E.F. Dave

06-06-2011, 08:33 PM
That's a pretty convincing video Jim. Thanks for posting.


Jim Hemmingway
06-06-2011, 09:03 PM
Hi Highbanker58 and ddmk6…yep, I agree that the video was kept simple and well done.

The SEF search coils are a variant of DD coils… with a butterfly-like shape. Their main selling point at Kellyco is superior depth performance. I’ve seen a few mixed reviews but have no experience using a SEF coil.

The coil comparison run by Keith is intended to demonstrate the SEF coil’s superior signal on a nickel located under a brick…that serves as a ‘hotrock’. The unit is first ground-balanced over the concrete floor at GB75 and then tested over the brick (that ground balances at GB88). The SEF does give a better signal on the nickel when placed below the brick. Keith mentioned similar results using the next size larger SEF coil as well.

The second interesting aspect of the test that Keith pointed out is that with each coil he did the ground balance “Grab” starting with the MXT Pro’s default GB setting. The default ground balance with the SEF coil gave a noticeably milder signal to the concrete floor than did the Eclipse DD coil. The overall inference is that the SEF coil is less reactive to ground minerals than is the Eclipse DD coil.

In real world conditions, Keith noted that .22 calibre shells normally read about VDI 6 to 8 using the SEF over his harsh mineral ground, whereas the Eclipse DD reads lower at about “0” and sometimes reads as iron. That doesn’t surprise me at all since I’ve noticed the same thing with spent blasting caps in the areas I search with either the Eclipse DD or the 12” concentric. Mostly they read as iron at any depth beyond a few inches in our minerals.

Keith also mentioned that his tests reveal no loss of depth / sens performance with the 6"X 8" SEF compared to the 10" DD Eclipse.


06-08-2011, 07:34 PM
Thanks again Jim for the further narration. I guess the icing on the cake would be to know the depth difference between the 6x8 SEF and the next size larger. If you could get away with swinging the smaller 6x8, without much depth loss that would be sweet. I never used to worry about weight and swinging it all day until I bought this GPX 5000 and the 12x19 mono from Steve. Your working for it then :-) Not only the heavier machine but the deeeep holes.


07-17-2011, 09:48 AM
I bought a total of 8 coils just to do some testing because I got fed up with the lies dealers and reviews I kept reading and after buying
one and not finding any change I started to smell a rat, and they are so unbalanced as in more sensitive at the back than they are at the
front, the 10x12 was worse that the Minelab BBS 10" and that BBS was my most trusted coil ranked no2 and the best one was the coiltek 8x12
and at no3 was the little joey, the 15" wot coil is a legend anyway, the 10x12, and 7x5" was a joke the 6" detech was as sensitive as a hockey Puck,
the 14" Detech was powerful, 18x15 was not worth hooking it up, this test cost me a heap and I gave all the detech/sef coils away because
I could not sell them knowing how they performed, and then one day I went to the biggest importer/dealer in the UK and saw 2 and a 1/2 box'es
full of SEF Coils that had failed and had there cables cut off because Detech have a no return policy and I'm talking box'es 3ft square x 3ft x3ft.
so please be careful folks, and remember that there are enough coils out there for minelabs and Whites,