DD vs SEF DD coils

[Snowy]

Can anyone tell me the difference between the traditional DD coils out there and those new butterfly SEF DD coils for Whites?

[Lowjiber]

I only have one SEF Coil (12x15), but here's my view of the differences from a hunting (not electronic) viewpoint. My artwork is hardly the best, so bear with me please.

As depicted in the drawing below, the shape of the Transmit and Receive coils are &quot-shaped, placed back-to-back. The narrow detection area (my term) is indicated in RED. The narrow area allows for excellent target separation and provides the maximum minimization of the effects of ground minerals. However, the detection area (square inches) is considerably diminished.

The SEF coil has the oval Tx and Rx coils overlapped to create a wider detection area...shown in RED.

The SEF is (IMHO) a compromise between a traditional concentric coil (CC) and a DD. It offers better separation of targets than a CC, but not as good as a similar sized DD. The SEF is much less prone to the negative effects of ground minerals than a CC, but can't equal a DD in that area.

So, why even bother with an SEF coil? The answer is (IMHO) a larger detection footprint which results in increased depth when compared to a comparably-sized DD coil.

My limited SEF experience shows that the SEF is superior (depth-wise) to the DD in light-to-moderate ground mineral conditions. However, in areas of high mineralization...the SEF does not perform as well as the DD when seeking deep targets.

I know Cybersage has done a lot of good work with both SEF and DD coils in his test garden. Perhaps, he can offer some more insight than my overly simple viewpoint.

Hope this helps.

[Snowy]

Thanks, Lowjiber.... I appreciate the personal reflection.
Sounds like the SEF is a little more sensitive/delicate with soil while the traditional DD is more universal.

I love my Eclipse DD... it found me a 2-center today.
I've been curious about the SEFs though.
Thanks for a good explaination.

[RickO]

Great explanation and diagram Lowjiber. Sort of makes it clear why there is no one universal coil. Between you and Jack (Cybersage) I am getting a much better understanding of coil applications and capabilities. Thanks, RickO

[sheeplady]

I have been hearing a bit about the SEF coils lately. There is one in the mail with my name on it. I was wondering, when you pinpoint with the V3 using the SEF, where is the target under the coil? Is it about an inch down from the top as with the Bigfoot, or directly under center as with a DFX and the 950? Any help would be appreciated!

[ArmyVetPaul]

I have been hearing a bit about the SEF coils lately. There is one in the mail with my name on it. I was wondering, when you pinpoint with the V3 using the SEF, where is the target under the coil? Is it about an inch down from the top as with the Bigfoot, or directly under center as with a DFX and the 950? Any help would be appreciated!

There's a video on youtube that shows that pinpointing spot is right between the dogears where the coil attaches to the lower arm of the detector.....