Keep my SEF 10X12 for E-Trac use or stick with the Stock Coil

[GKMan]

Hello Folks
Earlier this year I had purchased an SEF 10X12 for use on my Explorer II and I was happy with it. Now that I am using the E-Trac and I am watching the E-Trac forum I don't see see as much talk about this coil. My question is that with regards to similar coil sizes to the stock coil, are many of you using much other than the stock coil on the E-Trac? I do understand the benefits of smaller coils and so I intend on keeping my small 8X5 SEF for trashy areas but if few fellow hunters have found much benefits with the SEF 10X12 I will sell it.
Thanks for your opinion

 

[DukeOBass]

I use my 12 x 10 SEF when I go back and re-hunt sites where I've used the ProCoil first. I find that the machine will run more stable at a higher sensitivity with the SEF in most cases. It covers slightly more ground than the stock coil does and I like the idea of having a similar sized coil in case my ProCoil would develop a problem. It's a good choice for a spare.

 

[GKMan]

Hi Duke
Interesting. I like the idea of stability at higher sensitivity. Do you see pinpoint off much from the stock aka Procoil?

 

[DukeOBass]

I don't use the pinpoint function button much. If you're just talking about 90 degree, coil-swing pinpointing, I watch the depth meter and watch where the signal drops off at the edges of the coil and dig where the depth meter is most shallow.

 

[smkunder]

Keep your 10x 12. I had one from my Explorer days, and just a couple of weeks ago my coil Pro coil went bad, so I put the 10 x 12 on while I waited for my new coil to come back from Minelab. well I have my new pro coil back and I have doing so good with the 10x12 SEF I have yet to put the Pro coil back on. It is always nice to have a back up coil for those kind of situations.

 

[GKMan]

It was a lucky coil for me on the Explorer.. I am swaying towards keeping it. On my first test run with the SEF I found a British Copper in the backyard outside my kitchen window..

 

[Barry NY]

You'll love the SEF. The pro coil is my backup.

 

[Jason in Enid]

I don't see the advantage of the 10x12 compared to the Pro coil. The E-Trac Pro is an 11" coil so you aren't gaining any depth against it. If the SEF is letting you run a higher sensitivity (for a similar sized coil), that means it's not reading the ground as much as the stock coil does, which means it's not reading the deep coins as well either.

 

[nge]

Pose your question to Doc64......he uses the 10X12 exclusively......NGE

 

[earthmansurfer]

I'd like to hear what you guys with the E-Trac have to say as a similar question has been asked on the V3i forum. I don't have an SEF coil but if you research the design, they are more efficient than DD coils and should theoretically (same size) be a bit deeper. This is because the receive/transmit coils transmit energy evenly where as DD coils have those two places on each coil where the curved coil winding meets the straight winding (in the middle) - Just imagine a "D" back to back on the DD coils VS a "O" back to back on the SEF coils. I read an article about it and it was interesting. I've read the SEF coils are even better in mineralized ground. BUT I heard they don't ID quite as good/consistently, wonder if this is true with the E-Tracs as well as they are known as being the most accurate on Target ID.

Anyway, look forward to more responses here,
EMS

 

[Jason in Enid]

I'd like to hear what you guys with the E-Trac have to say as a similar question has been asked on the V3i forum. I don't have an SEF coil but if you research the design, they are more efficient than DD coils and should theoretically (same size) be a bit deeper. This is because the receive/transmit coils transmit energy evenly where as DD coils have those two places on each coil where the curved coil winding meets the straight winding (in the middle) - Just imagine a "D" back to back on the DD coils VS a "O" back to back on the SEF coils. I read an article about it and it was interesting. I've read the SEF coils are even better in mineralized ground. BUT I heard they don't ID quite as good/consistently, wonder if this is true with the E-Tracs as well as they are known as being the most accurate on Target ID.

Anyway, look forward to more responses here,
EMS

LOL!!!

You have been reading KellyCos advertisements toooo much! Step away from the computer and engage your brain. Don't you think the engineers who designed it have pretty damn good understanding of what works best for the circuitry of the machine?

 

[ZOFCHAK]

It's been my experience that both coils are very similar performance wise. The Pro Coil has the advantage of being quite a bit lighter and it's round(er) shape makes it better suited for detecting around obstacles like heavy brush. The SEF coil does allow for a bit more coverage and I have found it to be slightly more stable in most locations. Overall I give a slight nod to the SEF and the deciding factor for me was the thin tabs on the Pro Coil. They just did not look like they would hold up to much abuse.

My suggestion would be to keep both coils... You never know when one will fail, and if you purchased a new E-trac the Pro Coil has the advantage of being under warranty for quite some time.

 

[earthmansurfer]

Jason, I actually never read anything from Kellyco so don't know what you are talking about. I have researched coils and am a bit familiar with them. I'm talking science here, not personal preference (I don't even have an SEF coil, rather a DD.) The point of my post is not to be right, it's for discussion.

There is a very good detectorist here in Europe (Italy to be precise) that goes by the name of Bodhi I believe. I am sighting a bit of his research as well as his scientific understanding of detectors (judging by his posts he has quite a bit). He also sites research done by a manufacturer. (At the bottom please find a section of a rough translation of his post. His point can be understood through the Italian translation.) Now, instead of LOL at me, try to understand what I am saying. Where the receive and transmit coils of a DD meet is the place in question. Where the roughly half circle meets the straight edge is an inefficient point, the field there is uneven relative to the rest of the coil. An SEF (or other rounder receive/transmit coil) does not have this "hot spot" and transmits the energy evenly. Now it is not a big difference, but it is a difference. It is easily visualized. Perfect spheres transmit/receive energy better than "D" shaped ones. I imagine that is a bit of why we don't see "D" shaped satellite dishes.

Ideally, the deepest coil would be a DD/SEF style design with two perfectly round circles overlapping. The deepest VLF detector in Europe has this design, but it's a rather large coil due to the perfect circles.

Now perhaps I'm wrong, but please reply with some facts and not LOL and making assumption about me reading Kellyco which are not at all true.

Thanks,
Albert

Time ago I read an interesting post by Carl Moreland (currently Chief Engineer of White's) on this type of technology that I would like to summarize here.

Carl remembered that one of the most important things to get good results and reduce the effects of ground mineralization is related to having a good balance of induction ("Induction Balance") between the transmitter and receiver coil ... well ... the so-called nulling

The plates are designed precisely so that this balance between TX and RX is the best possible. The more balance between TX and RX, the better the sensitivity of the machine.
The mineralization of the soil is primarily responsible for the so-called " Ground Effect ", ie the" flattening "of the electromagnetic field emitted by the transmitter coil. This deformation is detected by the coil RX (this is called "pairing") and this implies a loss of balance, causing a loss of induction of performance and false signals.

According to Carl, theoretically speaking the best form of the coils to avoid this problem would be perfectly circular (OO) with an overlay similar to the DD. If the coils are perfectly round, the crushing of the electromagnetic field appears to be symmetrical and precise and if the deformation is symmetric coupling is minimal.

The advantage of OO compared to DD is that the latter, due to the large curvature of the intersections between straight and curved produce concentrations of magnetic field. This implies a field TX is not symmetrical and defined and hence a non-symmetric crushing.

If we look at the SEF will notice that the coils are not perfectly round and oval.
This form implies that, in the side where the curve is narrower (top and bottom) we are more concentrations electromagnetic but obviously not as dramatic as in the double D This, at the end of games, results in better management of mineralization compared to DD. Here is revealed their secret ...

Taken from: SEF Theory