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I was reading about the "eliminator" coil the other night, has anyone taken one apart and knows whats inside? they say the allmetal mode only detects out the bottom of the coil not the top, how do they do that?
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Re: eliminator coil?
The Eliminator is a coaxial coil. It has a 3 loops stacked in a straight line, with the transmit loop in the middle and a receive loop above and below. The receive loops are connected out-of-phase for signal balance.
It detects out of the bottom and the top. However, the bottom loop detects things normally, the top loop detects things out-of-phase. So silver would give a negative response on top of the coil. That's why people say it detects only from the bottom. But iron gives a positive response on top.
Coaxial coils are good in areas of high electrical interference because the balanced receive loops cancel the interference. They also work a little better up close to metal fences and such because they are less sensitive around the edge. However, the balanced receive coils also reduce target sensitivity slightly.
- Carl -
Re: eliminator coil?
Hi Carl
What do you feel that they are like on depth and mineralization,say compared to DD
Regards Frank WallisComment
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Re: eliminator coil?
Have no idea, I've not used one although I do have a C&G Wildcat with one. In talking to Jack Gifford (formerly the "G" in C&G) I beleive he said they would handle mineralized ground pretty good but suffered in depth somewhat because the reverse receive coil would weakly detect the target and produce a slight amount of cancelation. DD, however, has non-coaxially aligned TX/RX coils which, I would think, would also reduce depth somewhat. But looking at the industry, DD clearly dominates so it must have a pretty good advantage.
- CarlComment
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Re: eliminator coil?
Hi Carl
Many thanks for your reply
Regards Frank WallisComment
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Re: eliminator coil?
What I can't understand here is if iron gives such a positive response from on top why is it the best coil for sweeping under wire fences. I thought it had more shielding under the top and this was why I could get under fences and overhead power lines where the stock coil could not cope.Comment
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Re: eliminator coil?
No, I think when people talk about using it around fences they mean chain link and such, ones that go all the way to the ground (and maybe into the ground). Coax coils are fairly insensitive in the lateral (edge-wise) direction, so you can get closer to metal poles and ground-level fencing before the coil goes crazy. Going under fencing (or any other metal) will still give a reading.
The double receive coils also cancel electrical interference better, regardless of which direction it's in.
- CarlComment
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Re: eliminator coil?
I have one, and I am not sure how the stacked coils are set up. But, it can go directly under large metal within just a couple of inches without any signal sensed from the top.
Sensing from the edge, I would guess is about half of the same size manuf. coil.
Depth is good, but the preamp needs to be higher, and can be run higher - the coil seems to pick up less electrical interference.Comment
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Re: eliminator coil?
Hi Rich
How would it compare for depth to other types of coils.
Regards Frank WallisComment
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Re: eliminator coil?
In my test garden, depth is almost identical with my Whites 6". That's with a higher preamp setting, but the coil is so stable and quiet that it works very nice at the higher settings.
It is expensive, and is thick, but light. I think it is worth the extra money- IF you have some places that you need to check around playground equipment, under bleachers, under slides or near large metal objects. I got mine in a detector trade or I probably would never have tried it.Comment
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Re: eliminator coil?
>Have no idea, I've not used one although I do have a C&G Wildcat with one. In talking to Jack Gifford (formerly the "G" in C&G) I beleive he said they would handle mineralized ground pretty good but suffered in depth somewhat because the reverse receive coil would weakly detect the target and produce a slight amount of cancelation. DD, however, has non-coaxially aligned TX/RX coils which, I would think, would also reduce depth somewhat. But looking at the industry, DD clearly dominates so it must have a pretty good advantage.
>- CarlComment
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