I've had my MXT several months and love it. The soil I hunt shows 83-86 in prospecting mode. I hunt in relic mode using the 950, 5.3, & 10x18 sef. My worry has been lowering the gain too much and losing depth, so I realize now I've gotten into a coil buying frenzy. Am I making too much of the mineralization? Bottom line is I think I should just ground balance and hunt instead of buying coils. Is my line of thought off base?
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MT get off the coil buying frenzy
- Thread starter donaldl
- Start date
I've used some really good coils, many peoples favorites, and after burning up a spot with one of them I can switch coils and go over the same area and find some stuff that was missed by the previous coils. They all have their pros and cons and specialty designs. For really high mineralization the 5.3 will work well. I've heard the SEF coils are designed for high mineralization but I havn't used them. I use the D2 coil a lot and it does really well in high mineralization because it sees very little ground at any given time(long narrow but deep signal). Generally speaking, the less ground the coil sees the better it will handle mineralization since it deals with less of it at once. Small coils and DD coils are good, SEF coils have a similar design to DD coils in that the TX & RF windings are side by side and create an overlapping signal in a narrow elongated shape.
The same principle applies to really large coils, especially large concentric coils. Because they are 'looking at' so much ground at once, there is a LOT of mineralization to see through which is like looking through extremely dense fog with high beams. Bigger is only better in a few places, you have to pick your coil to match the ground and sought after targets.
The same principle applies to really large coils, especially large concentric coils. Because they are 'looking at' so much ground at once, there is a LOT of mineralization to see through which is like looking through extremely dense fog with high beams. Bigger is only better in a few places, you have to pick your coil to match the ground and sought after targets.
Thanks. I have the 5.3 and I've never really given it a fair chance. Do you really lose critical depth by lowering the gain to compensate for the high mineral? The 10x12 sef is a great coil but I almost had myself convinced to buy the 6x8 sef. Maybe I'll work with the 5.3. The MXT is a great machine
Larry (IL)
Well-known member
That depends on you. I like to try just about all of the coils on the market, keep the ones that I will use and sell the ones I won't. I guess I don't understand the gain thing.......
You set your gain as high as you can and still maintain stability and go hunting. Gain will change with ground condition and the coil you are using. Mineralization is what it is, you can't change that but the DD and SEF coils will handle the mineralization better than the concentric coils.
You set your gain as high as you can and still maintain stability and go hunting. Gain will change with ground condition and the coil you are using. Mineralization is what it is, you can't change that but the DD and SEF coils will handle the mineralization better than the concentric coils.
Larry (IL)
Well-known member
There might not be any depth loss when reducing gain to conditions, more power is not always better and you might even gain some depth. You might not have heard this analogy, but think of mineralized ground as the fog and in heavy fog, your low beam headlights will work better than the high beams.
Flintstone
Well-known member
The 5.3 coil is a very good coil in most places, I have the 6x8 SEF, and it covers a little more ground, i use it in alot of trash. The 5.3 that is really a 6" coil, i use most of the time if not to trashy. It is a little lighter than the 9.5 and still gets good depth.
From what I understand, the GND VDI indicates the relative percentage of magnetic stuff versus electrically conductive stuff there is in the ground. A high GND VDI does not mean there are "more" minerals in the ground, only a higher ratio of magnetic minerals. Even if it is a very small amount of each type, if the ratio of magnetic minerals is higher the GND VDI will be higher.
QUOTE:
This could be in Jeff's book but that is not where I got it. It's in my MXT stuff from e mails Jeff sent me.
(1) Mineralized soil is soil that contains stuff to which a metal detectors search coil reacts, which is not a buried target.
(2) There are two distinct types of mineralization stuff that is magnetic and stuff that is electrically conductive.
(3) Soil most often contains a mix of magnetic stuff and electrically conductive stuff.
(4) The more mineralization stuff there is in the soil, the more mineralized the soil is. Soil with a lot of mineralization stuff in it is often called bad ground.
(5) Mineralization stuff that is just magnetic always produces a VDI number near -95 (GND 84).
(6) Mineralization stuff that is just electrically conductive always produces a VDI number near 0 (GND 4).
(7) The grounds VDI number, for the MXT, the GND number would range between about 84 and 4) based on the relative mix of how much magnetic stuff versus electrically conductive stuff there is in the soil.
(
Soil that has a mix of magnetic stuff and electrically conductive stuff in roughly equal proportions would have a VDI number (D.C. Phase) reading roughly halfway between -95 and 0 (around -47).
(9) The more magnetic stuff versus electrically conductive stuff there is in the ground, the closer the VDI reading will be to -95. The more electrically conductive stuff versus magnetic stuff there is in the soil, the closer the VDI reading will be to 0.
(10) The grounds VDI number only gives an indication of the ratio of magnetic stuff in the soil versus the amount of electrically conductive stuff in the soil. It does not indicate how much mineralization stuff is in the soil.
(11) A fifty-pound bucket of soil that contains 10 pounds of magnetic mineralization stuff and 1 pound of electrically conductive stuff would be very bad ground. The same bucket with 0.1 ounce of magnetic stuff and 0.01 ounce of electrically conductive stuff would not be bad ground. Both buckets of soil would have the same VDI number. Both buckets would have magnetic stuff in a 10:1 ratio to the electrically conductive stuff.
(12) The grounds VDI number does not indicate how bad the ground is. It does not indicate how much mineralization stuff is in the ground. It only indicates the relative amount of magnetic versus electrically
SOURCE: http://www.findmall.com/read.php?25,1042443
QUOTE:
This could be in Jeff's book but that is not where I got it. It's in my MXT stuff from e mails Jeff sent me.
(1) Mineralized soil is soil that contains stuff to which a metal detectors search coil reacts, which is not a buried target.
(2) There are two distinct types of mineralization stuff that is magnetic and stuff that is electrically conductive.
(3) Soil most often contains a mix of magnetic stuff and electrically conductive stuff.
(4) The more mineralization stuff there is in the soil, the more mineralized the soil is. Soil with a lot of mineralization stuff in it is often called bad ground.
(5) Mineralization stuff that is just magnetic always produces a VDI number near -95 (GND 84).
(6) Mineralization stuff that is just electrically conductive always produces a VDI number near 0 (GND 4).
(7) The grounds VDI number, for the MXT, the GND number would range between about 84 and 4) based on the relative mix of how much magnetic stuff versus electrically conductive stuff there is in the soil.
(
Soil that has a mix of magnetic stuff and electrically conductive stuff in roughly equal proportions would have a VDI number (D.C. Phase) reading roughly halfway between -95 and 0 (around -47).(9) The more magnetic stuff versus electrically conductive stuff there is in the ground, the closer the VDI reading will be to -95. The more electrically conductive stuff versus magnetic stuff there is in the soil, the closer the VDI reading will be to 0.
(10) The grounds VDI number only gives an indication of the ratio of magnetic stuff in the soil versus the amount of electrically conductive stuff in the soil. It does not indicate how much mineralization stuff is in the soil.
(11) A fifty-pound bucket of soil that contains 10 pounds of magnetic mineralization stuff and 1 pound of electrically conductive stuff would be very bad ground. The same bucket with 0.1 ounce of magnetic stuff and 0.01 ounce of electrically conductive stuff would not be bad ground. Both buckets of soil would have the same VDI number. Both buckets would have magnetic stuff in a 10:1 ratio to the electrically conductive stuff.
(12) The grounds VDI number does not indicate how bad the ground is. It does not indicate how much mineralization stuff is in the ground. It only indicates the relative amount of magnetic versus electrically
SOURCE: http://www.findmall.com/read.php?25,1042443
Donald, how do you like your 12x10 SEF? You and I are exact opposites. I have the 6x8 and contemplating the 12x10 or 15x12 SEF when I already have the 6x8. I didn't think the 5.3 would be a good choice when I already have the 6x8 SEF.
Does anyone know whether I'll get that much more depth with the 12x10 or 15x12 SEF over my 6x8 SEF?
Does anyone know whether I'll get that much more depth with the 12x10 or 15x12 SEF over my 6x8 SEF?
I love the 10x12. Wheat penny at 10" in heavy trash. Pin points very well. Indicated 9" and vdi very close. Money well spent. I'd like to get the 6x8 and just focus on the coils I have without buying more. I really need to learn the mxt better. Aarong81 and Larry both have helped tremendously.
Whitetail said:
Theoretically, if SEF coils are similar to DD coils, the size is determined by the narrowest part of the coil. So a 12x10 SEF should be viewed as a 10" coil and a 6x8 SEF is a 6" coil. That being said, I would expect a big difference in depth. The only way to compare them is to have both and try them out on the same tests because each person will have different opinions on depth. I'd like to try a 10x12 or larger SEF coil but they are very pricey. For now I'll keep swinging the D2, it does very well for me.
I use the 5.3 a lot. It's a great coil. We all have or opinions on the gain. I personally do not ever run with the gain at preset or below. If I can, I run at +3 and if it's unstable, i lower the discrimination. (I never run with the discrimination over 2 anyway). I do feel that sometimes I am running on the edge of insanity. I then lower the volume and see what I can pick out of the noise. This works well in trashy areas. It works so well that I have found I like trashy areas that everyone else skips over. I use this technique with the 5.3 coil in trashy areas. I too have been thinking of getting the 10 x 12 SEF for relic hunting. You need to go deep in plowed fields. I do like a lot of coils all for different uses.
John
John