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last i find the sulusion
my idea to build folder mono coil 5>9 like reg search coil
may this solve this issues
rgds
my idea to build folder mono coil 5>9 like reg search coil
may this solve this issues
rgds
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That's a good Idea because they work really well on the TDI's :Y:Moatazfaize said:
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this from mr reg who itink desgner folded mono :_
The dual field design coil was primarily developed to provide decent depth on large objects plus enhanced sensitivity to small gold. The design which was patented by the late Dan Geyer while he worked for Whites and works very well for this purpose.
Now, with that said, the dual field (DF) doesn't have quite the depth of a similar size mono plus it is more temperamental in bad ground making it more difficult to ground balance. That is why TDI's sent to OZ are sent with a mono coil.
Fortunately, in most places here in the US the DF ground balances well enough to work satisfactorily, but still may display a slight inability to GB as well as a similar size mono. In OZ, the inability to GB was very noticeable, thus the Mono coil was/is the coil generally preferred.
The foldback (FB) design was developed in 2009 as an alternative to the DF coil which meant it had enhanced sensitivity to small gold because of the foldback part and great depth because of the main coil size. Since the DF is patented, then duplicating would be a violation of White's patent, so something different had to be developed for those wanting similar features but not in violation of the White's patent.
Unfortunately, the design is such that it is tough to make a 12" FB design that works at the minimum delay. Instead, it sort of mimics a mono size if the foldback part was not folded back.
The idea of a FB is to create a larger mono, pinch it into a lopsided figure 8 with the top part much smaller than the bottom part of the 8. Then the top part is twisted a half turn and folded back into the lower portion. Finally, the smaller part is sort of pinched into a narrow elliptical inside the larger portion. This smaller elliptical enhances the small gold signals while the larger coil provides the depth on larger objects.
Here is a link to the post where I discussed the design.
http://www.geotech1.com/forums/showthread....light=fold+back
If you are interested in more information you can go to the link and learn more about its development. Drop down to my 7-3-09 post here I discuss the concept and reason for the design.
Now, what I found was the FB design has great depth plus enhances small gold signals also. The difference is the Foldback design doesn't have any of the negative GB problems while usually having greater depth when comparing similar size and shape coils.
A FB coil seemed to have a slight edge over a similar size and shape plain mono also.
You mentioned your use would be for relic hunting and if that is the case and you won't be hunting small gold then the DF or FB may not be the best choice. The exception would be if you have a need to find tiny pieces of metal. If that is not the case, the DF or even the Foldback may not be the best choice. Chasing small bits of metal when they are not the main desired target can be a real pain.
A simple mono might be cheaper and work better since it will do a better job of ignoring some of the real tiny stuff that might be detected with either the DF or the FB design.
Reg
The dual field design coil was primarily developed to provide decent depth on large objects plus enhanced sensitivity to small gold. The design which was patented by the late Dan Geyer while he worked for Whites and works very well for this purpose.
Now, with that said, the dual field (DF) doesn't have quite the depth of a similar size mono plus it is more temperamental in bad ground making it more difficult to ground balance. That is why TDI's sent to OZ are sent with a mono coil.
Fortunately, in most places here in the US the DF ground balances well enough to work satisfactorily, but still may display a slight inability to GB as well as a similar size mono. In OZ, the inability to GB was very noticeable, thus the Mono coil was/is the coil generally preferred.
The foldback (FB) design was developed in 2009 as an alternative to the DF coil which meant it had enhanced sensitivity to small gold because of the foldback part and great depth because of the main coil size. Since the DF is patented, then duplicating would be a violation of White's patent, so something different had to be developed for those wanting similar features but not in violation of the White's patent.
Unfortunately, the design is such that it is tough to make a 12" FB design that works at the minimum delay. Instead, it sort of mimics a mono size if the foldback part was not folded back.
The idea of a FB is to create a larger mono, pinch it into a lopsided figure 8 with the top part much smaller than the bottom part of the 8. Then the top part is twisted a half turn and folded back into the lower portion. Finally, the smaller part is sort of pinched into a narrow elliptical inside the larger portion. This smaller elliptical enhances the small gold signals while the larger coil provides the depth on larger objects.
Here is a link to the post where I discussed the design.
http://www.geotech1.com/forums/showthread....light=fold+back
If you are interested in more information you can go to the link and learn more about its development. Drop down to my 7-3-09 post here I discuss the concept and reason for the design.
Now, what I found was the FB design has great depth plus enhances small gold signals also. The difference is the Foldback design doesn't have any of the negative GB problems while usually having greater depth when comparing similar size and shape coils.
A FB coil seemed to have a slight edge over a similar size and shape plain mono also.
You mentioned your use would be for relic hunting and if that is the case and you won't be hunting small gold then the DF or FB may not be the best choice. The exception would be if you have a need to find tiny pieces of metal. If that is not the case, the DF or even the Foldback may not be the best choice. Chasing small bits of metal when they are not the main desired target can be a real pain.
A simple mono might be cheaper and work better since it will do a better job of ignoring some of the real tiny stuff that might be detected with either the DF or the FB design.
Reg
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I know the Folded mono is good for prospecting on the TDI's, And I would not use the standard DF for prospecting because I know it is not very sensitive to small nuggets because even air testing small bits of lead it struggles to see bits weighing 0.17grams, Most PI's will only see bits of that size within a couple of inches deep so even in hot ground a person would be better off using a VLF because if you are chasing Gold that size they are not going to be that deep no matter what type of machine you use.
Another annoying thing about the TDI SL and SPP is the slower sweep speed compared to the TDI Pro, Yes a person should take there time when prospecting but the SL and the SPP are just a bit too slow, Which is why when I am searching for small surface targets I prefer a VLF and they also ID junk,
One thing for sure, IF any of the TDI's are searching for Large Metals they will find it regardless of whether it is ground balanced or not, On larger Items the 12" DF will and can see them down to depths that can be measured in metres not feet, When it comes to large items the TDI SL is quite Brutal when it comes to depth and sometimes I think it is just Wired wrong because it has the power but it has it at the wrong time. I know of someone who found a piece of Iron the size of a 2 litre coke bottle at over 4 feet deep with the 12 DF on the TDI SL and I have found targets much deeper using the same set up.
Another annoying thing about the TDI SL and SPP is the slower sweep speed compared to the TDI Pro, Yes a person should take there time when prospecting but the SL and the SPP are just a bit too slow, Which is why when I am searching for small surface targets I prefer a VLF and they also ID junk,
One thing for sure, IF any of the TDI's are searching for Large Metals they will find it regardless of whether it is ground balanced or not, On larger Items the 12" DF will and can see them down to depths that can be measured in metres not feet, When it comes to large items the TDI SL is quite Brutal when it comes to depth and sometimes I think it is just Wired wrong because it has the power but it has it at the wrong time. I know of someone who found a piece of Iron the size of a 2 litre coke bottle at over 4 feet deep with the 12 DF on the TDI SL and I have found targets much deeper using the same set up.
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My first folded coil
Resistant 1.8 ohm
300uh
5v8 coil
I win to detect 0,3 gram gold
Later I am going to make the new design as with two separate folded coil in one rx tx file
As to give same DoD shape .
And what I understood that the delay 10sc need you make the search coil not more than 11inch
And after folded it you must care about 300 to 350uh
Rgds
Resistant 1.8 ohm
300uh
5v8 coil
I win to detect 0,3 gram gold
Later I am going to make the new design as with two separate folded coil in one rx tx file
As to give same DoD shape .
And what I understood that the delay 10sc need you make the search coil not more than 11inch
And after folded it you must care about 300 to 350uh
Rgds
