Nexus 30" and 21" Concentric Coils For Minelab GPX

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I am still wondering "Why" he is calling it a Concentric Coil, Because a Concentric coil is a VLF version of a Mono and as far as I know A Concentric by design won't work on a PI Machine.

But from what I know about Concentric Coils being able to use them in this Baby Milk Soil over here A Concentric coil will punch very deep on a VLF and they Air Test in Meters not Feet, And Mineralization can knock em sideways "But" Not always,

On my GMT the 6x10 Concentric made it see bits only a GBII can normally see and on other Machines placing targets on a Magnetic surface they can see bits down to a bit smaller than 0.006 grams when given the Full Beans, So yes they work well, But one thing I have found is that as DD's have progressed in the last 5 or so years I don't think that there is that bigger difference anymore,

My 950 Concentric is equally matched to my factory 10"DD when it comes to tiny targets and even in Air tests where there is no natural resistance due to the ground they seem to perform pretty much the same, There are one or two Concentrics which are very Hot, but the Gap between DD's and Concentrics has closed up a heck of a lot in the past 5 years.

As for a Concentric on a PI just does not compute,

J.
 
Ridge Runner said:
I am still wondering "Why" he is calling it a Concentric Coil, Because a Concentric coil is a VLF version of a Mono and as far as I know A Concentric by design won't work on a PI Machine.

But from what I know about Concentric Coils being able to use them in this Baby Milk Soil over here A Concentric coil will punch very deep on a VLF and they Air Test in Meters not Feet, And Mineralization can knock em sideways "But" Not always,

On my GMT the 6x10 Concentric made it see bits only a GBII can normally see and on other Machines placing targets on a Magnetic surface they can see bits down to a bit smaller than 0.006 grams when given the Full Beans, So yes they work well, But one thing I have found is that as DD's have progressed in the last 5 or so years I don't think that there is that bigger difference anymore,

My 950 Concentric is equally matched to my factory 10"DD when it comes to tiny targets and even in Air tests where there is no natural resistance due to the ground they seem to perform pretty much the same, There are one or two Concentrics which are very Hot, but the Gap between DD's and Concentrics has closed up a heck of a lot in the past 5 years.

As for a Concentric on a PI just does not compute,

J.

I call them concentric, because they are concentric. The TX is outside and the RX is in the centre.
Concentric coil is not a version of mono in any way, because there are two loops working in concentric and only one in Mono (short of White's developments).

In case of PI detectors concentric coils are not affected by mineralization like they appear to be with VLF detectors as PI works quite differently and coil shapes are not a factor of stability there.

Given that all parameters are equal DD, concentric and any other overlapping coil designs have the same depth and sensitivity. The differences come in the discrimination with VLF.

Concentric on a PI is as deep as mono, because the TX is the same size as mono and it's deeper than DD, because the TX is bigger than on DD.
 
Candigger said:
I call them concentric, because they are concentric. The TX is outside and the RX is in the centre.
Concentric coil is not a version of mono in any way, because there are two loops working in concentric and only one in Mono (short of White's developments).

In case of PI detectors concentric coils are not affected by mineralization like they appear to be with VLF detectors as PI works quite differently and coil shapes are not a factor of stability there.

Given that all parameters are equal DD, concentric and any other overlapping coil designs have the same depth and sensitivity. The differences come in the discrimination with VLF.

Concentric on a PI is as deep as mono, because the TX is the same size as mono and it's deeper than DD, because the TX is bigger than on DD.

A Concentric has much better Target ID and is a lot quieter when it comes to EMI, side by side testing a Concentric coil will ID Iron and Crown caps better than a DD,

I did not say it is a version of a mono, I said it is a "VLF's" Version of a Mono.

A Mono is a bit deeper than a DD when it comes to PI Machines, But when it comes to VLF's with coils that are Equal in size the difference between a Concentric and a DD is no where near as noticeable as it once was, Sensitivity is the same and unless they are compared on a machine like the GMT and then you will see a difference, But on normal VLF's there is next to know difference IF Any.

Modern Coil makers are pushing the limits to the Max trying to get every last drop out of their coils And out of the dozens of coils I have tested only "Two" coils on 2 different machines showed a marked improvement and One Larger concentric on one machine actually showed ZERO depth increase and a slight loss in sensitivity.

The limit on 99% of VLF's Under 20 KHz when it comes to small target sensitivity seems to be set across the board when it comes down to DD Vs Concentric with the exception of one or two combinations.

I found out a few years ago by accident about this effect on 2 machines So I pestered the life out of Whites for 2 or 3 years to make Concentric Coils for the GMT and in the end they started to produce them, and all this came about because I fitted the Older GM II Concentric on to my GMT and all of a sudden that GMT could see bits that made the Goldbug II Struggle, But when it comes to other machine / coil combo's there is no longer any difference between the 2 types of coils. And the only thing a Concentric has over a DD is better target ID and they are less effected by EMI.
 
Redfin said:
Me thinks Matt's testing methods leave a lot to be desired, he'll be flogging devining rods next.
....and then be telling everyone to throw their 30" CC in the bin because the $5,000 divining rods are much better that the fly shite all the other coils pick up :lol:
 
ProspectorPete said:
Redfin said:
Me thinks Matt's testing methods leave a lot to be desired, he'll be flogging devining rods next.
....and then be telling everyone to throw their 30" CC in the bin because the $5,000 divining rods are much better that the fly shite all the other coils pick up :lol:

Hey Pete, Here's the Ultimate Wish Stick, Complete with a Meter and built in battery pack, and it only weighs 475 grams,

LOL.

1561369920_lrl.jpg
 
Ridge Runner said:
ProspectorPete said:
Redfin said:
Me thinks Matt's testing methods leave a lot to be desired, he'll be flogging devining rods next.
....and then be telling everyone to throw their 30" CC in the bin because the $5,000 divining rods are much better that the fly shite all the other coils pick up :lol:

Hey Pete, Here's the Ultimate Wish Stick, Complete with a Meter and built in battery pack, and it only weighs 475 grams,

LOL.

https://www.prospectingaustralia.com/forum/img/member-images/3775/1561369920_lrl.jpg
Best you put a Patent on that one RR before Matt sees it :clap:
 
ProspectorPete said:
Ridge Runner said:
ProspectorPete said:
Redfin said:
Me thinks Matt's testing methods leave a lot to be desired, he'll be flogging devining rods next.
....and then be telling everyone to throw their 30" CC in the bin because the $5,000 divining rods are much better that the fly shite all the other coils pick up :lol:

Hey Pete, Here's the Ultimate Wish Stick, Complete with a Meter and built in battery pack, and it only weighs 475 grams,

LOL.

https://www.prospectingaustralia.com/forum/img/member-images/3775/1561369920_lrl.jpg
Best you put a Patent on that one RR before Matt sees it :clap:

The Mk II is going to have Cup holders and SATNAV with the optional Fly Swatter :playful: :playful: :playful: :perfect:
 
madtuna said:
Hi Chrisco, not a single nugget at that depth, rather multiple nuggets of various sizes from the same hole that kept going down.
Also have chased stringers down that far that started on the surface or just below.
Its interesting to watch people on Youtube videos sifting for their target, throwing handfuls of dirt away that havent been over the coil (coz a target is still registers in the scoop), & then backfilling the hole after finding their target, without running the detector over it again. Seems many people assume there is only ever one target/nugget in a hole!
 
Ded Driver said:
madtuna said:
Hi Chrisco, not a single nugget at that depth, rather multiple nuggets of various sizes from the same hole that kept going down.
Also have chased stringers down that far that started on the surface or just below.
Its interesting to watch people on Youtube videos sifting for their target, throwing handfuls of dirt away that havent been over the coil (coz a target is still registers in the scoop), & then backfilling the hole after finding their target, without running the detector over it again. Seems many people assume there is only ever one target/nugget in a hole!
Usually you can tell if you've got more than one target in your hand, but yeah always run your detector back over the spoils and in the hole.
 
madtuna said:
yep :Y:
Any rubbish here is surface or a max of 2 or 3 inches. If your signal is deeper than that then it's gold.

I have gone around a meter to find a bloody horse shoe. I got very excited when I hit calcrete at about 50cm. Then I got very disappointed to find an old rusty horse shoe 8.(
 
shakergt said:
madtuna said:
yep :Y:
Any rubbish here is surface or a max of 2 or 3 inches. If your signal is deeper than that then it's gold.

I have gone around a meter to find a bloody horse shoe. I got very excited when I hit calcrete at about 50cm. Then I got very disappointed to find an old rusty horse shoe 8.(
classic Fugget ... that would make you 8.(
 
Probably the coil is not Concentric but a DD.
I watched the video and wondered why it could not work on Mono or DD.

1561717625_123.jpg
 
Here is a new air test on the complete 30"CC design. The 30"CC is designed to work in two basic modes of operation - Maximum Depth and Hot Ground, controlled by a switch box behind the coil plug. These two modes are meant to cover any possible performance characteristic offered by Mono, DD and Concentric coils simultaneously, by compensating for some limitations of the GPX design.

 

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