Minelab 8000

[moodz]

There is no elegance in this design ... I cant see the mathematical principle that makes it superior to any prior art.

Ferinstance this patent is the same thing AFAIK. Fig 2 even has the dunny seat profile.
It describes a Z space bucking coil system with the Rx coil placed lowest / closest to the ground.

[Carl-NC]

[Aziz]

There is no elegance in this design ... I cant see the mathematical principle that makes it superior to any prior art.

Ferinstance this patent is the same thing AFAIK. Fig 2 even has the dunny seat profile.
It describes a Z space bucking coil system with the Rx coil placed lowest / closest to the ground.

In figure 2, there must be a mistake. The bucking coil displayed in the patent doesn't make any sense.

[Carl-NC]

Yeah, I think someone messed up on the drawing.

[Aziz]

Here is a better seat invention for all tired bones in the outback.

It doesn't require any bucking coil. And it has EMI noise cancellation feature. RX bottom and RX top as anti serial connected.


Red is the TX coil. Green are the RX coils.

Let me post this first then I'm going to go to the patent office and will provide the link here for the seat design.
The seat has an internal heater. This is a novel invention. No more freezing in the outback.

[Aziz]

This might be one of the 18 inch coils. Below is the cross-section view of the coil. Found this in the patent office.


There is no bucking coil. Two anti-phase RX coils (85 and 86). TX (84) and RX (85) coils are split into two halves to reduce the coil capacitances. This will make early sampling easy.
The coil axis is 83.

There are other coil configurations in the patent (WO2022126185A1).

My coil software is capable of simulating such coil arrangements. But I don't have much time right now. Below is a similar TX coil arrangement.

[JoyJo]

And in which application do you model the fields of the coil?

[Aziz]

And in which application do you model the fields of the coil?

Self coded Win32 application using Biot-Savart law developped since 1992 or so.

[Aziz]

Here is the current active AU patent: https://patents.google.com/patent/AU2021398587B2/en

[JoyJo]

Self coded Win32 application using Biot-Savart law developped since 1992 or so.

Is it freely available? Is it possible to model a DD coil in it?

[Aziz]

Is it freely available? Is it possible to model a DD coil in it?

No, it is a closed source application. Way to complex to use and there is no documentation there.

Yes, I can model DD coils too. Induction balance optimization is also implemented.

[Aziz]

This is also interesting. Figure-3 coil configuration.
If the flux area of the RX coils 25 and 26 are approximately the same, a good EMI cancellation is possible. Note, there isn't any real TX bucking coil.
TX bucking coils do increase the coil weight (more copper) and weaken the total magnetic field emitted. So the IB is achieved with a second anti-phase RX coil (26).

Nice seat!

[Aziz]

Nevertheless, we can design better coils.

These are the main improvement concepts:
1. Avoid TX bucking coil. Will lead to more coil weight and weaken the total magnetic field.
2. Use for IB configuration a nulling RX coil -> EMI noise rejection. Place nulling RX coil far away from ground (target).
3. Give coil windings more (volume) space -> more ampere turns count for a given fixed inductance and will lead to less coil capacitance.

For good EMI noise rejection (IB design):
4. The total RX coil flux area and the total nulling RX coil flux area must be same. The total flux area is the integral of the flux surface area of the each RX winding. So it is dependend on geometry and number of turns count.

For highly mineralized ground:
5. Realize the TX coil vertically (zylindric in Z direction for instance). We have already seen basket-weave coils earlier. This is not novel.
6. Place the TX coil slightly above the main RX coil. It has the same function by rising the coil slightly from the mineralized ground to reduce ground noise.
This will weaken the magnetic field strength at the ground level nearby the TX windings and will cause less ground noise. Due to point 5, it weakens the magnetic field strength nearby the TX windings more. Overall, less ground noise.

7. Make the TX coil larger than RX coil.
The magnetic field refraction on the heavy uniform ground mineralisation is acting like a magnetic field shield and the magnetic fields won't penetrate much deeper. Large TX coils will penetrate such high mineral ground at the center region much better as the magnetic fields won't be refracted much. Small TX coils have a small penetration area therefore. Small TX coils will have a more magnetic field strength at the ground level. This will lead to more ground noise. Simply avoid small TX coils.

Now you know the basic ground breaking design concepts.
Aziz

[moodz]

Three problems I already know the 8000 has.

1. You have to dig really big holes because you need to fit the coil in the hole to probe around.
2. It loves small bits of rusty iron ( if you already have a GPZ 7000 then you and your chiropracter know what I mean )
3. It cant discrim ... it can sort of with the stereo fairy dust audio ... but really ?

[Aziz]

Three problems I already know the 8000 has.

1. You have to dig really big holes because you need to fit the coil in the hole to probe around.
2. It loves small bits of rusty iron ( if you already have a GPZ 7000 then you and your chiropracter know what I mean )
3. It cant discrim ... it can sort of with the stereo fairy dust audio ... but really ?

4. It's astronomic high prize! 16.000+ $ or so...
Give your to Minelab. Or all of your gold findings.