New PI machine

[Aziz]

Pictures first

This is it.

The induction balanced coil configuration. Note, that the inner mean diameter is 102.3 mm whereas the outer mean diameter is 10 inch (inch != mm).



The distance gap due to coil bundle thickness (6 mm in this case).


The relation to the 10 inch round mono loop coil (=reference coil). Note, that the other coils are normalized to have same amount of EMI noise induction. So N*A (N=number of turns, A=flux surface area of the coil) is set equal to the reference round mono loop coil. Smaller RX coils will pickup less noise and we can increase the gain of the RX. This gain is taken into account in the relation tables.



Now the comparison figures:
The new DD-IB coil is 10" DD-IB ("ATX Coil"/Davor Coil)

Coil Comparison (Calculated Response Ratio to Reference Coil)
© 2013 by Aziz Ögüt. All Rights Reserved. 13-Sept-2013
Reference Coil: 300 µH Round Mono Loop Coil (SNR normalized to reference coil)
		10" Mono Loop Round Coil (Reference)	10" Mono Loop Round Coil (Reference)	10" Double-D Induction Balanced Round Coil	10" Concentric Co-planar Induction Balanced Round Coil (0.5)	10" DD-IB ("ATX Coil"/Davor Coil)
Target Depth [inch]	Target Depth [cm]	Reference Target Response Voltage [V]	Relation to Reference	Relation to Reference	Relation to Reference	Relation to Reference
1	2,5	0,224542198972	1,000	1,195	1,917	2,146
2	5,1	0,091886134762	1,000	0,930	3,104	1,996
3	7,6	0,054306336547	1,000	0,771	2,631	1,336
4	10,2	0,030898542907	1,000	0,703	2,126	1,031
5	12,7	0,017017280632	1,000	0,673	1,786	0,887
6	15,2	0,009367598034	1,000	0,657	1,563	0,810
7	17,8	0,005246952754	1,000	0,647	1,414	0,765
8	20,3	0,003016466978	1,000	0,641	1,310	0,736
9	22,9	0,001785876774	1,000	0,636	1,236	0,716
10	25,4	0,001089303660	1,000	0,633	1,182	0,702
11	27,9	0,000683797786	1,000	0,631	1,140	0,692
12	30,5	0,000440986616	1,000	0,629	1,108	0,684
13	33,0	0,000291588066	1,000	0,628	1,083	0,678
14	35,6	0,000197277483	1,000	0,627	1,063	0,673
15	38,1	0,000136302660	1,000	0,626	1,047	0,669
16	40,6	0,000095999056	1,000	0,625	1,033	0,666
17	43,2	0,000068809924	1,000	0,625	1,022	0,664
18	45,7	0,000050120032	1,000	0,624	1,012	0,662
19	48,3	0,000037048248	1,000	0,624	1,004	0,660
20	50,8	0,000027758749	1,000	0,624	0,997	0,658
21	53,3	0,000021059197	1,000	0,623	0,991	0,657
22	55,9	0,000016161269	1,000	0,623	0,985	0,656
23	58,4	0,000012535036	1,000	0,623	0,981	0,655
24	61,0	0,000009818718	1,000	0,623	0,977	0,654
25	63,5	0,000007761740	1,000	0,622	0,973	0,653
26	66,0	0,000006188195	1,000	0,622	0,970	0,652
27	68,6	0,000004973029	1,000	0,622	0,967	0,652
28	71,1	0,000004026289	1,000	0,622	0,964	0,651
29	73,7	0,000003282546	1,000	0,622	0,962	0,651
30	76,2	0,000002693717	1,000	0,622	0,960	0,650

There are more means to induction balance the coils:
- varying the distance gap
- offsetting the center position (like the usual DD coil)
- rotating (along the z-axis) one of the coils (either TX or RX)

The inner diameter and the distance gap is critical. There are inner diameters, which can't be induction balanced. The shown example should give you an indication, which allows an induction balance condition.


Cheers,
Aziz

[Aziz]

Excel Simulation Data (Zipped)

For your convenience of course.

Excel simulation data (zipped):
CoilComp5(CoilCMP2)-06.zip


Cheers,
Aziz,
the "World Leader in Coil Technology" *LOL*
having some beer now (excuse me please)

[Davor]

Nice. So there is some potential to it. Wonder how it does on difficult ground.

I had a little vine myself

[6666]

Something like this ?

[Aziz]

Nice. So there is some potential to it. Wonder how it does on difficult ground.

I had a little vine myself

The "World's Best IB Coil" is still the "Tophat"(c)(r)(tm) coil. *LOL*

BTW, watch the patent sites for new registered patents. I wouldn't be wondered if someone comes up with a new coil patent. *LOL*

Cheers,
Aziz

[Aziz]

Something like this ?

[ATTACH]26210[/ATTACH]

Yep!

[Koala]

How do we know the middle bump goes outward I paused the video and can't see. What would happen if the bump was inwards (maybe a test for Aziz). I take it this design will be easier to pinpoint as well as sensitive to small items.

[Davor]

You wouldn't be able to balance such coil. It does not matter that much for PI as it would for CW, but such direction would also reduce the field in the middle, so pinpointing would be seriously hurt.

Double field coils have the inner coil working in a same direction as the outer to enhance the field in a middle, and it is a good thing, so I'd say doing the opposite does not make much sense.

[Koala]

You wouldn't be able to balance such coil. It does not matter that much for PI as it would for CW, but such direction would also reduce the field in the middle, so pinpointing would be seriously hurt.

Double field coils have the inner coil working in a same direction as the outer to enhance the field in a middle, and it is a good thing, so I'd say doing the opposite does not make much sense.

Cheer for the explanation. Now I understand. Thought there must be a simple reason why the other possibility had not been mentioned.

[Aziz]

Hi all,

thank you for your great interest guys. Glad to see, that the zipped Excel file has been downloaded 20 times.

Cheers,
Aziz
PS: To the forum-trolls:
"The World Leader in Coil and Metal Detecting Technology!"(c)(r)(tm) *LOL*

[6666]

21 turns.

[WM6]

DD coil with CC characteristic (EM field shape).

[Aziz]

21 turns.

Nice 6666,

well done.

Note, that if you can't initially induction balance, you can bend the coil further to meet the IB condition. The inner coil half could be made slightly smaller (first trial) or slightly larger. Vary the distance gap. Or try to i.b. like the standard DD coil. Or rotate one of the coils slightly at the center axis of the coil arrangement.

Cheers,
Aziz

[dinyeper]

What are you think about garret atx and minelab gpx 500. Which is the best?

[kt315]

What are you think about garret atx and minelab gpx 500. Which is the best?

please be more accurate with your request what better. you are on forum of White's Electronics Company representatives.

the best is TDI. you know now why.