the relationship between the coil diameter and detect distance in PI metal detector?

[green]

I added two more coils to the comparison chart. I've wondered if the effective diameter of a DD coil was the larger diameter or the narrower width. I used some coils that I wound in the past so they don't match as close as I would like, but I think the trend might be correct. The DD coils had less noise when I made the measurements. The square coil isn't really square. A picture is included. Except for noise I don't see a lot of difference between any of the 5 inch coils measuring on the bench. There might be a difference in use, cancelling ground, etc. Curios if the plot make sense.

[6666]

The post about the DRS range of phone based detectors is interesting, the coil is an unusual shape, what does everyone think about it , separate TX and RX or maybe Omega ? Aziz have you done any sims on this shape coil ?

[Aziz]

The post about the DRS range of phone based detectors is interesting, the coil is an unusual shape, what does everyone think about it , separate TX and RX or maybe Omega ? Aziz have you done any sims on this shape coil ?

Hi 6666,

no, I haven't done it yet regards to EMI noise and ground response issue. I have done a simple coil comparison on the Omega-type coils however (RX within the TX coil).
This coil is obviously larger off-center of the standard Omega coil according to the coil picture. It is in principle possible and it is making induction balance coils possible too.

But I can't make coil simulations right now (PC kaput).
Cheers,
Aziz

[Aziz]

I Haven't Lost Any Data!

Hi all,

6666 has brought up the off-center omega coil into the interesting discussion. I have asked Mrs. Google and she (BTW a nice sexy girl ) gave me some interesting sexy answers. HEHEHEHE...


And I have found some interesting coil designs on my hard disk backup. They date 12.March.2008. Indeed, the 6666's request can be seen on the Jon.brin's foto stream on flickr.
Here is the link: http://www.flickr.com/photos/2425633...th/2328473699/
It is the CCC (Coin Coupled Coil).
Link: http://www.flickr.com/photos/24256333@N05/2329252616/

And we can see, why Garrett can't patent their ATX DD coil. It's the DccD coil type (near the other coil).
Link: http://www.flickr.com/photos/24256333@N05/2328473699/

It's all prior art.

Cheers,
Aziz

PS: I obviously have made the simple coil analysis for the CCC coil.
Search for "WM6-coin1.jpg" picture here in the forum.

[Aziz]

"WM6-coin1.jpg" must be lost here. Anyway.
I have the picture:


Aziz

[WM6]

And I have found some interesting coil designs on my hard disk backup. They date 12.March.2008. Indeed, the 6666's request can be seen on the Jon.brin's foto stream on flickr.
Here is the link: http://www.flickr.com/photos/2425633...th/2328473699/
It is the CCC (Coin Coupled Coil).
Link: http://www.flickr.com/photos/24256333@N05/2329252616/

And we can see, why Garrett can't patent their ATX DD coil. It's the DccD coil type (near the other coil).
Link: http://www.flickr.com/photos/24256333@N05/2328473699/

It's all prior art.

Cheers,
Aziz

PS: I obviously have made the simple coil analysis for the CCC coil.
Search for "WM6-coin1.jpg" picture here in the forum.

Jon.Brin is mine (forgoten already) stream at flickr. Thanks for posting.

My DccD coil drawing from 2008 really look like ATX coil solution. I only know that I didn't steal idea from Garrett.

All posted here on Geotech also:

http://www.geotech1.com/forums/showt...ual-coil/page2

[Aziz]

Jon.Brin is mine (forgoten already) stream at flickr. Thanks for posting.

My DccD coil drawing from 2008 really look like ATX coil solution. I only know that I didn't steal idea from Garrett.

All posted here on Geotech also:

http://www.geotech1.com/forums/showt...ual-coil/page2

Congratulations WM6!
If you didn't "steal" it from somewhere/someone, Garrett did "steal" it from you! *LOL*

Aziz

[6666]

Aziz, Wm6 thanks for finding that old thread etc, very interesting.

[6666]

Sure, I saw it years before. Anything new is a well forgotten old.

I saw one guy with old PI detector having small coil and small scoop
and digging targets pushing his hand with scoop into sand almost up to the shoulder
after whole squad of detectorists armed with Whites Dualfields left the area finding nothing.

I realized that it was old PI detector with concentric coil - 9" TX and very small RX.
Still looks fantastic to me.

Hi WS, do you remember any more on this detector, brand etc ?

[Waikiki_Sweep]

Hi WS, do you remember any more on this detector, brand etc ?

I have tried to find it on Internet today but without success. That man visiting our beach twice a year. Next time I will ask him. I remember he told me that it is pulse machine and he digging all bits of iron (that I saw)
but it has big and small rings in coil (it is not dualfield) as I understand it is TX and RX. I worried may be he has misleading me and it is not PI. I will tell you once I will have a clear picture.

[6666]

Thanks WS, it will be interesting to see what it is, cheers.

[6666]

I am not sure is it good idea to use twisted pair center tapped for PI detector because in twisted pair you will have extra interwire capacitance. Capacitance is what everyone fighting against in PI design.
Probably you can connect that pair in parallel and use as monocoil or TX.

Regarding of that discussion about what is better monocoil or separate RX and TX. It turns to be a separate version looks better
but there is not much practical implementation and tests because mostly everyone building monocoils last years.
Sure You can try that configuration with big TX and regular RX size. Any input on results is greatly appreciated.

Check what is inside Garrett Infinum LS coil because that detector is one of the best PI machines with separate TX and RX:
[ATTACH]27830[/ATTACH] 26 turns is TX, 40 turns is RX
[ATTACH]27831[/ATTACH]
Also Infinum coil looks balanced or adjusted very close to it. Such configuration gives a lot of benefits because RX receiving mostly targets (and ground) signals and less to nothing from TX decay signal.

WS do you have any more pictures of the Infinum coil that you could post please ?

[Waikiki_Sweep]

WS do you have any more pictures of the Infinum coil that you could post please ?

I found the page with Infinum pictures in good old days when Geotech was in Google Index: http://www.geotech1.com/forums/showthread.php?14582-How-to-approach-making-a-coil-for-Infinium/page2

Forum search is a dump. Only Google can provide smart enough, relevant results and also image search.