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A few last comments on coils and absolute depth

April 20, 2019 09:24AM
Monte - on your comment about concentric coils not having a "cone" shape field, technically you are correct, it is more "bowl" shaped. The point I was trying to make is independent of the final shape of the field, they are similar in shape, and the field from a 10" coil envelopes approximately 50% more ground than an 8" coil. So - 20% increase in coil size, but 50% more ground encompassed. This is why in mineralized soil, increasing coil size doesn't necessarily buy you more depth - with a VLF machine.

About absolute depth. Assuming mineralized soil - the deepest detector type there is, is the pulse induction machine. It pretty much "sees" right past ground minerals and can get the best depth, hands down. This is why for years and years now metal detector engineers have been trying to combine the depth of the PI with the discriminating abilities of the VLF detector (for coin hunting). The White's TDI was built, from an Eric Foster design, to attempt discrimination of iron. It succeeds somewhat.

See: [www.youtube.com]

I went to Shute Park in Hillsboro Or. with Monte's club some years back, with the goal of trying this coin hunting method with a TDI SL. Monte is familiar with this park and hunted it after they had scraped dirt from the surface. He knew there were still coins lurking deeper beneath the surface now. I managed to find a wheat penny at about 5" there. I was tickled pink, and thought this is the ticket! smiling bouncing smiley Well, upon more time in searching, I was picking up DEEP rusted nails. sad smiley This technique simply couldn't separate the rusty nails from a coin (at least I wasn't having much success at it). I came back a few more times after that, but never found any keepers - but had to dig several deep holes finding rusty nails (which I do not like to do in parks, especially when there's not much chance of success)!

I've read others do well with this PI and technique. If you want ultimate depth for a silver dime, this is probably it with present day technology - but be prepared for a long learning curve and perfected clean digging technique (unless you are lucky enough to hunt a field where you can use a shovel without ramification). And don't end up like the guy in the attached picture angry smiley
Attachments:
open | download - boots.jpg (130 KB)
Subject Author Views Posted

Important Topic by George: Deep coin shooting with a concentric coil???

glabelle 158 April 16, 2019 06:50AM

Related Reference if you're interested -

Rich (Utah) 65 April 22, 2019 11:47PM

Related Reference of interest? Well, I'm not, and I don't mind commenting on it, either.

Monte 65 April 23, 2019 07:55PM

Coils and Coins -

Rich (Utah) 45 April 23, 2019 08:46PM

Re: Related Reference if you're interested -

glabelle 50 April 23, 2019 07:11AM

Coil Sizes and Depth on Coins -

Rich (Utah) 42 April 23, 2019 08:40PM

Re: Coil Sizes and Depth on Coins -

glabelle 34 April 23, 2019 09:37PM

Coil Sizes and Depth on Coins -

Rich (Utah) 35 April 23, 2019 09:44PM

Re: Related Reference if you're interested -

OregonGregg 52 April 23, 2019 05:45AM

Re: Related Reference if you're interested -

Rich (Utah) 33 April 23, 2019 08:54PM

Pardon me George and others, but this is a great topic.

Monte 96 April 19, 2019 10:35AM

George, this is a great topic. Question for Harold,ILL

Rich (Utah) 62 April 19, 2019 05:45PM

Comments for Rich (Utah) from Monte.

Monte 64 April 20, 2019 08:40AM

What is DEEP ? - Some Detecting Options

Rich (Utah) 59 April 20, 2019 07:43PM

Re: What is DEEP ? - Some Detecting Options reply Rich Attachments

Kickindirt 50 April 20, 2019 09:12PM

Re: What is DEEP ? - Some Detecting Options

OregonGregg 49 April 20, 2019 08:06PM

Re: What is DEEP ? - Some Detecting Options

Rich (Utah) 44 April 20, 2019 09:22PM

Re: What is DEEP ? - Some Detecting Options Attachments

OregonGregg 43 April 20, 2019 09:35PM

Re: Pardon me George and others, but this is a great topic.

glabelle 51 April 19, 2019 04:43PM

George, I'll respond to your 5-points.

Monte 54 April 20, 2019 05:42AM

In a nutshell . . . . .

Rich (Utah) 41 April 19, 2019 07:48PM

Re: In a nutshell . . . . .

glabelle 55 April 19, 2019 08:42PM

Preferences -

Rich (Utah) 39 April 19, 2019 11:48PM

A few last comments on coils and absolute depth Attachments

glabelle 50 April 20, 2019 09:24AM

George, a simple reason I described the 'cone.'

Monte 55 April 20, 2019 03:59PM

Adjacency - And why is that still there thinking

Rich (Utah) 45 April 20, 2019 06:13PM

Re: Adjacency - And why is that still there thinking Great Post Richthumbs up

Druid 31 April 21, 2019 09:49AM

Re: A few last comments on coils and absolute depth

jmaryt 35 April 20, 2019 10:28AM

Re: Deep coin shooting with a concentric coil???

Kickindirt 73 April 16, 2019 06:46PM

Re: Deep coin shooting with a concentric coil???

glabelle 68 April 16, 2019 09:57PM

Balancing to ignore the ground?

Monte 52 April 20, 2019 09:22AM

Re: Balancing to ignore the ground?

glabelle 40 April 20, 2019 09:34AM

Re: Deep coin shooting with a concentric coil???

Kickindirt 58 April 17, 2019 11:05AM

Just a thought or two regarding coil size selection.

Monte 43 April 20, 2019 09:59AM

Re: Deep coin shooting with a concentric coil???

glabelle 58 April 17, 2019 04:13PM

What should I use to look for deep silver dimes?

Rich (Utah) 80 April 16, 2019 10:20PM

Re: What should I use to look for deep silver dimes?

glabelle 63 April 17, 2019 09:21AM

Re: What should I use to look for deep silver dimes?

Harold,ILL. 61 April 17, 2019 08:06AM

Re: What should I use to look for deep silver dimes?

jmaryt 55 April 17, 2019 10:44AM

Re: What should I use to look for deep silver dimes?

Rich (Utah) 63 April 17, 2019 04:12PM



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