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A few last comments on coils and absolute depth

April 20, 2019 08:24AM
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
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Subject Author Views Posted

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

glabelle 458 April 16, 2019 05:50AM

Related Reference if you're interested -

UtahRich 301 April 22, 2019 10:47PM

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

Monte 310 April 23, 2019 06:55PM

Coils and Coins -

UtahRich 212 April 23, 2019 07:46PM

Re: Related Reference if you're interested -

glabelle 265 April 23, 2019 06:11AM

Coil Sizes and Depth on Coins -

UtahRich 245 April 23, 2019 07:40PM

Re: Coil Sizes and Depth on Coins -

glabelle 206 April 23, 2019 08:37PM

Coil Sizes and Depth on Coins -

UtahRich 204 April 23, 2019 08:44PM

Re: Related Reference if you're interested -

OregonGregg 227 April 23, 2019 04:45AM

Re: Related Reference if you're interested -

UtahRich 216 April 23, 2019 07:54PM

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

Monte 338 April 19, 2019 09:35AM

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

UtahRich 311 April 19, 2019 04:45PM

Comments for Rich (Utah) from Monte.

Monte 288 April 20, 2019 07:40AM

What is DEEP ? - Some Detecting Options

UtahRich 281 April 20, 2019 06:43PM

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

Kickindirt 265 April 20, 2019 08:12PM

Re: What is DEEP ? - Some Detecting Options

OregonGregg 261 April 20, 2019 07:06PM

Re: What is DEEP ? - Some Detecting Options

UtahRich 247 April 20, 2019 08:22PM

Re: What is DEEP ? - Some Detecting Options Attachments

OregonGregg 261 April 20, 2019 08:35PM

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

glabelle 259 April 19, 2019 03:43PM

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

Monte 279 April 20, 2019 04:42AM

In a nutshell . . . . .

UtahRich 228 April 19, 2019 06:48PM

Re: In a nutshell . . . . .

glabelle 264 April 19, 2019 07:42PM

Preferences -

UtahRich 213 April 19, 2019 10:48PM

A few last comments on coils and absolute depth Attachments

glabelle 265 April 20, 2019 08:24AM

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

Monte 258 April 20, 2019 02:59PM

Adjacency - And why is that still there thinking

UtahRich 250 April 20, 2019 05:13PM

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

Druid 201 April 21, 2019 08:49AM

Re: A few last comments on coils and absolute depth

jmaryt 239 April 20, 2019 09:28AM

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

Kickindirt 284 April 16, 2019 05:46PM

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

glabelle 242 April 16, 2019 08:57PM

Balancing to ignore the ground?

Monte 268 April 20, 2019 08:22AM

Re: Balancing to ignore the ground?

glabelle 277 April 20, 2019 08:34AM

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

Kickindirt 257 April 17, 2019 10:05AM

Just a thought or two regarding coil size selection.

Monte 266 April 20, 2019 08:59AM

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

glabelle 290 April 17, 2019 03:13PM

What should I use to look for deep silver dimes?

UtahRich 304 April 16, 2019 09:20PM

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

glabelle 274 April 17, 2019 08:21AM

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

Harold,ILL. 283 April 17, 2019 07:06AM

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

jmaryt 282 April 17, 2019 09:44AM

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

UtahRich 319 April 17, 2019 03:12PM



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