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In a nutshell . . . . .

April 19, 2019 07:48PM avatar
George,

I should have asked earlier, do you have a favorite pairing of detector / coil for deep coins; specifically silver dimes? thumbs up

Rich




Quote
glabelle
Monte, thanks for the ultra clarifications :-)

In reading that, a couple of important points came to mind.

1) I think "standard" coils started getting larger due to marketing pressure. After all, if 'one company's detector "only" has an 8" coil, if we supply a 9.5" coil, the consumer will think that is better.'

2) Another thing to bear in mind, is that the coil housing might be 9.5", but the actual wire coil inside could still be 8"!

3) I did the math on the "volume of a cone", and if you look at the difference between an 8" and a 10" coil, you'll find, the volume of the 10" is 50% more than the 8". That means much more ground seen by the detector with a 10"er. That is OK, as long as the target is larger. I cannot find the reference again, but one of the top engineers mentioned that there is an optimum distance between the ground and the coil, depending upon the amount of mineralization. Reason is, if you "scrub" the ground, you might get 1/2" closer to the target, but the amount of ground the detector sees is considerably increased, actually reducing depth, or overloading the receiver!

4) This from Dave Johnson, another top engineer in metal detection engineering: "Searchcoil size Most standard searchcoils are approximately 8 inches (20 cm) in diameter if round, or approximately 10 inches (25 cm) in length if elliptical. Larger searchcoils allow covering more area with each sweep, and offer a slight increase in depth on medium and large size targets. Unfortunately they are heavier, more difficult to pinpoint with, tend to lose small targets, and provide poor target separation. Small searchcoils provide superior target separation (important in trashy areas) and ability to detect smaller targets (important in gold prospecting). Of course they don’t cover as much ground as a standard size coil. However (and this may surprise you) small searchcoils usually have nearly as much depth capability as standard size searchcoils."

5) Again, the coil size vs. target size is heavily influenced by the amount of mineralization in the area you are hunting.

Aloha
Subject Author Views Posted

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

glabelle 194 April 16, 2019 06:50AM

Related Reference if you're interested -

UtahRich 111 April 22, 2019 11:47PM

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

Monte 98 April 23, 2019 07:55PM

Coils and Coins -

UtahRich 71 April 23, 2019 08:46PM

Re: Related Reference if you're interested -

glabelle 84 April 23, 2019 07:11AM

Coil Sizes and Depth on Coins -

UtahRich 70 April 23, 2019 08:40PM

Re: Coil Sizes and Depth on Coins -

glabelle 55 April 23, 2019 09:37PM

Coil Sizes and Depth on Coins -

UtahRich 54 April 23, 2019 09:44PM

Re: Related Reference if you're interested -

OregonGregg 76 April 23, 2019 05:45AM

Re: Related Reference if you're interested -

UtahRich 59 April 23, 2019 08:54PM

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

Monte 126 April 19, 2019 10:35AM

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

UtahRich 99 April 19, 2019 05:45PM

Comments for Rich (Utah) from Monte.

Monte 96 April 20, 2019 08:40AM

What is DEEP ? - Some Detecting Options

UtahRich 103 April 20, 2019 07:43PM

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

Kickindirt 85 April 20, 2019 09:12PM

Re: What is DEEP ? - Some Detecting Options

OregonGregg 81 April 20, 2019 08:06PM

Re: What is DEEP ? - Some Detecting Options

UtahRich 67 April 20, 2019 09:22PM

Re: What is DEEP ? - Some Detecting Options Attachments

OregonGregg 75 April 20, 2019 09:35PM

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

glabelle 84 April 19, 2019 04:43PM

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

Monte 97 April 20, 2019 05:42AM

In a nutshell . . . . .

UtahRich 64 April 19, 2019 07:48PM

Re: In a nutshell . . . . .

glabelle 83 April 19, 2019 08:42PM

Preferences -

UtahRich 60 April 19, 2019 11:48PM

A few last comments on coils and absolute depth Attachments

glabelle 82 April 20, 2019 09:24AM

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

Monte 80 April 20, 2019 03:59PM

Adjacency - And why is that still there thinking

UtahRich 72 April 20, 2019 06:13PM

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

Druid 63 April 21, 2019 09:49AM

Re: A few last comments on coils and absolute depth

jmaryt 55 April 20, 2019 10:28AM

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

Kickindirt 102 April 16, 2019 06:46PM

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

glabelle 91 April 16, 2019 09:57PM

Balancing to ignore the ground?

Monte 83 April 20, 2019 09:22AM

Re: Balancing to ignore the ground?

glabelle 83 April 20, 2019 09:34AM

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

Kickindirt 82 April 17, 2019 11:05AM

Just a thought or two regarding coil size selection.

Monte 76 April 20, 2019 09:59AM

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

glabelle 89 April 17, 2019 04:13PM

What should I use to look for deep silver dimes?

UtahRich 114 April 16, 2019 10:20PM

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

glabelle 87 April 17, 2019 09:21AM

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

Harold,ILL. 100 April 17, 2019 08:06AM

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

jmaryt 83 April 17, 2019 10:44AM

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

UtahRich 97 April 17, 2019 04:12PM



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