Re: Coins/Rings.......Richard a little more help, please.?..MattR.Uk

[MattR]

[quote Jackpine Savage]What good would posting the Karat marking on the rings do??? The diameter and cross sectional area are the main factors in how gold rings read. Tom[/quote]

Reply. MattR

[size=medium]ALL parameters[/size] of any target, contribute to the resultant Target I.D. For example, using your input AND what 'fills' that x-sectional area, Tom.

ALL those are fundamental to what number is displayed. Along with the frequency of the alternating flux supplied by our search head.

Can I convince you without technical talk?

[attachment 51314 F75rings2.JPG]​

The diagram shows 3 identically sized rings, so the TWO parameters you've quoted are similar, but note how their TID's differ.

The answer is in the illustration......MattR.UK

 

[Richard@BackwoodsDetectors]

Class Ring 10K 31
Gold Band 10k 34
Sterling Band 66 tarnished
Gold Band 68 no markings --probably gold plated


FWIW, a 14K gold band also read in the low 30ths...falling in the nickel range...
Really this is good info if the rings are grouped in that area.

Best to all, Richard

 

[MattR]

n/t

 

[Jackpine Savage]

22K rings found at least in my area. I see you understand my point so no need to convince me. What difference does the frequency make when the displayed numbers are chosen by the engineer?? F-75 and T2 are the same frequency however the number values do not match target for target.

Tom

 

[MattR]

[quote Richardntn]Class Ring 10K 31
Gold Band 10k 34
Sterling Band 66 tarnished
Gold Band 68 no markings --probably gold plated


FWIW, a 14K gold band also read in the low 30ths...falling in the nickel range...
Really this is good info if the rings are grouped in that area.[/quote]

***********************************************

Thanks for the prompt reply.

Most average 'gold' rings will fall into the 30 to 40's region.
Mass/shape will affect variations in TID.

From your data, the 68 'gold' band is not a 22k.
Its TID of 68 indicates either gold on silver, (or copper?)
For the conductivity difference between silver and copper is about 7%
(Generally the 'best quality' gold wedding rings in the UK are 22K.
and usually very thick, chunky pieces. The conductivity for PURE gold is about 4.0 E7 compared with debased 9k or 14k which have a figure of 4.7-4.5 E7.

Gold Band 68 no markings --probably gold plated

So any 'gold' rings of equal dimensions will have a relative TID value where the lower the TID the purer the gold!

It is a very difficult thing to demonstrate if comparing rings of differing dimensions and design, even though they may be marked as having the same karat.

To answer Tom's question about the effect of frequency.

If you read the same ring using two different frequencies then you would get two different values.

Using the DFX as my tool.

At 3.5 KHz. 22k ring = 36
At 15 KHz 22k ring = 80

The XLT 6.5 KHz = 65 (The 'normalised' value on DFX)

..............

Tom, if you were to use 100KHz on Richard's '68 plated wedding band' you would find the TID altering; (Depending on the layer thickness) That's the Skin effect coming into play.

 

[Jackpine Savage]

The DFX.. very true!

Matt does the DFX when operated at 15Khz and not using normalized values give greater TID resolution on lower conductive objects? I would assume so...<p>
Also you stated:

So any 'gold' rings of equal dimensions will have a relative TID value where the lower the TID the purer the gold!

<p>
I disagree on that one. Alloyed gold generally reads lower than gold in a more pure state all other factors being equal. Detecting concensus = very likely (greater than 90% probability).

Tom