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  #21  
Old 11-05-2019, 06:14 PM
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Originally Posted by ToddB64 View post
Hi Dflan83

Sorry for my ignorance; I'm guessing "TLDR" in your post is an Internet slang acronym, or maybe an abbreviation for something, but my curiosity gets the better of me as I've never come across that one and so have to ask; what does it stand for/represent ?

Thanks !

ToddB64
To Long Didn't Read = TLDR

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  #22  
Old 11-06-2019, 09:53 AM
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It is both technically true, and technically untrue.

For the purposes of hobby metal detectors, there is little difference between 3Khz and 45Khz. They will both equally detect highly conductive or low conductive tarrgets. But, in the all encompassing realm of physics, there is a difference. More conductive targets will produce a stronger response at lower frequencies and less conductive targets will produce a stronger response at higher frequencies. This is all due to eddy currents and the skin effects. Is there a significant enough difference in response signals for at a given target at a given frequency to make a huge difference? That answer likely comes down to how the signal processing software is written.

The one advantage of lower frequencies over higher frequencies comes as the ground VDI approaches -95. Higher frequencies tend to produce higher VDI values for a given target opposed to lower frequencies. For larger, highly conductive targets, higher frequencies will tend to cause those targets to wrap into the negatives, where as at lower frequencies, the VDIs will not wrap into the negatives.

So, if you are looking for highly conductive targets in -93VDI ground or lower, you will want to use lower frequencies to prevent quarter sized targets or larger from wrapping into negatives. If you are looking for 14k gold in the same soil conditions, higher frequencies will do you just fine with no risk of wrapping.

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  #23  
Old 11-06-2019, 10:20 AM
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Originally Posted by BottleCapKing View post
It is both technically true, and technically untrue.

For the purposes of hobby metal detectors, there is little difference between 3Khz and 45Khz. They will both equally detect highly conductive or low conductive tarrgets. But, in the all encompassing realm of physics, there is a difference. More conductive targets will produce a stronger response at lower frequencies and less conductive targets will produce a stronger response at higher frequencies. This is all due to eddy currents and the skin effects. Is there a significant enough difference in response signals for at a given target at a given frequency to make a huge difference? That answer likely comes down to how the signal processing software is written.

The one advantage of lower frequencies over higher frequencies comes as the ground VDI approaches -95. Higher frequencies tend to produce higher VDI values for a given target opposed to lower frequencies. For larger, highly conductive targets, higher frequencies will tend to cause those targets to wrap into the negatives, where as at lower frequencies, the VDIs will not wrap into the negatives.

So, if you are looking for highly conductive targets in -93VDI ground or lower, you will want to use lower frequencies to prevent quarter sized targets or larger from wrapping into negatives. If you are looking for 14k gold in the same soil conditions, higher frequencies will do you just fine with no risk of wrapping.
Yea what he said!

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  #24  
Old 11-10-2019, 09:49 AM
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Default electrons abound but no TID

Hello, maybe this is the right place to question what I found.

I "tested" my detector on everything metal I could find in my house. I came across a herringbone-like necklace that went undetected. it is surely metal and silvery in color. it even conducts electricity ....

what the heck could it be? pewter? cadmium? whatever metal is used in shielding cables and wires ?

thanks

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  #25  
Old 11-10-2019, 10:10 AM
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Originally Posted by BottleCapKing View post
It is both technically true, and technically untrue.

For the purposes of hobby metal detectors, there is little difference between 3Khz and 45Khz. They will both equally detect highly conductive or low conductive tarrgets. But, in the all encompassing realm of physics, there is a difference. More conductive targets will produce a stronger response at lower frequencies and less conductive targets will produce a stronger response at higher frequencies. This is all due to eddy currents and the skin effects. Is there a significant enough difference in response signals for at a given target at a given frequency to make a huge difference? That answer likely comes down to how the signal processing software is written.

The one advantage of lower frequencies over higher frequencies comes as the ground VDI approaches -95. Higher frequencies tend to produce higher VDI values for a given target opposed to lower frequencies. For larger, highly conductive targets, higher frequencies will tend to cause those targets to wrap into the negatives, where as at lower frequencies, the VDIs will not wrap into the negatives.

So, if you are looking for highly conductive targets in -93VDI ground or lower, you will want to use lower frequencies to prevent quarter sized targets or larger from wrapping into negatives. If you are looking for 14k gold in the same soil conditions, higher frequencies will do you just fine with no risk of wrapping.
Sorry, but it is not the "skin effect" that is responsible.

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  #26  
Old 11-10-2019, 03:02 PM
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Originally Posted by SoOregonMd View post
To Long Didn't Read = TLDR
SoOregonMd...Thanks for defining TLDR =Too Long Didn't Read, but I wonder who Dflan83 was referring to, me, Rudy or the thread ?

Not pointing a finger here, just curious, cause I see this all the time. Are folks afraid to address the person they are replying to for fear of "poking-the-bear", tired typing, or what ? I realize this question is off-topic, but opportunities usually arrive random ! Guesses are welcome.

ToddB64.....Now 78

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