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G2+ large iron objects read high VDI numbers ?
Posted by: Speedlunker
Date: April 24, 2017 10:33PM
Several times I have had solid tones and high 80+ VDI numbers that have turned out to be large cast iron objects. I would have expected these to be in the 40's and below. Is this normal?

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Re: G2+ large iron objects read high VDI numbers ?
Posted by: Jackpine Savage
Date: April 25, 2017 04:02AM
Perfectly normal with all high gain units such as the G2's. Non-ferrous objects such as coins/bullets are conductive (can carry a current), Iron is both magnetic and conductive so at times the conductivity causes the high reading. Flat farm iron from cultivators and mower blades also fall into this category. You will learn the trick of ID'ing large iron in time. Most coin/bullet size non-ferrous will drop out when raising the coil a few inches while sweeping. Large iron will usually still read high with the coil raised well in the air while sweeping the coil. Many times a faster sweep over the target will reveal the iron by the breakup in the sound. It's the small rusty nails and rusty wire bits at depth that that are the real foolers.

Tom



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Minelab Advantage, G2, Omega 8500, X-Terra 705, F75 DST and a Fisher ID Edge

Re: G2+ large iron objects read high VDI numbers ?
Posted by: Speedlunker
Date: April 25, 2017 09:18AM
Funny that you mention that about the rusty nails and wire. Just this past weekend I had a couple nails and some rusty wire showing up solid in the 70's. Totally fooled me. Interestingly I have found 4 horseshoes and my buddy with an AT Pro has found none. He doesn't dig low numbers and I usually don't either but these have come in at high numbers so I dug them. I think this is why I have found several and he has not. I have noticed that some of the bigger iron objects send mine into overload with a fast beep but some just hit a solid tone and have really fooled me.

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Re: G2+ large iron objects read high VDI numbers ?
Posted by: Jackpine Savage
Date: April 26, 2017 05:11AM
Why small rusty nails the size of a tack are detectable at the depths they can be found at and with machines that are not even known as depth demons is beyond me. The amplitude of the signal must be off the charts and with a phase angle reading in the high conductor range, Jeez!

Tom



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Minelab Advantage, G2, Omega 8500, X-Terra 705, F75 DST and a Fisher ID Edge



Edited 1 time(s). Last edit at 04/26/2017 05:13AM by Jackpine Savage.

Re: G2+ large iron objects read high VDI numbers ?
Posted by: Speedlunker
Date: April 26, 2017 11:16AM
Originally I was concerned something was off or wrong with my machine. My friend would sweep the same targets and tell me they were iron without hesitation and his VDI numbers would be 40's and below. My machine was hitting solid with high numbers so I was beginning to think maybe mine was off. From the responses I am getting I think my machine is ok it's just a different animal. Oddly enough both of our machines read Mid 70's to Mid 80's on aluminum cans. We both identify them with a greater degree of accuracy now by raising the coil up sometimes almost a foot and still getting solid pings.

Re: G2+ large iron objects read high VDI numbers ?
Posted by: Minas man
Date: May 08, 2017 08:25PM
With my GB pro I get the 80's on the large iron and have learned to raise the coil to see if it is big iron.
Minas man

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