TDI discrimination

[Carl-NC]

Practically all metals, including iron, can show up anywhere on the conductivity scale. This has more to do with thickness than the metal type. TDI detects small gold nuggets as low conductive but large gold nuggets can be high conductive. Most silver coins are high conductive, but if it's thin enough it will be a low conductor. As Davor says, it's due to skin depth effects.

[Davor]

Gold plated is not the same as gold bulk. A few micron of gold plating will have the same effect as aluminium foil against the bulk aluminium. Unfortunately gold flakes share this property with thin foils of any other metal that shortens it's tau because the sheet thickness is smaller than the skin depth.

Who knows what kind of junk you have beneath the gold plating of your targets.

[Geo]

TDI has the ability to discriminate between low and high conductivity. We know that iron has low conductivity and gold and silver has high. Before some days i went to check a place with 45 buried gold coins. TDI detected them but as Low conductivity but at another place with silver it gave audio for high conductivity. The same with iron. So my question is why see the gold as low conductivity and the iron as high since all we know that the gold is one of the best conductive material!!!!