GTA550 and GTAx1250---reaction to OLD aluminum cans

I don't know whether it's peculiar to the Garret GTA's or whether it extends to the whole Garrett line, but.....

....I was struck by how much OLD aluminum cans (the cans that had to be opened with either a church key or the old style pull-tab) sound like silver dollars --- especially when hunting in either coin or jewelry mode.   I was getting the full, clear, sharp bell tone that I associate with silver coins, and the graphics were showing $1, but all that was coming out of the hole were old schlitz and shasta cans.  Fortunately, whole old cans were too plentiful, so I dug everyone of them (but my heart didn't race quite as much after the 4th one as it did the 1st and 2nd time).

The newer cans aren't a problem since they seem to have a "trashier" sound to them.

BA

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bitburg, I noticed the same thing with the 250 and to a less extent the 150.  Especially the hybrid cans. those that were made with a steel outside and aluminum top . The steel rusts away and nothing is left but the top which on the 250 gives a clear coin ring. I walk around the target to see if the ring changes when scanned from a different direction. I dug one Sunday. A hybrid juce can with aluminum top and bottom.

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GD, I agree, Here is a test I did back in March with the 150 and 250 to see how well they do in a junk field. This junk field is iron with 25 cents mixed in, You see the steel lid in the lower edge. That was the only object in this field that gave the characterisic coin ring by both machines. Neither could pick the quarters out of the junk.

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BA, it would probably happen no matter what machine you use. It's part and parcel of how we detect metals. Shape is more important that the metal content itself.

We have a person now experimenting with tone discrimination of different metals using audio discrimination and a PC based analyzer. I'd be interested to see the same experiments done with identical shapes of a variety of metals. I've done tests like that in the distant past and even have some old SuperCalc spreadsheets from those bygone days somewhere on a tape backup.

Why I save those tapes I'll never know. I'm not even sure I have a tape drive around here any more that works. Sigh. Surrounded by technology and most of it just too obsolete to even power up.

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What ID machines are really set up for is COIN id, and the conductivity of  a metal object of approx imately the conductivity of an object whatever the shape, cans can be smashed in all kinds of configuratuon, rusted tore up, or perfect, so what ID will it show?? who knows, if you have a readout that is absolutely perfect on any shape of coin regardless of shape or condition, the ID will be perfect, but that don't happen anyplace but a labratory, where the coins are nice and all at the same angle=on and on=ya just gotta digit to see what it is
here's a fresh dig that pegged my ID, it was in Sand, also a small necklace and a  dinky car, ID's were trash, and quarter, could a been a  Reale =BUT?

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