Graphic Target Imaging question.

[Mick in Dubbo]

Can anybody tell me what the precise sizes are for the 5 different sizes on the GTI units? i.e. A=20mm max (3 quarters of an inch) B=25mm (1in) eta. If you told me in coin sizes; it would be harder to relate them to a different currency.
Hope the answer's not too tough.
Mick Evans.

 

[John-Edmonton]

I don't think giving you a precise size of objects is possible. The angle of the coin, the halo effect, the shape of the object, the soil mineralization all interfere with it's sizing somewhat. That said, this is how the GTI 2500 (usually) reads my coins in my soil. I know from experience, that a Canadian 5 cent silver piece 15.494 mm in size can read both as a "A" or "B" size targets. Our one and two dollar coins (26.5 mm & 28 mm) read as "C" size targets. Pennies, nickels, dimes and quarters ( 19.05 mm 21.2 mm 18.03 mm 23.88 mm) tend to read as "B" size objects most of the time. But the larger targets, sized from different angle usually read as "D" or larger.

The ACE 2500 also usually sizes 22 shells and projectiles as "A" objects also. The best probability of sizing an object correctly decreases with depth, usually beyond 7-8 inches. Of course you will always dig a target reading 10 inches, as it is probably old anyways.

Hope this helps Mike. ( I saw your post on the Infinium forum too )

Hope this helps!

<center>

 

[Uncle Willy]

The sizing like everything else on an ID detector is not an exact science or a given but a probability based on the multitude of variables presented to it when detecting.

Best way to get a fair idea is to air test a number of coins and objects you hope to encounter and see what the imaging sizes it at. This will give you a fair idea of what to expect in the real world, remembering that in - the - ground readings may vary due to a host of obstacles and effects not present in an air test. Hope this makes sense.

Bill

 

[Mick in Dubbo]

Thanks for the info John. That's very useful. From what you have just described, I assume that square pull tabs will fluctuate between A and B and screw caps will probably read as a C. I'm just trying to figure out how good the profiling is at sorting out common rubbish targets from coins. It would be nice to get my hands on one to play around with, but the nearest Garrett dealer is 1200kms away. So I'm just going to have to figure it out like this.
Mick Evans.