Chet sent me some targets from old hydraulic mining areas east of Sacramento Ca. A chart of some clay he sent. The x axis is time in usec after coil turn off.
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gold nugget simulation?
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Originally posted by Chet View PostHi green
The clay I sent is attracted quite readily to a rare earth magnet. Does Alabama clay have the same magnetic characteristics?
Thank you,
Chet
You weren't kidding. I got two or three pieces when I stirred the magnet in the Al clay. Shaft diameter .075 inches (2 mm).Attached Files
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More targets from Ca. Charted the nails linear-log and log-log. Plotted straighter log-log. Added the -1.25 slope line on log-log charts (clay slope). (90) is the target rotated 90 degrees. Coil on time 90 usec.
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More targets from Ca. Depending on target size I use different coils to get enough signal to noise to chart the time constants. The targets today were large for the 38mm coil that I've been using for the nuggets and smaller targets. I've compared TC's for coins and some other targets in the past using different coils and saw little difference. I compared the targets today with the 38mm diameter and a 100 x 265mm coil.There is a difference with the large nails, The Ca clay has a -1.25 slope with both coils. The slope did change when I spread clay to a thin layer with the 100 x 265mm coil ( not much signal) so maybe thickness and amount of material might effect the slope. Didn't try it with the 38mm coil but I will the next time I plot some targets. Some of the nail tests had a slope close to -1. All plot close to a straight line on a log log scale. (90) is the target rotated 90 degrees (target vertical)
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Originally posted by Chet View PostHi green
Is there a difference in time constants between old nails and new nails? Could you plot the data from the new nails in post #42 on the same log-log scale as the chart "nails_38mm" for comparison?
Thank you,
Chet
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Originally posted by Chet View PostHi Dan
Thank you for the information. Do you know what characteristics the Chance PI uses for discrimination? Is the software is controlled or is there a description of it somewhere? Does it have ground balancing? How well does the discrimination work on ferrous objects?
Thank you,
Chet
The software is not open source. Silver Dollar has a 60 page version of it. If you visit the Russian CHANCE PI page there are some charts of the target responses and effects of the three masking levels. It's a place to start.
Regards
Dan
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Originally posted by baum7154 View Post____________________________
The software is not open source. Silver Dollar has a 60 page version of it. If you visit the Russian CHANCE PI page there are some charts of the target responses and effects of the three masking levels. It's a place to start.
Regards
Dan
I read the entire Chance PI forum and went to the website. Looks like only a few of you in the forum completed Silverdog's PCB. Overall the performance results seem to be inconclusive. Without the source code it does't look like something that I want to try.
Thank you for your response,
Chet
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Charted the Ca nails with a 275mm DD coil. Orientation doesn't effect the slope as much as it does with the other coils I used.
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