I am still hoping there may be a flaw in my tests or detector settings rather than a problem with my detector. Those of you with test gardens can probably give more insight into the following thoughts/observations on the detector settings and their effects. It seems to me that of the settings available, noise cancel, volume, and threshold only effect what you hear. They do not effect the actual performance of the detector. Regardless of these settings, the detector is able to detect a given target at the same depth and IDs the target the same. My limited experience is that all metal and discrimination patterns also do not affect the ID or depth to any significant amount (I suspect <1 inch if at all). That leaves ground balance and sensitivity. The results I got were after ground balancing but varying ground balance to the extremes had no noticeable impact on the ID behavior or depth indicators. My thought is that ground balance should have zero impact on ID but will have a small impact on depth (both the depth the detector is capable of and the accuracy of the detector's depth feedback). Sensitivity did impact both but only by causing the ID to be erratic at high settings (varying sensitivity did not cause a target to give a different stable ID). Sensitivity did what I expected -it varied the depth the detector would sound off on a target. At high settings on shallow (4 inch) targets where the ID was erratic, the depth was also overestimated but this was corrected with lower sensitivity. In summary, none of the detector's settings (with the exception of too much sensitivity) should impact the ID the detector gives. If you have a test garden, I am interested in your observations of the above settings and their impact on your detector. Let me know what your target was and its depth and how varying the settings impacted your detector's feedback.
I am questioning my testing method since I do not have a test garden in the ground. These tests are done in a large container of soil. The results are reproducible whether the container is in the garage or moved outside, so outside interference from near metal objects (ie, rebar in the floor) should not be the cause. I have sunk a PVC tube (#1) at an angle (~45 degrees) from the top to the bottom of the container and have another PVC tube (#2) with the bottom taped which slides inside #1. I drop a target into tube #2, and vary how far it slides down tube #1. I have calibrated tube #2 to reflect vertical depth from the soil's surface. Set up in this manner the soil density is not uniform due to the PVC tubes' volume but I do not see how this should matter.
My results with a nickel at 4 inches = +3 to -3 , at 5 inches = -6, at 6 inches = -6, at 7 inches = -9. At all depths from 4 to 7 inches the detector gave 4 arrows depth on the nickel. On average, my targets iD's dropped one notch (ID of 3 units per notch on the 505) for each inch of depth (I only looked at 4-9 inches and most targets became undetectable around 7 inches). Targets included Kennedy half, quarter, foil, pull tab (newer style), zinc penny, wheat penny, 1847 large penny, nickle, newer 1$ coin, 7mm REM Mag. brass shell casing, jean rivet, thin wedding band, med. mens 10K class ring, and #8 framing nail. The only targets which did not drop in ID significantly were the wheat which was 27 at 4 inches and all over the place deeper, the small foil which was -6 to -9 at 4 inches and undetectable deeper, and the nail (45 degree angle in tube) which was -6 at 4 inches and -9 at 9 inches ( you can't look much more like steel than a nail does regardless of depth).
My testing method may be to blame for these results, but I do not see how the results can be explained. All input will be appreciated.
Thanks in advance, S505
