My first type of air test consisted of placing the target on the ground, with the shown settings of discrimination and threshold, with the discrimination setting set at zero. To maintain a certain level of reliability, I performed the test wearing sweat pants, T-Shirt, no rings, wallet, belt, empty pockets and shoes with no metal. The measurements were taken from a static fixture, my leg, where the horizontal coil would barely yet audibly get a reading from the target lying horizontal on the ground, on an area free of any metal. I have fairly neutral ground, consisting of a humus layer in the upper stratus of about 3 inches, with clay below. The test was taken in my backyard, about 25 feet from my house. I had to deal with a large amount of EMI, having to retune the ATX at time to quiet it down at times. As previously mentioned, I measured the audio barely audible however still repeating against the still audible EMI. As predicted, the large gold ring managed to get the greatest depth. My understanding of the ATX platform is that it was specifically tweaked for gold. The other gold ring, considerably smaller in mass and diameter, also fared well. My favorite target for depth testing is a small lead 22 projectile, which came in at about 8 inches, with a sensitivity set at 6, possible max out at 13 and a threshold setting at 4 with a possible max a also at 13. Running both these settings any hire just made the ATX too unstable at it's location. And, as a typical household, we ave a couple large screen TV.s, cable, wi-fi for computer and cell phones.
This second test was was again performed in my back yard, only I moved the test away from the house another 10 feet. And again to maintain a certan level of reliability, I performed the test wearing sweat pants, T-Shirt, no rings, wallet, belt, empty pockets and shoes with no metal. What made this test different from the one above, is that instead of placing the target on the ground, I performed strictly an air test, measuring the distance between the coil and target, with no matrix past the coil except air. I was curious as to the amount of EMI present. As it turned out, the EMI was slightly less, however probably due to the air tests being performed further away from the source (house). One purpose of the test was to show the difference in depth with an increase of threshold on the ATX. The increase of threshold from six to 10 while still maintaing a sensitiviry of 8 showed about 1 inch increase with the large gold ring, 1 inch increase on the nickel and a doubling of depth on the small fleck of gold...so tiny it won't read on my electronic weigh scale set in grams. I used the nickel in my air tests this time, as a nickel can be a good indicator for a piece of gold, and I also wanted to see how it would read, assuming that the ATX was tweaked for gold.
Please remember......these are air tests, and reading for depth in the ground will deviate from my results, based on ground conditions, water, moisture, target size, EMI, coil used, how the machine is programmed. Air tests are useful for comparisons of settings against a target, and also comparisons against numerous targets, under different conditions.
rI have yet another test (TEST #3) nearly completed. It will show how the non-motion mode compares to the motion mode, and also how the ATX operates with both sensitivity and threshold cranked up to near max. Some of my results indicated such an increase with the air test that I want to redo a few targets again. This test was performed about 6 miles south of Edmonton, on a gravel with no above or below power lines nearby
