I will paste the article here
Allow me first to say that this technique is NOT of my own making. I learned it from NasaTom during my telephone consultation with him. Here's the technique. I have found that the square nails in the bed I am hunting are coming in around 27 to 29 on the VDI of my Garrett AT Pro. Tom had told me to find out what the nails are reading and then lower or raise the discrimination until the nails become a 'click' or 'pop' in the audio reporting. So I set my discrimination at 27. I started pulling bullets, coins, and other non-ferrous items from among the nails! But first, I created a scenario at home like this: I dug a hole and placed 4 square nails saved from the old homesite that I am speaking of in the hole at 4 corners. In the middle, I placed a 58 cal Minie Ball. I also used a Mercury dime in place of the bullet after testing with the bullet. Sure enough, the detector would NOT give any audio or visual indication that there was a non-ferrous item in the hole. (I am ground balanced at 78 and the ground is fairly mineralized) This is with Disc at 0. But then I placed disc at 27 and scanned the hole WITH ONLY the 4 nails. I got 4 pops or 4 clicks. I them placed a bullet amongst the 4 nails, or a mecury dime, and I would get a solid repeatable mid-tone. This is all with iron audio off. Again, with disc set at 27 and only 4 square nails, I would get 3 or 4 pops or clicks. I then placed a bullet ot silver dime amongst the nails and got one solid repeatable mid-tone. The VDI was bouncy and didn't give much useful info. But the audio told me that amongst the square nails was a non-ferrous item.
By now those of you who have read NasaTom's article about the F-75 and Disc at 6 and Monotone will realize that I have simply applied those principles to the AT Pro. Set your Discrimination to make those square nails click and then, when your scanning an old homesite and get a solid repeatable mid-tone, you may have unmasked a goody like I did last Saturday. I also own and use an F75SE with an extra coil (5 inch DD) and love learning what these devices are trying to tell me. Needless to say, about the only way to learn what the unit is saying is to get ready to do alot of digging. My hands are SO dry and cracking now from staying in the dirt! I hope this helps some new guy. I'm a new guy too and I would stress that we should listen to what the guys on this board have to say because many of them have been doing this for years. Happy Hunting!
