Hello Joe, I think I have a gist as to what your saying so, be patient with me! Concrete can give off readings that can confuse. You can't be sure there isn't anything set inside such as nails or other rubbish. Walk away and try another spot not too far from it, but with no concrete. See if there's a difference there. Hot rocks here are anything that contain iron, copper, iron or copper sulphites, as in the rusting or leeching process. Water that contains these sulphites will cause the detect to give constant tones or signals. What I would do is this: When you are detecting in highly mineralised ground, throw a coin down onto it, and swipe your coil over it. If you read the signal loud and clear, your mind will learn the signal is different to the barrage of signals you's normally get in this type of ground. Thrown other coins down onto the ground, as this will help to verify what you need to listen for. It is possible to detect in mineralised ground and pick up true targets. I do it all the time on the goldfields here. Now bury the coin, and see if the detector will pick it up. Forget the pinpoint mode for the moment, and just pick up your targets without using this mode. You can do it. I rarely use pinpoint mode on the beach, as I always have a good idea where my targets are, just from coming at it from all angles with my coil, and drawing lines on the sand with my foot, till I have the precise location. The pinpointing mode is better used when you have difficulty pinpointing the target with your mind's eye. If you keep digging, the hole gets bigger, and you just aren't finding anything, sounds to me like there's nothing there other than a soil condition that's making your detector go heywire. Or, a larger object will read deeper than the 12 or so inches the detector depth graph shows. And when you're pinpointing with the pinpoint mode, even the very tiniest, slightest raise on a bar, will show something's there. You may only get a tiny glimpse of any bar on the graph, so the object could be very deep. On the beach, I've gone down almost two feet for a lead sinker that's several inches long, by several inches in width, and a thickness of 1cm or so. I know something is there, because as I dig, the signal becomes louder and clearer, as I get nearer to the target. So, if you keep digging, and getting a signal, usually as a rule, the signal will get clear or louder as you get closer to the target. If not, and the signal remains the same, no matter how much you dig, it's a possibility that there is no target, and you're just getting a barrage of sounds due to ground conditions.
Try detecting in All Metal Mode, no discrimination, and whatever you set your sensitivity to, take into consideration the depth between your coil and the ground, if you are detecting in grassy areas. But don't think that you have to set the sense right up in case you'll miss targets. Try the sense at around 12 or 14, and see how you go. If your coil is flat on ground when sweeping, you should still be able to locate targets to depths of 12 to 14 inches and a little more. You really don't lose out. Try and get used to the barrage of noises in All Metal Mode, throw a coin down every so often, to help verify to yourself the detector is working fine, and just noise cancel every other hour or so. If you are in mineralised ground, and it's confusing you, for the moment, try detecting elsewhere.
If you are detecting in trashy ground, for better target separation, use a smaller coil, set your trash to High Trash, keep your sense to lower than normal, say around 12, no need to noise cancel constantly. Sometimes, I don't noise cancel for ages if my detector is still picking up targets, and conditions have not changes at all, and the machine is doing everything I expect it to do.
In the end Joe, it's a learning curve we just have to go through ourselves, until we sort out all the nuances of the detector for the types of detecting we do, in the ground we're in. When I first started using the Quattro, 3 years ago, I was in the worst possible ground there could be and thought hell, I'm never going to know what I'm doing here. I lived on old goldfields ladden with rubbish from the mining days, the soil changed in areas from red mineralised ground, to iron infested ground to soft black, damp soil conditions down in the gullies, to brown soil the hardness of concrete. To me, the hardest ground to detect in was the concrete hardness of brown soil. Most of the signals are iffy signals that disappear and come back as you dig, till you get real close to the targets. My best relics came from this type of ground.
Anyway, hope I've helped somehow, Golden
