Steve I made a point of posting to your forum versus others hoping that you might reply and reply you did!!! Thank you and to the others that replied as well.
The more a learn about metal detector technology and trying to use that technology to solve a problem the more I am amazed out how technical it is. When I knew nothing about metal detectors I thought all you had to do was swing the thing side to side until it beeped alerting you to a metallic item of interest. Was I ever ignorant.
Before I started this thread I had never heard of a Falcon MD20 despite having put a good 100+ hours of research into this over the past few months. I have now bought a Falcon MD20.
The Falcon MD20 comes with a business card that has been laminated with three things to it for you to play with. Pyrite, Gold (yes, a tiny spec of real gold) and little pile of black sand. This is what I experienced:
Pyrite - silence no matter what you do.
Gold - only makes sounds approaching it, never leaving it.
Black sand - only makes sounds leaving it, never approaching it.
The Falcon MD20 definitely makes noise with my auriferous rock. I'm calling it "noise" because my ears are virgin to metal detectors. I can't hear the difference yet between a zip, beep or a boing, I just hear noise or silence. The probe only makes noise approaching my auriferous rock, never leaving the rock (no matter what the acceleration or velocity of it leaving the rock). No matter what setting or anything I do, I cannot not get the MD20 to make any sound whatsoever as the probe moves away from my rock. The faster I approach the rock the louder it screams.
Ground scanning: Just like everyone has said it is not a ground scanner. This needs to be almost touching the rocks for it to work and therefore you can't hover it over the ground. Hovering an inch off the ground makes this useless but it is not useless because it wasn't designed for that. I bought the pole mount for it (just some white PVC pipe) so I can walk around and poke/touch rocks with it. You often can't swing the probe over your target rock because there is no space to do so (i.e. branches, other rocks, crevice, etc.). I found a poking/stabbing motion worked best because you can always do that. From a distance I must look like a blind person lost in a rock field with my white walking cane. I have never used a metal detector but this no doubt is a much slower process than swinging a "normal" metal detector designed to scan the ground quickly and to some depth. However I can poke it into tight areas a search coil can't fit.
Now my confusion with hot and cold rocks and how that relates to my Falcon MD20 and my quest for Auriferous rocks. Bear in mind as you read this that I have zero experience with "normal" ground scanning metal detectors and about 8 hours now with my Falcon MD20. I find I get only one of three results. No sound, sound when the probe is approaching the object or sound when the probe is moving away from the object. I tried experimenting with ways to get sound while both approaching and leaving and could not. The sound seems to be mutually exclusive to either approaching or leaving the object, never both. I have experimented with all kinds of metals and they all give the exact same result: sound when approaching, never when leaving. So I am confused then as to how the black sand on their sample card causes the opposite result. To me black sand is metal and should therefore I would expect the same result I get with metal, sound when approaching and not leaving. I watched a bunch of Youtube videos about this Falcon MD20 and a few of the video mention that this detector discriminates, non-ferrous sounds when approaching and ferrous when leaving, however that is not what I experience at all with the exception of the black sand sample. I am confused. Without understanding what is really happening my current guess is that sound you get when pulling the probe away from an object is from a semi-conductive material, but then I would think pyrite would make a sound and it is silent. I am still trying to wrap my head around what cold and hot rocks are and from what Steve is trying to explain to me sounds very similar to what I am experiencing with the probe only making sound when approaching or leaving an object but not sound in both directions, ever. Does hot and cold rocks have any relation to what I am experiencing?
Steve, you mention the "old Tesoro Diablo uMax" that had two ground balance settings. If you balance out the overall ground and rocks that only make sound when leaving them, you would be left with only getting sound on approaching a rock, which therefore has solid metal in it of some kind.?
If a metal detector responds to both conductive and/or magnetics does that mean you could detect a ceramic magnet (ceramic can't conduct)? Would my Falcon MD20 make as sound approaching or leaving the ceramic magnet? I'm guessing leaving?
Auriferous