Hey Dan, since you're new at this, heres a little tip for you:
VDI readouts are as susceptible to jumping, innaccuracy and inconsistency as cursors.
Each is just a way to represent a "point" on the scale of conductivity. The visual indicator is just
potential: a visual CLUE, not an absolute. Your instruments job is to alert to the presence of something in the ground. Maybe it can ID it, maybe not. There are so many types of "trash" items that it would be impossible to catalog them all. I have a coupla mountains of trash and none of it can be catalogued as precisely this or that. Much of it read as good, much of it didnt. Here's a pic of one of my mounds:
Just yesterday I dug a nice bracelet that ID'ed as trash - jumpy cursor, crackly audio, the whole bit. If I was to solely believe my ID indications, it was a low tab reading. Finely worked jewelry has many facets and little surface area to act as an inductor, so the audio is often crappy, sometimes almost unlockable. I found a 14K gold charm that was
exactly that last week. For all intents, it read as a bit of foil junk to my detector.
I only recovered these two items because I had made my mind up to dig all signals but obvious iron, no matter how iffy. At these particular locations I had a good idea of the trash suite I would encounter and knew what I could expect to find. But anomalies surface nonetheless. Yesterday, I found a few dimes that ID'ed as something else and which I would normally have passed as tab/screwcap trash. Several things I was sure were nickels (or the elusive piece of gold), weren't. And there
were those hard to ID goodies.
What Ive grown more an more fond of is TONE ID. A nice compromise, it doesnt confound you with cursors or numbers, it either is or it isnt. I wish Garrett would go to 4-tone ID.
I know I sound like a broken record, but I'll risk it:
"Expecting your detector to positively ID trash from treasure is a fool's game and self-defeating. Instead of deciding NOT to dig based on some easily fooled display, your aim should be towards recovery. When a target gives a repeatable signal IN AT LEAST ONE DIRECTION, eEven if it's "iffy" - dig! Otherwise you are merely locating targets."