Strange MXT VDI readings...

[GoldChaser]

Just got back from a trip to the Sierra Nevada's, and found a small piece of iron around 10" deep, like an old can piece, and it gave a weird VDI reading. I had my MXT set on the pre-set Gain (9+), ground balanced at around GND=64 then set on Lock, and in the Prospecting mode. Attached are pics of the rusted iron (very magnetic), along with screen shots that I took in my back yard after sweeping twice, at 90 degree angles. It had VDI readings of 94 and 86 with Iron Probabilities of 20%.
I have come to expect high VDI readings on objects that are very large like complete cans, but getting these readings from rusted iron only about the size of a couple quarters bugs me because most of my detecting is in the Gold Country of northern California where there is a ton of rusted iron. (VDI readings on regular coins are accurate.)
Is this something I am going to have to live with? :-(

 

[srf2112]

That is confusing to me also. All I can think is that it was an errant reading because of the mix of target size, shape etc and it is "fooling" the machine just by a fluke. If your machine is reading correctly otherwise, as you said, I would have to think it's not sick. I assume it gives the same VDI in relic, and C/J modes also . .? Update any findings please and good luck . .

 

[HuntinDog]

GoldChaser,
I also hunt the gold country and have hit a few of the old sites.
What coil are you hunting with??? this can make a big differance.
When I'm hunting the gold camps I hunt in Relic with track in ground. The minerals in my areas change by the foot!
I run Gain @ 10+ to all the way up. depends on how much trash.
Disc around 2 with the trigger centered and a slight hum.
Also most of the time it's the 6X9 or in heavy trash 4X6.
Now as far as the nails and pieces of tin go...
When I get one of those high VDI readings I back the coil off the target and just "tip" bump the target.
This will must of the time bring the VDI back down into the iron range if it is a "bad" target.
I do the same thing on bottle caps in the parks.
If it's a "good" target it will stay good.
Don't get me wrong a few of those iron targets Can be good iron relics, so I dig most all the "good" readings.
What I think is happening with the high readings is what they call wrap around.
I hope this is helpful. It's all a learning curve......

HH