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Title: Digging Minus VDI Post by: ORDOVIC on February 28, 2010, 08:34:40 PM While out detecting today with my MXT on pasture I dug up two deep signals and showed up on the VDI scale as minus readings between -12+0.At first I thought they where Coke signals but when I pin pointed them I got a very faint narrow signal rather than a wide one like you get if coke is near the surface so I decided to dig them and to my surprise one was a Victorian penny which was around 7-8" down and the other was a Musket ball from about the same depth.
Has anyone else experienced the same situation ? ORDOVIC Title: Re: Digging Minus VDI Post by: Tafflaff (Rob) on February 28, 2010, 08:38:43 PM My programme on the DFX allows down to -25 as a good signal though I dont dig under 5 , everytime I've have its been ultra thin foil or iron. Pick a day on a quietish field - one you've done to death and dig every signal whilst noting the numbers . Gives you a good idea on how accurate the machine can be.
Title: Re: Digging Minus VDI Post by: rjm on February 28, 2010, 09:24:02 PM This is common with a lot of machines.
On my Minelab I only used to dig positive numbers until I read a post and then accepted some negative with a good tone to them. They turned out to be coins that had some crud or rust on them. By accepting some negative VDI you are more likely to locate a target near iron than if you were accepting all positive VDI's. On my V3 coke usually comes in with a buzzy sound and a VDI of 3, and normally the coke is an inch or so below the surface. I normally only accept positive VDI's unless the field is quiet then I open up and accept some negative VDI's. It's a case of knowing your machine and how quiet or noisy you want the audio! |