Does anyone know ?

[Anonymous]

why some pieces of iron register as a coin or non-ferrous... I use an MXT and generally hunt in the coin and jewlry mode. But when I come across very old iron (usually old barbed wire and once an old cut nail) the VDI number comes up in the + range.. When switching to the all metal mode,,, I get a high beep....... Can anyone explain what the heck is happening. <img src="/metal/html/shrug.gif" border=0 width=37 height=15 alt=":shrug"> Thanks in advance for your imput..... Gene

 

[Anonymous]

Gene,
Its all in the design of the filter circuits. I'm not a tech and don't know squat about the math involved but here is a link that gives a good laymans explanation.
I have posted this before and hope Robert doesn't mind (again).
Hope this helps,
Tom

 

[Anonymous]

Try pinpointing to see where it is and then sweeping the target under the edge of the coil - often ferrous items get taken out by the discrimination then.
Sometimes raising the coil to weaken the signal also lets the ID jump to the correct (negative) value.
let us know
John

 

[Anonymous]

Thanks John and Tom...... Have copied the Iron VDI link and will try to figure it out. Also will try moving the coil around when things thaw out around here. thanks again for your imput....Gene