Odd signals

[john65803]

When detecting, sometimes I get a signal that will read +50's up to the 90's on the right swing but on the same target I'll get a -"0" or lower ID on the return swing. Any ideas why?

 

[Tin Nugget]

Dig it up and see. Could be a rusty old bottle cap. They can read as high as 83 on one swing and iron on the next. Could be an odd alloy or odd shaped piece of junk. 99.9% of the time it's some kind of rusty scrap.

 

[BarberBill]

Another thing to try on this sort of situation is to pinpoint with the trigger in all metal pinpoint as accurately as you can, then with the coil still over the best pinpoint spot, move it just slightly back and forth and check the id. Often this technique gives a more accurate idea than your normal swing as you'll have the hot spot on the coil directly over the target.
HH
BB.