Tom_in_CA
Elite Member
- Joined
- Dec 23, 2013
- Messages
- 20,836
I am trying to learn the different sounds and signals my metal detectors give. I have all my base metals but only silver as a precious metal. I need gold, platinum and palladium.. ....
I have read through all the replies on this thread so far, and only Jason's is the only to give the "aha moment" so far :
.... your detector has ZERO clue what is under it and is only giving responses to pre-programmed expectations. The size of the target, the shape of the target, the thickness of the target, the depth of the target, the minerals between the detector and the target, other targets close to the target, EMI interference all play roles in the repsonse you get....
Or put another way: The detectors TID (graphs, #'s, tones, etc....) are not reading COMPOSITION (eg. gold, silver, brass, platinum, etc...). They are only reading conductivity. And ... unfortunately, that gets screwed around with via size ! Also purities (alloys, karats, etc...).
For the size and mass concept, here's the easiest way to explain/show this:
Take an aluminum can. Snip out a thumbnail size piece. Test it. It will read around nickel. Right ? Ok, now wave an entire aluminum can. What does it read ? Penny or dime or quarter. Right ? Ok, what changed ?? Nothing! ONLY THE SIZE ! The composition, in all cases, was exactly the same: ALUMINUM.
So too is it for gold : A teensy gold ring might read in the foil range. A mid sized gold ring might read tab. A fat men's 10k ARMY ring might read zinc penny. A $20 gold piece (or entire gold bar) can read penny or quarter.
And don't forget gold come in endless purities (and shapes and sizes): 9k, 10k, 14k, 18k, 22, and pure 24k. A small 24k gold ring might read in the penny range (because there are no alloys). But a small14k gold ring might read at nickel.
See ?