How close to a good iron disc PI.?

[David]

Here we go again, but I have not heard for a very long while. Does anyone know from any maker how close in a time frame we are to a very good iron discriminating PI and still be able to detect smaller sized gold successfully at the same time.?

It is not on the market yet and is what we need very badly to come out, and who ever makes one will sell many 1000's of units and will bring in million$. (Not the inferior and poorer systems like on the GPX-5000, Infinium LS, and TDI out now. Like with the TDI a person can get rid of iron but you lose smaller sized gold also, but you can still get larger sized gold and silver though.)

Dave Emery's Pulse Devil Nemesis was suppose to do that but he has disappeared now.?

 

[Reg]

Hi David,

Actually, you shouldn't lose small gold when ignoring larger iron. Simply reverse the process that you use for coin hunting. Set the detector to low conductor. Increase the GB to normal and hunt away. Most larger and thicker iron is ignored. Small tin type iron from tin cans or similar metal and small parts of nails still sound off as low conductor signals, but generally, they have a much stronger signal. Also, quite often this thin tin can type trash is at or near the surface so the signal is very strong and abrupt, which is much different from the smoother response you get from gold.

Years ago, I used this technique with a different low powered PI before the days of the TDI and found if I used a DD coil, small surface iron would respond differently, meaning it would reverse signals if near the surface. So, I didn't dig much iron junk at all.

Reg

 

[mikebg]

David, your description shows that you need a "multifrequency" metal detector for beachcombing, which can discriminate crown-corks from gold chain. Despite the term "multifrequency", their principle of operation is PI (non-sinusoidal induction) with more complicated form of TX current and wideband signal processing. I think Excalibur, Sovereign and Fisher CZ use such principle, but I don't know if they are enough sensitive to gold chains.

 

[David]

Very good tip Reg and thank you very much for the help. "Actually, you shouldn't lose small gold when ignoring larger iron. Simply reverse the process that you use for coin hunting. Set the detector(TDI) to low conductor. Increase the GB to normal and hunt away."

Yes Mike a "multifrequency" metal detector will handle wet saltwater sand and gives great discrimination, but a disadvantage is they are not sensitive enough to very fine gold chains. In the goldfields a "multifrequency" unit is not good on gold smaller than about 1/2 gram or so in the high minerals.