It would be interesting on how a large spiral wound DD goes up a against a large spiral wound Concentric and for a fair comparison be the same overall diameter?

Hi 6666,

Is this the one?

If not,let me know the number of turns and spacing, size etc and I'll draw one up for you, no probs..

cheers

muntari

Thank you this is what I was looking for , much appreciated.

Hi Mylab,

Yep, that's in the works too.
One version at same diameter as inner RX, another version at TX size or outer shell size.
Any other ideas let me know and I'll put that on the todo list...

cheers

Muntari

For interest do you cad a spiral by hand or is there a template ?

Thanks I will check them out, cheers.

Did anybody continue with this experiment ?

Another type of coil could be a coil for patch hunting. A wide scan with good sensitivity to small nuggets ( a gram) at shallow depth and most of all "LOW" weight.

Thank you for the feedback.

Could you expand a little on your remarks?

Do I understand right when you say a 1 gram nugget is small?

Low weight coil: I am afraid about 550grams for the 200mm coil with cable is the best I can do. The amount of copper is the limiting factor. It is always a tradeoff between battery weight and coil weight.

Wide scan: Our proof of concept nugget coil is a 200mm round "mono coil". An elongated coil of 200x300mm coil would give about the same depth and sensitivity. Is that what you mean?

Our present extreme sensitivity, with all the settings at maximum, 33k PPS, max sensitivity, max power, is passing the test for detect-no detect for a 0.0002gram gold nugget.
Would you consider a 320mm diameter coil that passes the 0.1 gram test as good?

Could you describe what you mean by "patch hunting". I live up in the mountains in Switzerland. Far, far from any gold fields. Any information, pictures and descriptions of actual gold detecting would be very welcome.