I agree
that the eTRAC does indeed struggle with jewelry specifically certain small jewelry especially when thin, some types of chain necklaces, open or small split rings.
When i got my eTRAC, i did what most everyone does when they get a new detector, lay out a bunch of different targets then air test them all.
While impressed with the eTRAC's ability to detect coins in that test, some jewelry targets, not so much.
Case 1, small gold plated half open semi-circle earring. The eTRAC could not detect it even in all metal. My ATPro had absolutely no problem detecting it.
Case 2, heavy solid 14K gold chain necklace. eTRAC could not detect it using the stock coin pattern but did barely detect it in all metal. ATPro, no problem detecting it.
Case 3, tiny split open silver plated ring. eTRAC barely detected it. Again, ATPro had no problems detecting it.
My guess, it has something to do with FBS multiple frequency phase relationships possibly causing eddy current magnetic fields to cancel each other out as the single frequency ATPro outshines the eTRAC for 'some' jewelry targets.
Thats not to say the eTRAC will not detect jewelry just some small mass, certain form factor jewelry.
If i were going after jewelry say hunting a beach, i'd use my ATPro. But being primarily a trashy park hunter for coins this is where the eTRAC outshines the ATPro.
In those trashy parks i'd have to dig up a pound of pull tabs to find one piece of jewelry. Not fun. Also the reason i don't find many nickels. I decided to spend my limited detecting time searching for high conductivity coins rather than iffy nickel/jewelry IDs.
What i have tried recently as an experiment is to dig up the first few nickel/gold IDs. So far all i have to show for that experiment is foil and pull tabs.
Having said all that, if i get a nickel or gold type ID that is relatively deep beyond pull tab depth for that particular site or any solid 2-way nickel ID, i'll dig it.
I understand talking to some people who actually dug up the holy grail of targets, gold coins.... they're typically deep.