desmond said:
Maybe the Sovereign idsdifferent then the Excal 2.
Someone with a Sovereign can correct me if I am wrong but I don't think they would ID differently as they both use 17 frequency BBS technology. I even think they use the same 8" / 10" Tornado coil (just the one on the Excal is hard wired while the one on the Sovereign can be changed). If your Excal is not hitting on older pennies and silver then I suspect your coil was not over any, the targets were too deep, the settings not ideal, etc. I suppose there could be a malfunction with your machine as well so you may want to run some tests.
I mostly hunt the wet sand and water. I may change my mind in the future but at this point I plan to simply grab an Excal for land hunting. Since the Excal is basically a waterproof Sovereign it should be plenty capable for land hunting. I would try hunting that park again. It may have been just an unlucky day.