Metal Detector Help

Hi People,

Just trying to get familiar with it, took my brand new ACE 250 into the yard and got a hit within 15 seconds, a penny. About a minute later another hit, another penny. Couple minutes later another hit, this time a Rosey dime, then another hit on an old miniature pocket knife. Then another hit, Canadian penny. Great!

Next day took it out to the fairgrounds and nothing but false hits. Tried it in 2 areas about 75 yards apart. Same thing, just false hits. The ground was really hard and difficult to dig so I gave up after about an hour. Thought perhaps it was a ground balance problem which I've read about. The Garrett doesn't have any manual adjustments for that. Played with the sensitivity and discrimination settings to no avail.

Went back to my yard and nothing but false hits (bunches) just like the fairgrounds. I was using the same settings as when I was getting the positive hits, which was coins only with the sensitivity on the 3rd bar down from the high end which is default I believe. Lowering it didn't seem to help at all. Going to the all metal mode just made it start jumping all over the place.

Air tested it with some different coins and a gold ring and it seemed to respond OK in that it is giving me the audible alarms but when I have it in jewelry only mode it still gives me an alarm when I use a coin and when I'm in the coin only mode, it still gives me an alarm when I use the gold ring.

Any ideas on why all the false hits? Operator trouble? Coil problems?

Thanks,
James...