Tried a little experiment this evening

I went to an old school yard that was torn down in 1964.The playground equipment is still standing.The school yard just got mowed so it was easy to hunt.This place has yield silver dimes,wheaties,rings,silver halfs.I set up a gird of an area that produced no coins the last 2 hunts with my CZ3D and 2 hunts with my CZ 70.This area was about 25 feet by 25 feet.I extracted 3 wheaties and a 1943 nickel from it.There were once again old plugs where I dug coins and trash before.One wheatie was a measured 10 inches deep.It was a repeatable solid signal,it pinpointed nice and soft.ID numbers were 62-63.Depth said 7 inches.I dug down carefully taking out a deep plug.It was still in the hole.I carefully dug down until I exposed it.Then I measured the depth.The ground is powder dry.All the other coins were 3 to 6 inches deep but in heavy trash.Bottlecaps,rusty ones came in at 71-73,there was no indication on the FE meter that they were iron.They were all rusty and 1 to 6 inches deep.I could not tell the difference between them and a coin signal.ID numbers didn't bounce around,they pinpointed soft and small and no rise on the FE meter.I dug 26 of them.In this dry soil the F 75 outhunts my CZ's and rusty bottlecaps sound just like coins.I tried wiggling over them(short quick sweeps),raising the coil up,nothing caused them to break up.I just thought this was strange.Next time I go hunt I'm going to take the CZ 70 and F-75.I'm going to mark targets I get with the F75 then check them with the CZ 70.I found 11 old sites out in the country to hunt on the way home.I have to work the next 6 nights then I have 8 days off.Bill

Try one thing before you dig your 'marked location' targets. BEFORE YOU DIG, Drop ground balance about 30 - 40 points (manually perform this).......... and see if these bottle caps (now) will start to ID better.......... or..........at least... go to a inconsistent ID on the F-75. Do NOT go to the 'BC' mode..... as you will lose too much depth capabilities........... unless everything is verified quite shallow (usually...this is hardly the case).