A pull tab should never read 81 unless it was a silver pull tab. Tabs read between 50 and 60. 81 is a dime or copper penny. 87 is a quarter. Do an air test and see if you get these same numbers.I just had my AT Pro out last night. I am still learning as well. I had it at Pro/Coin, Descrim. at 40, sensitivity at 3 bars, make sure you ground balance it. I went to two different parks and one GB setting was at 50 and the other was at 70.
Also, I am learning the number, 78 would be bottle cap, 81 is a pull tab, (so is a dime on my machine) the numbers will jump around and 81 comes up as well.
Before I started I took out my own change to see the readings. I only dug those numbers all 90's and 50's in case of gold. If you dig 50's you will get some junk.
Good Luck
A pull tab should never read 81 unless it was a silver pull tab. Tabs read between 50 and 60. 81 is a dime or copper penny. 87 is a quarter. Do an air test and see if you get these same numbers.
I have an At Pro as well, I took it to the beach and park so far. It is hard to get use to the numbers jumping around (even if it is a coin)
I use the standard / coin mode with the dec. set at 40. and Iron off. I have done testing with coins, caps, and tabs. It is hard to figure out what is good vs. junk. I have watched tones of Youtube video on the At Pro. it is like they have a different machine then what I have.
The good thing is if there is metal in the ground it will pick it up. I was digging alot of gum foil at the beach. I hit the elem. button on that number and it keep beeping. When I went over foil. I read something that said it takes about 100 hrs. to figure out the good and bad sounds.
I have detected for years with the Whites Surfmaster PI, if there is metal it picks it up. I wanted a new machine to discriminate.
I have about 10 hrs on the AT PRO, so maybe 90 hrs I will be a pro.
I agree with perses, guys the cool trick to make your ATP and dirt eating monster is to auto ground balance and the manually drop it by 5s until it starts to chatter then go back up some until its clear enough. By doing so it makes the targets scream in the ground. Like if you know that at 8-10" you are stretching to get a consistent signal then the GB tuning as I said will give you just that. I've been able to make targets that wouldn't show on the screen actually show by using the little trick. I've found targets measured at 18" using this.
Get your facts first, then distort them as you please-Mark Twain