for all you who know the F2 i need help. it chatters like an old atari game. i know its not defective..at least i hope its not. what would be the best setting for it? I currently run in it in all metal with about 4 bars.using the standered coil it comes with. ( not the 4 inch) i can say though that the pinpointer on it is right on....help would be great as i am still trying to figure it out, thanx in advance for any advice. my hunting grounds are parks and schools. mainly.