I have a QD II also: I set the Sens on about 1 o'clock some times 3 o'clock set the dis. at about 11 o'clock or higher to get rid of the iron , I mostly dig the mid tones an high tones,
low tones are junk most of the time but nickels come in on the low tone also, an so do gold (digging low tones depends where I'm at ) public area's have a lot of trash in them
the QD II comes on in the AL metal mode when turned on, you can use the three button's (Dis.,,Notch, An auto Notch) to get rid of the iron foil and other junk,,
but if you dis. to much you may louse good target's also. Ck your book on set up,, an use different object's to learn the 3 tones an where to set your dis. as you set it higher you can dis out different metals.
and ck your led readings most of the time it will tell you what you found, some time's it Lie's too,, the depth gage is close most of the time that lies too LOL but both work well I think,
Back yard's not a good place to practice keep in min that you may have telephone wires an other cables under ground, an gas lines they all give off a signal tone. I re posted two good videos a few days ago ck the link for Help movies
http://i460.photobucket.com/player.swf?file=http://vid460.photobucket.com/albums/qq325/vsTabago/DetectingwithQuickDrawll1.flv">
http://i460.photobucket.com/player.swf?file=http://vid460.photobucket.com/albums/qq325/vsTabago/DetectingwithQuickDrawll2.flv">
Good Luck Tabago