Hello I have had my quattro for about 18 months I love the machine I have found many coins and farm field relics however most of the fields and parks I hunt are truly iron infested and there are many areas I get a constant threshold null I have read and tried some of the suggested settings from the mastering the Quattro book. But I find when I try the high trash setting with any sense setting including auto I get a machine that either nulls or just becomes crazy many tones and jumping I'd numbers I have tried many times to dig signals that read 38 39 but find nothing is there a way to make the machine more stable or to make it better in iron I have hunted next to a friend that uses a machine made in Oregon and he can find coins where I just get a threshold null and in high trash can't determine a good target he regularly finds large coins colonial coppers that I can't. Unless the area is fairly clear of iron. On the other hand I have found deep deep deep silver and copper he can't even hear just need help in iron thank you ct ps I'm using the prot coil by minelab I traded the stock coil for it