@Roughrider.. that sounds like a rough bird.. so if i understand correctly you never made a call untill you got setup and the entire time you were closing the distance he was gobbling on his own ??
if this is the case i dont even know what to think as far as calling that bird in.. seems as if hes been educated.. one thing i would try is to setup exactly where you heard him way before hes in that area.. setup either a blind or some camo berlap or just inprove a blind to conceal your movement and hunt him like a deer.. try to leave the calls at home and hunt him like a deer.. id even be afraid of using decoys being that he might know this trick already.. yea it doesnt sound fun not making him gobble call call gobble gobble but hey, a dead tom is a dead tom..
i shot my biggest bird ever doing exactly this.. he was a big ol boy that knew all the tricks except this one !!!!
one more thing.. iv heard some hens in the woods that sounded worse then a beginner caller.. never take for granted that every hen sound in the woods is another hunter. even if it is, mimic exactly what the other "hen , hunter" is doing. same loudness and a little more aggressive. if its a hunter he would most likley do the same thing back at you over and over.. if it was a hen, she will repeat you then add some more.. also she will try to cut you off.. also you want to cut her off and or cutt off the other hunter.. if the tom hears your two fighting, and hes henless, he'll come to the more aggressive dominate "hen".. so basically as your acting like a real hen, your telling that other "hen,Hunter" that this is your tom and your territory.. use that to your advantage...