When mentioning the stem, we're talking about the little curly (can't think of the name right now) thing not too far from the stem that's connected to the fruit? Not the actual stem. Another thing is to look at the bottom, if it's got a lot of white on it then you're either there or it's close.
Another thing with the cantaloupe is to smell it. If it smells like cantaloupe it's ready. I can grow the heck out of cantaloupes and about anything else. For what ever reason I can't grow water melons or gourds.