I've had them be able to sneak up on me from even the front. One used a channel or canyon for concealment in the desert to get close. I got him on the runxsn10's , The Johnny Stewart MS512 was a cassette tape caller With a good amplifier and quality speaker .I truly wish they were still available The early FoxPro's didn't come close to the abilities of the MS512's . Some of the early FoxPro sounds were ones that were the same as the Johnny Stewart sounds as well as some of them were ones that Bill Austin had on cassette tape . As with what Coyote Shadow Tracker does I used to record my own tapes on high quality tapes . Memorex did make the best tapes , they would record what ever pitches the animal put out . Also like Reemty J. I do what it takes to get the animal that is causing problems . I started calling in the 70's but was exposed to it in the 60's by a guy that only used his hand or lip squeaks . So I know that you can call with out putting much money out to do so if need be and have found that the simple way often will get the ones that others or myself have taught about the newer e-callers . I don't care who you are it happens to all of us and if we say it doesn't we are kidding ourselves we all will educate some , sometimes . They will come from behind or the side and we won't see them before they detect us , they may be out a long way when we shoot another one and we didn't see them before the shot turned them around , they may just come in some of the way and decide it's just not quit right and set or lay down then might see or smell us and leave . It's all part of the life of hunting and calling especially coyote . I still want to hear how others are doing their calling that is also part of learning more about hunting and calling sharing with each other what we do to fool the animals into coming to us instead of us going to them . The stalking of them is a whole different and very challenging world of hunting that can have a large amount written on it as well Reemty J. hint , hint !wink wink ! see this old dog can still learn some .