One more thing to add- I have called coyotes more than once when I got frustrated and was blowing the call absolutely as loud as I could, just to see how loud it would go. One of these was the first coyote I ever called some 30+ years ago. After a zillion and half stands of being "polite", I got mad and started giving that poor Burnham Bros all it could handle and more. I had it SCREAMING!!! After a minute or two, I looked up and there was a line of dust heading my direction from across the prairie. No, couldn't be, no way. A few minutes later, a coyote came running into the salt cedar bottom where I was, evidently behind chased by this line of dust. His tongue, saliva dripping, dragged the ground. His eyes were red, his belly growled, and he was moving FAST. I was scared to death. This thing was gonna EAT me!!! So, I leveled my .22 LR his direction, fired a warning shot, and just like that, there was a line of dust going back the direction it came!
So, I dunno.... if you're not getting anything, don't be shy.