A predator hunting scientist wrote an article about Coyote Olfactory Senses a while back. The gist of the article was that there is no way to mask the human scent, but by misting the air with a mix of other smells you can confuse the Coyote's brain into ignoring the human component of what he's scenting enough to get him to lower his guard. He may be right. I figure I can use every advantage when it comes to fooling those wily critters!
Okay, so here's the thing. I am a long time predator hunter and have killed my fair share. We all know we're supposed to "play the wind". But there ARE exceptions on times when you might want to play it a little differently. For instance, when I first started calling I thought having the breeze directly in my face when calling was the best I could get. Didn't realize that a decent amount of dogs that I never saw probably circled down wind behind me. Actually I know they did because I've had them come running in full-tilt (from behind me) and almost run me over. Personally speaking I usually try to call a cross wind, where the wind is blowing to my shooting side (in my case, I am right handed and therefore shoot to my left.) A lot of times we try to plan this downwind side to an "open area" where the coyote would have to come out and through to get downwind. This is a good idea...unless of course you're dealing with extremely smart dogs, which is often the case. Once a coyote gets fooled in and blasted once or twice, they don't forget. I hunt in the middle of extremely high pressured areas and do pretty well because I am doing some things different than most guys. Good example would be calling on a completely flat piece of ground. Most guys want to find an elevated stand where they can see dogs coming in. In a perfect world, great. If you have to have it like you see it on t.v. fine. (Same thing goes for turkey hunting. Worked as a guide for 10 years and some guys wouldn't shoot a bird unless it came in to a call set up in full strut, while gobbling, etc.) But if you want to kill dogs (or turkeys) that others won't have a chance at try some things different. Calling on a flat sage-covered piece of ground is difficult (mainly cause we like to see them coming) but it's SUPER effective, mainly because 1. The coyote feels more confident because there is some cover and 2. They learn the spots that regularly get called. Take a shotgun and try it. If you have an electronic caller set it upwind 20 yards and hang on. I do all of my calling by mouth and on a sage flat often make a howl and then sneak 20-50 yards downwind after calling once, wait a few minutes and repeat. It's more of a run and gun style but can be awfully fun.
Wind is a funny thing, I've had them come bombard me (up to 5 at a time) directly from down wind across a wide open field from 100's of yards out. There are times I've walked a long distance in to a stand and had the wind change (to bad) and still called it and been successful. I've had this happen with deer to. Had them walk right up to me from straight downwind. You darned well they can smell you, but SOMETHING you're doing or offering is just too much for them to pass up. Those are the glory sets. Those are the ones where they come runnin' SO HARD you can even get them to stop for a shot and you don't kill the dang thing...but who CARES!? That was awesome!