I have been using the iPhone app called "iHunt" with an external speaker setup. It seems to work pretty good but I haven't bagged a coyote yet with it :evil:
I use both, each have their good and bad points. sometimes you just gotta mix it up! They get wise very quickly to the same old call.
I'm sure I told you all that my life long buddy and his neighbors in Upstate New York raise chickens, goats, and one even has a dairy cow. They also have a coyote problem...and over the last few years both him and I go out every 2-3 months and cull the yote population when the body count starts to rise within the farm community...including one small lap dog that got snatched. Well...I finally got around to dumping the kill pics to my laptop. The tool used to drop them was my Olympic Arms M4 in 5.56 that I've had for decades...62 grain SP's and/or HP's usually do the trick. We use both a ground blind and 2 separate tree stands and call them in with FOX PRO distress calls over chicken scraps for bait. Here are a few that I have harvested:
Here is one I clipped at 300yds about to take a leak on my corn pile... Naked eye view. Scope view. That's him just above the cross.