Which call to use?

I'm not a huge coyote hunter but I have gone out with friends in the past and this year I have gone out twice on my own. I over heard some guys talking about it being their breeding season. My question is, is this the time i should use a challenge bark and a greeting howl? The caller I purchased has several different calls but I'm just not sure which call is best and when to use it. I used a rodent sqeak yesterday because it was windy and I figured the higher pitched sound would cut the wind better. No results though.