When I lived out in the woods I'd use an airhorn to get the coyote packs away from directly outside the house.
Discussion
That's a good idea. I often just yell "go away" really loudly and turn up some music or beep the car horn a bit.
The other night that wasn't working. Something was circling our camp and wouldn't go away no matter how much barking Satoshi and I did. Ended up letting off a warning shot and that seemed to do the trick.
From my order history.