I have had bad days with the electronic calls and bad days with the hand calls. Sometimes it seems like more bad days than good. But then you hit a really good day and it is all worth while. The Coyotes won't come in if they see a vehicle. Typically this is behind a slight rise or hill where we can park on one side, walk over the top, and call the other side.
Trees work well to hide the vehicle too.
Deep canyons rarely produce. Gentle slopes seem to do better. Don't slam doors and don't talk. A quiet car that you ease into the area is a plus too. The time it takes to collect up and walk to the set is usually sufficient to settle the area down from the vehicle.