Placing an electronic caller away from your setup, and possibly using a decoy of some sort, is a cool and effective method of hunting predators.
But as Eve told James Bond in a memorable scene from "Skyfall," "Sometimes the old ways are the best."
Adding a handcall to your predator-hunting arsenal should be as routine as combining peas and carrots with your venison roast. It may be a diaphragm, howler or reed call, or even natural voice. You can scream to the hills or make subtle mouse squeaks depending on the situation, all with the end result of getting a predator within range.
Watch this episode of Foxpro Hunting TV as Al Morris with Foxpro and Tom Austin put the lead to coyotes in Arizona. Combining their e-caller with handcalls is an effective tactic and one you should use.