The answer to your question about using an imitation coyote caller to deter cats is not readily available. However, it is doubtful that a coyote call would work very long in repelling cats as they would habituate to it.
Coyote urine of meat-fed coyotes is universally repellent to mammalian herbivores. Since a cat is not an herbivore, it is not likely that coyote urine would be repellent. Be careful that you are not wasting your money here.
