Best way to repel /deter a cat from pooping by my house?

I have wild cats that poop all over my front porch and yard in the bushes. It smells terrible. What is the best way to repel or deter a cat? I tried that fox urine in granules - doesnt work, I tried citrus - doesnt work, I tried shake-away - it doesnt work. Now I bought that electronic cat deterrant and Im testing it. Any other ways that may work???