I know this is off topic but....

[nofishfisherman]

One other thing I shoudl have mentioned. Cats will continue peeing in the same spots. The smell acts as a marker for them and they'll use the same sport over and over.

I would lay down the scent deterent and also clean everything as well as you can. There are products out there that break down the enzymes that cause the smell. I've used Natures Miracle before and its works great. You can get it at any big box pet store. Usually one good cleaning is all it takes, in your case if its a well used spot it might take a few extra cleanings but it should work to get the smell out. Hard part will be to find all the spots as I'm sure its more than one.

[JONOV]

Have you thought of either a sling shot or red rider type of bb gun? Not something with enough power to break the skin, but it might provide the negative reinforcement you need without noise, or the risk to human life and property. Also, not sure how feasible it is, but cats hate walking on chicken wire. Lay some down around the border of building/wherever you think they're getting in.