OK so she doesn't really "bark."
I have this stray that seems to be someone's house cat that got abandoned during the last economic downturn. She's docile, spayed, and affectionate, lives in my gazebo and has the annoying habit of scratching at the bay window in the mornings. I feed her, but prefer to do it on my schedule not hers.
To keep her from getting to the window from the nearby deck railing, I bought a surplus 800V power supply. ($2) One of those low current gizmos that are used to power cold cathode fluorescent tubes with high frequency. It works on 12 volts, and is connected to some low voltage lighting power supply nearby. I ran the hot electrode to a spray of stainless steel wires (have to get down past the fur before she feels it) and mounted the wires on the railing.
So far it's been working for a year. She did learn how to bat the copper wires down and then step over them, but she hasn't been able to do that with the SS wire. (old fishing leader wire - spring steel)