Keeping cats away

[maryfield48]

Every week at my home game I seem to have a coughing fit and general respiratory discomfort. I'm just getting over the flu, and had attributed it to that, but we noticed some small white hairs on the playing surface. We think that a stray cat has been coming in and sleeping on the table (my table is on an open verandah). Apparently I'm having a reaction. I have never shared a domicile with a cat, so I didn't know I was allergic. But the evidence is pointing that way.

Short of causing it greivous bodily harm, anyone know of techniques for keeping cats away?