yeah, its just a reflector, and itll work...poorly, odds are.
I worked for a WISP in kansas a few years ago, and the company bought another WISP and I was sent to upgrade them to the Motorola Canopy equipment we used. All the customers were on 2.4ghz equipment, and the AP was on top of a water tower.
Im not sure what the AP was....but in one home the customer equipment was a linksys wireless bridge, zip-tied to a rafter in the attic of the house, with the antenna aimed out parallel to the water tower, and stapled to the rafter a few inches behind the bridge was some chicken wire in the shape of a parabolic reflector...
the customer was ~3/4mi from the AP. the bridge worked, but only sporadically. i wish i had taken a picture of that shitty setup :-/