Today I took a soup can and turned it into a cantenna. Once again here is the link to Gregory Rehm's excellent cantenna guide. I tested it by perching it out my office window, taped to a microphone stand. I don't have reference figures yet for the AP with it's original rubber omni-directional antenna, but I measured signal strength using my cell phone (A Oneplus One). According to the app I downloaded for the purpose, I'm getting -64 to -74 dBm across the furthest throw I can measure in the yard. Due to obstructions and where this window is located, I can only test about 300 feet. The can is still uncomfortably close to both the aluminum siding and a first floor roof section.
Additional pictures of this process can be found in the gallery