This works well, but can be further improved with the use of screen door mesh [the metallic kind, of course] laid on the outside of the strainer [the convex side]. I have gotten about 25-35% more distance by doing this with a strainer that was 14 inches in diameter.

Very interesting… would this work with a cell phone? I work nights and am stuck in a small concrete room below a 5 story building. No internet. But there is free dial up I can get onto if/when my cell phone is able to pick up a good signal (and in the middle of the night I have free minutes…not the best connection speed but better than nothing at 2am.)