Just picked up a 25dbi parabolic wifi antenna utilizing our Alfa USB adapter. Did the quick and dirty test tonight while swatting mosquitoes. Didn't take much effort and I doubled, or tripled the networks I could see with the 7dbi omni-directional antenna.
Why? Because RV park wifi generally sucks, and with this thing, you can pick up the clubhouse signal (usually the strongest), or shoot it across town (line of sight) to the local Starbucks or McDonalds wifi.
Cheap investment (about $120) for the adapter, antenna, and low loss cable.