As promised...

...I've just made my first return trip to a location where I'd experienced signal strength problems before fixing my laptop's antenna. Sure enough, I'm showing all five bars and an "Excellent" strength rating at the Plaza Library. If memory serves, the only other places I really bombed out at were the Town Pavilion downtown (although I still think the problems there were on their end, since I didn't have trouble at the coffeehouse across the street) and the Atlanta Bread Company cafe in Lee's Summit. It'll be a while, but just to be fair I'll try and hit both again in the coming weeks.