I spent about an hour, and about $15 today building a Pringles can antenna, in the hopes of being able to work down at the creek during this lovely warm weather.
It didn't help at all. Presumably that's because of geography, rather than due to incompetence, but I don't really know. The creek is situated such that there's a hill between it and the antenna, so I'm going to blame that. But I really don't know how to test whether it worked at all.
However, when I reassembled my wireless router with the original antennas, it worked better. Not sure what to make of that, but maybe I'll be working down at the creek next week after all.