Working the world with a Douglas fir (or two).
I recently gave a presentation to a local ham radio club I belong to on a few antennas that are reasonably easy to build, effective, and above all else easy to hide in a big tree. That last part might be a bit of a stretch though. While you can't see the antennas themselves very easily, the rope holding them up tends to be pretty obvious.
When I first got into HF, I was told that reaching Europe from the Pacific Northwest was hard. There's mountains, Canada, ice, aurora, loud stations on the East Coast, and loud stations in Europe that I'd have to contend with to make a contact. So when I was trying to figure out how to setup my first dipole, I looked at a typical map of the world and thought a North-South oriented dipole would work best. Europe is straight east, and Asia is straight west. Done.
Over the ensuing months, I only heard stations in Europe 2 or 3 times but I would regularly get pile ups from operators in Japan, and could often hear myself on SSB in New Zealand. I chalked it up to the aurora. It wasn't until much later that I pulled out a great circle map and realized my mistake: Europe is north of me, not east of me. While I felt a bit dumb not to have thought of that sooner, it meant that there was hope that I could improve my chances at working stations in Europe with a different antenna.
Armed with the knowledge that Europe was 20º from north of me, I spent a chunk of time staring up at the trees in our yard. Two months and several antennas later, I had built a vertical dipole, a quarter-wave vertical for 80 meters that worked reasonably well on 30 meters, and a two-element 20 meter phased vertical array. Although not all of the antennas worked out, I did make contact with a good number of DX stations and contacts as far away as South Africa. I can safely say I learned a thing or two.
If you are interested in knowing more about the setup and the results, you can find the PDF of my presentation here. Let me know what you think at email@example.com.