I have an EARCHI EFHW (40:1 unun)antenna that I used quite successfully until it fell from a tree. I wasn't able to get it back up, so ran it along my wooden fence temporarily. Unfortunately, the wire was shorter than the original (~60 ft), and I had trouble getting it to match with a less than 3:1 SWR on several bands.
Somehow, I ended up adding a couple of shorter (about 10ft) lengths of wire to the antenna terminal of the match box. NOW the thing matches on 80-6 meters, with SWR of less than 3:1! And with a decent signal (I get out to South America for example). Note these are not like radials for a vertical which are connected to ground, these are connected to the center or positive terminal of the coax. Is this a sort of off center fed fan dipole? Whatever it is it works surprisingly well...especially on 80m!