Update....I've done absolutely nothing so far! Now that it's getting warmer though, I'm starting to get the fever. I was out in the yard today looking at the trees. I have trees and branches where I could lay out a pretty good sized horizontal loop if I can figure out getting lines over the branches with one of the already mentioned suggestions. I'm not sure about putting up a vertically polarized loop. Have to look into that some more. One question about loops, vertical or horizontal. Do they need to be a wavelength long at the lowest frequency or can they be some odd length? For instance, if I use all 368 ft. of wire, that's over a wavelength on 80 but short of one on 160. I know the ramifications of short antennas but what about one that is overly long like for instance the 368 ft. on 80 meters?
I am in the middle of building a Half Square for 80, 40 and 30 meters for my small lot I have 2 40ft trees 150 feet apart with a a north/south direction of radiation. Please read this on the Half Suqare http://rudys.typepad.com/ant/files/antenna_halfsquare_array.pdf
Mine is going up in a couple of months because I am putting the 30M up this weekend to test out first then the 40M one until fall then the 80M one will go up. A freind and me were talking about low band antennas for dx'ing and since dipole are NVIS at low hights I talked him into a Half Square he put up his 40M on Monday and he is hearing and working stations he can not hear or just in the noise on his rotatable dipole at 60ft and they are S7 to S9 on the Half Square at 50ft.
I modeled the 80M HS on 4NEC2 and the swr was 1:40:1 on the design frequency and doing a Sweep of 1MHZ to 20Mhz there are good dips for the 160M and 60M band that a tuner should handle fine. You have enough wire for the 80M Half Square. All you need is 2 trees 140 to 150 apart in the direction you need for the antenna pattern to be broadside to and 40 to 60 feet high.