If you don't have the room for a full sized dipole (even after you bend its ends down or in) one solution is a loaded dipole. You lose a bit of performance and a lot of bandwidth (or a lot of performance and a bit of bandwidth) but one is still a good way to get onto a particular band. And the way conditions are at the bottom of the cycle, even a limited capability on 80 metres can be very valuable.
A loaded dipole has some sort of loading. Either capacitive loading at the end of its element or inductive loading along it. You can make the latter by winding wire on a plastic pipe. Depending on how the coils are positioned you can even make a loaded dipole work on two bands (with the higher frequency band being served by both sides of the antenna wire between the loading coils and feedline).
Here's some ideas for and examples of loaded dipoles:
* Coil shortened dipole calculator
* M0MCX shortened 40m dipole for attics
* VK1HW 80 and 40m loaded dipole
* Adding 80m to a 40m dipole (video)
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