A fan dipole has multiple dipoles with the same feed using spreader
insulators at the end of each shorter dipole. Full size 40 meter dipole
usually works on 15 with a tuner as it is not far from a 3/4 wave, and 80
might work on 10. I always wanted a full size cage dipole for 80 and 75.
This has several wires for broad band operation. HF Discone is another
interesting broadband antenna. You could use the tower as a support but
takes up some space.

Good luck