Kele:
ON4UN shows a vertical about 85 ft / 26 meters tall, with a linear
loading for 160, and L-networks to match the low impedance on 160 & high
impedance on 80.
Another option is to use a loading coil on the bottom for 160 tapped for
50 ohm match and an L-net for 80. A W7 ham wrote one of these up maybe 20
years ago. I don't remember the magazine issue.
73, Good luck
George, K8GG