In Singapore space is limited, and in our appartment it is difficult to setup any HF antenna. Our balcony is the only place where I have a space to mount something. Even there, officially nothing is allowed to extend out from the building.
I decided to setup a simple vertical, using a telescopic fiberglass pole, which I can pull out temporarly, when it is getting dark. The pole has a total length of 10 m, approx. 1 m (the lowest segment) safely mounted to the balcony railing and sidewall.