I like it!
Is the entire tube helically wound, or just the black part that looks kind of like an inductor coil wound about 2/3 of the way up the pvc?
In either case, you can add additional capacitive or "top hat" loading, but in a room a "hat" is hard to do.
In this case, I would run a wire horizontally across the top, perhaps just along the rod that support(ed) the blinds, and in the middle of that wire, attach it to the top of your small vertical. Mechanically it just looks like two wires attached to the top of the vertical, each one running directly opposite and horizontally from each other for a few feet or two.
Adding capacitive reactance like this to the top of any vertical, especially one with a lot of coil inductance, helps.