My father and I built this tower when I was in high school. The purpose was to be able to reach wireless internet in town. The tower is about 42 feet tall with 6 1/2 feet in the ground. Yes, I dug the hole with manual post hole diggers in the hard packed clay soil. We poured five and a half sack concrete in the hole on the bottom section of the tower. The tower section effectively acted as re-bar. We bolted the tower together in sections to make assembly easier. The tower is attached to the roof of the house for additional support.
My father doesn't need the tower for internet anymore, and it is sturdy enough to keep going up especially if guy wires were introduced; therefore, if I have anything to do with it, there will be an amateur radio antenna on top.