Note: The Cannonball facility is located on private property and not accessible to the public. It was visited and photographed by special permission from the owners.
Interior description and cross-section view of tower(Courtesy of John Cross)
The Cannonball tower is approximately 103 feet tall and 25 feet in outside diameter, constructed of reinforced concrete with walls about 15 inches thick. It has no windows, and a single exterior door (not shown).
The recessed section at the top is a two-level antenna deck, which was completely enclosed by two circular rows of Plexiglas panels, coated with opaque paint. Behind each row of panels is space for mounting the parabolic microwave antennas ("dishes"), six feet in diameter, which linked Cannonball with other stations in the network. The panels allowed radio waves to pass through but prevented the curious from seeing where the dishes pointed, and thus locating the other towers. Due to vandalism, only fragments of the panels remain in place. The dishes themselves are gone, too - as is all of the tower's communications equipment.
Cannonball appears to have a single basement level, of the same diameter as the above-ground floors. However, this could not be positively determined because the space was almost completely full of water.
The tower's sole entrance was secured by a heavy steel blast door - essentially a vault door - which was welded shut when the tower was abandoned in 1977. Despite that precaution, the door has been stolen. Only the frame and attached hinges remain.
The circular opening above the doorway is the exhaust for the tower's ventilation system.
The rectangular outline surrounding the doorway, the vertical pieces of lumber attached to the wall, and the bolts protruding from the wall and stoop suggest that the tower had an enclosed porch.
This photo shows the tower's entrance area, as seen from just inside the exterior doorway. The rusted door frame at the extreme left leads into what was probably a decontamination booth. The two vertical bars in the background, at the center of the image, are guide rails for an electric elevator which ran from the basement to the floor just below the antenna deck. The doorway at the center, under the "snakes" graffito, gives access to the ground floor's main room.
This small room is immediately to the left of a person entering the tower. The operation of its door (now missing) was coordinated with that of the exterior door by a mechanical linkage in the doorframe, so that both doors could not be open at the same time.