"These eight anti gravity towers stabilise our gravity here inside Alpha." says Victor Bergman in Black Sun. The towers first appeared as the flashing beacon towers in Nuclear Disposal Area One in Breakaway. A full sized prop was built for Black Sun, and it was seen on the alternative Earth in Another Time, Another Place. The towers were orange-red in Black Sun and most episodes, but in other episodes they were white/grey. The tower models were used to make revolving antennas, in the year 2 titles and The Metamorph. One was also used as the antenna of the Altares probe in Into Infinity. More details
The tower consists of 4 feet, and a cone structure of 4 beams sloping to the top, wrapped by 8 rings, with a disc on top. Along one side is a ladder. In the centre are four central pipes, which project through the top disc to the drum. The full sized prop is similar, but only has two central pipes.
This is one of the smallest of the tower models, just 77 mm / 3 inches tall. The top drum has been lost, some of the lower rings have broken sections, and one foot pad has broken off. The base ring is 30mm diameter; the top disc is 12mm; the beams are 77mm; the foot plates are 7mm diameter and the legs extend out about 20mm.
This photo (with the Eagle laser turret) shows a larger model