lattice towers

Definition

Lattical towers are L- structural steel shapes screwed to a cable tray. They are suitable for tower heights of more than 100 meters.

Wikipedia definition (similar term):

A lattice tower or truss tower is a freestanding framework tower. They can be used as electricity transmission towers especially for voltages above 100 kilovolts, as a radio tower (a self-radiating tower or as a carrier for aerials) or as an observation tower. Before 1940, they were used as radio transmission towers especially for short and medium wave, occasionally lattice towers consisting of wood were utilized. The tallest wooden lattice tower was at Mühlacker, Germany. It had a height of 190 metres (620 ft) and was built in 1934 and demolished in 1945.Most wood lattice towers were demolished before 1960. In Germany the last big radio towers consisting of wood were the transmission towers of the Golm transmitter and the transmitter Ismaning. They were demolished in 1979 and 1983 respectively. The tallest lattice tower is the Tokyo Skytree, with a height of 634 metres (2,080 ft). Lattice towers are often designed as either a space frame or a hyperboloid structure.

Source: Wikipedia - Lattice tower