Radio masts and towers Radio masts and towers Radio masts and towers are, typically, tall structures designed to support antennas (also known as aerials) for telecommunications and broadcasting, including television. There are two main types: guyed and self-supporting structures. They are among the tallest man-made structures. Masts are often named after the broadcasting organizations that originally built them or currently use them. In the case of a mast radiator or radiating tower, the whole mast or tower is itself the transmitting antenna. The terms "mast" and "tower" are often used interchangeably. However, in structural engineering terms, a tower is a self-supporting or cantilevered structure,
Ketch Sir Francis Chichester's earlier "Gypsy Moth" ketches had five staysails (each of almost equal size), none of which were boomed. If a ketch has no jibs, it is called a "cat ketch" or a "periauger". On older, larger ketches the main mast may in addition carry one or more square rigged topsails. The square-rigged ketch was largely supplanted by the brig, which differs from the ketch by having a forward mast smaller (or occasionally similar in size) than the after mast, and by the hoy, which was fore-and-aft rigged. Other similar craft include the snow and the pink. Both the