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 mizzen. To assist going to windward, a ketch will usually carry at least one foresail such as a jib or genoa. Although both the single-masted Bermuda sloop and cutter have simpler rigging and are more efficient, the sails on a ketch are smaller and more easily handled, and its mainmast is shorter. A modern ketch's sails may be any type of fore-and-aft sail, in any combination, and most are Bermuda rigged. The modern ketch is popular in northern Europe and among long distance cruisers. Both the ketch and the yawl rig have proved generally to be more suitable for motorsailers