Microwave relay station at Cresson, Wyoming, USA, part of the US AT&T Long Lines microwave relay network. This was part of the first transcontinental line finished in 1951, and used an early type of antenna called a dielectric lens antenna, which was later replaced by other types. It consisted of a pyramidal horn with a convex "lens" made of plastic and metal in the mouth to focus the microwaves into a beam. Two antennas were used for each microwave link, one for receiving and one for transmitting. Each microwave beam had a radiated power of only a few watts, and could carry hundreds of telephone calls.