The Development of the Standard Design for Self-Supporting Radio Towers for the United Fruit and Tropical Radio Telegraph Companies

This paper is an historical review of the United Fruit Company's Radio Towers, and describes the origin of a 1906 design for 200 ft. (61 m.) towers; of 50 ft. (15 m.) extension added in 1910; of the hurricane wrecks of 1914, 1915, and 1916, of data deduced from them, and of the reconstruction of the towers. It discusses the effect of a new policy that "radio communication should be made so reliable that, when all other means fail, the public can confidently look to the radio stations to maintain service, which can be done if only the towers remain standing." The preliminary designs for three-legged towers made in 1915 are described, and their economy and advantages as compared with four-legged towers, the saving due to adjustable rod bracing and the low cost of shop work effected by making all leg sections equal short chords of a circular arc, are pointed out. The design of the Tegucigalpa (Honduras) towers, with antenna bridges and the latest revised, "Standard Plan of 400 ft (122 m.) self-supporting towers, with 150 ft. (46 m.) antenna bridges," are shown with the specified loads, unit stresses, and notes on the most favorable direction of wire pull in relation to cross-section of tower. The design of sections and details are briefly referred to, with the limiting heights of towers to which similar sections are applicable. Two pairs of 100 ft. (30.5 m.