Radio Tower at Tufts College 



THE radio tower recently erected at 

 Tufts College, Medford, Massachu- 

 setts, is attracting unusual attention. 

 In September, when the tower was 

 completed to a height of over 275 ft., 

 one of the temporary guy ropes parted 

 during a high wind and allowed the 

 tower to topple over. Instead of snap- 

 ping at some point above the ground 

 the structure pulled away from the 

 sub-base and fell as a complete unit. 



It has been shown that the collapse 

 was not due to faulty design, and the 

 tower has been re-erected without im- 

 portant changes. 



The tower itself is built entirely of 

 angle irons and assembled in the manner 

 shown in the illustration. It is 288 ft. 

 above the concrete base, and 3 ft. 4 in. 

 square in section from base to top. 

 The corner, or upright, angle-irons are 



3 ins. by y^ in., while the diagonal and 

 cross angle-irons are 2 ins. by 3/16 in. 

 The corner angles are each nearly 12 ft. 

 long and, as shown by the diagram, are 

 divided into three sections. The sections 

 are placed directly on top of each other 

 and held together by means of angle- 

 irons fitting inside of the corner angles 

 and extending several inches either 

 side of the joint. These angles are 

 secured by bolts >^ in. in diameter and 

 I in. long. This bolt construction is 

 employed throughout the tower, there 

 being no rivets. Washers are not used 

 with the bolts. 



The structure is mounted on two 

 concrete bases. The upper base is 5 ft. 



4 ins. square and 12 ins. thick. It is to 

 this base that the iron work of the 

 tower is secured. This sur-base rests on 

 four porcelain insulators set so as to 

 leave 5 ins. between the two bases. The 

 lower base is the same size in section as 

 the upper base, but extends 6 ft. into 

 the ground. When the first tower 

 collapsed these two bases pulled apart. 



As the tower is not self supporting, 

 the system of guying is of great import- 

 ance. Three sets of four guys each 

 have been adopted, thus giving 120- 

 degrec guying with four guys fastened 

 to each of the three deadmen. These 



guys consist of stranded steel cable with 

 rope core, the two upper of which are 

 yi in. in diameter and the two lower 

 ^in. 



After the complete erection of the 

 tower the fourth guy was added to each 

 of the three sets at a 

 point about 75 ft. 

 from the ground. 

 These guys are extra 

 and were not included 

 in the original design, 

 but as it now stands 

 the tower has 12 guys. 



The guys are broken 

 up by porcelain strain 

 insulators 5 ins. in 

 length and 3 ins. in 

 diameter. The ends 

 of the wire are secured 

 by a series of Crosby 

 clamps. Twelve- 

 inch turn-buckles 

 are inserted in each 

 set of guys. 



The three dead- 

 men are made of 

 concrete and weigh 

 about 25 tons each. 

 On the surface they 

 are 5 ft. 3 ins. 

 square. They are 

 placed 150 ft. from 

 the base of the tower so as to give an 

 angle of 45 degrees to the lower guy, 

 which is placed mid-way up the tower. 



The tower was erected aloft, each 

 separate piece being placed in position 

 before another was secured. Temporary 

 guy ropes were used in large numbers 

 during the erection of the second tower, 

 as it was due to insufficient temporary 

 guying that the first structure collapsed. 



Harold J. Power, for whom the tower 

 was erected, is a graduate of Tufts 

 College. While there he was president 

 of the Wireless Society, to which organi- 

 zation he has granted the use of the new 

 tower and experimental station. 



Many methods of mast construction 

 have been tried, and while a serviceable 

 tower of wood can be built, wood is 

 generally considered inferior to steel. 



Construction details 

 of the tower 



949 



