cable of special design and manufacture. Accordingly, the network of trenches requested was complex, (requiring approximately 19 drawings to depict), and the shielding requirements imposed necessitated a considerable amount of engineering consideration. The first shielding problem, that of affording adequate protection to the coaxial cables running between Eberiru and Aomon, called for an evaluation of various suggested schemes including the laying of steel or rubber conduit in a trench in the floor of the channel between these islands. After investigation at the site by representatives of the H & N Engineering Division, it was recommended that the most direct solution to the problem was the provision of an earth fill causeway in which a wood frame conduit could be provided for the coaxial cable, Such a causeway would have the additional advantage of serving as a direct above-water roadway between the islands, to facilitate both scientific and construc- tion operations, This recommendation was approved, designs for the causeway were executed, and construction accomplished. Additional shielding requirements involved the placement of coral terms over the buried rigid and semi-flexible coaxial lines. The heights of these berms varied from more than thirteen feet to five feet, decreasing with distance from zero. As indicative of the magnitude of the problems involved in connection with coaxial cable, it will be seen from Table 5.18-3 that a total of more than 360,000 feet of rigid and semi-flexible coaxial cable and more than 2,000,000 feet of flexible coaxial cable was installed. tained as many as fifty of these cables. Some trenches con- TABLE 5.18-3 COAXIAL CABLE Runit Rigid* Quantity in Lineal Feet Aomon Engebi Engebi (E+) Total Estimated Installed 13,300 13,530 106,200 115,870 58,000 60,600 18,000 41 ,903 195,500 231 ,930 Estimated Installed 15,000 19,000 22,000 35,560 64,000 59,700 28 ,000 16,450 129 ,000 130,710 Estimated Installed 1,104,500 1,136,500 180,300 166,300 751,200 757,600 7,800 4,391 2,043,800 2,064,791 Estimated 9,000 Semi-Flexible** Flexible### Other*#### Installed Site Total Estimated Installed 8,755 24,400 37 ,400 9,100 16,100 71 ,600 1,141 , 800 1,177,785 345,900 342,130 882,100 887,400 69 ,900 65,721 2,439,700 2,476,036 9,500 2,977 45,632 * Rigid cable, 1-5/8 inch and 3-1/8 inch diameter ** Semi-Flexible, 7/8 inch diameter *"* Flexible, RGL8U, RG 8U, and RG 360 eHee Other, 2/c #12, 2/c #4, Teleseal, and 7-Quad 9-255