A NEW KEY WEST^HAVANA CARRIER TELEPHONE CABLE 201 



the effect of the armor wire is negUgible from the attenuation stand- 

 point. Magnetic modulation due to the presence of the armor wire 

 was investigated carefully and likewise found to be negligible. The 

 lay, or pitch, of the copper return tapes was made much longer ^ than 

 was the case in the 1921 cables. This brought about a substantial 

 decrease in the effective resistance of the tapes themselves and reduced 

 the eddy-current losses which are due to the helical nature of the 

 return tapes. 



In all matters of mechanical design accepted cable practice was 

 followed. A discussion of some of the mechanical features of cable 

 design, as well as some account of the general submarine cable problem, 



KEY WEST DISTANCE ALONG THE COURSE OF THE CABLE HAVANA 



O 10 20 30 40 50 60 70 80 90 100 110 N M. 







TYPE 



OF 



ARMOR 



Fig. 2 — Depth of water along route of cable. 



has been gi\en by Martin, Anderegg, and Kendall in the paper above 

 referred to. 



The new cable is 108.6 nautical miles (125.2 statute miles) in length. 

 It was manufactured by the Norddeutsche Seekabelwerke-x'\.G. of 

 Nordenham, Germany and laid by their cable steamer "Neptun." 

 Its route is shown in Fig. 1 , and the profile of the route in Fig. 2. The 

 maximum depth attained is 1080 fathoms (6480 feet). The particulars 

 of the core structure are given in Table II and those of the armor in 

 Table III. Cross-sections of the various types of cable are shown in 

 Fig. 3. A photograph of three of the types is shown on Fig. 4. The 

 attenuation of the cable and its characteristic impedance are shown 

 in Figs. 5 and 6, respectively. The attenuation is characteristic of a 

 non-loaded cable in that it increases rapidly at low frequencies but 

 less rapidly at high frequencies whereas the reverse is true, in a 



^ U. S. Patent No, 1700476, January 29, 1929. 



