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BELL SYSTEM TECHNICAL JOURNAL 



broadcasting and with efforts to produce less interference between 

 stations in the United States operating on similar wave-lengths, but 

 their use has been much smaller than their use in radio links of the 

 telephone system. Directive antennas are of great importance in 

 telephone links for the reason that in operating over great distance, 

 where weak signals must be received all or most of the time, much 

 power may be saved if directive antennas at the transmitter are used 



Fig. 14 — Element of the Sterba directive antenna. 



to send as much energy as possible in the desired direction, and used 

 at the receiver to exclude as much noise from undesired directions as 

 can be done. 



In connection with the directive antennas used in the telephone 

 system, quite a variety have been developed. Figure 14 indicates 

 the principle of what is known as the Sterba ® antenna, invented by 

 the late Mr. E. J. Sterba. This is an elemental section, the complete 

 antenna being built up of a number of elements of this kind. The 



