Abstracts of Technical Articles by Bell System Authors 



Commercial Broadcasting Pioneer. The WEAF Experiment: 1922-1926} 

 William Peck Banning. WEAF, the radio call letters which for nearly a 

 quarter of a century designated a broadcasting station famous for its 

 pioneering achievements, ceased last November to have its old significance. 

 WNBC are the new call letters. This book is an excellent record of the 

 four years during which this station was the experimental radio broad- 

 casting medium of the American Telephone and Telegraph Company. 



The author indicates that the WEAF experiment aided the development 

 of radio broadcasting in three ways: 



First, in the scientific and technological field. 



Second, in the emphasis of a high standard for radio programs. 



Third, in determining the means whereby radio broadcasting could 

 support itself. 



When TF£/1 F changed hands from the American Telephone and Telegraph 

 Company to new ownership, public reaction to almost every type of broad- 

 cast had been tested, network broadcasting had been established and the 

 economic basis upon which nationwide broadcasting now rests had been 

 founded. A trail had been blazed that thereafter could be followed without 

 hesitation. 



In so far as radio broadcasting is concerned, this book is a significant 

 chapter in communication history. 



A Multichannel Microwave Radio Relay System} H. S. Black, J. W. 

 Beyer, T. J. Grieser, F. A. Polkinghorn. An 8-channel microwave 

 relay system is described. Known to the Army and Navy as AN/TRC-6, 

 the system uses radio frequencies approaching 5,000 megacycles. At 

 these frequencies, there is a complete absence of static and most man-made 

 interference. The waves are concentrated into a sharp beam and do not 

 travel along the earth much beyond seeing distances. Other systems 

 using the same frequencies can be operated in the near vicinity. The 

 transmitter power is only one four-millionth as great as would be required 

 with nondirectional antennas. The distance between sets is limited but 

 by using intermediate repeaters communications are extended readily to 

 longer distances. Short pulses of microwave power carry the intclHgence 

 of the eight messages utilizing pulse position modulation to modulate the 



1 Published by Harvard University Press, Cambridge, Massacliusetts, 1946. 

 ^ Elec. Engg., Trans. Sec, December 1946. 



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