RADIO BROADCASTING TRANSMITTERS 



137 



250 volts for filaments and grid bias, the other 2,000 volts and 4,000 

 volts for the plates of the air-cooled and water-cooled tubes, respec- 

 tively. A power input of 10 kw. is required. 



Fig. 13 — Rear view of 6-B radio transmitter. 



Radio Transmission Phenomena 



Radio transmission phenomena in the broadcasting band have 

 been given considerable study, and the general nature of the efTects 

 likely to be encountered are fairly well understood. Important con- 

 tributions have been made by Bown and Gillett, by Bown, Martin, 

 and Potter, by Goldsmith, and by Espenschied.'' The second paper 

 referred to is particularly noteworthy on account of the insight which 

 it afTords into the complexities of the process of transmission and the 

 evidence which it presents concerning the injurious effects of fre- 

 quency modulation. The latter has not yet fully received the atten- 

 tion which it deserves; many otherwise well designed transmitters 



* See attached list of references. 



