TRANSATLANTIC TELEPHONY ' 171 



telegraphy extending down to nearly 10,000 cycles. At the upper end 

 are the short waves already more or less exploited extending to about 10 

 meters, that is, 30,000,000 cycles. 



It is interesting to note that one frequency range around 60,000 

 lying near the lower end of the scale and another frequency range 

 extending from about 10,000,000 to 20,000,000 near the upper end of 

 the present scale appear to be the most suitable for transoceanic trans- 

 mission. 



The left-hand figure has no bearing on our present subject. It is, 

 however, rather interesting. It shows the whole gamut of frequencies 

 with which we are familiar. This plot has near its lower end a fre- 

 quency of one cycle per 2,000 years which is supposed to characterize 

 a particular comet. From this it proceeds through the frequencies 

 corresponding to solar periodicities, through the frequencies used in 

 commercial power systems, through the voice frequencies, the wire 

 carrier, the radio frequencies, the longer heat waves, the visual light 

 rays, ultra-violet rays. X-rays and to the very hard rays sometimes 

 called cosmic rays with which Dr. Millikin's name is here associated 

 because of the investigations which he has carried out regarding them. 

 This whole matter of frequency range and the relation of each part 

 to human needs is of the greatest significance and interest. 



In considering now how these long and short radio waves are handled 

 in forming the transoceanic circuit, we will look first at the transmitting 

 stations and antennae, next at what happens to these waves in space 

 and then at the receiving antennae and stations. 



At the transmitting end Fig. 5 shows a picture of the long wave 

 antenna at Rocky Point, which well suggests the characteristics of 

 these long waves. A frequency around 60,000 cycles corresponds to a 

 wave length of about three miles and needs these physically large 

 structures to effectively radiate the power into space. This antenna 

 has six towers each 400 feet high. These long waves are in a frequency 

 range which is much used and relatively narrow so that it is essential 

 that the frequencies be employed the most economical way possible. 

 This has resulted in the employment for the long waves of what is 

 known as a single side band carrier suppression method of trans- 

 mission, a refinement of transmission which, so far as I know, is not 

 employed anywhere else in radio services although it is employed to a 

 large extent in carrier over our wire circuits. With ordinary radio 

 telephone transmission such as is used in broadcasting there is a 

 constant steady frequency emitted even when no speech is being sent 

 out and somewhat over 2/3 of the total energy radiated is in this steady 

 carrier frequency which, of course, transmits no message. In the 



