TRANSATLANTIC RADIO TELEPHONY 



319 



tating the transmission of a relatively wide band of frequencies, it must 

 pass such a band without undue discrimination against any frequency 

 contained therein. To utilize the vertical and the loop antennas 



Vertical Antenna 

 Total N.R.F. = 1.000 

 Back End N.R.F. = 1.000 



Loop Antenna 

 Total N.R.F. = 0.707 

 Back EndN.R.F. = 0.707 



Wave-Antenna 

 (One Wave-Length Long) 

 Total N.R.F. = 0.435 

 Back End N.R.F. = 0.058 



Wave-Antenna 

 (Two Wave-Lengths Long) 

 Total N.R.F. = 0.361 

 Back End N.R.F. = 0.048 



Pig, 5 — Comparison of polar diagrams of simple antennas. (The unit for the radii 

 is output current into the same resistance for a constant impressed field.) 



efficiently, it is desirable that they be tuned, introducing the frequency 

 discrimination of a tuned circuit. If these types of antennas be used 



