TRANSATLANTIC RADIO TELEPHONY 



357 



VIV 



m = V'/V 



Nfi' 



j = <- I 



e 



Velocity ratio. 



Reciprocal of the velocity ratio. 



The angle between the axis of the wave-antenna and the 

 direction of propagation of space waves measured in 

 a clockwise direction. 



le 



R.D.R. = Y- Relative directional receptivity. numeric 



■'0 



APPENDIX 2 



Antenna Arrays 



The directional discrimination yielded by a single antenna can be 

 increased by utilizing several such antennas in an array." In Fig. 18, 



Fig. 18 



a general array of n antennas is indicated, of which only the first and 

 the ^'th are portrayed. 



Each antenna in the array is completely specified by the coordinates 

 of the initial end of the antenna, the angle between the zero axis of 

 the coordinate system and the axis of the antenna, and the current 

 delivered at the receiving end of the antenna for a given electric field 

 impressed on the antenna at each angle of incidence with the antenna. 

 Literally, the first and the ^'th antennas are specified as follows: 



Coordinates of initial end ol antenna. . . 



Direction of antenna 



Current delivered by antenna for a con- 

 stant electric field propagated in the 

 direction d 



First Antenna 



(0,0) 







k'th Antenna 



