﻿Directive 
  System 
  of 
  Wireless 
  Telegraphy. 
  649 
  

  

  place 
  with 
  reference 
  to 
  the 
  radiation 
  from 
  the 
  vertical 
  

   antenna, 
  a 
  phase-difference 
  between 
  the 
  emissions 
  of 
  the 
  two 
  

   systems 
  should 
  exist, 
  for 
  equality 
  of 
  phase 
  in 
  the 
  excitations. 
  

   As 
  will 
  be 
  seen 
  further 
  on, 
  the 
  experiments 
  have 
  shown 
  that 
  

   this 
  phase-difference 
  is 
  90° 
  or 
  near 
  to 
  that 
  value. 
  The 
  aerial 
  

  

  Fiff. 
  7. 
  Fig. 
  8. 
  

  

  10 
  

   Fiff. 
  9. 
  

  

  Fie. 
  10. 
  

  

  

  -WflfW 
  

  

  of 
  the 
  unilateral 
  system 
  is 
  formed 
  by 
  the 
  aerial 
  of 
  the 
  directive 
  

   circuit 
  to 
  which 
  has 
  been 
  added 
  a 
  vertical 
  antenna 
  in 
  a 
  position 
  

   symmetrical 
  with 
  reference 
  to 
  the 
  first. 
  To 
  secure 
  the 
  simul- 
  

   taneous 
  excitation 
  of 
  the 
  closed 
  oscillatory 
  circuits 
  and 
  of 
  the 
  

   vertical 
  antenna, 
  various 
  arrangements 
  have 
  been 
  employed 
  

   which 
  are 
  diagrammatically 
  depicted 
  in 
  figs. 
  7, 
  8, 
  9, 
  10. 
  

  

  

  