424 



BELL SYSTEM TECHNICAL JOURNAL 



than 20 times the line spacinj^^, the power radiated by a two-wire 

 line terminated in its characteristic impedance is approximately: 



in which: 



= 160 — watts/ (amperes)^, 



(6) 



D/\ is the line spacing and 



/ is the r.m.s. value of the current in the line. 



100 

 75.0 



50.0 



^ 



2.5 



30 40 60 80 100 



FREQUENCY - MEGACYCLES 



200 300 



Fig. 9 — Calculated power radiated by 600-ohm lines terminated in the character- 

 istic impedancefor several common conductor sizes. Note that line length is not in- 

 volved. 



Under these conditions the radiated power is independent of line length. 

 More accurate equations appear in an appendix to this paper. It may 

 be concluded from (6) that the power radiated by a terminated line is, 

 in magnitude, approximately twice that radiated by a doublet antenna 

 of length equal to the line spacing. Thus, the most simple circuit with 

 which it is possible to terminate an open-wire line, a resistance of 



