RADIATION CHARACTERISTICS OF AN ANTENNA. 237 



PART IV. 



Computations of Radiation Resistance. 



19. Equation for Radiation Resistance. — If 



a = length of vertical part in meters, 

 b = length of horizontal part in meters, 

 Xn= the natural wavelength of the antenna in meters, 

 X = the wavelength in meters of the antenna as loaded with inductance 

 at its base, 



we may obtain the radiation resistance of the antenna by dividing the 

 power radiated b\' the mean square of the current at the base of the 

 antenna. This mean square current at the base of the antenna is bv 

 (5) 



jr, _ IHin^ {q/2) 



Performing this division as to the flat-top power employing equation 

 (106) and adding the result to the radiation resistance for the vertical 

 portion as given in equation (44) we obtain for the total radiation 

 resistance of the antenna the equation 



^« = • 2 / /ON \ Ri — Ricosq — R3 sin q + 

 sm-^ (?/2) ( 



nA^ + nA' - nA' - rU' + nA^ + • • • I • (107) 



