196 PIERCE. 



It is also to be carefully noted that when / = 0, equation (1) becomes 



J . ttXo . 'Ittc . ,^s 



iQ = 1 sm~ sin — t, {o) 



so the amplitude at the base of the antenna is 



7o = / sin — (6) 



Now, finally, when the antenna has a flat-top it is assumed that the 

 top part of the antenna is bent over without any significant change in 

 the magnitude of the current at the various points. 



When the equation (1) is to be applied to the vertical portion of 

 the antenna, we shall call 



/ = z', (7) 



where 



z' = vertical distance from the ground of the point P' on the 

 antenna. 



When the equation is to be applied to the horizontal part of the 

 antenna, w^e shall call 



1= a-\- .x', (8) 



where 



a;' = distance along the horizontal part of the antenna to any 

 point P" on the flat-top. 



The discussion will now be divided into several Parts: Part I. 

 Electromagnetic Field Due to Vertical Portion of the Antenna; 

 Part II. Field due to Horizontal Portion of the Antenna; Part III. 

 The Mutual Term in Power Determination. Part IV. Compu- 

 tations of Radiation Resistance. Part V. Field Intensities and 

 Summary. ■ . 



