HORIZONTAL RHOMBIC ANTENNAS 



143 



output design by equation (7). By substituting (12) into (10), this 

 becomes 



0.371X 



/ = 



sin- A 



(13) 



Therefore, aUgnment design is obtained by the use of equations (3), 

 (6) and (13). This shows that to change from maximum output 

 design to alignment design it is only necessary to reduce the length to 

 approximately seventy-four per cent of the value recommended for 

 maximum output. 



Figures 5 and 6 are examples of the directive patterns secured by such 



ANGLE IN DEGREES 

 90 80 70 60 50 40 



1 2 



RELATIVE RECEIVER CURRENT 



Fig. 5 — Alignment design. Receiver current diagram of incident plane directivity 



for a 17.5° wave-angle. 



90 80 70 60 50 



ANGLE IN DEGREES 

 40 30 



Fig. 6 — Alignment design. Receiver current versus azimuth angle for a 17.5° 



wave-angle. 



