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BELL SYSTEM TECBNICAL JOURNAL 



reflector for the antenna in Mark 28 was approximately doubled. The 

 Mark 28 is a 10 cm system and employs a conical scanning antenna similar 

 to that described for Mark 19. The essential difference is that the spun 

 steel parabolic reflector is 45 inches in diameter which provides a beam 

 width of ai)pr<).\imately 6.5° and a beam shift of 4.5° making a total of 11°. 



Fig. 56 — Mark 28 Antenna Mounted on 40 MM Gun. 



The minor lobes are down more than 17 db (one way) from the maximum; 

 and the gain of this antenna is 26 db. It was found necessary to perforate 

 the reflector of this dimension in order to reduce deflection caused by gun 

 blast and by wind drag on the antenna assembly. The antenna assembly 

 for Radar Equipment Mark 28 is shown in Fig. 56. This assembly i§ 

 shown mounted on a 40 mm Gun. 



