RADAR ANTENNAS 



301 



radar that the polyrod antenna emerged to fill the rapid scanning need a 

 early and as well developed as it did. 



The Polyrod Fire Control antenna is a horizontal array of fourteen identi- 

 cal fixed elements, each element being a vertical array of three polyrods. 

 Energy is distributed to the elements through a waveguide manifold. The 

 phase of each element is controlled and changed to produce the desired scan 

 by means of thirteen rotary phase changers. These phase shifters are 



J 1 ly ""f|~ Tf?ANSMISS10N 



MINOR LOBE SUPPRESSOR ANTENNA '—MMN ANTENNA LINE 



Fig. 51. — Shi[)borne Anti-Aircraft Fire Control Antenna 



geared together and driven synchronously. Figure 52 is a schematic 

 diagram of the waveguide and phase changer circuits. 



Figure 39 shows an experimental polyrod antenna under test at Holmdel. 

 Figure 53 is another view of the Polyrod antenna. 



14.9 The Rocking Horse Fire Control Antenna 



It was long recognized that an important direction of Radar develop- 

 ment lay towards shorter waves. This is particularly true for fire 

 control antennas where narrow, easily controlled beams rather than great 

 ranges are needed. The Polyrod antenna had pretty thoroughly demon- 



