RADAR ANTENNAS 317 



and forth. Toggle arms are attached to this push rod at frequently spaced 

 intervals which provides the motion for varying the width of the waveguide 

 while assuring precise parallelism of the side walls throughout its length 

 (Fig. 63). 



The normal range of horizontal scanning exhibited by this linear array, 

 extends from a line perpendicular to the array to 30° in the direction of the 

 feed. By alternately feeding each end, a total scanning range of ±30° 

 from the perpendicular is achieved. Appropriate circuits to synchronize 

 the indicator for this range are included. 



The use of alternate end feed on the AN/APQ-7 antenna requires that 

 the amount of energy fed to the individual dipoles is somewhat less than if a 

 single end feed is employed. 



The AN/APQ-7 antenna is 16| feet in length and weighs 180 pounds 

 exclusive of air foil housing. 



The following data applies; 



Gain = 32.5 db 



Horizontal beamwidth = 0.4° 



Vertical beam characteristic = modified csc^ 



Scan — Array scanning 



Scanning Sector — ± 30° Horizontal 



Scanning Rate = 45°/second 



Acknowledgments 



Contributors to the research and development of the radar antennas 

 described in this paper included not only the great number of people directly 

 concerned with these antennas but also the many people engaged in general 

 research and development of microwave components and measuring tech- 

 niques. A complete list of credits, therefore, will not be attempted. 



In addition to the few individuals mentioned in footnotes throughout 

 the paper, the authors would like to pay special tribute to the following 

 co-workers in the Radio Research Department: C. B. H. Feldman who with 

 the assistance of D. H. Ring made an outstanding contribution in the 

 development of the polyrcd array antenna; W. A. Tyrrell for his work on 

 lobe switches; A. G. Fox, waveguide phase changers; A. P. King, paraboloids 

 and horn antennas; A. C. Beck, submarine antennas; G. E. Mueller, 

 polyrods. 



