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BELL SYSTEM TECHNICAL JOURNAL 



with a Train Meter of the zero center type which indicated the direction of 

 deviation from true target position. One of these meters of early design 

 can be seen in Fig. 38. Two meters of later design are shown in Fig. 39 

 mounted immediately below optical telescopes. The pulse generator, 

 receiver, transmitter, rectifiers, etc., were located below decks in the Trans- 



Fig. 19 — Train or elevation indicator — Radars Mark 2, 3 & 4 



mitter-Receiver, or Main Unit which was ver}' similar in appearance to 

 the Main Unit of Radar Mark 1 shown in Fig. 9. 



Two types of antennas were provided for this radar: a 6 ft. by 6 ft. 

 parabolic array similar to the Mark 1 antenna, and a 3 ft. by 12 ft. parabolic 

 array. Either one or the other of these antennas was mounted on top of 

 the gun director and rotated with it in azimuth. Both were provided with 

 azimuth lobe switching to be described later. Because of the relatively 

 narrow elevation beam of the 6 ft. by 6 ft. array, this antenna required gyro 



