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the " 3 o'clock " or " 9 o'clock " positions of the circle. This possibility 

 was considerably reduced by employing the ellipse in Fig. 9 instead of 

 the circle. For general observation purposes the ellipse was used but 

 for more accurate time delay measurements the circle was employed. 

 The British Post Office station transmitted pulses at intervals of 

 0.02 second. In order to synchronize with them, an oscillator variable 

 about 50 cycles was used to keep the pulse position stationary. A 

 split-phase circuit feeding the four cathode ray plates produced the cir- 

 cular or elliptical sweep. This equipment is also shown in Fig. 10. 



Fig. 10 — Cathode ray oscillographs, their amplifiers, and the sweep circuit installai ion. 

 The meter in the center of the table is the antenna position indicator. 



Some studies of general carrier fading were made with a pair of 

 magnetic counters actuated by trigger gas tubes. These fading count- 

 ers were operated together with automatic recorders so as to maintain 

 the same integrated average signal output. Since, in the recorder inte- 

 gration, ten-second intervals elapsed between gain readjustments, the 

 fading counters operated to record all quick faces, during these inter- 



