202 



BELL SYSTEM TECHNICAL JOURNAL 



PROPORTIONAL TO 

 FIELD- STRENGTH 



HIGH FREQUENCY 



LOW FREQUENCY 



Fig. 6 — Cathode ray oscillograph figure for no selective fading when observed with 



wobbled carrier. 



PROPORTIONAL TO 

 FIELD-STRENGTH 



HIGH FREQUENCY 



LOW FREQUENCY 



Fig. 7 — Cathode ray oscillograph figure for severe selecti\'e fading when obser\ed 



with wobbled carrier. 



operated on a simple antenna system, as a standard of comparison, 

 while the second was connected to the adjustable directive antenna. 

 Fig. 10 is a photograph of this apparatus. 



Other tests also going on at Holmdel, N. J., were concerned with 

 the measurement of the comparative delay times and the respective 

 angles of the various paths of the waves. ■^ To permit this, the British 

 Post Office transmitter sent pulses of very short duration. At the re- 

 ceiving point, a single transmitted pulse frequently appeared as several 

 spaced pulses when a sweep circuit was employed. The spacing en- 

 abled the measurement of the relative time delays. It was found to 



