A MULTIPLE UNIT STEERABLE ANTENNA 



397 



= 7.8 decibels calculated for the non-fading wave of Case I, Fig. 34. 

 (The fact that only one branch was used in the measurements instead 

 of the two branches of Case I does not affect the situation since the 

 idle branch was disconnected and so contributed no signal and no 

 noise.) A reduction of the order of one decibel from the calculated 

 improvement could be expected since all of the waves of one bundle 



TEST NO. 13 



16 



O 0.6 



z 



0.8 

 111 



o 

 < 



H 0.6 



O 

 > 



uj 0.4 



NO. I ANTENNA 



SIX ANTENNAS 



S/N IMPROVEMENT = -^^ = 5.6 DB 



Fig. 36 — Sample of measured noise plotted against time. GAU (18,620 kilocycles) 

 Rugby, September 19, 1935. 



cannot fall on the apex of the directional pattern. It was encouraging 

 to find that no more loss occurred; i.e., to find that the waves in a 

 single bundle may be phased so effectively. 



Before leaving these tests, the results for September 18 should be 

 mentioned. On this day the signal-to-noise ratio was so low, even 

 without antenna pads, that measurements could not be made. The 

 noise on this day was first taken to be thermal noise but was found 



