A MULTIPLE UNIT STEERABLE ANTENNA 



413 



the static output of one unit antenna and comparing it with the static 

 output of the six antennas combined as one MUSA branch. The 

 circuit shown in Fig. 35 was used for these experiments. The results 

 are tabulated in Table VIII. 



TABLE VIII 



The column headed fmc indicates the frequency to which the re- 

 ceiver was tuned. The MUSA was tuned to a desired station which 

 possessed a comparatively clear channel, and, following the sign-off 

 of the station, static was measured without a demodulating carrier. 

 The receiver was, of course, operated with manual instead of auto- 

 matic gain control. Care was taken, to insure that overloading did not 

 occur. The column headed "addition" gives the ratio in decibels of 

 the static output of the six-antenna branch to that of one antenna. 

 Where figures are entered in the middle of the column no effect of 

 steering was noticed. (Effects of the order of one decibel could have 

 been overlooked, however.) The column headed thermal noise gives 

 the ratio in decibels of receiver noise originating in one of the first 

 circuits (measured with a resistance replacing the antenna) to the 

 total noise measured with the unit antenna connected. It shows that 

 thermal noise was negligible. 



The star static ^^ was steady and therefore accurately measurable. 

 The crash static on 4.82 megacycles was so intermittent that it re- 

 quired the use of the fluxmeter to obtain a satisfactory measurement. 



'^ K. G. Jansky, "Electrical Disturbances Apparently of Extraterrestrial Origin;" 

 Proc. I. R. E., vol. 21, pp. 1387-1398, October, 1935. 



