A MULTIPLE UNIT STEERABLE ANTENNA 



361 



automatic gain control for use with either demodulator is obtained 

 from linear rectifiers but a different diversity connection is made for 

 each type of demodulator, in the interest of output volume constancy. 

 A choice of time constants of 0.06, 0.5, and 4 seconds is provided. 



Keys are provided, the ganged manipulation of which makes it 

 possible, among other things, to compare (1) the MUSA output versus 

 any one of the six antennas connected to one branch receiver, and 

 (2) any pair of antennas in ordinary diversity using both branch 

 receivers, versus one antenna using one receiver. 



Fig. 16 — Fujiit \ ii w 1)1 ili> AH sA uivi\inu ( (|iiipnh nt . Tlu' hiL;h-frequency 

 bay is at the lett and the audio-trequenc>' bay at the right. The branch receivers are 

 the panels directly above the phase shifting panels. The pulse receivers appear 

 above these. At the top of the bay containing the monitoring branch equipment are 

 the two oscilloscopes referred to in Fig. 3. The large tube with the ruled face is the 

 monitoring oscilloscope. 



In addition to the regular branch receivers with a 12-kilocycle band 

 width and the monitoring branch receiver with a 2.5-kilocycle band 

 width, two other receivers are provided in the experimental system. 

 These receivers have a 30-kilocycle band width and are used for pulse 

 reception. They are bridged across the inputs of the two regular 

 branch receivers and are connected to a cathode-ray oscilloscope 

 through a commutator.^ 



Various photographs of the MUSA receiver appear with explanatory 

 captions in Figs. 16, 17, and 18. 



