FLEXIBLE REPEATER DESIGN 



79 



1 INPUT TERMINAL 



2 INPUT BLOCKING CAPACITOR 



3 GROUNDING CAPACITOR 



4 CRYSTAL 



5 INPUT NETWORK 



6 VACUUM TUBE (FIRST STAGE) 



7 FIRST INTERSTAGE NETWORK 



8 VACUUM TUBE (SECOND STAGE) 



9 SECOND INTERSTAGE NETWORK 



10 VACUUM TUBE (THIRD STAGE) 



11 OUTPUT NETWORK 



12 BETA NETWORK (1) 



13 BETA NETWORK (2) 



14 GAS TUBE 



15 DRYER 



16 OUTPUT BLOCKING CAPACITOR 



17 OUTPUT TERMINAL 



Fig. 9 — Repeater make-up. 



back of 33-3-i db. With the restrictions noted above and the effect of 

 the potentiometer terms on the available feedback, the top edge of the 

 band is limited to about 165 kc with the desired feedback. 



Mechanical Design 



To provide a flexible structure the repeater unit is assembled in a 

 number of longitudinal sections mechanically coupled by helical springs 

 and electrically interconnected by means of bus tapes. The assembly is 

 composed of 17 sections. Figs. 9 and 10 show the repeater make-up and 

 an assembled unit. 



The sections consist of the circuit component, or components, mounted 

 in machined plastic forms and enclosed in a plastic container w^hich in 

 turn is enclosed in a housing of the same material.* The sections contain 

 circuit components grouped functionally such as input coupling net- 

 work, interstage, electron tube, or high \'oltage blocking capacitor. In 

 the case of the feedback network it was necessary to mount the network 

 in two sections because of the large numbers of components involved. 

 A typical network, container and housing are shown in Fig. 11. 



The bus tapes are placed in grooves milled in the outer surfaces of the 



* The material used is methyl methacrj-late which was chosen for its ph.ysical 

 and chemical stability and good machinability. 



f | i m i ppMll i)— H . i MIU c 



Fig. 10 — Overall view of the repeater unit. 



