BELL' SYSTEM TECHNICAL JOURNAL 



INSULATING BEAD 

 BRASS BLOCK - 



TAPERED BRASS PIN 



POLYSTYRENE 

 TAPE 



INTERMEDIATE 



FREQUENCY ^ 



AND 



DIRECT CURRENT 



OUTPUT 



DETAIL OF 

 COAXIAL CONDENSER 

 ASSEMBLY , 



I 



Fig. 3 — Schematic diagram of one of the early crystal converter blocks. 



The inserts and points in appropriate mounting blocks were widely used 

 in centimeter wave investigations prior to 1940.- The principal laboratory 

 uses were in frequency converter circuits in receivers, and as radio fre- 



2 G. C. Southworth and A. P. King, "Metal Horns as Directive Receivers of Ultra- 

 short Waves," Proc. L R. E. v. 27, pp. 95-102, 1939; Carl R. Englund, "Dielectric Con- 

 stants and Power Factors at Centimeter Wave Lengths," Bell Sys. Tech. Jour., v. 23, pp. 

 114-129, 1944; lirainerd, Koehler, Reich, and WoodrulT, "Ultra High Frequency Tech- 

 niques," D. Van Nostrand Co., Inc., 250-4th Avenue, New York, 1942. 



