612 



BELL SYSTEM TECHNICAL JOURNAL 



The three tubes, tlie 2K2v^, 2K54 and 2K55 were inteiuled to couple to 

 wave guide circuits. Although direct coupling to the guide through a wave 

 guide output would have been desirable in some ways, it would have re- 

 sulted in a very large and awkward structure. It seemed best, therefore, to 

 retain the coaxial output feature of tubes designed for beating oscillator 

 service. From a standpoint of convenience, it would have been desirable 



0.485" 



Fig. 101. — A transiluccr ck-si^iicd to adiipt tlic 2K2,\ 2K.^4 and 2K55 oscillators to a 

 terminated wave guide load. If the hack piston of this coujiling is set at a distance of 

 1.08" from the center of the prohe the impedance presented to the oscillator line is 50 

 ohms with a 1 dl) variation over the re(|uired fre(|uency range. 



to have had the wave guide probe an integral part of the tube, as is the case 

 in the 2K2vS. However, the length of a quarter wave probe at the operating 

 wave lengths of the AN/TRC-C system made such a design hazardous. 

 Because of this a transducer was developed into which the tube could be 

 plugged. This is shown in Fig. 101. The central chuck e.xtends the center 

 conductor of the output coa.xial ot" tiu' tube into the guide. It had been 



