MAGNETRON AS GENERATOR OF CENTIMETER WAVES 



331 



milled into this piece on either end. This center slab is "capped" on each 

 end by a slab of copper, in which are contained the magnet pole pieces 

 and appropriate surfaces on which to build the rest of the magnetron. Some 

 of the details of this structure may be seen in the cutaway model of Fig. 75. 

 Despite the large impedance transformations involved, the output cir- 

 cuit is quite frequency insensitive. As it appeared that these magnetrons 

 might be made tunable, considerable attention was paid to this characteris- 

 tic. Numerous tests of the output circuit and its component parts were 



Fig. 73 — An external view of the 4J50 "packaged" magnetron (280 kw., 9375 mc/s). 

 Note the circular glass window in the wave guide output circuit and rugged axial input 

 lead which requires no external protecting boot. 



made over the 8500-9600 mc/s band. The iris and quarter wave length 

 guide section were studied theoretically in this regard as well. The trans- 

 former properties of the window and choke coupling combination is the 

 most frequency sensitive part of the entire output circuit. By adjustment 

 of the distance from the H-section to the window, it was found possible to 

 cancel some of the sensitivity of the two parts. 



External views of the 4J50 (4J78) and the 4J52 magnetrons are shown 

 in Figs. 73 and 74 respectively. The internal view of the 4J52 is shown 

 in Fig. 75. 



Except for magnet size and cathode supporting structure all three of 



