MAGNETRON AS GENERATOR OE CENTIMETER WAVES 



301 



of scaling discussed in PART I had been studied in connection with the 

 extension of magnetron frequencies into the 20 to 45 cm. and 3 cm. wave- 

 length ranges and were fairly well understood by this time. These new 

 strapped magnetrons were coded as the 706AY-CiY and the 71-iAY. The 

 frequency variation over the 706AY-GY band was accomplished by varia- 

 tion of the resonator slot width. The characteristics of these magnetrons, 

 apart from frequency, are essentially the same as those of the 718AY-EY 

 series (see Table II). External and internal views of the 706AY-GY type 

 are shown in Figs. 60 and 61. The strapping scheme to be seen in Fig. 61 

 is the early British system depicted schematically in Fig. 24(a). 



Fig. 60- An external view of a 706AV-GY magnctnm (150 kw., -3U00 mc/s). 



The means of fabricating the anode block in manufacture is also of interest. 

 This had to be inexpensive and fast. As worked out by Western Electric 

 engineers, it consisted of boring the interaction space hole lirst and turning 

 the end spaces into the solid copper block. This was followed by two opera- 

 tions in a multiple spindle drill press in which the eight resonator holes are 

 drilled to size. Following this, a broach consisting of eight tapered series of 

 projecting cutting edges, spaced equally around the main shaft, was drawn 

 through the interaction space hole, cutting the eight slots to size in a single 

 operation. 



Although more powerful magnetrons were subsequently developed, these 

 10 cm. magnetrons of power output below 200 kw. are still considered to be 

 highly satisfactory designs. Together with similar designs in C.reat Britam, 

 they have been produced by several manufacturers in large quantity and 



