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through" design. Experimental models were released for systems tests and 

 the need developed for such magnetrons to be used in some special radar 

 systems. The 730A is identical to the 725A except for external mechanical 

 details. An external view is shown in Fig. 67. 



Details of the fnial design of the 725A (and 730A except for the mechan- 

 ical differences noted) may be seen in Fig. 66. Data on these magnetrons 

 and their performance are given in Table III. A typical performance chart 



Fig. 66— A view of a cut-away 725A magnetron (55 kw., 9375 mc/s). Note the breaks 

 in the double ring straps, the so-called "halo" loop above the hole of the output resonator, 

 the step in the center conductor of the output coaxial providing the necessary impedance 

 transformation, and the details of the coaxial to wave guide junction. 



is shown in Fig. 68. Experience has indicated that it is entirely adequate for 

 150 kw. input at duty cycles up to 0.001 and, with later cathode designs, at 

 pulse lengths-up to 5ms. The RF spectrum is satisfactor}- even under rather 

 extreme conditions of mechanical vibration and shock, and the operation 

 under a variety of conditions is remarkably free from "moding". Difficul- 

 ties have been encountered in attempts to push its power input with 5/xs 

 pulses much above 175 kw. although with short pulses at lenient duty cycle 

 operation with as much as 300 kw. peak input power has been achieved. 



