TRAVELING WAVE TUBE FOR 6,000-MC RADIO RELAY 1343 



VI. ACKNOWLEDGMENTS 



The M1789 TWT is the outcome of an intensive efTort which has 

 included many individuals in addition to the authors. R. Angle, J. S. 

 Gellatly, E. G. Olson, and R. G. Voss all have contributed to the me- 

 chanical design of the tube and to its reduction to practice. R. W. 

 DeVido has materially assisted with the electrical testing. M. G. Bodmer 

 and J. F. Riley have been responsible for setting up the life test program 

 and J. C. Irwin and J. A. Saloom contributed importantly to the design 

 work on the electron gun. P. P. Cioffi and M. S. Glass have been largely 

 responsible for the design of the magnetic circuits and P. I. Sandsmark 

 for the helix-to-waveguide transducers. D. 0. Melroy studied the 

 effects of positive ions and performed the experiments on ion bombard- 

 ment referred to in Section III. D. R. Jordan contributed to the studies 

 on noise. In addition to the above, the authors would like to thank 

 E. D. Reed for his very helpful criticism of this manuscript. 



Appendix I — Gain Calculations 



The gain calculations for the M1789 follow the procedure outlined 

 by Pierce"^ with some minor modifications. The steps involved in the 

 gain calculations for the loss free region of the helix are as follows: 



- (1) The experimental synchronous voltage is used to determine 

 ya and the dielectric loading factor as defined by Tien.^ 



(2) From 7a the value of helix impedance K is obtained from Ap- 

 pendix VI of Pierce.^ 



(3) The value of K is corrected using Tien's^ results and C is then 

 calculated in the usual manner. 



(4) The number of wavelengths Ni per inch of helix is obtained using 

 the experimentally determined (from synchronous voltage) wave- 

 length. 



(5) The value of cog/w is determined. In this calculation the curves 

 for cop/cog from Watkins^ are employed. 



(6) QC is determined from 



QC = 



(7) From QC, B is determined from Fig. 8.10 of Pierce'^ and the gain 

 BCNi in the loss free region is calculated. 



In calculating the effect of the attenuator section, we have had to 

 make some rather gross assumptions. Fortunately, it turns out that the 



