FIRE-CONTROL RADARS FOR XAVAL VESSELS 



•IS 



saw-tooth wave having maximum rate of change in the center of the sweep; 

 the latter being derived from the range notch selection pedestal. The 

 combined sweej) is then applied to tiie horizontal plates of the cathode ray 

 tube. The return trace is blanked by applying to the control grid of the 

 cathode ray tube a voltage obtained by differentiating the sweej) wavefcjrm. 



Transmitter 



As mentioned earlier the transmitter oscillator tube problem was one 

 of the major obstacles in the march of radar development to higher fre- 

 quencies. Intense development effort on many possible types of tubes was 

 underway in several laboratories in this country and abroad during 1939 



Fig. 29— \V. 10. 70U-l\ 1)0 magaetruii— one side removed 



and 1940. The first significant improvement came in England where work 

 with multicavity magnetrons showed that this device was probably the 

 answer to radar's need for a highly intermittent duty oscillator suitable for 

 high power in the microwave region. A sample of this device was brought 

 to this country by the Government and was tested in Bell Telephone Lab- 

 oratories in October 1940. It produced pulses of several kilowatts at a 

 frequency in the neighborhood of 3000 mc. .A tremendous development 

 of this device got under way immediately^ and the multicavity magnetron 



6 "The Magnetron as a Generator of Centimeter Waves," J. B. Fisk, H. G. Hagstrum, 

 and P. L. Hartman, B. S. T. J., January, 1946. 



