DEVELOPMENT OF LINEAR POWER TUBES.

An engineering model which meets the requirements of Phase II intermodulation distortion of -45 db maximum third order and -50 db maximum fifth order with power output of 2000 to 5000 watts PEP was delivered. A test report, which includes a proposed test specification prepared in MIL format, was also completed and submitted. The test report includes test results on two tubes of the same model. One tube was shipped and the other is available for further tests. For a given set of operating conditions, the intermodulation distortion ratio for both tubes is 50 db third and fifth order from zero to 5000 watts PEP output, with better than 50 per cent efficiency. Engineering models, using the EIMAC 4CX15000A as prototype, are being built and tested. These models are designed to meet the requirements of Phase III 5000 to 15000 watts PEP output with -40 db maximum third order intermodulation distortion. The first experimental models, which were scaled from the successful Phase II design, were compared to the EIMAC 4CX15000A and were not as good in intermodulation distortion performance as the standard tube. The EIMAC 4CX15000A, when operated with zero signal plate current of 1.25 amperes, gives an intermodulation distortion ratio of 40 db third and fifth order in the power range from zero to 15 kW PEP. Additional experimental models are being designed and built in an attempt to reduce the required zero signal plate current and improve efficiency of operation. Author