. The Bell System technical journal . I789. Stated briefly, the performance characteristics undernominal operating conditions arc: 1285 1286 THE BELL SYSTEM TECHNICAL JOURNAL, NOVEMBER 1956 Frequency Range 5,925-6,425 mc Power Output 5 watts Gain at 5 watts output 31-35 db Noise Figure < 30 db The tube is designed for use with w-aveguide input and output input voltage standing wave ratio (VSWR) is less than and theoutput VSWR is less than over the 500-mc band when the tube isdelivering 5 watts of output. Fig. 1 shows a photograph of an MI789and of an experimental perman
. The Bell System technical journal . I789. Stated briefly, the performance characteristics undernominal operating conditions arc: 1285 1286 THE BELL SYSTEM TECHNICAL JOURNAL, NOVEMBER 1956 Frequency Range 5,925-6,425 mc Power Output 5 watts Gain at 5 watts output 31-35 db Noise Figure < 30 db The tube is designed for use with w-aveguide input and output input voltage standing wave ratio (VSWR) is less than and theoutput VSWR is less than over the 500-mc band when the tube isdelivering 5 watts of output. Fig. 1 shows a photograph of an MI789and of an experimental permanent-magnet focusing circuit. In developing this tube we have endeavored to produce an amplifierwhich could be considered practical for use in a transcontinental radiorelay system. Because such an application requires a high degree ofreliability and refinement in performance, the tube was rather con-servatively designed. This made it possible to obtain the desired gainand power output without difficulty. On the other hand, the contem-. Fig. 1 — The M1789 traveling-wave tube and an experimental permanent mag-netic circuit used to focus it. The circuit contains two specially shaped bar mag-nets l)et\veen which the tube is mounted. The magnetic flux density obtained is600 gauss, and the overall circuit weight is about 25 pounds. TRAVELING WAVE TUBE FOR 6,000-MC RADIO RELAY 1287 plated system application made it necessary to investigate in detail theproblems associated with band flatness, matching, noise output, certainsignal distortions, reproducibility, and long life. The solution of some of these problems required the development of aprecisely constructed helix assembly in which the helix winding is bondedto ceramic support rods by glaze. Others required the initiation of a lifetest program. Early results indicate that life exceeding 10,000 hourscan be obtained. This, in no small measure, is a result of a dc potentialprofile which minimizes the ion bombardment of the cathode. S
Size: 1727px × 1447px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
