Rca1948FrequencyModu.. - The New Jersey Antique Radio Club

MODULATION BY ELECTRON BEAMS 477using a twelve-vane magnetron oscillator shown schematically inFigures 6 and 7, which show a multivane magnetron with two rectangularbeams introduced between the vane structures. On one sideof the resonant cavity block is the beam gun structure, which includesa cathode, control grid, and acceleration aperture or grid; on the otherside of the block is a collector (or reflector for multiple transit). Thebeam is focused by the magnetic field. Measured values of the changein frequency per milliampere of beam current are shown in Figure5(b) plotted as a function of *> c/u for two different transit times.These curves have the same form as the theoreticalcurves shown inFigure 5(a). The L/d ratio for the cavity was 3, and the effectivecapacitance C was estimated to be about 2 X 10 -12 farads. At a beamitfMEASURED FREQUENCY PER MA BEAM CURRENT