The Orbital-Beam Secondary-Electron Multiplier for Ultra-High-Frequency Amplification

A developmental ultra-high-frequency receiving tube in which secondary-emission electron multiplication has been applied to a conventional high-transconductance tube structure to increase the transconductance without a corresponding increase in interelectrode capacitances and input conductance is described. It was designed primarily for wide-band amplification at a frequency of approximately 500 megacycles, as required for television radio relay systems. The tube uses conventional circuits and requires a power supply of less than 400 volts. The structure adopted permits the most efficient use of the secondary-emission multiplier consistent with satisfactory life and good high-frequency performance. The structure also permits the use of beam deflection to provide a convenient gain-control method, free from the input capacitance and conductance variations attending the usual gridbias control. A novel method of measuring interstage gain, involving the use of transmission lines, is discussed.