500-Mc. Transmitting Tetrode Design Considerations

Performance characteristics for a good power amplifier in the 30- to 500-Mc. region are discussed and some tube design considerations are presented. It is shown that tetrodes inherently self-neutralize the radio-frequency feedback due to the plate-to-grid capacitance. This self-neutralization frequency may readily be shifted by simple circuit modifications. A comparison of neutralized triodes and neutralized tetrodes in the limiting frequency range is made, and tetrodes are shown to be inherently more stable as well as providing circuit advantages. Two new transmitting tetrode tubes are presented, one of which delivers 100 watts at 500 Mc.