The heater-cathode structure of the 6146B / QE05/40 is designed to supply ample tube current with heater voltages from 6.0 to 7.5 volts; however the tube will perform satisfactory with heater voltages ranging from 5 to 8 volts. Satisfactory operation throughout a wide range of supply voltages makes possible reliable performance under the conditions normally encountered in mobile service.
Adequate shielding and effective RF grounding are facilitated by the cathode, grid 3, and internal shield all of which are connected to 3 base pins. Isolation of output from input is further enhanced by a top-cap plate connection.