This receiver was found in a Popular Electronics from the 90's. Its different configuration shows a tuning circuit after the tube that works as an aperiodic amplifier. Observe supply voltages.
The previous circuit (CB5050E) triggers when the temperature exceeds the limit set on the...
Found in a 1960s Electronic Design, this circuit provides a signal from the sensing of an analog...
We found this sensitive high input impedance voltage amplifier in the November 1970 Radio...