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.
This circuit is from a 90's publication but uses components that are still common in our market....
This RF preamplifier for the 450 MHz band was found in an amateur radio documentation from the...
This low hysteresis circuit was obtained from old documentation. The circuit must be powered by a...