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.
Two identical transformers can be used as a single improvised isolation transformer. The maximum...
This transmitter can send its signals from several kilometers away, depending only on the antenna...
This circuit was found in Radio Electronics magazine from January 1959. The power transistor must...