This circuit for signals up to 30 MHz can improve your reception in the medium and short-wave band. We found it in the Radio Electronics magazine of February 1989.
Found in a Popular Electronics from 1992, this circuit uses a PLL567 in an audio meter bridge that...
This circuit was found in a 1991 publication. The transistor can be a general-purpose type....
This is a different circuit for a component from the past, the zirconium arc lamp used in...