This commercial receiver for the mid-wave range of the 1960s was found in Japanese documentation at the time. The supply is 9 V, and the configuration is superheterodyne type.
This circuit was found in a Popular Electronics from the 90s. The frequency depends on the...
This circuit consists of a “zero crossing detector” that provides a rectangular output signal...
Low power RF transistors such as the BF494 or BF495 and even those in the BC series can oscillate well...