This circuit aims to increase the selectivity of receivers whose FI is 455 kHz. The circuit is from 1975 documentation. The transistors can be the modern BF494 equivalents.
This circuit is used in transceivers, enabling input selection by diode switching through polarity...
This configuration was found in an American publication from the 90s. Operators admit equivalents just...
This circuit was found in an Italian magazine Elettronica Prática of 1977. The transistors can be...