This low noise circuit was obtained from a 1980s US RF publication. Transistors used are uncommon today and the gain is 19 dB..
This circuit is recommended for alarm systems since it has a good output stage. The circuit is...
) Suggested by Philips in a 1968 documentation this circuit has very high 10 ohm on-load voltage...
No information is given about the transformers in this circuit suggested by Motorola in a 1968...