This 5 W transistor amplifier for the car was found in an English documentation from 1969. The transistors are from that time and the transformer is of a special type.
This circuit was obtained from an 80's Electronic Engineering. The circuit detects ice formation...
We found this zener regulator in a 1978 radio amateur documentation. The operational can be...
The suggestion for using this circuit from an old American documentation is to use small antennas...