This circuit for medium and short wave range was found in an American documentation from 1992. The circuit can use general purpose transistors and the antenna can be external or telescopic.
This is the basic configuration of an operational amplifier sample & hold circuit. The FET and...
The integrated circuit 4136 consists of operational amplifiers of type 741 in the same enclosure and...
We find this circuit in a 1987 publication. It makes use of comparators constructed around the 741...