This amplifier with gain control was obtained in a documentation from Signetics of the 80's. Transistors are of power and operational amplifiers are not common nowadays.
The signal itself captured by the (long) antenna serves to feed this simple experimental circuit....
This voltage level-triggered circuit was found in a 1969 Ferranti English documentation. Modern...
This amplifier makes use of a simple 12 to 30 W source, having been found in the SGS manual of...