This circuit is from Motorola's Linear Interface ICs from 1993. The MC1723 is the equivalent of the well-known 723. The transistor supports equivalents.
This configuration makes use of an integrated circuit of the time having been found in a 1976 NASA...
The signal itself captured by the (long) antenna serves to feed this simple experimental circuit....
From different input voltages V, it is possible to reduce the voltage to several fixed values...