We found this circuit in the 1992 special edition of the Electronics Experimenter Handbook. The components used are still current, many admitting equivalents.
This conventional series reducer circuit reduces the voltage of a 12 V battery to the selected value...
In the figure we have a converter that generates a negative voltage from a positive voltage...
This circuit covers the bands from 1.8 to 150 MHz, with plug-in coils whose characteristics are...