This circuit is from a 1967 documentation. It makes use of varicap and diode tunnel in addition to currently uncommon FET. It serves as a reference.
This circuit was obtained in a Maxim documentation from the 90's. The circuit applies to...
Used in satellite TV receptions in the 1980s, this circuit was found in the March 1980 issue of...
We found this circuit in the April 2013 issue of Electronics Now. Any JFET can be used. Note the...