This circuit is from an old documentation making use of a 3,579,645 MHz analog color television crystal. The audio amplifier supports the equivalent.
The sensor diode used in this circuit is the common type of germanium. Experiments may be made...
April 2017 - Mouser Electronics already has in stock the Texas Instruments' new TPS54418A...
This circuit was found in a 90s Wels' Think Tank. The frequency depends on C2 and R3. The handset...