This circuit is from a Radio Electronics magazine from July 1979. It uses the well-known IC 7107, a liquid crystal exciter that became popular in circuits of this type at the time.
A 100 nF capacitor and 100 uH inductor form this circuit suggested by General Electric in a 1964...
We found this configuration in a 1974 publication. Transistors can be replaced with equivalents such as...
This circuit responds to frequencies from 100 Hz to 3 MHz. We find it in a 90s Radio Electronics....