Found in a 1991 publication this circuit can be assembled with more modern components. We can use 2N2646 for Q1. See the component section for electronics how to calculate C1 for the desired frequency. Key is a common telegraphic key.

Found in a 1991 publication this circuit can be assembled with more modern components. We can use 2N2646 for Q1. See the component section for electronics how to calculate C1 for the desired frequency. Key is a common telegraphic key.