This transmitter for the 2-meter range with a power of 1.5 W was found in a magazine 73 for radio amateurs. No information was provided about the coils.
This circuit was published in an English magazine from 1972, but it can be easily implemented...
This circuit from a Popular Electronics from the 90s allows you to use an old PC as a digital...
With the values of the components of this circuit, tone recognition can be done in the range of...