This variable frequency oscillator for radio transmission covers the range from 1.6 MHz to 20 MHz, depending only on the coil used. The circuit is very stable and can be used in amateur equipment.
The figure shows how to implement an alarm buzzer in an LM3914 to warn about crossing the scale...
This circuit can act as a shield being controlled by a microcontroller by pin 1 or 2. The...
This circuit was obtained from a 1980's QST magazine. The circuit can generate 1 to 15 MHz signals...