Found in an old American documentation this FM modulator makes use of a varactor diode. The circuit can be easily implemented given the small number of components used.
This simple standing waveform (ROE or SWR) meter is used to adjust antenna matching with...
The 4046 consists in a PLL with na internal oscillator controlled by voltage (VCO). Figure bellow...
This microtransmitter operates at a frequency between 3.5 MHz and 10 MHz determined by the...