FM Oscillator

a VCO and buffer that operates across the entire FM broadcast band (88-108 MHz). I stole the main idea from the local oscillator in a radio shack scanner (pro2004). I like this design because it doesn't require a tapped coil, it tunes very broadly, it's stable, and it has a nice, hot output

As with all VHF circuits, pay particular attention to construction technique. I recommend cutting little square islands on one side of a two-sided copper-clad board. Use the remainder of that side as the ground plane, and leave the bottom side to serve as a shield. If you keep all lead lengths short, the circuit is quite stable.
With the parts listed here, effective frequency range extends well beyond the FM broadcast band in both directions. If a 6V zener is substituted for CR2, the circuit will run from a 9V battery, with a slightly smaller tuning range. The output is hot enough that the signal can easily travel a city block using just a clip lead for an antenna.