The mods are simple — snipping out the 25 MHz reference crystal on the LNB board and replacing it with a simple LC bandpass filter. This allows the local oscillator on the LNB to be referenced ...

The theremin is based on a simple LC oscillator built around a 7400 quad NAND gate IC, a wire antenna, and a few caps and resistors. When a hand moves closer to the antenna, the frequency of the ...