Oscillators

Does anyone have a circuit of a simple R-C / inverter oscillator circuit that I can use to create a square wave for my theremin.

I had a circuit using inverters & an inductor but I practically had to touch the antenna to get any change in the oscillator frequency.

What frequency range do you typically want your output signal to be?

Would a simple 555 IC chip suffice? You could stick a low-pass filter the output of your heterodyning circuit to get a control voltage for regulating the frequency of the 555.