Is there any other way to tune the circuit without using a variable capacitor? I know stretching out the coil will change the inductance but I don't know how much or how precise that will be.
I've been looking at some of the other types of oscillators and I saw some that used a crystal. Have you tryed those before, if so does the crystal provide the tuning for the circuit?
I don't really want to use a pre-desined device, i'm trying to figure out how to build one on my own, but as you can see, its not working as good as I hoped.