LC Oscillator...Help

Hello.

I am trying to design an LC Colpitts oscillator.



This is the circuit. I came up with this based on the Colpitts oscillator shown on this website http://www.electronics-tutorials.ws/oscillator/colpitts.html, except that I did not have a high frequency-blocking choke to connect the collector to the positive power supply, and used the 10 K ohm resistor instead. The potentiometer biases the transistor.
What happens when I turn the circuit on is (1) It does not oscillate until I turn the power supply up to its maximum of 18 V. (2) The oscillation, at ~2 MHz, is very weak (millivolts). Why does the circuit require 18 V and how can I increase the signal amplitude? I tried connecting the collector to +V through the primary winding of a transformer (as a replacement for a choke) and got no oscillation. On another note, I tried using a the primary winding of a transformer as the inductor in the tank circuit, and that also didn't work...so if it's possible to make that work in some way, that would be helpful to because I have more transformers than I do inductors.

 

Thanks! I just got another RF choke today. I've been trying to teach myself from the web how to properly set up the biasing and gains for transistor amplifiers, which was actually why I put the pot there, not for setting frequency.

I'll try that and see how that works.