Indeed I do not need a specific freq. But since you wrote about 'resonance freq' I asked myself how to achieve it. Now I know: with a trimming cap. And checking which parameter while trimming?Your main goal is to get the right frequency.This you can do by picking up the right amount of capacitor.For example, placing several capacitors in parallel or using a tuning capacitor.Although I do not understand why you need this frequency.My circuit is not critical to the frequency.