LC receiver - resonance frequency
Don't you just hate when we say, &quot;well, it depends&quot;?
Your 30mH coil might have been designed for an application at a much lower frequency. Its inductance in the 30-40 kHz range may be much different, requiring less capacitance than 800 pf for resonance. Having a handful of 100pf capacitors to apply in parallel may be a good plan.
If you are adding a wire antenna to this resonator, its added capacitance should be considered as well.
Calculated resonance should be checked with a measurement.
An example: An antenna was built for 60kHz. Many turns of #26 magnet wire was wound on a circular form 25 inches in diameter. No ferrite was used. This coil needed no capacitance to resonate at 60 kHz - capacitance between turns is enough for self-resonance @ 60 kHz. Resonance is not sharp, but this antenna works well.
You might benefit some by measuring your inductor's DC resistance. This will set an upper limit on resonator Q, which will tell you how sharp resonance is. For example, a 50 ohm DC resistance gives a Q of about 132, which sets resonant bandwidth to less than 265 Hz.
It is likely that losses in its ferrite core will yield a Q much lower, giving a wider bandwidth. The loading of this resonator by an amplifier will lower Q too. So adding resonating capacitance in 100pf increments is a good plan.