Calculating the frequency based on LC circuit

[guns]

Hi all,

I am currently building up a lightning detector based on this website: http://www.techlib.com/electronics/lightningnew.htm
as the diagrams shows, the resonance tank included a 10mH inductor and a 10pF capacitor.
As I want to calculate the resonant frequency (using the formula f = 1/2pi*sqrt(LC)), the answer was 5Hz, which is far from the desired range (should be around 200kHz)
is there any mistake in my calculation or concept? Thanks for your help.

Guns

 

[mfb]

How did you get your answer? Did you consider the SI prefixes (milli, pico)?
I think there are brackets missing in your equation.

 

[guns]

mfb,
I did it this way:
1/2pi*sqrt(10^(-3)*10^(-12))
which approxmately equals to 5 Hz.

 

[milesyoung]

Following up on mfb's post, you're missing brackets and are using the wrong values for the SI units:

10 mH = 10*10^(-3) H
10 pF = 10*10^(-12) F

1/(2*pi*sqrt(10*10^(-3)*10*10^(-12))) Hz = 503.3*10^3 Hz = 503.3 kHz

 

[guns]

oh my, silly me.
Thanks mfb and milesyoung!