Are you quite sure you have no way to measure inductance? Even if you
have only an AC voltmeter and a signal generator and some capacitors,
you should be able to measure the inductance. One of the best ways to
"measure" it for your application is to try a capacitor and see what
the resonant frequency actually is; then adjust the capacitor (by a
factor equal to the square of the ratio of resonant and desired
frequencies) and try again, repeating until it's trimmed to the
desired resonance.

Cheers,
Tom


Tim Robbins wrote in message . ..
I have a 300 long x 50mm dia. Schumann coil that measures 18.75KOhms.
I have no way to measure inductance. It has an annealed steel core 1M
long.

What capacitor value do I need to tune it to an 8Hz center frequency?

Thank you,

Tim