The inductance of a toroid, in MICRO-henries, is -

L = 0.6283 * Mu * Square( N ) * B

where

B = D1 - Squareroot( Square( D1) - Square( D2 ) )

Mu = permeability of core material.
N = number of turns.
D1 = mean diameter of ring in metres.
D2 = diameter of ferrite core material in metres.

If the core is not circular, use the equivalent diameter which has the
same cross-sectional area.

To calculate number of turns just rearrange the formula.

To obtain high Q, you MUST use HF grade permeability material.

Permeability can be calculated using the formula by winding some turns
on a core and measuring inductance. A very good instrument to use is
an Autek RF Analyst-1

But, of course, if you are able to measure inductance there will be no
need to calculate permeability. You can calculate the required number
of turns immediately.
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Reg.