Richard Clark wrote:

Hi Herbert,

Pass a wrap of wire around the material if it is a bar, or through it
if it is a toroid. Connect this to the output of the SWR meter. Hit
it with a short blip of power and note the SWR. You have the
multiple/divisor of 50 Ohms. . .

Sorry, that's simply not true. You're almost certain to have reactance
-- possibly, a lot of it -- in which case the SWR can be vastly
different than the impedance divided by 50 ohms or its inverse.

Roy Lewallen, W7EL