David G. Nagel wrote:
Like many others I don't know everything. In line with reducing my
ignorance could you amplify on how the phenomena is measured with a
"fiber optic probe". What type of transducer is used to convert energy
of an electrical nature to energy of an optical nature with out
"perturbing the magnetic and electric fields".

Like you (unlike W8JI) I don't know everything. :-) I have
hardly any idea how they used a "fiber optic probe" to make
their measurements. I suspect they superposed local RF phasors
and used a fiber optic system to report the results. That's
what I would do.

I have invited Jim, W6RMK, to join the discussion. Maybe
he can answer your questions.
--
73, Cecil http://www.qsl.net/w5dxp