Keith Dysart wrote:
This is good; a continuum with high coherence at one end, low
coherence at the other and medium in the middle, and, of course,
since the ends are infinitely small, no such thing as perfect
coherence or "NO" coherence (at least in the real world).

But remember that definition is for fiber optics
sources, not amateur radio sources. Coherency
in amateur radio systems can get as close as
a zero reading on a reflected power meter.

Still there are those nagging assertions of Born
and Wolf that for two equal magnitude signals,
the total intensity possible for incoherent
signals is double the intensity of one signal.
The total intensity possible for coherent
signals is four times the intensity of one
signal.
--
73, Cecil http://www.w5dxp.com