Richard Harrison wrote:
Richard Clark, KB7QHC wrote:
"The velocities of what?"

Figure 8-32 labels the ordinate values as "relative phase velocity".
Phase velocity is defined in my electronic dictionary as:
"The velocity at which a point of constant phase is propagated in a
progressive sinusoidal wave."

In other words, pick a point on a waveform. The rate at which it moves
is phase velocity. That`s the velocity of propagation.

What Kraus may be talking about is the apparent speeding
up of the signal compared to the "threaded bolt" calculation.
When 600 inches of wire is coiled into a helix, how can
EM waves travel through that 600 inches of wire faster than
it can travel through 600 inches in free space? Reckon that
is what he is talking about?
--
73, Cecil http://www.w5dxp.com