On 9/16/2010 1:45 PM, lu6etj wrote:
On 13 sep, 17:23, Roy wrote:
On 9/13/2010 11:31 AM, Richard Clark wrote:



What is the characteristic Z of free space or air?

What is the characteristic Z of Water (plain, with mud, or salty)?
. . .

Anyone with EZNEC, including the demo program, can easily get the value
of intrinsic Z of various media. Just define a Real ground type in any
model and enter the ground constants. Then open the Utilities menu and
select Ground Info. A wave normal to the ground will reflect exactly as
it would from the junction of two transmission lines with one having the
impedance of free space (about 377 + j0 ohms) and the other having the
ground's impedance. The nature of oblique reflections depend on the
polarization of the wave relative to the reflecting plane (the ground),
but a reflection always occurs whenever the wave encounters a change in
the impedance of the medium, or a "mismatch" as Richard calls it.

Roy Lewallen, W7EL

Hello Roy:

Very good and youseful info. Is it possible change the reflecting
angle in that result?

Miguel

Sorry, I'm not sure what result you mean. You can't change the
reflecting angle -- the angle of reflection is always equal to the angle
of incidence. And the intrinsic impedance of a medium doesn't change
when a wave strikes it, reflects off it, or propagates through it.

Roy Lewallen, W7EL