ve2pid wrote:
Hi ot all

It is well known that the real ground seems to ''reflects'' a radio
wave. But I think that the term ''reflects'' is a bit confusing. My
understanding of the phenomenon is that the ground absorbs the
incident wave and, with that energy it re-radiates a new wave with a
different phase/amplitude value.

Not quite. The wave creates a current in the ground which produces a
field. For most ground types, the field which is produced resembles a
reflection that's altered in magnitude and phase.

That new wave modifies the TO angle as a real optical-type reflection
would do. Then, it seems that it is not a ''bending'' of the wave, but
the production of a new one. With the value of the modification of the
TO angle, one can deduces a ''reflected'' wave's angle, even if it not
a real reflection.. Am I right?

At any point in space, the total field is the sum of the original wave
and the "reflected wave". This sum is different from the original wave,
and the amount and way in which it's different depends on the point in
space. If by "TO angle" you mean the elevation angle at which radiation
is maximum, yes, that angle is often modified by the reflection because
of the different magnitude and phase of the reflection at each elevation
angle.

Also, I read in a older version of the ARRL's Handbook that ''The
effective ground plane, that is the plane from which ground
reflections can be considered to take place, seldom is the actual
surface of the ground, but a few feet below it, depending upon the
characteristics of the soil.''

I hope that's not in the current versions of the Handbook.

Considering what I said about re-routing with phase/amplitude
modifications, how to interpret the text form the Handbook? How to
determine the depth of that 'effective gorund plane'? Or is there any
depth at all? As is, it could be interpreted as a optical reflection
like occuring somewhere deep in the real ground..

I have no idea in what way an "effective ground plane" is "effective".
You can't put a perfect ground plane at any depth and get the same
reflection as you do from dirt.

Roy Lewallen, W7EL