On Jul 15, 3:14*am, Owen Duffy wrote:
I note some variation in the use of the term 'Radiation Resistance' (Rr)
that suggests that it has different meanings to different folk.

One suggestion is that it is the resistance seen by a transmission line *
connected to an antenna that expresses its coupling to distant regions of
space.

If that is the case, Rr would not capture energy that is lost in
reflection from real ground. So, Rr would be the sum of power in the far
field divided by RMS current squared.

If indeed it is the "resistance seen by a transmission line", then the
current above would be the current at the end of the transmission line.

Does the term have an accepted single clear meaning? Is the above
correct?

Some implications of the above are that:
- Rr of a horizontal half wave dipole with zero conductor loss, above
real ground, would have Rr less than R at the feedpoint by virtue of some
loss in waves reflected from real ground;
- Rr of a half wave folded dipole of equal conductor diameters would be
around 300 ohms.

Thanks
Owen

Owen
Can I suggest that you look at things differently?
Radiation is created by the acceleration of charge
which effectively that which creates an acceleration of a particle
such as a bullet from a rifle. The reaction to the firing of the
bullet is the recoil
which is considered as the resistance to radiation.
If you expend energy in other places to get to the point of firing
they can only be referred to as losses.
Thus radiation is a point vector and should not be confused by
multiple vectors that create a plasma.
All radiation equations are formed by the use of boundary equations
which requires recognition
of vectors or point charge and NOT by acceptance of the term "waves."
As an illustration, a superconductive material has the minimum
resistance possible to ensure the credibility of Ohms law. This
resistance has nothing to do with "dc resistance" because current flow
is at or near the surface because of the destruction of skin depth
resistance phenomina, which also means the cancellation of magnetic
fields.( Not destruction as the magnetic field is transformed into a
energy bank)
Thus ejection of particles can be considered as purely that of the
displacement current formed.
Expansion of static laws to those of dynamic form
establishes the use of particles with the use of boundary laws
(vectors) together with conformety with Classical laws.
Regards
Art