On Jul 1, 4:35 pm, Cecil Moore wrote:
Richard Harrison wrote:
Radiation resistance is a resistance. Radiated energy has its current
in-phase with its voltage.

The IEEE Dictionary is pretty clear when they define two
types of resistances: (A) a resistor with resistance and
(B) a virtual resistance with the V/I ratio in phase.
--
73, Cecil http://www.w5dxp.com

I could not find "virtual resistance" in "IEEE 100, The Authoritative
Dictionary of IEEE Standards Terms, Seventh
Edition".

Do you have a reference?

Interesting, they explicitly define "radiation resistance" as
"The ratio of the power radiated by an antenna to the
square of the RMS antenna current referred to a specified
point.
Notes: 1. The total power radiated is equal to the power
accepted by the antenna minus the power dissipated in the
antenna.
2. This term is of limited utility for antennas in lossy
media."

There seems to be a lot of opportunity for confusion with
this definition: "referred to a specified point" indeed.
Which point?

The IEEE definition of "resistance" is hardly less obtuse:
"(1)(A)(network analysis) That physical property of an
element, device, branch, network, or system that is the
factor by which the mean-square conduction current must be
multiplied to give the corresponding power lost by
dissipation as heat or as other permanent radiation or
loss of electromagnetic energy from the circuit.
(B)(network analysis) The real part of impedance.
Note: Definitions (A) and (B) are not equivalent but are
supplementary. In any case where confusion may arise,
specify definition being used. See also: resistor."

....Keith