Mark Keith, NM5K wrote:
"Why are your`s so special?"

Art can`t answer but I will. Art is dead wrong.

Radiation resistance is a resistance. Radiated energy has its current
in-phase with its voltage.

FCC defines output power of a transmitter as RF current at a designated
common-point of known resistance, thus calculated as I squared R.

Terman says on page 2 of his 1955 opus:
"A plane parallel to the mutually perpendicular lines of electric and
electromagnetic flux is called the wavefront."

Mutually perpendicular describes the physical positions of the fields,
not the timing of their waxing and waning, which is simultaneous.

The intrinsic impedance of free-space is the E/H ratio, a resistance of
377 ohms. The vector product of E and H gives the Poynting vector, or
power flow in watts per square neter in the direction of propagation.
The above is found on page 7 of E.A. Laport`s "Radio Antenna
Engineering".

Art has been promulgating pure baloney no matter how it is sliced about
vector analysis. I recommended B. Whitfield Griffith,Jr.`s
"Radio-Electronic Transmission Fundamentals" to Art for an understanding
of Maxwell and radiation. He obviously hasn`t yet studied Mr.
Griffith`s work.

I hate to dash the dreams of an old man, but he is leading others
astray.

Best regards, Richard Harrison, KB5WZI

On Sun, 1 Jul 2007 09:02:42 -0500, (Richard
Harrison) wrote:

he is leading others astray.

Hi Richard,

That would be true if anyone could follow him.

In the 20 Questions thread, there have been 19 questions and 25
answers, and Arthur is no further than explaining what he understands
from Faraday - imagine what it would take to get to Gauss, through his
work, and on to Maxwell, then Heavisides beyond him. Then comes the
pioneers of antennas.

As I recall, the game of 20 Questions could resolve an answer with
less work. Imagine, Arthur's final answer is:
the right hand
rule
is still preserved

What insight! There's more interest in the morbid lock-step of how
many questions until Arthur spits on Dave. I'm taking the pool number
of 43.

73's
Richard Clark, KB7QHC

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

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

Keith Dysart wrote:
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.

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

Do you have a reference?
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."

Sure do, Keith - your own quote. An example of Definition
(A) is a resistor. An example of Definition (B) is the
characteristic impedance of a transmission line which
is a virtual dissipationless resistance. Another example
of (B) is the feedpoint impedance of a standing wave
antenna. Another example of (B) is the virtual impedance
at the end of a quarter-wave series section transformer.
Another probable example of (B) is the dissipationless
part of a generator's source impedance.
--
73, Cecil http://www.w5dxp.com

On Jul 1, 11:14 pm, Cecil Moore wrote:
Keith Dysart wrote:
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.

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

Do you have a reference?
Sure do, Keith - your own quote. An example of Definition
(A) is a resistor. An example of Definition (B) is the
characteristic impedance of a transmission line which
is a virtual dissipationless resistance. Another example
of (B) is the feedpoint impedance of a standing wave
antenna. Another example of (B) is the virtual impedance
at the end of a quarter-wave series section transformer.
Another probable example of (B) is the dissipationless
part of a generator's source impedance.

I understand now. "Virtual resistance" is a term of your
own invention, not the IEEE, which explains why it is not
in the dicionary.

It is not a bad term for the concept, just misattributed.

....Keith

Keith Dysart wrote:
I understand now. "Virtual resistance" is a term of your
own invention, not the IEEE, which explains why it is not
in the dicionary.

I didn't invent the term, Keith. It is simply
descriptive of a resistance when the resistance
is not a resistor - a virtual resistance as
opposed to a physical resistor.

The fact that there are two definitions, (A) and
(B), for resistance in the IEEE dictionary is what
is important. But their definition has (A) as a
subset of (B). So what do we call a resistance that
satisfies the (B) definition but not the (A) definition?
Walter Maxwell calls it a virtual resistance and that's
good enough for me.

It is not a bad term for the concept, just misattributed.

I believe the first time I encountered the word
"virtual" used for an impedance was when I read
Walter Maxwell's early QST articles some 30 years
ago.
--
73, Cecil http://www.w5dxp.com