From Kraus: Antennas

" 1-1. Definitions. A radio antenna may be defined as the structure
associated with the region of transition between a guided wave and a
freespace wave, or vice versa.
In connection with this definition it is also useful to consider what is
meant by transmission line and by resonator. A transmission line is a device
for transmitting or guiding radio-frequency energy from one point to
another. Usually it is desirable to transmit the energy with a minimum of
attenuation, heat and radiation losses being as small as possible. This
means that while the energy is being conveyed from one point to another it
is confined within the transmission line or to the vicinity of the line.
Thus, the wave transmitted along the line is one-dimensional in that it does
not spread out into space but follows along the line. From this general
point of view the term transmission line includes not only coaxial and
two-wire transmission lines but also hollow pipes, or wave guides.
A generator connected to an infinite, lossless transmission line produces
a uniform traveling wave along the line. If the line is short-circuited, a
standing wave appears because of interference between the incident and
reflected waves. A standing wave has associated with it local concentrations
of energy. If the reflected wave is equal to the incident wave, we have a
pure standing wave. The energy concentrations in such a wave oscillate from
entirely electric to entirely magnetic energy and back twice per cycle. Such
energy behavior is characteristic of a resonant circuit, or resonator.
Although the term resonator, in its most general sense, may be applied to
any device with standing waves, the term is usually reserved for devices
with stored energy concentrations that are large compared with the inflow or
outflow of energy.(2)

(2) The ratio of the energy stored to that lost per cycle is
proportional to the Q, or sharpness of resonance of the resonator."



From Wikipedia:

"In physics, power (symbol: P) is the rate at which work is performed or
energy is transmitted, or the amount of energy required or expended for a
given unit of time.
When the rate of energy transfer or work is constant, all of this can be
simplified to

P=W/t=E/t

where W and E are, respectively, the work done or energy transferred in time
t (usually measured in seconds)."


Yuri and W9UCW also found that
on a quarter wave resonant vertical antenna, which is a standing wave
circuit, and demonstrates that at the current maximum at the base, or at the
bottom of the loading coil, the current heats the wire. At the tip, where
there is a voltage maximum, the corona or neon bulb lights up. Both effects
demonstrating that there is power (energy over time) being exhibited.
Kraus so effectively explains it in the introduction to his book, but the
"expertise" on this news group insists on otherwise - "no power in standing
wave circuit".

73 Yuri, K3BU.us

"Yuri Blanarovich" wrote in message
...

From Kraus: Antennas

" 1-1. Definitions. A radio antenna may be defined as the structure
associated with the region of transition between a guided wave and a
freespace wave, or vice versa.
In connection with this definition it is also useful to consider what is
meant by transmission line and by resonator. A transmission line is a
device for transmitting or guiding radio-frequency energy from one point
to another. Usually it is desirable to transmit the energy with a minimum
of attenuation, heat and radiation losses being as small as possible. This
means that while the energy is being conveyed from one point to another it
is confined within the transmission line or to the vicinity of the line.
Thus, the wave transmitted along the line is one-dimensional in that it
does not spread out into space but follows along the line. From this
general point of view the term transmission line includes not only coaxial
and two-wire transmission lines but also hollow pipes, or wave guides.
A generator connected to an infinite, lossless transmission line produces
a uniform traveling wave along the line. If the line is short-circuited, a
standing wave appears because of interference between the incident and
reflected waves. A standing wave has associated with it local
concentrations of energy. If the reflected wave is equal to the incident
wave, we have a pure standing wave. The energy concentrations in such a
wave oscillate from entirely electric to entirely magnetic energy and back
twice per cycle. Such energy behavior is characteristic of a resonant
circuit, or resonator. Although the term resonator, in its most general
sense, may be applied to any device with standing waves, the term is
usually reserved for devices with stored energy concentrations that are
large compared with the inflow or outflow of energy.(2)

(2) The ratio of the energy stored to that lost per cycle is
proportional to the Q, or sharpness of resonance of the resonator."



From Wikipedia:

"In physics, power (symbol: P) is the rate at which work is performed or
energy is transmitted, or the amount of energy required or expended for a
given unit of time.
When the rate of energy transfer or work is constant, all of this can be
simplified to

P=W/t=E/t

where W and E are, respectively, the work done or energy transferred in
time t (usually measured in seconds)."


Yuri and W9UCW also found that
on a quarter wave resonant vertical antenna, which is a standing wave
circuit, and demonstrates that at the current maximum at the base, or at
the bottom of the loading coil, the current heats the wire. At the tip,
where there is a voltage maximum, the corona or neon bulb lights up. Both
effects demonstrating that there is power (energy over time) being
exhibited.
Kraus so effectively explains it in the introduction to his book, but the
"expertise" on this news group insists on otherwise - "no power in
standing wave circuit".

73 Yuri, K3BU.us

Since you are drawing power, by lighting a neon bulb, or by creating a
corona, or by heating a wire through current flow, it cannot be a standing
wave in the theoretical sense. It is possible to use perfect or ideal
components in a theoretical analysis, but real life tends to throw a spanner
in the works. In any real standing wave circuit there are power losses due
to radiation or resistance. The nearest one could come to the idealised
standing wave circuit is the current flow around a superconductor. The
current flows continuously until an outside influence such as a magnetic
field interrupts the flow. Depending on the circumstances, a physical
(magnetic) repulsive force may be generated or a feedback loop may develop
resulting in rapid temperature rise, loss of superconductive properties and
a rather loud bang as the circuit comes apart. Clearly power does flow in
all real life standing wave circuits.

Mike G0ULI

Yuri Blanarovich wrote:
Kraus so effectively explains it in the introduction to his book, but the
"expertise" on this news group insists on otherwise - "no power in standing
wave circuit".

The energy in the traveling waves was supplied as power
by the source during the power-on transient state and is
exactly the amount of energy needed to support the forward
and reflected waves. The energy in the forward and reflected
waves is dissipated during the power-down transient state.

Assuming an integer number of cycles per second, a one second
long lossless transmission line with a forward power of 200
watts and a reflected power of 100 watts contains 300 joules
of energy.
--
73, Cecil http://www.w5dxp.com

On Feb 13, 9:31*pm, Cecil Moore wrote:
Yuri Blanarovich wrote:
Kraus so effectively explains it in the introduction to his book, but the
"expertise" on this news group insists on otherwise - "no power in standing
wave circuit".

The energy in the traveling waves was supplied as power
by the source during the power-on transient state and is
exactly the amount of energy needed to support the forward
and reflected waves. The energy in the forward and reflected
waves is dissipated during the power-down transient state.

Assuming an integer number of cycles per second, a one second
long lossless transmission line with a forward power of 200
watts and a reflected power of 100 watts contains 300 joules
of energy.
--
73, Cecil *http://www.w5dxp.com

This is demonstrated everytime a pulsed radar fires. Energy for the
next pulse is stored in a Pulse Forming Network that is either a
transmission line or lumped circuit representation of a transmission
line. High energy devices such as radar, lasers and xray equipment
often use the lumped circuit (LC ladder)representation of a
transmission line to store energy. I dont know if there is a practical
example of an actual transmission line being used for this purpose
outside of a design laboratory due to physical impracticality but
under those lab conditions it was discovered that an actual
transmission line provide a pulse of superior shape than the lumped
circuit PFN. It should be noted that when a radar fires more power is
taken from the PFN in say 1uS than was placed into it during any uS
while the PFN was charging. MIT/ Lincoln Labs is probably the best
source of data for anyone who wants to research this further. The use
of a transmission line to store energy is covered in just about any
introductory level radar theory book.

For quite some time now I have followed this thread(s) wondering if
all the arguement is about whether or not a transmission line can
store energy or not. If this is in fact the question then the answer
is definitely YES.

Jimmie

JIMMIE wrote:
For quite some time now I have followed this thread(s) wondering if
all the arguement is about whether or not a transmission line can
store energy or not. If this is in fact the question then the answer
is definitely YES.

Joules of energy delivered to the standing wave during the
key-down transient state can be enormous when very high
SWRs are involved. When key-up occurs, that energy has to
go somewhere. More than ten times the steady-state power can
easily be delivered to the load during the key-up transient
state.
--
73, Cecil http://www.w5dxp.com

JIMMIE wrote:
. . .
For quite some time now I have followed this thread(s) wondering if
all the arguement is about whether or not a transmission line can
store energy or not. If this is in fact the question then the answer
is definitely YES.

The little program I wrote and referenced a little while ago, TLVis1,
shows graphically how much energy is at each point along a line at every
time from turn-on to steady state. And it even shows separately how much
is stored in the electric and magnetic fields.

Roy Lewallen, W7EL