"Cecil Moore" wrote in message
et...
Richard Harrison wrote:
Cecil, W5DXP wrote:
"Have you ever measured such?"

My Bird Model 43 Instruction book says:
"---designed to measure power flow and load match in 50 ohm coaxial
transmission lines."
I`ve used it many times.

Would you agree it is indirectly measuring joules/sec
not watts/sec? That would be energy flow.
--
73, Cecil http://www.w5dxp.com

actually, its not measure energy or power, its measuring voltage and current
and presenting you with the result of a calculation that represents power.

"Richard Fry" wrote in message
...
"Roy Lewallen" wrote:
All the power produced by the transmitter arrives at the antenna
less whatever is lost as heat in the transmission line.
_________

Roy,

If a transmitter produces r-f power, and a load connected to that
transmitter via a transmission line dissipates any of that r-f power, then
would you not agree that such an r-f transmission line conducts at least
whatever r-f power is dissipated by that load?

And if such a transmission line can conduct power in one direction
(incident), it can also conduct power equally well in the opposite
direction (reflected), until the net result of incident + reflected causes
line failure.

When the Zo of a transmission line matches the Zo of a load at its far
end, then that far-end Z absorbs nearly 100% of the power delivered there
by that transmission line.

If those impedances are not matched, a reflection is generated that may
lead to the real-world, destructive and periodic effects on the
transmission line that I reported from personal experience, earlier in
this thread.

RF

no transmission line conducts power. it conducts moving electrons which are
measured as a current or voltage. power is a figment of our mathematics
that has created a convenient way to take the current and/or voltage and/or
impedance (only 2 of the 3 are needed) and convert them to a measure of
energy flow, or power, that happens to be a nice conceptual way to view
things. we could just as well give up all readings of power and state taht
a transmitter produces 1 amp into a 50 ohm load instead of that it produces
50 watts... the former is more descriptive, the latter is simpler for the
non-engineer.

Cecil Moore wrote:
Gene Fuller wrote:
In the standing wave model the energy simply sloshes back and forth
within a single half-wave loop. No energy collisions; no problems at all.

The problem is that it is impossible for EM waves to
do that. An EM wave flows in one direction until it
encounters a physical impedance discontinuity. It
cannot "slosh back and forth" in reality.

I guess you still cannot get over your fixation on traveling waves. Too
bad; you miss so much when wearing blinders.

73,
Gene
W4SZ

Dave wrote:
"Cecil Moore" wrote:
Would you agree it is indirectly measuring joules/sec
not watts/sec? That would be energy flow.

actually, its not measure energy or power, its measuring voltage and current
and presenting you with the result of a calculation that represents power.

Like I said, it is indirectly measuring power -
by sampling the voltage and current at a fixed
point in a known Z0 environment and performing
some in-phase and out-of-phase phasor additions.

The point is that it is displaying watts at a
*fixed* point, i.e. average joules flowing past
a fixed point in one second. It is the joules
that are flowing, not the watts.
--
73, Cecil http://www.w5dxp.com

Dave wrote:
power is a figment of our mathematics

With EM waves, you can say the same thing about
voltage and current. The energy in the photons
has a much more basic relationship to reality.
--
73, Cecil http://www.w5dxp.com

Gene Fuller wrote:
I guess you still cannot get over your fixation on traveling waves. Too
bad; you miss so much when wearing blinders.

Sloshing EM energy is only a math shortcut which
violates the laws of physics and exists only in
your mind (and others). Traveling EM waves agree
with the laws of physics and can be observed with
one's own eyes.

When math shortcuts become one's religion, one
has a definite problem.
--
73, Cecil http://www.w5dxp.com

Cecil Moore wrote:
Gene Fuller wrote:
I guess you still cannot get over your fixation on traveling waves.
Too bad; you miss so much when wearing blinders.

Sloshing EM energy is only a math shortcut which
violates the laws of physics and exists only in
your mind (and others). Traveling EM waves agree
with the laws of physics and can be observed with
one's own eyes.

When math shortcuts become one's religion, one
has a definite problem.

Cecil,

I will not argue with you about mobile antenna shootouts.

However, I will compare my physics education to yours any day. Which
law(s) of physics do you think I have violated?

8-)

73,
Gene
W4SZ

"Roy Lewallen" wrote:
All the power produced by the transmitter arrives at the antenna
less whatever is lost as heat in the transmission line.

How about a case of a non-resonant transmission line whose Zo equals the
load Z except for a discrete mismatch somewhere in the line? Reflections
from that mismatch will be dissipated in the reverse port termination of a
circulator installed at the input of the line. Clearly not all of the power
available at the output of the circulator arrived at the antenna (less line
loss).

..Unless the line is perfectly matched, there will be repeating points of
high current and of high voltage. Depending on the nature of the conductor
and insulator, either or both of these can cause localized heating. In the
example you gave, the damage is almost certainly caused by high current
rather than high voltage. ...

I agree, and misunderstood your original post.

RF

Gene Fuller wrote:
However, I will compare my physics education to yours any day. Which
law(s) of physics do you think I have violated?

"Sloshing" EM waves violates the conservation
of momentum principle.

What reverses the momentum of an EM wave at the
point where it starts "sloshing" around when
there is no physical impedance discontinuity?

In terms of optics, how does light energy just
start "sloshing" around in free space when
there is no change in index of refraction in
the medium?

Given Hecht's equation for a light standing wave
in free space, where are the terms that cause
the "sloshing"?
--
73, Cecil http://www.w5dxp.com

Cecil Moore wrote:
Gene Fuller wrote:
However, I will compare my physics education to yours any day. Which
law(s) of physics do you think I have violated?

"Sloshing" EM waves violates the conservation
of momentum principle.

What reverses the momentum of an EM wave at the
point where it starts "sloshing" around when
there is no physical impedance discontinuity?

In terms of optics, how does light energy just
start "sloshing" around in free space when
there is no change in index of refraction in
the medium?

Given Hecht's equation for a light standing wave
in free space, where are the terms that cause
the "sloshing"?

Cecil,

That's a good one. I did not know that a transmission line is "free space".

Try again.

73,
Gene
W4SZ