On Dec 5, 10:01 am, Cecil Moore wrote:
Keith Dysart wrote:
I thought that when you specified 5 and 10 degrees in your
problem statement, you meant electrical degrees. That is, the
phase shift encountered by the forward travelling wave.

That specification is the same for physical and electrical
degrees because we are dealing with a single Z0 piece of
transmission line. The 100 ohm line is indeed 10 degrees
long both physically and electrically.

Certainly, the answer was in terms of electrical degrees. That is,
the phase shift encountered by the forward travelling wave.

You, and others, are going to be surprised to find out the
600 ohm section is only 43 degrees of physical length.

Hardly surprised. After all, the same can be achieved with an
inductor and/or capacitor which has essentially
0 physical (or electrical) length.

How
can 43 degrees of 600 ohm line add to 10 degrees of 100 ohm
line to equal 90 electrical degrees of stub? Hint: Like I
told Roy and Tom years ago, there's a 37 degree phase shift
at the impedance discontinuity between the 600 ohm line and
the 100 ohm line. 43+37+10 = 90 electrical degrees.

So the important take-away is that the system phase shift is
NOT equal to the sum of the phase shifts of the components.

This then begs the question, is the physical (or electrical) phase
shift in the components of much interest?

Keith Dysart wrote:
Hardly surprised. After all, the same can be achieved with an
inductor and/or capacitor which has essentially
0 physical (or electrical) length.

Only true for a lumped inductor which doesn't exist
in reality. Any large coil, such as the coil tested
by W8JI, has considerable electrical length at 4 MHz.
This electrical length is what some folks have been
denying for years even though they should certainly
know better by now.

This then begs the question, is the physical (or electrical) phase
shift in the components of much interest?

It is - when someone tries to convince the world that
there is a 3 ns delay through a 2" dia, 10 TPI,
100 turn coil. The electrical length (phase shift)
through a coil is necessary and sufficient to kill
the old wives tales being supported by some so-called
"experts" on this newsgroup.
--
73, Cecil http://www.w5dxp.com

On Dec 5, 10:40 am, Cecil Moore wrote:
Keith Dysart wrote:
Hardly surprised. After all, the same can be achieved with an
inductor and/or capacitor which has essentially
0 physical (or electrical) length.

Only true for a lumped inductor which doesn't exist
in reality. Any large coil, such as the coil tested
by W8JI, has considerable electrical length at 4 MHz.
This electrical length is what some folks have been
denying for years even though they should certainly
know better by now.

This then begs the question, is the physical (or electrical) phase
shift in the components of much interest?

It is - when someone tries to convince the world that
there is a 3 ns delay through a 2" dia, 10 TPI,
100 turn coil. The electrical length (phase shift)
through a coil is necessary and sufficient to kill
the old wives tales being supported by some so-called
"experts" on this newsgroup.

But again, given that the key message is "that the system phase shift
is NOT equal to the sum of the phase shifts of the components.",
why is the question of delay through the coil important?

Is it just to have a "debate" with some called experts?

Or does it offer some advancement in the solution of antenna
problems? Having computed (or measured) the delay through
the coil, how would this alter the design of the antenna?

....Keith

"Keith Dysart" wrote in message
...
On Dec 5, 10:40 am, Cecil Moore wrote:
Keith Dysart wrote:
Hardly surprised. After all, the same can be achieved with an
inductor and/or capacitor which has essentially
0 physical (or electrical) length.

Only true for a lumped inductor which doesn't exist
in reality. Any large coil, such as the coil tested
by W8JI, has considerable electrical length at 4 MHz.
This electrical length is what some folks have been
denying for years even though they should certainly
know better by now.

This then begs the question, is the physical (or electrical) phase
shift in the components of much interest?

It is - when someone tries to convince the world that
there is a 3 ns delay through a 2" dia, 10 TPI,
100 turn coil. The electrical length (phase shift)
through a coil is necessary and sufficient to kill
the old wives tales being supported by some so-called
"experts" on this newsgroup.

But again, given that the key message is "that the system phase shift
is NOT equal to the sum of the phase shifts of the components.",
why is the question of delay through the coil important?

Is it just to have a "debate" with some called experts?

Or does it offer some advancement in the solution of antenna
problems? Having computed (or measured) the delay through
the coil, how would this alter the design of the antenna?

...Keith


That train of arguments and nitpicking developed from the main argument
about distribution of (standing wave) current along the loading coil and
antenna.
"Gurus" and some literature claimed that current is the SAME at both end of
the coil (Kirchoff "said so"). That would mean that current remains constant
along the coil and then drops drastically towards (almost) zero at the tip.
This makes loaded whip antenna look better than it is.

The reality is that current drops around 40 - 60 % along the loading coil,
which makes the distribution along the remaining stinger starting with less
and overall efficiency less.

The key to understand the loaded radiator is to trying to maximize the
current in the physical "straight wire" - so the higher the coil, larger
hat, will stretch the high current portion of the radiator and make it more
efficient. Fooling yourself by modeling the loading coil as a lumped
inductance and making it look better in modeling program does not help.
Again, this effect is magnified in multi element loaded arrays, so while
some might consider this not a big deal in a mobile whip, the errors would
magnify in multielement designs.

I hope I can get the main "problem" across, the rest was digging into the
smaller effects like coil radiates, junction impedance discontinuity, bla,
bla....

Now I also understand the small "bump" increase in the current at the bottom
of the coil due to some loses that reflected wave encounter on the way
"there and back" to the tip of the radiator from the bottom of the coil (?)

73 Yuri, www.K3BU.us

Yuri Blanarovich wrote:
Now I also understand the small "bump" increase in the current at the bottom
of the coil due to some loses that reflected wave encounter on the way
"there and back" to the tip of the radiator from the bottom of the coil (?)

I suspect that current bump is caused by magnetic linkage
between the central windings while the end windings would
not experience it to such a degree. It is the thing that
increases the velocity factor over the purely helical
path.
--
73, Cecil http://www.w5dxp.com

Keith Dysart wrote:
But again, given that the key message is "that the system phase shift
is NOT equal to the sum of the phase shifts of the components.",
why is the question of delay through the coil important?

Is it just to have a "debate" with some called experts?

That's as good a reason as any. :-)

Or does it offer some advancement in the solution of antenna
problems? Having computed (or measured) the delay through
the coil, how would this alter the design of the antenna?

I don't know.
--
73, Cecil http://www.w5dxp.com

Cecil Moore wrote:
Keith Dysart wrote:
Hardly surprised. After all, the same can be achieved with an
inductor and/or capacitor which has essentially
0 physical (or electrical) length.

Only true for a lumped inductor which doesn't exist
in reality. Any large coil, such as the coil tested
by W8JI, has considerable electrical length at 4 MHz.
This electrical length is what some folks have been
denying for years even though they should certainly
know better by now.

This then begs the question, is the physical (or electrical) phase
shift in the components of much interest?

It is - when someone tries to convince the world that
there is a 3 ns delay through a 2" dia, 10 TPI,
100 turn coil. The electrical length (phase shift)
through a coil is necessary and sufficient to kill
the old wives tales being supported by some so-called
"experts" on this newsgroup.

Cecil,

No one has ever said that there is a 3 ns delay *through* the coil. Ask
Richard Harrison if Faraday screens work, even without any conduction
path at all. Radiation is real.

You keep trying to change the topic, but the only debate is the relative
contributions of "round and round the wire" vs. other coupling. The math
is not easy, and the problem is not readily amenable to solution by
intuition and word games.

73,
Gene
W4SZ

Gene Fuller wrote:
No one has ever said that there is a 3 ns delay *through* the coil.

That's simply a false statement. Here's W8JI exact words:

"On 80-meters ... time delay is about 3nS. How does the
current travel through the inductor so fast?

Gene, "through the inductor" is through the coil. W8JI
said there is a 3 ns delay *through* the coil. W7EL
seems to agree.
--
73, Cecil http://www.w5dxp.com

Cecil Moore wrote:
Gene Fuller wrote:
No one has ever said that there is a 3 ns delay *through* the coil.

That's simply a false statement. Here's W8JI exact words:

"On 80-meters ... time delay is about 3nS. How does the
current travel through the inductor so fast?

Gene, "through the inductor" is through the coil. W8JI
said there is a 3 ns delay *through* the coil. W7EL
seems to agree.

Cecil,

You're losing your touch. That isn't exactly a subtle selective quote.

Here are the rest of the words following the question, "How does the
current travel through the inductor so fast?"

"At first this seems impossible, but the answer is actually quite
obvious. Time-varying current gives rise to time-varying magnetic flux.
This magnetic flux, since conductor spacing is close and the distance
very small, links the starting turn very tightly to the next turn. The
rapidly changing magnetic flux causes charges to move in the next
conductor, and the changing magnetic field couples through all the close
spaced turns with very little time delay. It is this magnetic flux
coupling that provides the primary mechanism for energy transfer through
the inductor, and the path is much shorter than the circuitous and much
longer path along the conductor."


But you already knew that . .

73,
Gene
W4SZ

Gene Fuller wrote:
But you already knew that . .

Of course I did. "Through the coil" does NOT mean "through
the coil wire". It means "through the coil". You still uttered
a falsehood but I doubt that you will ever admit it.
--
73, Cecil http://www.w5dxp.com