Steve's info will get you a beginners understanding of circuit
theory which is based on a low-frequency, quasi-static simplification
of electromagnetic theory. Unfortunately, anything that has any
appreciable length, such as a transmission line or an antenna, or
a long coil of wire as Yuri and Cecil are arguing about,
can't be adequately explained by simple circuit theory; you have to
study wave mechanics to get any real idea of what is happening
in these situations. That isn't the end of it, though, since in order
to understand what is happening when an object radiates, you
have to understand Maxwell's equations. In order to understand
Maxwell's equations, you'd better know vector calculus. That isn't the
end, either, but it's as close as any *normal* human wants to go.
Whenever someone who was taught circuit theory tries to
apply its vocabulary and concepts to explain all electromagnetic
phenomena, that someone is going to run into trouble and
come up with a multitude of idiocies for which which he'll find no end of
people ready to criticize him.
This is the problem: Cecil and Yuri want to explain the current taper
through a long solenoidal coil using the vocabulary and concepts of
circuit theory rather than the difficult but more precise
language of electromagnetic theory. So far they've failed
miserably, not least because they don't even seem to have
a coherent idea of what they mean by "current flow." I
wish them luck, but I hope no one takes any of their
ideas seriously.
73,
Tom Donaly, KA6RUH






Steve wrote,

Unable to resist at least trying to provide the basis for some
understanding, Steve proceeds.



Jim, you know who you are...



Thank you. Here's a go at a start.



Apparently, because of the way the big bang occurred, when we put a voltage
across a resistor current flows in a manner that we discovered follows the
equation called Ohm's law. The resistor "resists", determines or limits the
current. Oh yea, resistors have this characteristic we call resistance
measured in "Ohms", just for using in the formulas.



Ohms law: I = V/R

Say... 12 Volts on a 50 ohm resistor results in 0.24 amps flowing.



For the same reason (big bang) this removes power from the circuit, or
"dissipates" it. Poof! Gone from the circuit. Resistors happen to turn this
power into heat. The value being discoverable by the power formula:

P=IxV and the variations P=E^2/R and P=I^2xR



It also turns out that ANYTHING else that removes power from a circuit looks
just like a resistor to the circuit (obeys Ohm's law), and *ONLY* things
that LOOK just like a resistor (behave or conduct current according to Ohm's
law) will so remove power from said ckt. IF you didn't catch this, there
are things that are not really resistors, yet act just like them as far as a
circuit is concerned.



Unfortunately, life is fraught with dangers and we have capacitors (C) and
inductors (L)(or things which behave just like them or combinations of
them). When we get into this realm, the "R" from above, just doesn't do it.
Things get all messed up.

These things also "resist" current flow. (or determine or limit it). We
call this form of resisting "Reactance", use the letter "X" to represent it
and it also is measured in "Ohms", just for using in the formulas. Oh yea,
we also use the little subscript letter to indicate if it is an inductive
(l) or capacitive (c)reactance.



Xc ("X" sub c) = 1/(2 x pi x f x C )

Xl ("X" sub L) = 2 x pi x f x L



When we want to talk about the effect or either an "L" or a "C" we simply
use the term "Reactance" It's like a good substitute for "he/she" (the
"wrong one being "they").



Because of (big bang again) the way the current in these (C & L)
corruptions, of our purely resistive world, work out to be 90 degrees out of
phase with the voltage (we are talking about AC now), we had to find a way
to account for them. I won't trouble you with just why now, but we use what
is called the "Series Representation". It looks like two numbers with a +
or - sign between them and all together we call this new kind of (corrupted)
resistance "Impedance". And use the letter "Z" to represent it. It has
some Resistance and some Reactance in there and it will have numbers on
ohms:

In general: It looks like this:

Z = R + jX



The "R" is the same kind of resistor as above, the "X" is one of the
reactances. The "j" helps the mathematicians do the math - like ohms law -
but with the reactance accounted for. In "math speak" the "R" is the "real"
part and the "X" is the "Imaginary" part of the impedance.



Impedance also resists current flow, but with the reactance in there, you
can't use Ohm's law like you used to.



SO... When I say "Impedance" or use "Z" I am talking about whatever happens
to be there. Since I don't know if it is only resistive, called also
"Purely resistive", or has some reactance in it, called "reactive", (or if I
am just too lazy to figure it out at the time), I use this word or symbol to
cover any situation.



Finally, since only the "resistive part" of a circuit dissipates any power,
we like to remove (somehow) all the reactance (or imaginary part) and
somehow make the real part (the resistive part) what we like best (for a
given situation). Doing this is the infinitely complex subject called
"impedance matching". When we make this happen on an antenna, the remaining
"resistive part" sucks power from the circuit (the transmitter circuit)
Poof! BUT converts it into radiated radio frequency energy (RF) also called
an electromagnetic field or wave.



Fortunately for us in this modern day and age, because if it didn't all the
receivers that we have would be useless and we would wonder why we built
them.



Help any???



73 Steve--
Steve N, K,9;d, c. i My email has no u's.

Time out!! You people are taking all this far to seriously. Just throw
an aerial out the window, feed it to your rig via a tuner, and enjoy
Amateur radio.

Butch Magee KF5DE

Tdonaly wrote:
Steve's info will get you a beginners understanding of circuit
theory which is based on a low-frequency, quasi-static simplification
of electromagnetic theory. Unfortunately, anything that has any
appreciable length, such as a transmission line or an antenna, or
a long coil of wire as Yuri and Cecil are arguing about,
can't be adequately explained by simple circuit theory; you have to
study wave mechanics to get any real idea of what is happening
in these situations. That isn't the end of it, though, since in order
to understand what is happening when an object radiates, you
have to understand Maxwell's equations. In order to understand
Maxwell's equations, you'd better know vector calculus. That isn't the
end, either, but it's as close as any *normal* human wants to go.
Whenever someone who was taught circuit theory tries to
apply its vocabulary and concepts to explain all electromagnetic
phenomena, that someone is going to run into trouble and
come up with a multitude of idiocies for which which he'll find no end of
people ready to criticize him.
This is the problem: Cecil and Yuri want to explain the current taper
through a long solenoidal coil using the vocabulary and concepts of
circuit theory rather than the difficult but more precise
language of electromagnetic theory. So far they've failed
miserably, not least because they don't even seem to have
a coherent idea of what they mean by "current flow." I
wish them luck, but I hope no one takes any of their
ideas seriously.
73,
Tom Donaly, KA6RUH






Steve wrote,

Unable to resist at least trying to provide the basis for some
understanding, Steve proceeds.



Jim, you know who you are...



Thank you. Here's a go at a start.



Apparently, because of the way the big bang occurred, when we put a voltage
across a resistor current flows in a manner that we discovered follows the
equation called Ohm's law. The resistor "resists", determines or limits the
current. Oh yea, resistors have this characteristic we call resistance
measured in "Ohms", just for using in the formulas.



Ohms law: I = V/R

Say... 12 Volts on a 50 ohm resistor results in 0.24 amps flowing.



For the same reason (big bang) this removes power from the circuit, or
"dissipates" it. Poof! Gone from the circuit. Resistors happen to turn this
power into heat. The value being discoverable by the power formula:

P=IxV and the variations P=E^2/R and P=I^2xR



It also turns out that ANYTHING else that removes power from a circuit looks
just like a resistor to the circuit (obeys Ohm's law), and *ONLY* things
that LOOK just like a resistor (behave or conduct current according to Ohm's
law) will so remove power from said ckt. IF you didn't catch this, there
are things that are not really resistors, yet act just like them as far as a
circuit is concerned.



Unfortunately, life is fraught with dangers and we have capacitors (C) and
inductors (L)(or things which behave just like them or combinations of
them). When we get into this realm, the "R" from above, just doesn't do it.
Things get all messed up.

These things also "resist" current flow. (or determine or limit it). We
call this form of resisting "Reactance", use the letter "X" to represent it
and it also is measured in "Ohms", just for using in the formulas. Oh yea,
we also use the little subscript letter to indicate if it is an inductive
(l) or capacitive (c)reactance.



Xc ("X" sub c) = 1/(2 x pi x f x C )

Xl ("X" sub L) = 2 x pi x f x L



When we want to talk about the effect or either an "L" or a "C" we simply
use the term "Reactance" It's like a good substitute for "he/she" (the
"wrong one being "they").



Because of (big bang again) the way the current in these (C & L)
corruptions, of our purely resistive world, work out to be 90 degrees out of
phase with the voltage (we are talking about AC now), we had to find a way
to account for them. I won't trouble you with just why now, but we use what
is called the "Series Representation". It looks like two numbers with a +
or - sign between them and all together we call this new kind of (corrupted)
resistance "Impedance". And use the letter "Z" to represent it. It has
some Resistance and some Reactance in there and it will have numbers on
ohms:

In general: It looks like this:

Z = R + jX



The "R" is the same kind of resistor as above, the "X" is one of the
reactances. The "j" helps the mathematicians do the math - like ohms law -
but with the reactance accounted for. In "math speak" the "R" is the "real"
part and the "X" is the "Imaginary" part of the impedance.



Impedance also resists current flow, but with the reactance in there, you
can't use Ohm's law like you used to.



SO... When I say "Impedance" or use "Z" I am talking about whatever happens
to be there. Since I don't know if it is only resistive, called also
"Purely resistive", or has some reactance in it, called "reactive", (or if I
am just too lazy to figure it out at the time), I use this word or symbol to
cover any situation.



Finally, since only the "resistive part" of a circuit dissipates any power,
we like to remove (somehow) all the reactance (or imaginary part) and
somehow make the real part (the resistive part) what we like best (for a
given situation). Doing this is the infinitely complex subject called
"impedance matching". When we make this happen on an antenna, the remaining
"resistive part" sucks power from the circuit (the transmitter circuit)
Poof! BUT converts it into radiated radio frequency energy (RF) also called
an electromagnetic field or wave.



Fortunately for us in this modern day and age, because if it didn't all the
receivers that we have would be useless and we would wonder why we built
them.



Help any???



73 Steve--
Steve N, K,9;d, c. i My email has no u's.

"Butch" wrote in message
...
Time out!! You people are taking all this far to seriously. Just throw
an aerial out the window, feed it to your rig via a tuner, and enjoy
Amateur radio.

Butch Magee KF5DE


It just not that simple, Butch.

I'm sure you have heard that Ham radio is a hobby that has many facets;
construction, public service, contesting, field trips, QRP DX, etc. Some of
our members get their kicks merging theory with rag chewing. I don't think
there's any structure to this sub-category, other than to require at least
one mention of Maxwell in every discussion.


Ed
WB6WSN

Oh yea! that too... I forgot "Maxwell"
--
Steve N, K,9;d, c. i My email has no u's.


"Ed Price" wrote in message
news:YFmZb.5138$C21.2768@fed1read07...

"Butch" wrote in message
...
Time out!! You people are taking all this far to seriously. Just throw
an aerial out the window, feed it to your rig via a tuner, and enjoy
Amateur radio.

Butch Magee KF5DE


It just not that simple, Butch.

I'm sure you have heard that Ham radio is a hobby that has many facets;
construction, public service, contesting, field trips, QRP DX, etc. Some
of
our members get their kicks merging theory with rag chewing. I don't think
there's any structure to this sub-category, other than to require at least
one mention of Maxwell in every discussion.


Ed
WB6WSN

Yep!! Very Good Coffee!!!!!!!!!!!

Steve Nosko wrote:

Oh yea! that too... I forgot "Maxwell"

Someone sed: "I don't think
there's any structure to this sub-category, other than to require at least
one mention of Maxwell in every discussion".
======================

I'm a Folgers man myself! Never did like Starbuck's.

73 de Jack, K9CUN

Know what ya mean Ed. Used to mention Maxwell every now and then
myself but lets face facts, the coffee just isn't that good. Know whut
I mean!

Ed Price wrote:
"Butch" wrote in message
...

Time out!! You people are taking all this far to seriously. Just throw
an aerial out the window, feed it to your rig via a tuner, and enjoy
Amateur radio.

Butch Magee KF5DE



It just not that simple, Butch.

I'm sure you have heard that Ham radio is a hobby that has many facets;
construction, public service, contesting, field trips, QRP DX, etc. Some of
our members get their kicks merging theory with rag chewing. I don't think
there's any structure to this sub-category, other than to require at least
one mention of Maxwell in every discussion.


Ed
WB6WSN

Well, then there's that too..

-- (:-)
Steve N, K,9;d, c. i My email has no u's.

"Butch" wrote in message
...
Time out!! You people are taking all this far to seriously. Just throw
an aerial out the window, feed it to your rig via a tuner, and enjoy
Amateur radio.

Butch Magee KF5DE

Tdonaly wrote:
Steve's info will get you a beginners understanding ...
...quasi-static.
...electromagnetic theory. ...
...wave mechanics...
...Maxwell's equations....
...vector calculus.
...any *normal* human...
...multitude of idiocies
...no end of people ready to criticize him.

Tom,I agree with much of what you say but the problem goes much deeper
than that, and much of the blame rests with academics taught.
Let us look at what is called by some as a 'simple dipole'.
The dipole is very inefficient radiator.
The only claim that you can place on it is that it is has a low
impedance
at resonance...Period. There is no calculation available in any of the
touted books that maximum gain per unit length is design related to a
dipole! The dipole is only a reference that other antennas can be
related to even tho it is a very inefficient radiator per unit length.
Over time academics have made the dipole as something very efficient
about which every advance must be related .
That Tom is very incorrect and it is that which is what prevents the
emergence of new ideas that push the envelope. If one just spouts what
is in present day books then they are just followers that suck up the
dipole aproach which thus prevents them from contributing anything
that pushes out the envelope. Education
can only take you so far and it is dependent on those who have
received an education to push the envelope further. If one doesn't do
this then they are just quoting things that were told to them or they
read in some book and thus are not equiped to pushing the envelope.
Until the simple dipole is shead of its illusionary powers by the
academics who write the books newcomers can only copy, and not
progress. Ofcourse, academics who just memorise can still attack
people, those who do not agree with them, in a personal way in the
hope that a raucous crowd of peasants will echo the academics trash
around the Gillotine.

Regards
Art






(Tdonaly) wrote in message ...
Steve's info will get you a beginners understanding of circuit
theory which is based on a low-frequency, quasi-static simplification
of electromagnetic theory. Unfortunately, anything that has any
appreciable length, such as a transmission line or an antenna, or
a long coil of wire as Yuri and Cecil are arguing about,
can't be adequately explained by simple circuit theory; you have to
study wave mechanics to get any real idea of what is happening
in these situations. That isn't the end of it, though, since in order
to understand what is happening when an object radiates, you
have to understand Maxwell's equations. In order to understand
Maxwell's equations, you'd better know vector calculus. That isn't the
end, either, but it's as close as any *normal* human wants to go.
Whenever someone who was taught circuit theory tries to
apply its vocabulary and concepts to explain all electromagnetic
phenomena, that someone is going to run into trouble and
come up with a multitude of idiocies for which which he'll find no end of
people ready to criticize him.
This is the problem: Cecil and Yuri want to explain the current taper
through a long solenoidal coil using the vocabulary and concepts of
circuit theory rather than the difficult but more precise
language of electromagnetic theory. So far they've failed
miserably, not least because they don't even seem to have
a coherent idea of what they mean by "current flow." I
wish them luck, but I hope no one takes any of their
ideas seriously.
73,
Tom Donaly, KA6RUH






Steve wrote,

Unable to resist at least trying to provide the basis for some
understanding, Steve proceeds.

Snip

Art, KB9MZ wrote:
"The dipole is a very inefficient radiator."

Kraus, unfortunately, wasn`t one of my books until recently. I don`t
have the words memorized or know where they appear as I do with some of
Terman.

I seem to remember Kraus saying 95% efficiency was not unusual as a
dipole efficiency. As there are so many variations, it`s like a baseball
statistic, there must be a statistic that fits somewhere.

In any case, "efficient" is only as compared with similar devices.
Recall that dBd is the norm as an isotropic antenna is only a
theoretical creature. Catalogs are filled with antenna characteristics
as compared with a 1/2-wave dipole in free space. It is the standard of
comparison. It could hardly be correctly called inefficient.

Best regards, Richard Harrison, KB5WZI