On Sun, 29 Apr 2007 15:36:43 -0500, "amdx" wrote:

This is then a characteristic of the Capacitor called D (dissipation).
Any increase in current tied to loss immediately goes to the bottom
line of resistance - it is a square law relationship, after all.

So your saying yes, the thought experiment would show more loss,
but the loss is in the capacitor. The loss in a capacitor would be
dielectric
and loss in the plates right?

Hi Mike,

Depending upon construction, most assuredly. However, little loss is
found in dielectrics (unless you are using particularly crummy
examples). For bad dielectric, you can expects arcs and sparks
followed by carbon, and then catastrophic heat accumulation. Most
lost is in what is specified in ESR (effective series resistance)
which you have already identified as in the plates, but often more in
the leads and their connections to the plates. To pack in more
capacitance, the trend is for thinner plates for a given package
volume. You can guess where the resistance will rise there when the
circulating currents are see-sawing in that thin metal.

(let's not get into radiation resistance right now)

Why not? Small loops suffer by comparison, and multi-turn loops even
more so.

I figure it would only confuse the issue.
I was trying to stay away from radiation resistance because my experience of
the effect Bill ask about has been with small aircore inductors. But on
second thought
even those have Rr.

The smaller, the worse. It is not so much about the size of Rr, but
its relation (ratio) to Ohmic loss. For instance, a 1 meter loop
composed of #40 wire is going to be deaf and dumb at 80M, but you
might have a chance with 10cM hollow pipe with tight connections. Both
exhibit the same Rr, but the wire's Ohmic loss is clearly deadly in
comparison to it, than for the pipe's Ohmic loss. Rr in this band,
for this size, runs on the order of 0.0075 Ohms.

Why does the reistance go up near resonance?

I haven't seen that happen. However, for the same resistance, as you
approach resonance, the circulating currents climb, and loss is by the
square.

73's
Richard Clark, KB7QHC

"Richard Clark" wrote in message
...
On Sun, 29 Apr 2007 15:36:43 -0500, "amdx" wrote:

This is then a characteristic of the Capacitor called D (dissipation).
Any increase in current tied to loss immediately goes to the bottom
line of resistance - it is a square law relationship, after all.

So your saying yes, the thought experiment would show more loss,
but the loss is in the capacitor. The loss in a capacitor would be
dielectric
and loss in the plates right?

Hi Mike,

Depending upon construction, most assuredly. However, little loss is
found in dielectrics (unless you are using particularly crummy
examples). For bad dielectric, you can expects arcs and sparks
followed by carbon, and then catastrophic heat accumulation. Most
lost is in what is specified in ESR (effective series resistance)
which you have already identified as in the plates, but often more in
the leads and their connections to the plates. To pack in more
capacitance, the trend is for thinner plates for a given package
volume. You can guess where the resistance will rise there when the
circulating currents are see-sawing in that thin metal.

I gave you a little bit of a trick question when I ask,

The loss in a capacitor would be dielectric and loss in the plates right?

In my inductor the interwinding capacitance is made of a dielectric
(some type of insulation and air) and the plates (made by the wire).
The wire has more current because of that interwinding capacitance,
and as you say "loss is by the square".
Is my argument moving you at all?



(let's not get into radiation resistance right now)

Why not? Small loops suffer by comparison, and multi-turn loops even
more so.

I figure it would only confuse the issue.
I was trying to stay away from radiation resistance because my experience
of
the effect Bill ask about has been with small aircore inductors. But on
second thought
even those have Rr.

The smaller, the worse. It is not so much about the size of Rr, but
its relation (ratio) to Ohmic loss. For instance, a 1 meter loop
composed of #40 wire is going to be deaf and dumb at 80M, but you
might have a chance with 10cM hollow pipe with tight connections. Both
exhibit the same Rr, but the wire's Ohmic loss is clearly deadly in
comparison to it, than for the pipe's Ohmic loss. Rr in this band,
for this size, runs on the order of 0.0075 Ohms.

Why does the resistance go up near resonance?

I haven't seen that happen.
Try measureing the Q of an aircore coil close to it's self resonance
(or worse, at self resonance without an additional capacitor)
and then at half that frequency.

However, for the same resistance, as you
approach resonance, the circulating currents climb, and loss is by the
square.

I'm defining circulating currents as those that circulate between turns
and don't necessarily go through the capacitor used to resonate the coil.
Does that fit your definition as used in your paragraph above?

Thanks, Mike

On Sun, 29 Apr 2007 18:51:52 -0500, "amdx" wrote:

I gave you a little bit of a trick question when I ask,

The loss in a capacitor would be dielectric and loss in the plates right?

In my inductor the interwinding capacitance is made of a dielectric
(some type of insulation and air) and the plates (made by the wire).
The wire has more current because of that interwinding capacitance,
and as you say "loss is by the square".
Is my argument moving you at all?

Hi Mike,

I'm afraid that if you have expressed an argument, it was lost on me.

Why does the resistance go up near resonance?

I haven't seen that happen.
Try measureing the Q of an aircore coil close to it's self resonance
(or worse, at self resonance without an additional capacitor)
and then at half that frequency.

You have a moving target. Skin effect is shifting as you double/halve
the frequency. What does it mean to compare Q at so disparate
frequencies? Are you exploring an intellectual curiosity or trying to
remedy a defect in application?

However, for the same resistance, as you
approach resonance, the circulating currents climb, and loss is by the
square.

I'm defining circulating currents as those that circulate between turns
and don't necessarily go through the capacitor used to resonate the coil.
Does that fit your definition as used in your paragraph above?

Going between turns can be through a turn-to-turn capacitive coupling,
the magnetic coupling has already been discussed in regard to
increased skin effect due to proximity. Loss still remains the
province of resistance. Your best argument is that Capacitance
exacerbates loss, but it does not cause it.

73's
Richard Clark, KB7QHC

"Richard Clark" wrote in message
...
On Sun, 29 Apr 2007 18:51:52 -0500, "amdx" wrote:

I gave you a little bit of a trick question when I ask,

The loss in a capacitor would be dielectric and loss in the plates
right?

In my inductor the interwinding capacitance is made of a dielectric
(some type of insulation and air) and the plates (made by the wire).
The wire has more current because of that interwinding capacitance,
and as you say "loss is by the square".
Is my argument moving you at all?

Hi Mike,

I'm afraid that if you have expressed an argument, it was lost on me.

Why does the resistance go up near resonance?

I haven't seen that happen.
Try measureing the Q of an aircore coil close to it's self resonance
(or worse, at self resonance without an additional capacitor)
and then at half that frequency.

You have a moving target. Skin effect is shifting as you double/halve
the frequency. What does it mean to compare Q at so disparate
frequencies?

I agree that skin effect is just one more charactistic that needs to be
added to the mix.

Are you exploring an intellectual curiosity or trying to
remedy a defect in application?

No, I just have experienced the effect that Bill ask about and
gave my own pet theory about why it happens.
Now I'm looking for a little confirmation or where I went wrong.



However, for the same resistance, as you
approach resonance, the circulating currents climb, and loss is by the
square.

I'm defining circulating currents as those that circulate between
turns
and don't necessarily go through the capacitor used to resonate the coil.
Does that fit your definition as used in your paragraph above?

Going between turns can be through a turn-to-turn capacitive coupling,
the magnetic coupling has already been discussed in regard to
increased skin effect due to proximity.

Loss still remains the province of resistance.

Richard, That's like saying rain has water in it. No matter how many times
you say it,
I'm still going to agree with you.


Your best argument is that Capacitance exacerbates loss.

I would rephrase that as "interwinding capacitance exacerbates loss".

And with that, you have summed up my argument perfectly.

You have helped reduce my argument to 4 words.

Now, do you agree that interwinding capacitance will reduce Q?
(yes, I know it's the province of resistance)

Thanks, Mike

On Mon, 30 Apr 2007 06:37:10 -0500, "amdx" wrote:

Are you exploring an intellectual curiosity or trying to
remedy a defect in application?

No, I just have experienced the effect that Bill ask about and
gave my own pet theory about why it happens.
Now I'm looking for a little confirmation or where I went wrong.

Hi Mike,

Well, that is fine and good, but neither of you have given us any real
data, and certainly no Q values to judge if what you both experienced
was within the range of "normal" or out in left field. RF
measurements are difficult to do to any particularly fine accuracy,
and what was observed may have been simple variation due to the
measurer's proximity (offering just one of many things that can go
wrong).

Loss still remains the province of resistance.

Richard, That's like saying rain has water in it. No matter how many times
you say it,
I'm still going to agree with you.

Then this diverges from Bill's premise of Capacitance being the source
of loss and you and he are separable at this point of your common
experience.

Your best argument is that Capacitance exacerbates loss.

I would rephrase that as "interwinding capacitance exacerbates loss".

And with that, you have summed up my argument perfectly.

You have helped reduce my argument to 4 words.

Now, do you agree that interwinding capacitance will reduce Q?
(yes, I know it's the province of resistance)

Give me some metrics to show it is not skin effect.

The issue at hand is your (both you and Bill, or either of you
separately) loops keep changing to fit to the loss rather than to the
application. It makes for a rather strained progression of design as
loops are added, proximity becomes a greater issue, as coil length
collapses, insulation is added, and as frequency shifts to follow
these changes. It is as though a good 10M loop is evolving to operate
poorly there or, worse, in the 160M band where its resonance has
finally come to rest through optimizing for loss.

I can imagine there being enough turn-to-turn capacitance to induce
large currents, but so many correlating factors would have to ride
along with this that they could easily eclipse that contribution of
loss. In other words, it seems the goal of your argument is to raise
that capacitance, which by ordinary means has you drawing the loops
together (insulated or not). This compounds the skin effect and for a
constant frequency demands a lower inductance. The lower inductance,
in turn, then demands a smaller coil which forces a lower Radiation
resistance. A smaller coil (to again follow the demand for more
Capacitance) drives closer loops.

It seems like this is in an infinite regress.

73's
Richard Clark, KB7QHC

"Richard Clark" wrote in message
...
On Mon, 30 Apr 2007 06:37:10 -0500, "amdx" wrote:

Are you exploring an intellectual curiosity or trying to
remedy a defect in application?

No, I just have experienced the effect that Bill ask about and
gave my own pet theory about why it happens.
Now I'm looking for a little confirmation or where I went wrong.

Hi Mike,

Well, that is fine and good, but neither of you have given us any real
data, and certainly no Q values to judge if what you both experienced
was within the range of "normal" or out in left field. RF
measurements are difficult to do to any particularly fine accuracy,
and what was observed may have been simple variation due to the
measurer's proximity (offering just one of many things that can go
wrong).

Yes, RF measurements are difficult to do to any particularly fine
accuracy.
And I claim no great knowledge of how to minimize errors or even how to
recognize where they come from.


Loss still remains the province of resistance.

Richard, That's like saying rain has water in it. No matter how many times
you say it,
I'm still going to agree with you.

Then this diverges from Bill's premise of Capacitance being the source
of loss and you and he are separable at this point of your common
experience.

Your best argument is that Capacitance exacerbates loss.

I would rephrase that as "interwinding capacitance exacerbates loss".

And with that, you have summed up my argument perfectly.

You have helped reduce my argument to 4 words.

Now, do you agree that interwinding capacitance will reduce Q?
(yes, I know it's the province of resistance)

Give me some metrics to show it is not skin effect.

The issue at hand is your (both you and Bill, or either of you
separately) loops keep changing to fit to the loss rather than to the
application. It makes for a rather strained progression of design as
loops are added, proximity becomes a greater issue, as coil length
collapses, insulation is added, and as frequency shifts to follow
these changes. It is as though a good 10M loop is evolving to operate
poorly there or, worse, in the 160M band where its resonance has
finally come to rest through optimizing for loss.

My experience is limited to winding small inductors rather than
loop antennas.

I can imagine there being enough turn-to-turn capacitance to induce
large currents, but so many correlating factors would have to ride
along with this that they could easily eclipse that contribution of
loss. In other words, it seems the goal of your argument is to raise
that capacitance, which by ordinary means has you drawing the loops
together (insulated or not). This compounds the skin effect and for a
constant frequency demands a lower inductance. The lower inductance,
in turn, then demands a smaller coil which forces a lower Radiation
resistance. A smaller coil (to again follow the demand for more
Capacitance) drives closer loops.

It seems like this is in an infinite regress.

I don't understand why you think we want more interwinding capacitance,
We want less.
I will agree that the mechanics involved in trying to reduce interwinding
capacitance
will probably reduce proximity effects and so to seperate out any affect
from the
reduces interwinding capacitance would be difficult.
I need to go,
Later, thanks Richard

"amdx" wrote in message
...

"Richard Clark" wrote in message
...
On Mon, 30 Apr 2007 06:37:10 -0500, "amdx" wrote:

Are you exploring an intellectual curiosity or trying to
remedy a defect in application?

No, I just have experienced the effect that Bill ask about and
gave my own pet theory about why it happens.
Now I'm looking for a little confirmation or where I went wrong.

Hi Mike,

Well, that is fine and good, but neither of you have given us any real
data, and certainly no Q values to judge if what you both experienced
was within the range of "normal" or out in left field. RF
measurements are difficult to do to any particularly fine accuracy,
and what was observed may have been simple variation due to the
measurer's proximity (offering just one of many things that can go
wrong).

Yes, RF measurements are difficult to do to any particularly fine
accuracy.
And I claim no great knowledge of how to minimize errors or even how to
recognize where they come from.


Loss still remains the province of resistance.

Richard, That's like saying rain has water in it. No matter how many
times
you say it,
I'm still going to agree with you.

Then this diverges from Bill's premise of Capacitance being the source
of loss and you and he are separable at this point of your common
experience.

Your best argument is that Capacitance exacerbates loss.

I would rephrase that as "interwinding capacitance exacerbates loss".

And with that, you have summed up my argument perfectly.

You have helped reduce my argument to 4 words.

Now, do you agree that interwinding capacitance will reduce Q?
(yes, I know it's the province of resistance)

Give me some metrics to show it is not skin effect.

The issue at hand is your (both you and Bill, or either of you
separately) loops keep changing to fit to the loss rather than to the
application. It makes for a rather strained progression of design as
loops are added, proximity becomes a greater issue, as coil length
collapses, insulation is added, and as frequency shifts to follow
these changes. It is as though a good 10M loop is evolving to operate
poorly there or, worse, in the 160M band where its resonance has
finally come to rest through optimizing for loss.

My experience is limited to winding small inductors rather than
loop antennas.

I can imagine there being enough turn-to-turn capacitance to induce
large currents, but so many correlating factors would have to ride
along with this that they could easily eclipse that contribution of
loss. In other words, it seems the goal of your argument is to raise
that capacitance, which by ordinary means has you drawing the loops
together (insulated or not). This compounds the skin effect and for a
constant frequency demands a lower inductance. The lower inductance,
in turn, then demands a smaller coil which forces a lower Radiation
resistance. A smaller coil (to again follow the demand for more
Capacitance) drives closer loops.

It seems like this is in an infinite regress.

I don't understand why you think we want more interwinding capacitance,
We want less.
I will agree that the mechanics involved in trying to reduce interwinding
capacitance
will probably reduce proximity effects and so to seperate out any affect
from the
reduces interwinding capacitance would be difficult.
I need to go,
Later, thanks Richard


Ok, I'm back.
Richard, I was starting to lean towards proximity effect possibly causing
all of the affect we have been discussing, so I did some Googling. I kept
find the
same line " increased capacitance lowers Q" But, I think you agree that as
I said
above most efforts to reduce capacitance will also reduce proximity effect.
I ran across W8JI's page, he's usually pretty exacting in his wording, and
he says,

"Capacitance across any inductor carrying time-varying current increases
circulating
currents in the inductor, increasing loss while simultaneously reducing
system bandwidth."

snip "Anything that increases capacitance will reduce component Q"

He never mentions the correlation between interwinding capacitance and
proximity effect

These line were taken from;
http://www.w8ji.com/loading_inductors.htm

What do you think?
Mike