On Thu, 04 Mar 2004 18:18:46 GMT, "aunwin"
wrote:

Why must only series circuits be considered for radiators?.

Hi Art,

I don't know if there's a "must" to this. Every series circuit can be
seen as a parallel circuit; and on the flip side, every parallel
circuit can be seen as a series circuit. It is all a matter of where
you put your leads to drive/measure/load/receive.... The same
components vary only slightly in frequency from their being series
resonant or parallel resonate. Without that
drive/measure/load/receive path, there is no energy transfer and power
consumption is all strictly a matter of component ohmic loss.

What is it about parallel circuits that make them unsuitable?

They are used every day to load up halfwave verticals, which in turn
are also parallel equivalent circuits. The input to the parallel
interface is performed through divider action (usually a tapped coil,
but could be through a capacitor divider).

Is stagger tuning a parallel circuit ?

No, but it could be. Stagger tuning, by convention is a chain of
separately tuned circuits, be they RC, RL, or LC (or, of course RLC).
One RC or RL circuit exhibits a 6dB/Octave or 10dB/Decade roll-off.
One LC circuit exhibits twice that or a 12dB/Octave or 20dB/Decade
roll-off. Again, it is all a matter of connections for the identical
components (which will show a slight shift in parallel to series
resonance frequency - which is to say it is application dependent).

Two RC or two RL, or one RC with one RL in cascade constitute "stagger
tuning" irrespective of what frequencies their roll-off occur at (this
sets the stage for Bandwidth) and their sum contribution equal roughly
one LC circuit (which does not qualify as "stagger tuned") as long as
they share the same characteristic frequency (where the roll-off
occurs which is generally defined at the 3dB inflection).

Now, as to the expression "roll-off" used liberally above. All such
circuits may be called "de-emphasis" (where roll-off is evident) or
"pre-emphasis" (where roll-up would be more descriptive). The
application is strictly a matter of where the drive is applied, and
where the load takes its output.

73's
Richard Clark, KB7QHC

"Richard Clark" wrote in message
...
On Thu, 04 Mar 2004 18:18:46 GMT, "aunwin"
wrote:

Why must only series circuits be considered for radiators?.

Hi Art,

I don't know if there's a "must" to this.

At last.... at last somebody said
'I don't know'
Perhaps Walter will now say he doesn't know!


Every series circuit can be
seen as a parallel circuit; and on the flip side, every parallel
circuit can be seen as a series circuit. It is all a matter of where
you put your leads to drive/measure/load/receive.... The same
components vary only slightly in frequency from their being series
resonant or parallel resonate. Without that
drive/measure/load/receive path, there is no energy transfer and power
consumption is all strictly a matter of component ohmic loss.

Yes, partially understood , so to the question......



What is it about parallel circuits that make them unsuitable?

They are used every day to load up halfwave verticals, which in turn
are also parallel equivalent circuits.

Did you mean that? A halfwave vertical is a parallel circuit!

The input to the parallel
interface is performed through divider action (usually a tapped coil,
but could be through a capacitor divider).

Yes I know that but the question did say antennas didn't it?

You gave an answer to a question that was not asked. What you are refering
to is not for its radiation attributes is it? I hope we are not going into a
multi heading thread mode in less than 12 hours.


Is stagger tuning a parallel circuit ?

No, but it could be. Stagger tuning, by convention is a chain of
separately tuned circuits, be they RC, RL, or LC (or, of course RLC).

You mentioned the all important word of "tuned" so all of the above are
parallel circuits....right?

One RC or RL circuit exhibits a 6dB/Octave or 10dB/Decade roll-off.
One LC circuit exhibits twice that or a 12dB/Octave or 20dB/Decade
roll-off. Again, it is all a matter of connections for the identical
components (which will show a slight shift in parallel to series
resonance frequency - which is to say it is application
dependent).

I totally miss this point and probably the blame is mine. I think you are
saying that yes, they are parallel circuits, but you have an exception that
you want to point out i.e.slight shift in parallel to series...........

Not sure if you are saying 'yes'. I personaly think it is a parallel
circuit to which I would answer 'yes'.
Are you asking for some wriggle room? Two elements that are physically
separated is much too hard for me to describe as a series circuit. So I ask
the question in the context of the first two questions to prevent answers to
the like of 'just habit.'
Now I am not being awkward, believe me or I would not have responded. Force
12 has stagger tuning, if it is series devised then it gives more ammo to
the 'do not use parallel circuits for antennas' argument which seems to be
prevalent with antenna experts.

Two RC or two RL, or one RC with one RL in cascade constitute "stagger
tuning" irrespective of what frequencies their roll-off occur at (this
sets the stage for Bandwidth) and their sum contribution equal roughly
one LC circuit (which does not qualify as "stagger tuned") as long as
they share the same characteristic frequency (where the roll-off
occurs which is generally defined at the 3dB inflection).

Now, as to the expression "roll-off" used liberally above. All such
circuits may be called "de-emphasis" (where roll-off is evident) or
"pre-emphasis" (where roll-up would be more descriptive). The
application is strictly a matter of where the drive is applied, and
where the load takes its output.

I lost the point that you had in mind with the above and I wish you had not
mentioned bandwidth since it will bring another fork to the thread

73's
Richard Clark, KB7QHC

No rudeness intended anywhere Rich.. I seriously need reasonable specific
answers before I spend a lot of money.
Art

On Thu, 04 Mar 2004 21:36:22 GMT, "aunwin"
wrote:
What is it about parallel circuits that make them unsuitable?

They are used every day to load up halfwave verticals, which in turn
are also parallel equivalent circuits.

Did you mean that? A halfwave vertical is a parallel circuit!

That is the longstanding convention. Same thing applies to a one
wavelength dipole. All such are the basis of the J-Pole and the Zepp
(when you strip away their matching sections).

The input to the parallel
interface is performed through divider action (usually a tapped coil,
but could be through a capacitor divider).

Yes I know that but the question did say antennas didn't it?

Antennas don't find much application without some method of driving
them. Very few successful halfwave designs exist without matching.
This is because the halfwave vertical, looking like a parallel
circuit, has a considerable amount of Z that rejects power (unless
your rig is a van-de-graff generator). Adding the radiation
resistance to a high Z hardly allows any current into the radiation
resistance. On the other hand, a quarterwave looks like a series
resonant circuit with very low Z, and thus the radiation resistance
absorbs all the power applied. Very simple electronics.

One solution to feeding the halfwave tall vertical is to break it in
half and feed it half way up (where the two sections look like series
resonant, low Z elements feeding the radiation resistance without much
impediment). This is simplified, of course, but it illustrates how
the same circuit can support either a series resonant or parallel
resonant description determined only by the topology of connection.

You gave an answer to a question that was not asked. What you are refering
to is not for its radiation attributes is it? I hope we are not going into a
multi heading thread mode in less than 12 hours.

Matching sections to the J-Pole and the Zepp are contributors to
radiation due to the unbalanced nature of those antennas designs. How
much they contribute is perhaps arguable, but when they are built in
without care, their contribution cannot be denied. The matching
circuits contain both circulating currents and common mode currents.
The common mode currents, as a function of the physical length
compared to wavelength, offer radiation. The radiation may aid, or it
may hinder, but it is there none the less.

Is stagger tuning a parallel circuit ?

No, but it could be. Stagger tuning, by convention is a chain of
separately tuned circuits, be they RC, RL, or LC (or, of course RLC).

You mentioned the all important word of "tuned" so all of the above are
parallel circuits....right?

No, but they could be. The application of drive and loads determine
the topology:

One RC or RL circuit exhibits a 6dB/Octave or 10dB/Decade roll-off.
One LC circuit exhibits twice that or a 12dB/Octave or 20dB/Decade
roll-off. Again, it is all a matter of connections for the identical
components (which will show a slight shift in parallel to series
resonance frequency - which is to say it is application
dependent).

I totally miss this point and probably the blame is mine. I think you are
saying that yes, they are parallel circuits, but you have an exception that
you want to point out i.e.slight shift in parallel to series...........

No, they are NOT parallel - they could be, but there is nothing
inherently parallel and it all depends on the drive and load applied.

Not sure if you are saying 'yes'. I personaly think it is a parallel
circuit to which I would answer 'yes'.

No, they are NOT parallel - they could be, but there is nothing
inherently parallel and it all depends on the drive and load applied.

Force
12 has stagger tuning, if it is series devised then it gives more ammo to
the 'do not use parallel circuits for antennas' argument which seems to be
prevalent with antenna experts.

Force 12 makes many antennas, I will presume you are speaking of some
beam array. Stagger tuning, in that sense, is much akin to the
reflector, radiator, director relationship of the yagi. That design
is stagger tuned, but such stagger tuning is to accomplish various
delays that aid gain in one direction, and negate it in another. Such
stagger tuning is not directly engaged upon for the purpose of
bandwidth, although it may have indirect consequences. I have a beam
array for 440 that employs an LPDA radiator tied into the conventional
reflector and directors. As such it performs stagger tuning for the
purpose of beam forming AND bandwidth.

The elements in the Fan Dipole or the Log Periodic Dipole Array more
closely align to the conventional meaning of stagger tuning. The Fan
Dipole is the most obvious case. It's metaphor would be as many
parallel, series resonant circuits as there are elements, each
slightly tuned off from the other, all feeding in series and combining
in parallel to average a wider bandwidth response than any single
series resonant element.

73's
Richard Clark, KB7QHC

"Richard Clark" wrote in message
...
On Thu, 04 Mar 2004 21:36:22 GMT, "aunwin"
wrote:
What is it about parallel circuits that make them unsuitable?

They are used every day to load up halfwave verticals, which in turn
are also parallel equivalent circuits.

Did you mean that? A halfwave vertical is a parallel circuit!

That is the longstanding convention. Same thing applies to a one
wavelength dipole. All such are the basis of the J-Pole and the Zepp
(when you strip away their matching sections).

Well that is new to me, I never consider the matching circuit as part of an
antenna but only a required band aid. Can you point me
to where this is discussed ? ( J pole I know nothing about but the others I
would like to read of what you refer to as a parallel circuit) This could
be the point of confusion.





The input to the parallel
interface is performed through divider action (usually a tapped coil,
but could be through a capacitor divider).

Yes I know that but the question did say antennas didn't it?

Antennas don't find much application without some method of driving
them. Very few successful halfwave designs exist without matching.
This is because the halfwave vertical, looking like a parallel
circuit, has a considerable amount of Z that rejects power (unless
your rig is a van-de-graff generator). Adding the radiation
resistance to a high Z hardly allows any current into the radiation
resistance. On the other hand, a quarterwave looks like a series
resonant circuit with very low Z, and thus the radiation resistance
absorbs all the power applied. Very simple electronics.

One solution to feeding the halfwave tall vertical is to break it in
half and feed it half way up (where the two sections look like series
resonant, low Z elements feeding the radiation resistance without much
impediment). This is simplified, of course, but it illustrates how
the same circuit can support either a series resonant or parallel
resonant description determined only by the topology of connection.

You gave an answer to a question that was not asked. What you are
refering
to is not for its radiation attributes is it? I hope we are not going
into a
multi heading thread mode in less than 12 hours.

Matching sections to the J-Pole and the Zepp are contributors to
radiation due to the unbalanced nature of those antennas designs. How
much they contribute is perhaps arguable, but when they are built in
without care, their contribution cannot be denied. The matching
circuits contain both circulating currents and common mode currents.
The common mode currents, as a function of the physical length
compared to wavelength, offer radiation. The radiation may aid, or it
may hinder, but it is there none the less.

Is stagger tuning a parallel circuit ?

No, but it could be. Stagger tuning, by convention is a chain of
separately tuned circuits, be they RC, RL, or LC (or, of course RLC).

You mentioned the all important word of "tuned" so all of the above are
parallel circuits....right?

No, but they could be. The application of drive and loads determine
the topology:

One RC or RL circuit exhibits a 6dB/Octave or 10dB/Decade roll-off.
One LC circuit exhibits twice that or a 12dB/Octave or 20dB/Decade
roll-off. Again, it is all a matter of connections for the identical
components (which will show a slight shift in parallel to series
resonance frequency - which is to say it is application
dependent).

I totally miss this point and probably the blame is mine. I think you are
saying that yes, they are parallel circuits, but you have an exception
that
you want to point out i.e.slight shift in parallel to series...........

No, they are NOT parallel - they could be, but there is nothing
inherently parallel and it all depends on the drive and load applied.

Not sure if you are saying 'yes'. I personaly think it is a parallel
circuit to which I would answer 'yes'.

No, they are NOT parallel - they could be, but there is nothing
inherently parallel and it all depends on the drive and load applied.

Well on that note I see a dipole as a single series circuit fed by a
generator( ARRL book), where-as I see a bandpass circuit as a parallel
circuit.
This can be made to LOOK like several series circuits IF and Only IF one
discardes the intercoupling factor, and I do not see how one can
realistically refer to such an arrangement in any way as a quasi or
something else with the term 'series'
..

Force
12 has stagger tuning, if it is series devised then it gives more ammo to
the 'do not use parallel circuits for antennas' argument which seems to
be
prevalent with antenna experts.

Force 12 makes many antennas, I will presume you are speaking of some
beam array. Stagger tuning, in that sense, is much akin to the
reflector, radiator, director relationship of the yagi. That design
is stagger tuned, but such stagger tuning is to accomplish various
delays that aid gain in one direction, and negate it in another. Such
stagger tuning is not directly engaged upon for the purpose of
bandwidth, although it may have indirect consequences.


Oh I will have to leave that for others to comment upon as that is not what
I consider stagger tuning to be. I mentioned in another posting what I
thought it to be, so obviously there are comments on the way to put me
straight, hopefully in a factual way that puts the majority at ease. without
a complication factor.


I have a beam
array for 440 that employs an LPDA radiator tied into the conventional
reflector and directors. As such it performs stagger tuning for the
purpose of beam forming AND bandwidth.

The elements in the Fan Dipole or the Log Periodic Dipole Array more
closely align to the conventional meaning of stagger tuning. The Fan
Dipole is the most obvious case. It's metaphor would be as many
parallel, series resonant circuits as there are elements, each
slightly tuned off from the other, all feeding in series and combining
in parallel to average a wider bandwidth response than any single
series resonant element.

I just don't understand what you are saying here, I must understand the
parallel circuit part of a zepp or dipole part first to intellegently
discuss all this other stuff you are talking about.
The statements you are making on parallel versus series I view as enormous.
Read the ARRL book on antennas and they dwell on series circuits as in
dipole, why the big difference with this newsgroup? Your comments seem to
rotate about phase changes more than it does about coupling as to the main
focal point.
No comments on your other posting yet .(pro and con) which suggest the
experts are unified on your statements.
I will have to choose my words very, very carefully tomorrow on that one.Up
to now I feel fully exposed on what I don't know that which every body else
knows
73's
Regards
Art
Richard Clark, KB7QHC

Art, KB9MZ wrote:
"Well that is news to me. I never consider the matching circuit as part
of an antenna, but only a required band aid."

Art only recently changed his mind it seems. A year or so ago he was
arguing that the tuned T-matched arrangement he claimed to have invented
added gain from its radiation to that of his dipole. I said ,
"impossible because radiation from a small loop is directed in the plane
of the loop." So Art hates me.

More recently we discussed current distribution on short loaded vertical
antennas and if current had to be the same at both ends of a loading
coil. It doesn`t. Yuri presented in evidence Fig 9-22 from page 9-15 of
the 2nd edition of ON4UN`s "Low-Band DXing". Art shows disdain for
experts and books, so he may have paid no attention or quickly forgot.

One of the six examples in ON4UN`s figure is a continuously loaded
radiator. No doubt, no matter how feeble it is, the radiation emanates
from the loading coil which comprises the entire antenna.

Richard Clark was showing that the choice of series resonant or parallel
resonant as a model may be based on application or impedance.

A parallel resonant circuit exhibits high impedance. It is used for high
isolation as a trap, and as a phase inverter for a collinear as in the
self-resonant coil from Kraus presented by Cecil. A parallel resonant
circuit is also used to match end-fed 1/2-waves and similar high
impedance antennas. Many cheap small radios just connect the high
impedance antenna to to the hot end of the tank circuit.

The J-pole drives an end-fed 1/2-wave antenna from a short-circuited
1/4-wave stub. The stub is equivalent to a parallel resonant circuit and
exhibits a high impedance at its open-circuit end. This was another of
Richard Clark`s examples.

I regret Art fails to see the relevance of much of the accurate
information offered.

Best regards, Richard Harrison, KB5WZI

Richard you have started to wander again. If a matching unit is used for
matching input inpedance of a radiator and not for the purpose of radiating
then it is certainly not part of the antenna.
If the radiating circuit has some lumped loads on it which can be
varied in value then that is certainly part of the antenna. Try and stay
focussed.
Regards
Art
"Richard Harrison" wrote in message
...
Art, KB9MZ wrote:
"Well that is news to me. I never consider the matching circuit as part
of an antenna, but only a required band aid."

Art only recently changed his mind it seems. A year or so ago he was
arguing that the tuned T-matched arrangement he claimed to have invented
added gain from its radiation to that of his dipole. I said ,
"impossible because radiation from a small loop is directed in the plane
of the loop." So Art hates me.

More recently we discussed current distribution on short loaded vertical
antennas and if current had to be the same at both ends of a loading
coil. It doesn`t. Yuri presented in evidence Fig 9-22 from page 9-15 of
the 2nd edition of ON4UN`s "Low-Band DXing". Art shows disdain for
experts and books, so he may have paid no attention or quickly forgot.

One of the six examples in ON4UN`s figure is a continuously loaded
radiator. No doubt, no matter how feeble it is, the radiation emanates
from the loading coil which comprises the entire antenna.

Richard Clark was showing that the choice of series resonant or parallel
resonant as a model may be based on application or impedance.

A parallel resonant circuit exhibits high impedance. It is used for high
isolation as a trap, and as a phase inverter for a collinear as in the
self-resonant coil from Kraus presented by Cecil. A parallel resonant
circuit is also used to match end-fed 1/2-waves and similar high
impedance antennas. Many cheap small radios just connect the high
impedance antenna to to the hot end of the tank circuit.

The J-pole drives an end-fed 1/2-wave antenna from a short-circuited
1/4-wave stub. The stub is equivalent to a parallel resonant circuit and
exhibits a high impedance at its open-circuit end. This was another of
Richard Clark`s examples.

I regret Art fails to see the relevance of much of the accurate
information offered.

Best regards, Richard Harrison, KB5WZI

"Richard Harrison" wrote in message
...

onant as a model may be based on application or impedance.

A parallel resonant circuit exhibits high impedance.

Read what the book says about circuits that exhibit high impedance and what
the formula omits as being inconsequential
With reference to a large radiating parallel circuit containing both
distributed and lumped passive circuits
figure out what the numbers are that you can or can not place in the simple
circuit that proves your point.

I regret Art fails to see the relevance of much of the accurate
information offered.

Best regards, Richard Harrison, KB5WZI

On Fri, 05 Mar 2004 01:24:04 GMT, "aunwin"
wrote:
That is the longstanding convention. Same thing applies to a one
wavelength dipole. All such are the basis of the J-Pole and the Zepp
(when you strip away their matching sections).

Well that is new to me, I never consider the matching circuit as part of an
antenna but only a required band aid. Can you point me
to where this is discussed ? ( J pole I know nothing about but the others I
would like to read of what you refer to as a parallel circuit) This could
be the point of confusion.

The archives are rich in this discussion. The following quote from me
covers it adequately:

Matching sections to the J-Pole and the Zepp are contributors to
radiation due to the unbalanced nature of those antennas designs. How
much they contribute is perhaps arguable, but when they are built in
without care, their contribution cannot be denied. The matching
circuits contain both circulating currents and common mode currents.
The common mode currents, as a function of the physical length
compared to wavelength, offer radiation. The radiation may aid, or it
may hinder, but it is there none the less.

Not sure if you are saying 'yes'. I personaly think it is a parallel
circuit to which I would answer 'yes'.

No, they are NOT parallel - they could be, but there is nothing
inherently parallel and it all depends on the drive and load applied.

Well on that note I see a dipole as a single series circuit fed by a
generator( ARRL book), where-as I see a bandpass circuit as a parallel
circuit.

This is a product of your shortfall of experience and instruction. I
can construct a bandpass circuit using only resistors and capacitors.
There is NOTHING resonant there. I can build a notch filter (the
opposite of a bandpass filter) with a parallel circuit and EVERYTHING
is resonant there. I can build a bandpass filter with a series
resonant circuit. It is all a matter of connections, the topology as
has been pointed out.

Read the ARRL book on antennas and they dwell on series circuits as in
dipole, why the big difference with this newsgroup?

I have observed absolutely no discussion that would deny a series
resonant analysis of a half wave dipole.

Your comments seem to
rotate about phase changes more than it does about coupling as to the main
focal point.

I have commented in no way, shape, or form about phase. It is wholly
inappropriate to the topic.

No comments on your other posting yet .(pro and con) which suggest the
experts are unified on your statements.

As if I cared.... Engineering is not a democracy.

I will have to choose my words very, very carefully tomorrow on that one.Up
to now I feel fully exposed on what I don't know that which every body else
knows

Them? Hardly. Few dwell on these matters as there is a script in the
amateur rags that offer equivalent circuits presented at the drive
point for various length radiators. The point at which you may go
seriously off the track is to interpret those equivalent circuits into
physical structures of an over-strained imagination.

It is fine and well to simply observe that the full wave dipole has an
equivalent with a parallel resonant circuit. It is vastly different
to assign the physical elements of the structure of the antenna to
roles of capacitor, inductor and so on to make that parallel circuit
"real."

73's
Richard Clark, KB7QHC

Richard Clark wrote:
This is a product of your shortfall of experience and instruction. I
can construct a bandpass circuit using only resistors and capacitors.
There is NOTHING resonant there.

Are you not aware that resistors and capacitors possess inductance?
--
73, Cecil http://www.qsl.net/w5dxp



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Cecil, W5DXP wrote:
"Are you not aware that resistors and capacitors possess inductance?"

Richard Clark well knows that. I`d wager he was thinking of curtailing
low-frequency transmission with a small coupling capacitance. He could
then limit high-frequency response with a large capacitance shunting the
transmission path. Or, he could have been thinking of a gyrator.

With both high-frequwncy and low-frequencies limited, a band-pass filter
results. Op-amp gain and feedback produce a rich variety of response
tailoring possibilities.

I bought and installed a Thordarson resonant equalizer in one of the 2A3
amplifiers I used to build long ago. It`s amazing the difference
passband slopes can make in the sound.

Best regards, Richard Harrison, KB5WZI