Why must only series circuits be considered for radiators?.

What is it about parallel circuits that make them
unsuitable?

Is stagger tuning a parallel circuit ?

Regards
Art

Art KB9MZ wrote:
"Why must only series circuits be considered for radiators?"

It is convenient to follow custom.

Art also wrote:
"What is it about parallel circuits that make them unsuitable?"

We are more familiar with impedance than admittance in most cases due to
our instruction.

A parallel resonsant circuit is a high impedance (low admittance).
A series resonant circuit is a low impedance (high admittance).

For a parallel circuit, Q=R/X.
For a series circuit, Q=X/R.

The series circuit has its equivalent parallel circuit.
The parallel circuit has its equivalent series circuit.
The mathematical conversion from one to the other is simple and shown in
my 19th edition of the ARRL Antenna Book on page 24-12.
(By coincidence the action of 1//4-wave and 1/2-wave transmission line
sections is shown on the next page, 24-13) Commentors on using a
1/2-wave of foreign line inserted in a 50-ohm system, and what the ITT
Handbook says should consult the Antenna Book or some other book that
not only gives you the basic information but also tells you how to use
the information.

Best regards, Richard Harrison, KB5WZI

This is silly......... and you can't blame this on web tv.

Not one answer to any of the questions that anybody can hang their hat on!,
Just talking out loud from a book that fell open at a page. When are you
going to make some sense with your responses, most of us know and use the
formulas that you keep regurgitating but only when they are relavent.

Did your posting get cut short and the answers destroyed or did you forget
why you are posting?

There are three simple questions only. Simple answers should
suffice............. if........ you know your stuff.
If you find the answers to the simple questions in a book then please let me
know and I can read it in context for myself and I will thank you..

When Johny Carson gave the answers first on his show and one then had to
find a suitable question for it it was funny first time around only, so you
should quit doing it.
If you don't know the answers then it O.K. you don't have to respond if you
don't know, certainly better than verbal diarrea.
Art


"Richard Harrison" wrote in message
...
Art KB9MZ wrote:
"Why must only series circuits be considered for radiators?"

It is convenient to follow custom.

Art also wrote:
"What is it about parallel circuits that make them unsuitable?"

We are more familiar with impedance than admittance in most cases due to
our instruction.

A parallel resonsant circuit is a high impedance (low admittance).
A series resonant circuit is a low impedance (high admittance).

For a parallel circuit, Q=R/X.
For a series circuit, Q=X/R.

The series circuit has its equivalent parallel circuit.
The parallel circuit has its equivalent series circuit.
The mathematical conversion from one to the other is simple and shown in
my 19th edition of the ARRL Antenna Book on page 24-12.
(By coincidence the action of 1//4-wave and 1/2-wave transmission line
sections is shown on the next page, 24-13) Commentors on using a
1/2-wave of foreign line inserted in a 50-ohm system, and what the ITT
Handbook says should consult the Antenna Book or some other book that
not only gives you the basic information but also tells you how to use
the information.

Best regards, Richard Harrison, KB5WZI

"Richard Harrison" wrote in message
...

A parallel resonsant circuit is a high impedance (low admittance).
est regards, Richard Harrison, KB5WZI

Now go back to your books since your memory is poor and check out what
restrictions apply.
Do you ignore all connection lengths between lumped circuits.
Do they say all parallel circuits ALWAYS have a high impedance without
exception?
Does this simple formula account for radiation ?
Does a parallel circuit in macro form that radiates apply with respect to
this simple formula regardless of interconnection lengths?
Must all distributed passive forms be ignored and why?

Art, KB9MZ wrote:
"Now go back to your books since your memory is poor and check out what
restrictions apply."

My statement was: "A parallel resonant circuit is a high impedance (low
admittance)."

I reaffirm that statement. It assumes a high-quality circuit. It is
general and nonspecific. It is not all-inclusive. It allows exceptions.

In the ideal case, only perfect inductance and capacitance comprise the
circuit. Z = XL/R. As R goes to zero, Z goes to infinity.

The impedance of a parallel resonant circuit is:
Q(XL).

Best regards, Richard Harrison, KB5WZI

Well you are too far gone down memory lane, you are unable to focus for any
length of time and can't remember things or what you have said in the
past.No wonder you keep close to books, your memory has gone. Now go back to
your book and see that the high impedance comes from a parallel circuit with
lumped components to which radiation is not considered and there is no
length to the connections between them. It does not mean that a radiating
antenna which is in a parallel configuration will have a high impedance., It
can have a high impedance or even a low impedance and you must account for
distributed loads in any of your calculations to determine whether it will
be high or low when the bandpass array is resonant.
Now you probably will not find that statement in a book so you are in the
hole with no way of getting out. You just blew it and you are stuck with the
statements you made including the one that states that such an arrangement
violates all the laws of nature as well as remembering what post you are
responding to. Or is that deliberate because you found it embarrasing to
think of responding to it, as you have not got the ability to speak in
fractured English like Shakespeare which allows for a lot of wriggle room. I
leave it at that and maybe while you are still alive somebody will be kind
to you and explain that which you cannot comprehend or if you are still
around in a couple of years you may be able to read it for yourself when it
is in print. I didn't really expect that you could come up with anything of
detail, just words
Bye


"Richard Harrison" wrote in message
...
Art, KB9MZ wrote:
"Now go back to your books since your memory is poor and check out what
restrictions apply."

My statement was: "A parallel resonant circuit is a high impedance (low
admittance)."

I reaffirm that statement. It assumes a high-quality circuit. It is
general and nonspecific. It is not all-inclusive. It allows exceptions.

In the ideal case, only perfect inductance and capacitance comprise the
circuit. Z = XL/R. As R goes to zero, Z goes to infinity.

The impedance of a parallel resonant circuit is:
Q(XL).

Best regards, Richard Harrison, KB5WZI

On Mon, 08 Mar 2004 06:11:32 GMT, "aunwin"
wrote:

fractured English like Shakespeare

Art,

Why do you hate Brits so?

73's
Richard Clark, KB7QHC

Art, KB9MZ wrote:
"It does not mean that a radiating antenna which is in the parallel
configuration will have a high impedance."

Parallel configuration can mean several things. I will take it to mean
the antenna shares some of the characteristics of a parallel resonant
circuit.

Experience is that an end-fed 1/2-wave antenna has a high feedpoint
resistance while an end-fed 1/4-wave antenna has a low feedpoint
resistance. Since Art is hunting discrepancies, 1/2-wave and 1/4-wave
are only approximate wavelengths. Resonant lengths in an antenna are
shorter than free-space wavelengths due to reduced velocity along a wire
and due to capacitive effects near the open-circuit at the end of the
wire.

For a given power input to the antenna, the feedpoint voltage rises as
the feedpoint impedance rises. See Ohm`s law.

In 1949 I worked in a broadcast plant where two stations shared the same
tower. Both had frequencies, 950 KHz and 1320 KHz, that were higher than
the 1/4-wavelength frequency of the tower which was designed for the
previous occupant of the plant. Its frequency was around 740 KHz. The
1/2-wave resonant frequency of the tower might have been around 1480
KHz. The high length of the tower was still enough to make it a high
impedance at its operating frequencies. 1320 KHz is emanating from that
that tower as I type. It is hot as a pistol. Big arcs can be drawn at
the base of the tower.

Art`s question was: "What is it about parallel circuits that makes them
unsuitable?"

Like Johnny Carson, I may have given the answer before revealing the
Question. A parallel resonant circuit shares the high impedance trait
with an end-fed wire near 1/2-wave long.

A series resonant circuit shares the low impedance trait with and
end-fed wire near 1/4-wave long.

A 1/4-wave series resonant circuit antenna with an open-circuit end
produces a low impedance at its driven end through an impedance
inversion caused by the reflected energy arriving back at the drive
point. Radiation and other resistance prevent the reflected wave from
causing a complete short-circuit at the drive point.

When I say a radiating antenna in the parallel configuration (Art`s
words) will have a high impedance (the 1/2-wave repeats high impedance
caused by the open circuit), it will mean that its radiation resistance
has grown with its length and its reactance will be zero if the antenna
length has reached 2nd resonance, or the reactance is non-zero between
resonant lengths.

High and low are relative terms. The questions should be, how high? or
how low?

Best regards, Richard Harrison, KB5WZI

"Richard Harrison" wrote in message
...
Art, KB9MZ wrote:
"It does not mean that a radiating antenna which is in the parallel
configuration will have a high impedance."

Parallel configuration can mean several things. I will take it to mean
the antenna shares some of the characteristics of a parallel resonant
circuit.

So now 'WILL' can now be read as 'CAN' with respect to impedance 'EXCEPT'
in the case of circuitry where radiation is ignored

At last,..... at last.... even tho grudgingly.
So now you cannot use that as a reason for me to lie about my having an
antenna in parallel form
You CAN have a low resistance of 1 ohm or you CAN have one 1000 ohms so play
your silly games about me being a lier, don't hold your breath, have no
integrity and also a thief, all of which have been thrown at me because I
stated I have a rotatable beam for 160 meters that has a moveable 5 khz pass
band. Now you have the problem of explaining to people that you can have a
parallel arrangement for an antenna and we were wrong to focuss on the high
impedance aproach to accuse Art of lying and all the other accusations that
was thrown at him. Now ask the people involved why they refused to check for
themselves or do they have a backup technical augument. You made a point
about the loop dipole well the patent office accepted it as viable even tho
my writing was not clear because they had a samplke. The University of
Illinois accepted it for review ( Yes I spoke also to the professor of Log
periodic fame as well, very interesting person)
The antenna director in charge or general Boss stated my claims were
confirmed.
So the antenna experts in this group don't understand how it functions so
immediately get in to gear to attack. Didn't Walter lead the last attack on
a guy, any attempt to squash inovation.
Now I can rest peacefully seeing that you are exposed for what you are. Now
when you see the next antenna in print you can chant what all followers
say....Well I knew that all the time, at least that is my experience when I
come up with something. The problem is that some people get degrees by
choice of multiple answers with a circular sweep of a pencil to make a dot,
first principles don't matter diddly as it is in a book written just like
that..

On Mon, 08 Mar 2004 17:09:08 GMT, "aunwin"
wrote:

Art, KB9MZ wrote:
"It does not mean that a radiating antenna which is in the parallel
configuration will have a high impedance."

Parallel configuration can mean several things. I will take it to mean
the antenna shares some of the characteristics of a parallel resonant
circuit.

Does not lead to:

You CAN have a low resistance of 1 ohm or you CAN have one 1000 ohms

Parallel resonant circuits exhibit a high impedance, there are no
other interpretations.

( Yes I spoke also to the professor of Log
periodic fame as well, very interesting person)
"Broadband Logarithmically Periodic Antenna Structures," 1957 IRE
National Convention Record, Part 1.
Dwight E. Isbell, U.S. Patent No. 3,210,767 teaches:
"...directivity... was better than 9db over isotropic."
"Advantageously, however, the antennas of the invention need
no adjusting for their performance over a wide band width
compared to the parasitic types...."
"The longest dipole element should be approximately
0.47 wavelength long."

It is difficult to mis-interpret this patent as it is only 5 pages
long with two of those pages as illustrations, and the last page is
less than half full of text. We may note many design issues that Art
has taken umbrage of having been pointed out repeatedly
1.) half wave, full size dipoles (series resonant structures);
2.) wide bandwidth as an advantage;
3.) comparison to standards, in this case isotropic;
4.) no loads or components adding to complexity (no adjustments);
5.) Dwight Isbell learned his craft from books and instructors who
wrote those ( -gasp!- ) books (he was a graduate student
with R. H. DuHamel);
6.) Such information as we have about his design are found in
( -gasp!- ) books;
7.) furthermore, Mr. Isbell has never exhibited Netourette's
Syndrome in these messages posted here.

73's
Richard Clark, KB7QHC