RSGB RadCom December 2007 Issue
 

Those that can get access to a copy should look at the Radio Society of
Great Britain, RadCom Magazine, December 2007 issue, Technical Topics column
by Pat Hawker G3VA. The topic? 50 Years of amateur antennas. He covers a lot
of the perennial topics of debate in this newsgroup and provides some
excellent commentary on element lengths, feedline lengths, SWR, ATU's, modes
of operation and some of the controversy. Okay, it has probably all been
covered elsewhere in books, on websites and in this newsgroup, but there is
a lot of useful information condensed into a couple of pages. Almost a
substitute fro Kraus and Terman! :-)

Mike G0ULI

RSGB RadCom December 2007 Issue
 

Mike Kaliski wrote:
Those that can get access to a copy should look at the Radio Society of
Great Britain, RadCom Magazine, December 2007 issue, Technical Topics
column by Pat Hawker G3VA. The topic? 50 Years of amateur antennas. He
covers a lot of the perennial topics of debate in this newsgroup and
provides some excellent commentary on element lengths, feedline lengths,
SWR, ATU's, modes of operation and some of the controversy. Okay, it has
probably all been covered elsewhere in books, on websites and in this
newsgroup, but there is a lot of useful information condensed into a
couple of pages. Almost a substitute fro Kraus and Terman! :-)

Mike G0ULI

Does he cover the radiation of antennas from 377 ohm "sweet spots", and
the concept of using antennas to match free space's impedance?

Roy Lewallen, W7EL

RSGB RadCom December 2007 Issue
 

Pat Hawker was the only part that I read but lately he seems to be
rambling.
The antenna reporter isn't really putting out anything of interest for
the
regular ham either tho I was pleased with the experimenting for QRP
I terminated my subscription to Radcom this year because there rarely
was anything else that was interesting. Wrote them a letter earlier
this year
but they didn't even acknoweledge it.
Have been to the HQ by the way at St Albans or was it Hatfield?
Art

Mike Kaliski wrote:
Those that can get access to a copy should look at the Radio Society of
Great Britain, RadCom Magazine, December 2007 issue, Technical Topics column
by Pat Hawker G3VA. The topic? 50 Years of amateur antennas. He covers a lot
of the perennial topics of debate in this newsgroup and provides some
excellent commentary on element lengths, feedline lengths, SWR, ATU's, modes
of operation and some of the controversy. Okay, it has probably all been
covered elsewhere in books, on websites and in this newsgroup, but there is
a lot of useful information condensed into a couple of pages. Almost a
substitute fro Kraus and Terman! :-)

Mike G0ULI

RSGB RadCom December 2007 Issue
 

art ) writes:
Pat Hawker was the only part that I read but lately he seems to be
rambling.

I'm rather surprised that he's still doing the column. It's been
thirty years since I bought a collection of Technical Topics, and later
I found a used one dating from the sixties. I have no idea when
he started doing it (wait, I guess if this is "50 years of antenna topics"
then it must be fifty years), but I suspect nobody has had such a long
running column in the ham magazines.

Of course, such columns are relatively easy to write, since it's a filtering
of a lot of material down to it's essence.


Michael VE2BVW

RSGB RadCom December 2007 Issue
 

"Roy Lewallen" wrote in message
...
Mike Kaliski wrote:
Those that can get access to a copy should look at the Radio Society of
Great Britain, RadCom Magazine, December 2007 issue, Technical Topics
column by Pat Hawker G3VA. The topic? 50 Years of amateur antennas. He
covers a lot of the perennial topics of debate in this newsgroup and
provides some excellent commentary on element lengths, feedline lengths,
SWR, ATU's, modes of operation and some of the controversy. Okay, it has
probably all been covered elsewhere in books, on websites and in this
newsgroup, but there is a lot of useful information condensed into a
couple of pages. Almost a substitute fro Kraus and Terman! :-)

Mike G0ULI

Does he cover the radiation of antennas from 377 ohm "sweet spots", and
the concept of using antennas to match free space's impedance?

Roy Lewallen, W7EL

Hi Roy,

He does mention that antennas possess radiation resistance, not to be
confused with and not the same as, characteristic impedence (or feedpoint
impedence) and that the characteristic impedence will vary along an antennas
length.

As for the actual point(s) along an element at which an antenna radiates
(transfers energy to free space) with maximum efficiency, he makes no
comment.

I seriously doubt that there is anything in the article that you would
dispute.

It seems that everyone was so busy laughing on this newsgroup, that no one
has actually provided any information as to whether any detailed research
has ever been carried out as to what is going on within the radiating
elements of an antenna. There is loads of theory in the text books, but I
have yet to see any empirical measurements or results. I am aware of the
research into small loops carried out by Professor Underhill (also published
in RadCom) but it seems that even his results have been disputed.

I may have submitted the post, tongue in cheek, to stir things up a bit, but
on reflection there seems to be something of merit in the idea. I am
revisiting the appropriate chapters in Kraus and Terman to see where the
error in my logic is. In the absence of any direct evidence of
contradiction, I think it may be worth developing this idea and making a few
measurements of my own to see what the truth of the matter is. Amateur radio
is supposed to be a learning experience, right? And you can't learn without
making mistakes. After 40 years of following the diktats of professional
communications and electronic theory, I think the time is right to kick off
the traces and challenge some of the accepted authodoxies. I do know all the
conventional stuff, it just doesn't satisfy my soul.

You probably know more about antennas than anyone has a right to know Roy,
but it's a strange universe out there and it's just possible that there's a
few more things to learn yet.

Regards
Mike G0ULI

RSGB RadCom December 2007 Issue
 

"art" wrote in message
...
Pat Hawker was the only part that I read but lately he seems to be
rambling.
The antenna reporter isn't really putting out anything of interest for
the
regular ham either tho I was pleased with the experimenting for QRP
I terminated my subscription to Radcom this year because there rarely
was anything else that was interesting. Wrote them a letter earlier
this year
but they didn't even acknoweledge it.
Have been to the HQ by the way at St Albans or was it Hatfield?
Art

Mike Kaliski wrote:
Those that can get access to a copy should look at the Radio Society of
Great Britain, RadCom Magazine, December 2007 issue, Technical Topics
column
by Pat Hawker G3VA. The topic? 50 Years of amateur antennas. He covers a
lot
of the perennial topics of debate in this newsgroup and provides some
excellent commentary on element lengths, feedline lengths, SWR, ATU's,
modes
of operation and some of the controversy. Okay, it has probably all been
covered elsewhere in books, on websites and in this newsgroup, but there
is
a lot of useful information condensed into a couple of pages. Almost a
substitute for Kraus and Terman! :-)

Mike G0ULI

Hi Art,

That is true, but he has been a columnist for years and years, and there
must come a time when you start to go round in circles. Rather too much
emphasis on low noise mixers and old valve circuits for my taste but
sometimes there is a real gem, like this month. The homebrew column that has
been appearing for the last few months has been very good and very
practical. The head office is in Potters Bar, just off the M25 motorway.
They have quite a nice station that licensed visitors can operate, with
prior notice. The staff are always friendly but are rather busy all the time
so are not really in a position to stand around having long chats.

Cheers
Mike G0ULI

RSGB RadCom December 2007 Issue
 

On Thu, 15 Nov 2007 02:47:05 -0000, "Mike Kaliski"
wrote:

It seems that everyone was so busy laughing on this newsgroup,

Hi Mike,

As well crafted a line for trolling as any....

that no one
has actually provided any information as to whether any detailed research
has ever been carried out as to what is going on within the radiating
elements of an antenna.

This, as the lawyers would say, argues a fact not yet in evidence.
Your statement appears to be one that can only be satisfied by meeting
a string of conditions:
1. The actuality of "actually," who is the arbiter of this? This
group has long experienced denial by inventors that their theories
have never been "actually" disproved. "Actually" is one of those
rubbery words that fits any argument that lack definition;
2. "detailed research?" Another qualifier that invites the rejection
of any contribution for lacking unspecified requirements;
3. "what is going on?" Now THERE is a technical goal for detailed
research to be provided as information.
4. "within the radiating elements?" Is this to presume there is some
distinct radiation from "within" elements? This would be a remarkable
measurement achievement to tease it out from the rest. [Could we use
a Gaussian sieve?]

There is loads of theory in the text books, but I

If you moved to the fiction shelves would you say there is loads of
drama in them? [More to the matter, what would you expect?]

have yet to see any empirical measurements or results.

Of what? Actual detailed results of what is going on within radiating
elements?

Help us out here. What instrumentation would be used? What units of
measure would be employed? (In "what is going on" are we talking
about Ohms, Volts, Amperes; or swimming, having a party, or getting
laid off?). What qualifies as detail? How would we recognize it
being actual?

I am aware of the
research into small loops carried out by Professor Underhill (also published
in RadCom) but it seems that even his results have been disputed.

Hmm, tantalizing, but how do small loops relate to "what is actually
going on?" More so, where within the loop did Professor Underhill
make his measurements, and what were they of? [I might point out
here, editorially, that little content was posted by you up until this
point, and it has evaporated following its solitary mention. If you
stripped out everything, and simply fleshed out this sentence into a
paragraph, it might be meaningful.]

I may have submitted the post, tongue in cheek

Then the joviality that your post heralds is merited, isn't it? This
is called leading with your chin.

, to stir things up a bit, but
on reflection there seems to be something of merit in the idea.

As your post seems to be wholly unrelated to the topic, and apparently
a stream of consciousness from another thread, then this idea is
adorned with rather vague suggestions.

73's
Richard Clark, KB7QHC

RSGB RadCom December 2007 Issue
 

Richard Clark wrote:

...
73's
Richard Clark, KB7QHC

Ahhh, at it again.

A careful argument based on semantics, the authors choice of words, and
standing on the arguments that no mistakes exist in our present
knowledge and that new discoveries in the deep workings of antennas are
yet to be discovered ...

Yanno Richard, you argument is really the same argument--over, and over,
and over again ...

I keep wondering if others ever notice, or they all, to the VERY LAST
ONE, are too polite to point out how childish it all really is?

Regards,
JS

RSGB RadCom December 2007 Issue
 

Mike Kaliski wrote:
and that the characteristic impedence will vary
along an antennas length.

Well, that's obviously false. The characteristic
impedance of a horizontal wire above ground is
constant at 138*log(4D/d)

The characteristic impedance is not to be confused
with the voltage to current ratio existing on a
standing-wave antenna any more than the characteristic
impedance of a transmission line is to be confused
with the voltage to current radio existing along
its length when the SWR is not 1:1.
--
73, Cecil http://www.w5dxp.com

RSGB RadCom December 2007 Issue
 

Cecil Moore wrote:
Mike Kaliski wrote:
and that the characteristic impedence will vary along an antennas length.

Well, that's obviously false. The characteristic
impedance of a horizontal wire above ground is
constant at 138*log(4D/d)

The characteristic impedance is not to be confused
with the voltage to current ratio existing on a
standing-wave antenna any more than the characteristic
impedance of a transmission line is to be confused
with the voltage to current radio existing along
its length when the SWR is not 1:1.

Have you verified this experimentally, Cecil? If you did,
how did you do it?
73,
Tom Donaly, KA6RUH

RSGB RadCom December 2007 Issue
 

"John Smith" wrote in message
...

And the skills test is, find the missing "not" in the previous post! ;-)

Regards,
JS

RSGB RadCom December 2007 Issue
 

Cecil Moore wrote:
Mike Kaliski wrote:
and that the characteristic impedence will vary along an antennas length.

Well, that's obviously false. The characteristic
impedance of a horizontal wire above ground is
constant at 138*log(4D/d)

The characteristic impedance is not to be confused
with the voltage to current ratio existing on a
standing-wave antenna any more than the characteristic
impedance of a transmission line is to be confused
with the voltage to current radio existing along
its length when the SWR is not 1:1.

Interesting point.

When I use a gamma match on a 1/2 wave vertical with counterpoise, I
have always wondered about the 50ohm impedance point where the gamma
taps the element.

To end feed the antenna, an impedance of thousands of ohms is
encountered, a, seemingly, "strange" distance up the element (in regards
to total element length) and a 50 ohm impedance point is encountered
(needing only a series capacitive reactance to correct for the gamma
rods' inductive reactance.)

It would be interesting if I had a formula which would predict what
impedance would be encountered for all points along the element--know of
any?

I have looked at setting up such a formula, but frankly have been
unsuccessful ... and of course, it is given that antenna length IS
resonate for the frequency in question.

Regards,
JS

RSGB RadCom December 2007 Issue
 

On Wed, 14 Nov 2007 19:41:42 -0800, John Smith
wrote:

A careful argument based on semantics, the authors choice of words, and
standing on the arguments that no mistakes exist in our present
knowledge and that new discoveries in the deep workings of antennas are
yet to be discovered ...

Talk about a mouthful of ****.

Spit it out tell us how your really feel.

73's
Richard Clark, KB7QHC

RSGB RadCom December 2007 Issue
 

Richard Clark wrote:
On Wed, 14 Nov 2007 19:41:42 -0800, John Smith
wrote:

A careful argument based on semantics, the authors choice of words, and
standing on the arguments that no mistakes exist in our present
knowledge and that new discoveries in the deep workings of antennas are
yet to be discovered ...

Talk about a mouthful of ****.

Spit it out tell us how your really feel.

73's
Richard Clark, KB7QHC

Huh? You jest, you have better mental comprehension than that ...

What, you applying for SSI disability and attempting to use your posts
to prove mental incompetence? Mad Cow Disease? ???

Get real ... yawn.

JS

RSGB RadCom December 2007 Issue
 

Michael Black wrote:

Of course, such columns are relatively easy to write, since it's a
filtering of a lot of material down to it's essence.


No, it's such comments that are easy to write.

Now try doing it :-)


--

73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek

RSGB RadCom December 2007 Issue
 

"Richard Clark" wrote in message
...
On Thu, 15 Nov 2007 02:47:05 -0000, "Mike Kaliski"
wrote:

It seems that everyone was so busy laughing on this newsgroup,

Hi Mike,

As well crafted a line for trolling as any....

that no one
has actually provided any information as to whether any detailed research
has ever been carried out as to what is going on within the radiating
elements of an antenna.

This, as the lawyers would say, argues a fact not yet in evidence.
Your statement appears to be one that can only be satisfied by meeting
a string of conditions:
1. The actuality of "actually," who is the arbiter of this? This
group has long experienced denial by inventors that their theories
have never been "actually" disproved. "Actually" is one of those
rubbery words that fits any argument that lack definition;
2. "detailed research?" Another qualifier that invites the rejection
of any contribution for lacking unspecified requirements;
3. "what is going on?" Now THERE is a technical goal for detailed
research to be provided as information.
4. "within the radiating elements?" Is this to presume there is some
distinct radiation from "within" elements? This would be a remarkable
measurement achievement to tease it out from the rest. [Could we use
a Gaussian sieve?]

There is loads of theory in the text books, but I

If you moved to the fiction shelves would you say there is loads of
drama in them? [More to the matter, what would you expect?]

have yet to see any empirical measurements or results.

Of what? Actual detailed results of what is going on within radiating
elements?

Help us out here. What instrumentation would be used? What units of
measure would be employed? (In "what is going on" are we talking
about Ohms, Volts, Amperes; or swimming, having a party, or getting
laid off?). What qualifies as detail? How would we recognize it
being actual?

I am aware of the
research into small loops carried out by Professor Underhill (also
published
in RadCom) but it seems that even his results have been disputed.

Hmm, tantalizing, but how do small loops relate to "what is actually
going on?" More so, where within the loop did Professor Underhill
make his measurements, and what were they of? [I might point out
here, editorially, that little content was posted by you up until this
point, and it has evaporated following its solitary mention. If you
stripped out everything, and simply fleshed out this sentence into a
paragraph, it might be meaningful.]

I may have submitted the post, tongue in cheek

Then the joviality that your post heralds is merited, isn't it? This
is called leading with your chin.

, to stir things up a bit, but
on reflection there seems to be something of merit in the idea.

As your post seems to be wholly unrelated to the topic, and apparently
a stream of consciousness from another thread, then this idea is
adorned with rather vague suggestions.

73's
Richard Clark, KB7QHC

Hi Richard

Thanks for yor comments and encouragement. I can well understand your
skepticism and accept that this idea is pretty far out. As you rightly point
out, there are a whole host of issues revolving around what is being
defined, measurement methods and interpretation of results.

The small transmitting loop efficiency experiments were carried out using
thermographic imaging to try and identify areas of heating within the loops.
The areas with maximum heating would indicate high current flow or high
resistance. This information was used to try and derive a theory of
operation and efficiency figures for the loops. The idea being to prove that
efficiency was in fact higher than predicted by the Chu theory. The
methodology and results of the experiment were challenged and Chu theory
seems to have won out, at least for the time being.

I don't see that there would be any need to invoke non standard units for
experimental measurements, ohms, amps and volts should suffice. I have not
worked out the best measurement methods or instrumentation to use, but I am
sure that existing equipment and techniques will suffice. Small sampling
coils, hall effect devices, temperature measurement
probes and thermal cameras are all available at prices which an amateur
experimenter can afford, so there is no reason why these experiments could
not be carried out in a domestic environment rather then an industrial one.

The reason for specifying a single radiating element is because directional
and reflecting elements absorb and re-radiate RF energy. Once the properties
of a single element are known, then it is possible to add additional
elements and make further measurements and assessments of performance. Since
it is already known that all the elements of an antenna interact with one
another, it is important to start with the basics and work up from there.

The choice of the word 'within' was unfortunate because I accept that there
is nothing going on actually within an antenna element, skin effect ensuring
that RF travels on the outside of conductors.

So I come back to my assertion that very little detail seems to have been
published about what is happening really close in to antennas i.e. on the
actual elements making up the antenna. Loads of stuff about near field and
far field experiments, but not specific points of radiation from the antenna
elements. It may all be a complete waste of time but at least I will have
fun and hopefully learn some new stuff doing it.

Regards
Mike G0ULI

RSGB RadCom December 2007 Issue
 

"Cecil Moore" wrote in message
...
Mike Kaliski wrote:
and that the characteristic impedence will vary along an antennas length.

Well, that's obviously false. The characteristic
impedance of a horizontal wire above ground is
constant at 138*log(4D/d)

The characteristic impedance is not to be confused
with the voltage to current ratio existing on a
standing-wave antenna any more than the characteristic
impedance of a transmission line is to be confused
with the voltage to current radio existing along
its length when the SWR is not 1:1.
--
73, Cecil http://www.w5dxp.com

Cecil

Are you sure you are not confusing the characteristic impedance of a dipole
antenna with the characteristic impedence of an open feed line? One is
constant, the other appears to vary along its length. A dipole antenna has
low impedence at a centre feed point and high impedence at it's ends.

Reminds me of the tales of old ladies who used to tie knots in electric flex
to stop the electricity leaking out! I actually met one in real life many
years ago.

Mike G0ULI

RSGB RadCom December 2007 Issue
 

Tom Donaly wrote:
Cecil Moore wrote:
The characteristic
impedance of a horizontal wire above ground is
constant at 138*log(4D/d)

The characteristic impedance is not to be confused
with the voltage to current ratio existing on a
standing-wave antenna any more than the characteristic
impedance of a transmission line is to be confused
with the voltage to current radio existing along
its length when the SWR is not 1:1.

Have you verified this experimentally, Cecil? If you did,
how did you do it?

Here's a quote from "Antennas Theory" by Balanis: "The current
and voltage distributions on open-ended wire antennas are similar
to the standing wave patterns on open-ended transmission lines.
.... Standing wave antennas, such as the dipole, can be analyzed
as traveling wave antennas with waves propagating in opposite
directions (forward and backward) and represented by traveling
wave currents If and Ib ..."

As Balanis suggests, the body of technical knowledge
available for "open-ended transmission lines" is applicable
to "open-ended wire antennas", e.g. dipoles, which really
are nothing but lossy *single-wire* transmission lines.

That characteristic impedance equation for a single-wire
transmission lines can be found in numerous publications and
is close to a purely resistive value. A #14 horizontal wire
30 feet above ground is very close to a characteristic
impedance of 600 ohms. (One half of a 1/2 wavelength dipole
is simply a lossy 1/4 wavelength stub with Z0 = ~600 ohms.)

Before he passed, Reg Edwards had some earlier comments on
the characteristic impedance of a 1/2WL dipole above ground.

Like a normal transmission line open stub, a 1/2WL
dipole supports standing waves that can be analyzed. For the
purposes of a voltage and current analysis, I^2*R losses and
radiation losses can be lumped together into total losses
associated with some attenuation factor, similar to analyzing
a 1/4WL lossy normal stub.

In fact, the losses to radiation from
one half of a 1/2WL dipole can be simulated by EZNEC using
resistance wire in a 1/4WL open stub. Using EZNEC with a
resistivity of 2.3 uohm/m for a 1/4WL open stub gives a pretty
good model of what is happening with one half of a 1/2WL dipole
which is only a lossy single-wire transmission line above earth.
--
73, Cecil http://www.w5dxp.com

RSGB RadCom December 2007 Issue
 

Mike Kaliski wrote:
Are you sure you are not confusing the characteristic impedance of a
dipole antenna with the characteristic impedence of an open feed line?
One is constant, the other appears to vary along its length. A dipole
antenna has low impedence at a centre feed point and high impedence at
it's ends.

The feedpoint impedance of a stub is NOT the same thing
as the Z0 of the stub. The feedpoint impedance of an
antenna is NOT the same thing as the Z0 of the antenna.

The characteristic impedance of a #14 wire 30 feet above
the ground is close to constant at 600 ohms. The formula
for a single-wire transmission line is 138*log(4D/d).
A horizontal dipole is nothing more than a single-wire
transmission line which is known to be lossy.

The characteristic impedance of a transmission line is
constant. If the SWR 1, the voltage to current
ratio varies along its length. That varying impedance
(V/I) is NOT the characteristic impedance which is
constant.

The characteristic impedance of a horizontal dipole is
~constant. Since a dipole is a standing wave antenna,
the voltage to current ratio varies along its length.
That varying impedance (V/I) is NOT the characteristic
impedance which is relatively constant for a horizontal
wire.
--
73, Cecil http://www.w5dxp.com

RSGB RadCom December 2007 Issue
 

On Thu, 15 Nov 2007 12:29:08 -0000, "Mike Kaliski"
wrote:

Thanks for yor comments and encouragement. I can well understand your
skepticism and accept that this idea is pretty far out. As you rightly point
out, there are a whole host of issues revolving around what is being
defined, measurement methods and interpretation of results.

Hi Mike,

OK, but this still tells me nothing of what issue you think I am
skeptical about!

The small transmitting loop efficiency experiments were carried out using
thermographic imaging to try and identify areas of heating within the loops.

Good, that is instructive.

The areas with maximum heating would indicate high current flow or high
resistance.

More properly, their product - Watts.

This information was used to try and derive a theory of
operation and efficiency figures for the loops. The idea being to prove that
efficiency was in fact higher than predicted by the Chu theory.

This names only one theory and doesn't actually illustrate any
differences.

The
methodology and results of the experiment were challenged and Chu theory
seems to have won out, at least for the time being.

Again, all of this is suggestive, not informative. Returning to your
earlier complaint of "detailed research" we have no details beyond
heat imaging challenging the establishment.

I don't see that there would be any need to invoke non standard units for
experimental measurements, ohms, amps and volts should suffice.

Too often, this group has to wade through "what it is not" instead of
"what it is." Tell us what specific units would be convincing for
you, as you have introduced a complaint that needs to be satisfied.

I have not
worked out the best measurement methods or instrumentation to use, but I am
sure that existing equipment and techniques will suffice.

I have worked on a world of instruments (more than anyone here).
Believe me, that experience has NOT answered the question of the ages.

Small sampling
coils, hall effect devices, temperature measurement
probes and thermal cameras are all available at prices which an amateur
experimenter can afford, so there is no reason why these experiments could
not be carried out in a domestic environment rather then an industrial one.

OK, by induction, I presume you are harkening back to these thermal
maps or imaging.

Well, in fact they have been done, their results have been posted to
the net and argued here. You didn't get the invitation?

Unfortunately, that contributor was arguing smaller loops, coils
specifically and the mapping was tangential to the rant. He promised
more data when Spring weather would allow him to pursue this line of
inquiry, but that was several Springs ago, and he has in the interval
chosen to -um- till the same ground.

The reason for specifying a single radiating element is because directional
and reflecting elements absorb and re-radiate RF energy. Once the properties
of a single element are known, then it is possible to add additional
elements and make further measurements and assessments of performance. Since
it is already known that all the elements of an antenna interact with one
another, it is important to start with the basics and work up from there.

True, and certainly it stands to improve clarity by reducing
variables.

The choice of the word 'within' was unfortunate because I accept that there
is nothing going on actually within an antenna element, skin effect ensuring
that RF travels on the outside of conductors.

Plus, thermal imaging would be hard pressed to peer inside a
conductor.

So I come back to my assertion that very little detail seems to have been
published about what is happening really close in to antennas i.e. on the
actual elements making up the antenna. Loads of stuff about near field and
far field experiments, but not specific points of radiation from the antenna
elements. It may all be a complete waste of time but at least I will have
fun and hopefully learn some new stuff doing it.

You mean you are unfamiliar with this work. I've posted my own here
to little attention, I don't think this cycle will attract much more,
but here it is:
http://home.comcast.net/~kb7qhc/ante...pole/index.htm

This doesn't actually attend your preference of thermal mapping, but
you are still vague to the point of "what is happening really close in
to antennas" (even qualified by "on the actual elements" - there's
that word actual again which lends nothing to a specification).

There is an entire field of Science devoted to this (beyond the scope
of many here who would anticipate my answer being "Fields"). This
field is called Plasmonics. Books are written about it, pictures are
taken of it, and I've sat through hours of presentations demonstrating
it. Unfortunately, this crowd of investigators, like Arthur, have
re-invented the wheel and they proclaim it is square.

The long and short of it is that you stand to become more confused,
but it could be rewarding if you wear asbestos.

73's
Richard Clark, KB7QHC

RSGB RadCom December 2007 Issue
 

Michael Black wrote:
art ) writes:

Pat Hawker was the only part that I read but lately he seems to be
rambling.


I'm rather surprised that he's still doing the column. It's been
thirty years since I bought a collection of Technical Topics, and later
I found a used one dating from the sixties. I have no idea when
he started doing it (wait, I guess if this is "50 years of antenna topics"
then it must be fifty years), but I suspect nobody has had such a long
running column in the ham magazines.

Of course, such columns are relatively easy to write, since it's a filtering
of a lot of material down to it's essence.



Actually, such columns can be very difficult to write. Distilling to
the essence, without losing an essential detail, can be quite
challenging. Anyone can write a 200 page tome that covers something in
all its gory detail, given sufficient time and effort. It's
substantially harder to make an adequate summary in 100 words, and doing
it on a deadline.

Sort of like writing meaningful abstracts for a technical paper.

RSGB RadCom December 2007 Issue
 

"Cecil Moore" wrote
The characteristic impedance of a horizontal dipole is
~constant. Since a dipole is a standing wave antenna,
the voltage to current ratio varies along its length.
That varying impedance (V/I) is NOT the characteristic
impedance which is relatively constant for a horizontal
wire.
--
73, Cecil http://www.w5dxp.com


Cecil,
How do we apply (calculate char. imp.) the above to say, full wave (quad)
loop or vertical monopole?

Yuri, K3BU

RSGB RadCom December 2007 Issue
 

Cecil Moore wrote:
Tom Donaly wrote:
Cecil Moore wrote:
The characteristic
impedance of a horizontal wire above ground is
constant at 138*log(4D/d)

The characteristic impedance is not to be confused
with the voltage to current ratio existing on a
standing-wave antenna any more than the characteristic
impedance of a transmission line is to be confused
with the voltage to current radio existing along
its length when the SWR is not 1:1.

Have you verified this experimentally, Cecil? If you did,
how did you do it?

Here's a quote from "Antennas Theory" by Balanis: "The current
and voltage distributions on open-ended wire antennas are similar
to the standing wave patterns on open-ended transmission lines.
... Standing wave antennas, such as the dipole, can be analyzed
as traveling wave antennas with waves propagating in opposite
directions (forward and backward) and represented by traveling
wave currents If and Ib ..."

As Balanis suggests, the body of technical knowledge
available for "open-ended transmission lines" is applicable
to "open-ended wire antennas", e.g. dipoles, which really
are nothing but lossy *single-wire* transmission lines.

That characteristic impedance equation for a single-wire
transmission lines can be found in numerous publications and
is close to a purely resistive value. A #14 horizontal wire
30 feet above ground is very close to a characteristic
impedance of 600 ohms. (One half of a 1/2 wavelength dipole
is simply a lossy 1/4 wavelength stub with Z0 = ~600 ohms.)

Before he passed, Reg Edwards had some earlier comments on
the characteristic impedance of a 1/2WL dipole above ground.

Like a normal transmission line open stub, a 1/2WL
dipole supports standing waves that can be analyzed. For the
purposes of a voltage and current analysis, I^2*R losses and
radiation losses can be lumped together into total losses
associated with some attenuation factor, similar to analyzing
a 1/4WL lossy normal stub.

In fact, the losses to radiation from
one half of a 1/2WL dipole can be simulated by EZNEC using
resistance wire in a 1/4WL open stub. Using EZNEC with a
resistivity of 2.3 uohm/m for a 1/4WL open stub gives a pretty
good model of what is happening with one half of a 1/2WL dipole
which is only a lossy single-wire transmission line above earth.

So you haven't verified it experimentally, and don't know how
to do so. Thanks for the answer.
73,
Tom Donaly, KA6RUH

RSGB RadCom December 2007 Issue
 

Yuri Blanarovich wrote:
"Cecil Moore" wrote
The characteristic impedance of a horizontal dipole is
~constant. Since a dipole is a standing wave antenna,
the voltage to current ratio varies along its length.
That varying impedance (V/I) is NOT the characteristic
impedance which is relatively constant for a horizontal
wire.

How do we apply (calculate char. imp.) the above to say, full wave (quad)
loop or vertical monopole?

That's a good question. For a horizontal wire, its obvious
that the forward wave reflects from the open-circuit at the
end of the wire. We know there are standing waves on a loop
but exactly where are the reflections originating? I
suspect they are originating at the feedpoint, i.e. the
forward wave travels all the way around the loop and is
reflected from the impedance discontinuity at the feedpoint.
Note that the feedpoint impedance of a full-wave loop is
in between the feedpoint impedances of a 1/2WL dipole and
a 1.5WL dipole indicating that the forward wave travels
about 1WL before being reflected in the loop.

Every segment of a monopole is a different
distance from ground and therefore has a slightly different
characteristic impedance which probably doesn't change very
fast as it is a log function. For instance, for the sake
of discussions, it seems reasonable to assume that the Z0
of a vertical stinger is in the neighborhood of a few
hundred ohms and would be easy to measure. At whatever
frequency causes the stinger to be 1/8WL, measure the
impedance. That will be fairly close to the characteristic
impedance of the stinger at the measurement point.
--
73, Cecil http://www.w5dxp.com

RSGB RadCom December 2007 Issue
 

Tom Donaly wrote:
Cecil Moore wrote:
Here's a quote from "Antennas Theory" by Balanis: "The current
and voltage distributions on open-ended wire antennas are similar
to the standing wave patterns on open-ended transmission lines.
... Standing wave antennas, such as the dipole, can be analyzed
as traveling wave antennas with waves propagating in opposite
directions (forward and backward) and represented by traveling
wave currents If and Ib ..."

So you haven't verified it experimentally, and don't know how
to do so. Thanks for the answer.

Do you distrust the theory of relatively because you
haven't verified it experimentally and don't know
how to do so?

I have simulated the configuration using EZNEC.

Tom, like you, I trust the great engineers and physicists
who came before me. I do not develop every concept from
first principles. If an analysis suggested by Balanis is
not good enough for you, that's your choice. Incidentally,
Kraus says essentially the same thing as Balanis about
analyzing standing-wave antennas.
--
73, Cecil http://www.w5dxp.com

RSGB RadCom December 2007 Issue
 

Cecil Moore wrote:
At whatever
frequency causes the stinger to be 1/8WL, measure the
impedance. That will be fairly close to the characteristic
impedance of the stinger at the measurement point.

As a data point, using EZNEC's VERT1.EZ 40m vertical,
the feedpoint impedance at 3.6 MHz is 6 - j356 ohms.
That would make the Z0 at the feedpoint around 360
ohms and Z0 no doubt increases with distance above
ground.
--
73, Cecil http://www.w5dxp.com

RSGB RadCom December 2007 Issue
 

Mike
I hope you learn from your exchange with Richard.
His only interest is not to aid in your thoughts but to take a
swipe at you after every paragraph. He is trying to taunt you.
He will also intimate, but without saying so, that he has all
the answers to your quandry as a way of enticing you for a longer
dialogue which for him are far and few between on this newsgroup.
Obviously you can now see why.
I have been informed that he has responded to the "skin" thread.
I have not read it nor will I reply to it, since I know before hand it
will contain nothing but taunts either to me or the prior poster.
The best thing for Richard's posts is if you must read them then smile
at his childish actions and then move on. Either way, from now on
he is going to take a swipe at you at every opportunity to provoke
you into a dialogue with him where the scenario will repeat itself
all over again.
Tolerate him but without engagement.
Best Regards
Art Unwin.....KB9MZ....xg

Richard Clark wrote:
On Thu, 15 Nov 2007 12:29:08 -0000, "Mike Kaliski"
wrote:

Thanks for yor comments and encouragement. I can well understand your
skepticism and accept that this idea is pretty far out. As you rightly point
out, there are a whole host of issues revolving around what is being
defined, measurement methods and interpretation of results.

Hi Mike,

OK, but this still tells me nothing of what issue you think I am
skeptical about!

The small transmitting loop efficiency experiments were carried out using
thermographic imaging to try and identify areas of heating within the loops.

Good, that is instructive.

The areas with maximum heating would indicate high current flow or high
resistance.

More properly, their product - Watts.

This information was used to try and derive a theory of
operation and efficiency figures for the loops. The idea being to prove that
efficiency was in fact higher than predicted by the Chu theory.

This names only one theory and doesn't actually illustrate any
differences.

The
methodology and results of the experiment were challenged and Chu theory
seems to have won out, at least for the time being.

Again, all of this is suggestive, not informative. Returning to your
earlier complaint of "detailed research" we have no details beyond
heat imaging challenging the establishment.

I don't see that there would be any need to invoke non standard units for
experimental measurements, ohms, amps and volts should suffice.

Too often, this group has to wade through "what it is not" instead of
"what it is." Tell us what specific units would be convincing for
you, as you have introduced a complaint that needs to be satisfied.

I have not
worked out the best measurement methods or instrumentation to use, but I am
sure that existing equipment and techniques will suffice.

I have worked on a world of instruments (more than anyone here).
Believe me, that experience has NOT answered the question of the ages.

Small sampling
coils, hall effect devices, temperature measurement
probes and thermal cameras are all available at prices which an amateur
experimenter can afford, so there is no reason why these experiments could
not be carried out in a domestic environment rather then an industrial one.

OK, by induction, I presume you are harkening back to these thermal
maps or imaging.

Well, in fact they have been done, their results have been posted to
the net and argued here. You didn't get the invitation?

Unfortunately, that contributor was arguing smaller loops, coils
specifically and the mapping was tangential to the rant. He promised
more data when Spring weather would allow him to pursue this line of
inquiry, but that was several Springs ago, and he has in the interval
chosen to -um- till the same ground.

The reason for specifying a single radiating element is because directional
and reflecting elements absorb and re-radiate RF energy. Once the properties
of a single element are known, then it is possible to add additional
elements and make further measurements and assessments of performance. Since
it is already known that all the elements of an antenna interact with one
another, it is important to start with the basics and work up from there.

True, and certainly it stands to improve clarity by reducing
variables.

The choice of the word 'within' was unfortunate because I accept that there
is nothing going on actually within an antenna element, skin effect ensuring
that RF travels on the outside of conductors.

Plus, thermal imaging would be hard pressed to peer inside a
conductor.

So I come back to my assertion that very little detail seems to have been
published about what is happening really close in to antennas i.e. on the
actual elements making up the antenna. Loads of stuff about near field and
far field experiments, but not specific points of radiation from the antenna
elements. It may all be a complete waste of time but at least I will have
fun and hopefully learn some new stuff doing it.

You mean you are unfamiliar with this work. I've posted my own here
to little attention, I don't think this cycle will attract much more,
but here it is:
http://home.comcast.net/~kb7qhc/ante...pole/index.htm

This doesn't actually attend your preference of thermal mapping, but
you are still vague to the point of "what is happening really close in
to antennas" (even qualified by "on the actual elements" - there's
that word actual again which lends nothing to a specification).

There is an entire field of Science devoted to this (beyond the scope
of many here who would anticipate my answer being "Fields"). This
field is called Plasmonics. Books are written about it, pictures are
taken of it, and I've sat through hours of presentations demonstrating
it. Unfortunately, this crowd of investigators, like Arthur, have
re-invented the wheel and they proclaim it is square.

The long and short of it is that you stand to become more confused,
but it could be rewarding if you wear asbestos.

73's
Richard Clark, KB7QHC

RSGB RadCom December 2007 Issue
 

On Thu, 15 Nov 2007 12:27:52 -0800 (PST), art
wrote:

I hope you learn from your exchange with Richard.

Hi Arthur,

Thanx for the flowers!

73's
Richard Clark, KB7QHC

RSGB RadCom December 2007 Issue
 

Cecil, W5DXP wrote:
"I suapect they (reflections) are originating at the feedpoint, i.e. the
forward wave travels all the way around the loop and is reflected from
the impedance discontinuity at the feedpoint."

That would be a reflection from a virtual impedance bump wouldn`t it?

The wave travels both wires of a feedline simultaneously, and enters
both ends of the loop at the same time. The collision is at the midpoint
of the loop opposite the feedpoint.

Arnold B. Bailey says on page 399 of "TV and Other Receiving Antennas":
"Now, in the loop, the far-end reflection point is a short circuit, and
hence, the current is high at this far end."

Best regards, Richard Harrison, KB5WZI

RSGB RadCom December 2007 Issue
 

Cecil Moore wrote:
Tom Donaly wrote:
Cecil Moore wrote:
Here's a quote from "Antennas Theory" by Balanis: "The current
and voltage distributions on open-ended wire antennas are similar
to the standing wave patterns on open-ended transmission lines.
... Standing wave antennas, such as the dipole, can be analyzed
as traveling wave antennas with waves propagating in opposite
directions (forward and backward) and represented by traveling
wave currents If and Ib ..."

So you haven't verified it experimentally, and don't know how
to do so. Thanks for the answer.

Do you distrust the theory of relatively because you
haven't verified it experimentally and don't know
how to do so?

I have simulated the configuration using EZNEC.

Tom, like you, I trust the great engineers and physicists
who came before me. I do not develop every concept from
first principles. If an analysis suggested by Balanis is
not good enough for you, that's your choice. Incidentally,
Kraus says essentially the same thing as Balanis about
analyzing standing-wave antennas.

I actually do know how to verify Einstein's predictions because the
fellows who did it wrote detailed articles on how they did it.

Thinking of antennas as transmission lines is an old practice. It
doesn't mean it's very practical, or that it hasn't been superseded
by a better analogy. For that matter, a vibrating guitar string can
be analyzed as a transmission line, as can any woodwind instrument.
That doesn't mean it's worth doing, but it can be done. The problem is
when a gentleman, such as the late, lamented Reg Edwards, or the still
kicking, unlamented you, write that an antenna, or a clarinet _is_ a
transmission line.
73,
Tom Donaly, KA6RUH

RSGB RadCom December 2007 Issue
 

Richard Harrison wrote:
Cecil, W5DXP wrote:
"I suapect they (reflections) are originating at the feedpoint, i.e. the
forward wave travels all the way around the loop and is reflected from
the impedance discontinuity at the feedpoint."

That would be a reflection from a virtual impedance bump wouldn`t it?

No, the impedance bump is physical. The physical Z0 of the
feedline is no doubt different from the physical Z0 of the
loop.

The wave travels both wires of a feedline simultaneously, and enters
both ends of the loop at the same time. The collision is at the midpoint
of the loop opposite the feedpoint.

Waves traveling in opposite directions in a constant Z0
environment don't interact. If the Z0 doesn't change, they
pass each other "like ships in the night".

Arnold B. Bailey says on page 399 of "TV and Other Receiving Antennas":
"Now, in the loop, the far-end reflection point is a short circuit, and
hence, the current is high at this far end."

If there is no physical impedance discontinuity, there is
no reflection. Reflections occur only at physical impedance
discontinuities. That virtual short circuit is an effect,
not a cause.
--
73, Cecil http://www.w5dxp.com

RSGB RadCom December 2007 Issue
 

"Richard Clark" wrote in message
...
On Thu, 15 Nov 2007 12:29:08 -0000, "Mike Kaliski"
wrote:

Thanks for yor comments and encouragement. I can well understand your
skepticism and accept that this idea is pretty far out. As you rightly
point
out, there are a whole host of issues revolving around what is being
defined, measurement methods and interpretation of results.

Hi Mike,

OK, but this still tells me nothing of what issue you think I am
skeptical about!

The small transmitting loop efficiency experiments were carried out using
thermographic imaging to try and identify areas of heating within the
loops.

Good, that is instructive.

The areas with maximum heating would indicate high current flow or high
resistance.

More properly, their product - Watts.

This information was used to try and derive a theory of
operation and efficiency figures for the loops. The idea being to prove
that
efficiency was in fact higher than predicted by the Chu theory.

This names only one theory and doesn't actually illustrate any
differences.

The
methodology and results of the experiment were challenged and Chu theory
seems to have won out, at least for the time being.

Again, all of this is suggestive, not informative. Returning to your
earlier complaint of "detailed research" we have no details beyond
heat imaging challenging the establishment.

I don't see that there would be any need to invoke non standard units for
experimental measurements, ohms, amps and volts should suffice.

Too often, this group has to wade through "what it is not" instead of
"what it is." Tell us what specific units would be convincing for
you, as you have introduced a complaint that needs to be satisfied.

I have not
worked out the best measurement methods or instrumentation to use, but I
am
sure that existing equipment and techniques will suffice.

I have worked on a world of instruments (more than anyone here).
Believe me, that experience has NOT answered the question of the ages.

Small sampling
coils, hall effect devices, temperature measurement
probes and thermal cameras are all available at prices which an amateur
experimenter can afford, so there is no reason why these experiments could
not be carried out in a domestic environment rather then an industrial
one.

OK, by induction, I presume you are harkening back to these thermal
maps or imaging.

Well, in fact they have been done, their results have been posted to
the net and argued here. You didn't get the invitation?

Unfortunately, that contributor was arguing smaller loops, coils
specifically and the mapping was tangential to the rant. He promised
more data when Spring weather would allow him to pursue this line of
inquiry, but that was several Springs ago, and he has in the interval
chosen to -um- till the same ground.

The reason for specifying a single radiating element is because
directional
and reflecting elements absorb and re-radiate RF energy. Once the
properties
of a single element are known, then it is possible to add additional
elements and make further measurements and assessments of performance.
Since
it is already known that all the elements of an antenna interact with one
another, it is important to start with the basics and work up from there.

True, and certainly it stands to improve clarity by reducing
variables.

The choice of the word 'within' was unfortunate because I accept that
there
is nothing going on actually within an antenna element, skin effect
ensuring
that RF travels on the outside of conductors.

Plus, thermal imaging would be hard pressed to peer inside a
conductor.

So I come back to my assertion that very little detail seems to have been
published about what is happening really close in to antennas i.e. on the
actual elements making up the antenna. Loads of stuff about near field and
far field experiments, but not specific points of radiation from the
antenna
elements. It may all be a complete waste of time but at least I will have
fun and hopefully learn some new stuff doing it.

You mean you are unfamiliar with this work. I've posted my own here
to little attention, I don't think this cycle will attract much more,
but here it is:
http://home.comcast.net/~kb7qhc/ante...pole/index.htm

This doesn't actually attend your preference of thermal mapping, but
you are still vague to the point of "what is happening really close in
to antennas" (even qualified by "on the actual elements" - there's
that word actual again which lends nothing to a specification).

There is an entire field of Science devoted to this (beyond the scope
of many here who would anticipate my answer being "Fields"). This
field is called Plasmonics. Books are written about it, pictures are
taken of it, and I've sat through hours of presentations demonstrating
it. Unfortunately, this crowd of investigators, like Arthur, have
re-invented the wheel and they proclaim it is square.

The long and short of it is that you stand to become more confused,
but it could be rewarding if you wear asbestos.

73's
Richard Clark, KB7QHC

Thank you Richard,

That has helped to clarify my thinking. I know people tend to insist on very
specific language and technical terms before being willing to accept
anything new on this newsgroup. I tend to agree that this is a good thing
and resorting to woolly, imprecise or made up terms does nothing to clarify
new concepts.

I guess you are skeptical that there might be a specific point on an antenna
that matches the impedence of free space and thus radiates energy more
strongly than the rest of the antenna. This is the subject that interests me
and I intend to try and establish to my own satisfaction whether this is or
is not the case. If this can be established in a scientifically robust
manner, then I will present my experimental method, measurements and
conclusions for critical examination. I am unfamiliar with work that has
been carried out in this field, so I will carry out further searches and
reading before embarking on reinventing the wheel. Thanks for the link and
the suggestion about plasmonics and fields, I will follow up on that.

Cheers
Mike G0ULI

RSGB RadCom December 2007 Issue
 

Tom Donaly wrote:
The problem is
when a gentleman, such as ... unlamented you, write that
an antenna, or a clarinet _is_ a transmission line.

But Tom, page 18 of "Antenna Theory" by Balanis,
shows how a transmission line can be opened up
to cause it to radiate. A dipole is indeed a leaky
transmission line. During steady-state, it loses
about 20% of the power stored in the standing
waves to radiation. Maxwell's laws don't change
from transmission lines to wire antennas.
--
73, Cecil http://www.w5dxp.com

RSGB RadCom December 2007 Issue
 

"art" wrote in message
...
Mike
I hope you learn from your exchange with Richard.
His only interest is not to aid in your thoughts but to take a
swipe at you after every paragraph. He is trying to taunt you.
He will also intimate, but without saying so, that he has all
the answers to your quandry as a way of enticing you for a longer
dialogue which for him are far and few between on this newsgroup.
Obviously you can now see why.
I have been informed that he has responded to the "skin" thread.
I have not read it nor will I reply to it, since I know before hand it
will contain nothing but taunts either to me or the prior poster.
The best thing for Richard's posts is if you must read them then smile
at his childish actions and then move on. Either way, from now on
he is going to take a swipe at you at every opportunity to provoke
you into a dialogue with him where the scenario will repeat itself
all over again.
Tolerate him but without engagement.
Best Regards
Art Unwin.....KB9MZ....xg

snip

Hi Art,

Thanks for your comments. I am prepared to listen/debate whatever anyone has
to say and consider their comments. As the USA is so fond of advising the
world, everyone has a right to free speech. I listen, consider and then
judge whether the comment is helpful or not in the circumstances.

Having a completely open mind allows others to fill it with junk. But
applying some critical judgement to the dross allows you to glean some
nuggets of gold occasionally, just like life in general. The skill lies in
being able to decide what is relevant and that comes with education and life
experience.

Cheers
Mike G0ULI

RSGB RadCom December 2007 Issue
 

art wrote:
Mike
I hope you learn from your exchange with Richard.
His only interest is not to aid in your thoughts but to take a
swipe at you after every paragraph. He is trying to taunt you.
He will also intimate, but without saying so, that he has all
the answers to your quandry as a way of enticing you for a longer
dialogue which for him are far and few between on this newsgroup.
Obviously you can now see why.
I have been informed that he has responded to the "skin" thread.
I have not read it nor will I reply to it, since I know before hand it
will contain nothing but taunts either to me or the prior poster.
The best thing for Richard's posts is if you must read them then smile
at his childish actions and then move on. Either way, from now on
he is going to take a swipe at you at every opportunity to provoke
you into a dialogue with him where the scenario will repeat itself
all over again.
Tolerate him but without engagement.
Best Regards
Art Unwin.....KB9MZ....xg

Well, yeah, that's going on to ...

Regards,
JS

RSGB RadCom December 2007 Issue
 

Mike Kaliski wrote:

...
Having a completely open mind allows others to fill it with junk. But
applying some critical judgement to the dross allows you to glean some
nuggets of gold occasionally, just like life in general. The skill lies
in being able to decide what is relevant and that comes with education
and life experience.

Cheers
Mike G0ULI

Yep, all part of the scientific process (method.)

Regards,
JS

RSGB RadCom December 2007 Issue
 

Mike Kaliski wrote:

Hi Roy,

He does mention that antennas possess radiation resistance, not to be
confused with and not the same as, characteristic impedence (or
feedpoint impedence) and that the characteristic impedence will vary
along an antennas length.

As for the actual point(s) along an element at which an antenna radiates
(transfers energy to free space) with maximum efficiency, he makes no
comment.

I seriously doubt that there is anything in the article that you would
dispute.

It seems that everyone was so busy laughing on this newsgroup, that no
one has actually provided any information as to whether any detailed
research has ever been carried out as to what is going on within the
radiating elements of an antenna. There is loads of theory in the text
books, but I have yet to see any empirical measurements or results.

If you haven't seen any measurements or results, you haven't looked in
any of the professional publications over the past hundred years or so.
There have been a great number of measurements of antennas made. Of
those, none to my knowledge have ever definitively shown results other
than the textbook theory predicts. That's pretty good confirmation of
the current theory.

If there is merit to alternative theories, they should predict exactly
(or at least within the most precise measurement capabilities we have)
the same results as the current textbook theories, because those
theories agree closely with measurement. That means the alternative
theories must come with equations which can be used to predict antenna
performance as well as what we use now with great success. Vague
hand-waving is adequate to convince a certain number of rraa readers,
but it doesn't go far with those of us who actually design antennas that
have to work.

. . .
I may have submitted the post, tongue in cheek, to stir things up a bit,
but on reflection there seems to be something of merit in the idea. I am
revisiting the appropriate chapters in Kraus and Terman to see where the
error in my logic is. In the absence of any direct evidence of
contradiction, I think it may be worth developing this idea and making a
few measurements of my own to see what the truth of the matter is.

There's a real problem here. Making even half decent measurements of
antennas is an extremely difficult undertaking. People without the
proper equipment, experience, and knowledge of tolerances to be expected
frequently make poor measurements and draw erroneous conclusions from
them. Before you get too involved, I suggest starting with a dipole,
loop, or some other very simple, well understood, and well documented
antenna and see just how good your measurement methods are. If you can't
do those simple antennas properly, then any other measurements you make
shouldn't be trusted. And those are the easiest ones. If you want a real
challenge, try a very short antenna. Just keeping the feedline from
being part of the system can be a nearly insurmountable task, and
measuring a very small resistance in the presence of a very large
reactance isn't easy either. Unless you can deal with these and other
measurement realities, your measurements might be fun, but they won't
mean anything. You can publish on rraa and draw a certain number of oohs
and ahs, but it won't be material for the IEE or IEEE -- not because
they're contradicting conventional theory, but because they're not
representative of reality.

Amateur radio is supposed to be a learning experience, right? And you
can't learn without making mistakes. After 40 years of following the
diktats of professional communications and electronic theory, I think
the time is right to kick off the traces and challenge some of the
accepted authodoxies. I do know all the conventional stuff, it just
doesn't satisfy my soul.

Have you considered religion? The rules of evidence are much more
relaxed in that environment, so alternative theories are more readily
accepted. Just look at the proliferation of denominations. There's
always room for a few more.

You probably know more about antennas than anyone has a right to know
Roy, but it's a strange universe out there and it's just possible that
there's a few more things to learn yet.

Indeed there are. When you have an alternative theory that agrees as
closely with measured results as the current ones, and which can be used
to predict antenna performance, I'd like to be among the first to read
your paper and benefit. Shoot, I might even incorporate the equations
into EZNEC to make it even more accurate than it is now. I'm a member of
the IEEE Antennas and Propagation, Broadcast, and EMC societies, so I'll
see any papers published in those journals. And I can easily get papers
published by the IEE or other societies. Have at it!

Roy Lewallen, W7EL

RSGB RadCom December 2007 Issue
 

Roy Lewallen wrote:

Of those, none to my knowledge have ever definitively shown results other
than the textbook theory predicts.
...
Roy Lewallen, W7EL

Yep, as long as you over look when those theories are based on math
which includes permeability and permittivity values for "nothing"
(space, a vacuum!) And denies the presence of any "ether type" media
which these COULD properly be allowed for!

Oh yeah, absolute proof alright--if 'ya don't look too close!

In accounting it is called "cooking the books!" ROFLOL

Regards,
JS

RSGB RadCom December 2007 Issue
 

"Roy Lewallen" wrote in message
...
Mike Kaliski wrote:

Hi Roy,

He does mention that antennas possess radiation resistance, not to be
confused with and not the same as, characteristic impedence (or feedpoint
impedence) and that the characteristic impedence will vary along an
antennas length.

As for the actual point(s) along an element at which an antenna radiates
(transfers energy to free space) with maximum efficiency, he makes no
comment.

I seriously doubt that there is anything in the article that you would
dispute.

It seems that everyone was so busy laughing on this newsgroup, that no
one has actually provided any information as to whether any detailed
research has ever been carried out as to what is going on within the
radiating elements of an antenna. There is loads of theory in the text
books, but I have yet to see any empirical measurements or results.

If you haven't seen any measurements or results, you haven't looked in any
of the professional publications over the past hundred years or so. There
have been a great number of measurements of antennas made. Of those, none
to my knowledge have ever definitively shown results other than the
textbook theory predicts. That's pretty good confirmation of the current
theory.

If there is merit to alternative theories, they should predict exactly (or
at least within the most precise measurement capabilities we have) the
same results as the current textbook theories, because those theories
agree closely with measurement. That means the alternative theories must
come with equations which can be used to predict antenna performance as
well as what we use now with great success. Vague hand-waving is adequate
to convince a certain number of rraa readers, but it doesn't go far with
those of us who actually design antennas that have to work.

. . .
I may have submitted the post, tongue in cheek, to stir things up a bit,
but on reflection there seems to be something of merit in the idea. I am
revisiting the appropriate chapters in Kraus and Terman to see where the
error in my logic is. In the absence of any direct evidence of
contradiction, I think it may be worth developing this idea and making a
few measurements of my own to see what the truth of the matter is.

There's a real problem here. Making even half decent measurements of
antennas is an extremely difficult undertaking. People without the proper
equipment, experience, and knowledge of tolerances to be expected
frequently make poor measurements and draw erroneous conclusions from
them. Before you get too involved, I suggest starting with a dipole, loop,
or some other very simple, well understood, and well documented antenna
and see just how good your measurement methods are. If you can't do those
simple antennas properly, then any other measurements you make shouldn't
be trusted. And those are the easiest ones. If you want a real challenge,
try a very short antenna. Just keeping the feedline from being part of the
system can be a nearly insurmountable task, and measuring a very small
resistance in the presence of a very large reactance isn't easy either.
Unless you can deal with these and other measurement realities, your
measurements might be fun, but they won't mean anything. You can publish
on rraa and draw a certain number of oohs and ahs, but it won't be
material for the IEE or IEEE -- not because they're contradicting
conventional theory, but because they're not representative of reality.

Amateur radio is supposed to be a learning experience, right? And you
can't learn without making mistakes. After 40 years of following the
diktats of professional communications and electronic theory, I think the
time is right to kick off the traces and challenge some of the accepted
authodoxies. I do know all the conventional stuff, it just doesn't
satisfy my soul.

Have you considered religion? The rules of evidence are much more relaxed
in that environment, so alternative theories are more readily accepted.
Just look at the proliferation of denominations. There's always room for a
few more.

You probably know more about antennas than anyone has a right to know
Roy, but it's a strange universe out there and it's just possible that
there's a few more things to learn yet.

Indeed there are. When you have an alternative theory that agrees as
closely with measured results as the current ones, and which can be used
to predict antenna performance, I'd like to be among the first to read
your paper and benefit. Shoot, I might even incorporate the equations into
EZNEC to make it even more accurate than it is now. I'm a member of the
IEEE Antennas and Propagation, Broadcast, and EMC societies, so I'll see
any papers published in those journals. And I can easily get papers
published by the IEE or other societies. Have at it!

Roy Lewallen, W7EL

Thanks Roy,

I appreciate that this is likely to be a protracted project and that
accurate measurements could be problematic to say the least. I intend to
examine the performance of a resonant dipole first, then non resonant dipole
elements and depending on results progress to more complex antennas. I am
fortunate enough to live very close to a surplus equipment supplier who has
a warehouse full of redundant commercial measurement equipment and
certification facilities, so I may become one of their more regular
customers. :-) I have more than enough qualifications to qualify for
membership of IEE and sundry other organisations so publication wouldn't be
a problem, but thanks very much for the kind offer.

I really am not interested in overturning current theory, I see this as an
opportunity of perhaps adding another aspect to it. Obviously any
'improvement' would have to match current results and enable enhanced
predictions to be of any practical use. I have spent well over 40 years
trying to understand how radio works. The wonder I felt as a child listening
to the radio and trying to understand how it could work has never
disappeared. Despite many courses, seminars and conversations with experts,
I still can't say that I really know how radio works.

As for religion, I attended a Jesuit run grammar school, put me off for
life. Needless to say, the main thing I learned was to question everything
and accept nothing at face value. So while it is true that current antenna
theory is good enough for all practical purposes, I think it is possible
that there may be room for improvement.

Regards
Mike G0ULI

RSGB RadCom December 2007 Issue
 

On 15 Nov, 16:13, Roy Lewallen wrote:
Mike Kaliski wrote:

Hi Roy,

He does mention that antennas possess radiation resistance, not to be
confused with and not the same as, characteristic impedence (or
feedpoint impedence) and that the characteristic impedence will vary
along an antennas length.

As for the actual point(s) along an element at which an antenna radiates
(transfers energy to free space) with maximum efficiency, he makes no
comment.

I seriously doubt that there is anything in the article that you would
dispute.

It seems that everyone was so busy laughing on this newsgroup, that no
one has actually provided any information as to whether any detailed
research has ever been carried out as to what is going on within the
radiating elements of an antenna. There is loads of theory in the text
books, but I have yet to see any empirical measurements or results.

If you haven't seen any measurements or results, you haven't looked in
any of the professional publications over the past hundred years or so.
There have been a great number of measurements of antennas made. Of
those, none to my knowledge have ever definitively shown results other
than the textbook theory predicts. That's pretty good confirmation of
the current theory.

If there is merit to alternative theories, they should predict exactly
(or at least within the most precise measurement capabilities we have)
the same results as the current textbook theories, because those
theories agree closely with measurement. That means the alternative
theories must come with equations which can be used to predict antenna
performance as well as what we use now with great success. Vague
hand-waving is adequate to convince a certain number of rraa readers,
but it doesn't go far with those of us who actually design antennas that
have to work.

. . .
I may have submitted the post, tongue in cheek, to stir things up a bit,
but on reflection there seems to be something of merit in the idea. I am
revisiting the appropriate chapters in Kraus and Terman to see where the
error in my logic is. In the absence of any direct evidence of
contradiction, I think it may be worth developing this idea and making a
few measurements of my own to see what the truth of the matter is.

There's a real problem here. Making even half decent measurements of
antennas is an extremely difficult undertaking. People without the
proper equipment, experience, and knowledge of tolerances to be expected
frequently make poor measurements and draw erroneous conclusions from
them. Before you get too involved, I suggest starting with a dipole,
loop, or some other very simple, well understood, and well documented
antenna and see just how good your measurement methods are. If you can't
do those simple antennas properly, then any other measurements you make
shouldn't be trusted. And those are the easiest ones. If you want a real
challenge, try a very short antenna. Just keeping the feedline from
being part of the system can be a nearly insurmountable task, and
measuring a very small resistance in the presence of a very large
reactance isn't easy either. Unless you can deal with these and other
measurement realities, your measurements might be fun, but they won't
mean anything. You can publish on rraa and draw a certain number of oohs
and ahs, but it won't be material for the IEE or IEEE -- not because
they're contradicting conventional theory, but because they're not
representative of reality.

Oh my, you sound so upset.
Your theory used in Eznec was designed
around known "reality" because you found the need to add the proviso
that there was a sino soidal current at all points on the radiator.
Number one, it is not legitamate to add a proviso or a special
condition
to a known law.( Electrical or Mechanical)
Number two It becomes a worse problem when the proviso added is in
error.
Number three, You should not retain a proviso if it proves incorrect .
The fact that present theory has passed the test of time means
nothing.
The threat of retaliation trumps science when humans are concerned.
Gallilao never saw the day that the earth was proven round which
stood the test for a very very long time.
But you could explain to the world how a sino soidal current passes
thru
a distributed capacitance and still retain its properties as it
encounters every segment. This is per the proviso you have placed
with
existing Maxwell's laws with respect to your computor program.
But no you can't! Until then I don't think you are equipped to say
that written theory can be taken as fact.Especially when known laws
are twisted so you can gyrate your program to known reality.
The old saying still stands, Garbage in will produce garbage out
unless the outputs are subject to reprocessing !

Art Unwin...KB9MZ






Amateur radio is supposed to be a learning experience, right? And you
can't learn without making mistakes. After 40 years of following the
diktats of professional communications and electronic theory, I think
the time is right to kick off the traces and challenge some of the
accepted authodoxies. I do know all the conventional stuff, it just
doesn't satisfy my soul.

Have you considered religion? The rules of evidence are much more
relaxed in that environment, so alternative theories are more readily
accepted. Just look at the proliferation of denominations. There's
always room for a few more.

You probably know more about antennas than anyone has a right to know
Roy, but it's a strange universe out there and it's just possible that
there's a few more things to learn yet.

Indeed there are. When you have an alternative theory that agrees as
closely with measured results as the current ones, and which can be used
to predict antenna performance, I'd like to be among the first to read
your paper and benefit. Shoot, I might even incorporate the equations
into EZNEC to make it even more accurate than it is now. I'm a member of
the IEEE Antennas and Propagation, Broadcast, and EMC societies, so I'll
see any papers published in those journals. And I can easily get papers
published by the IEE or other societies. Have at it!

Roy Lewallen, W7EL- Hide quoted text -

- Show quoted text -