On Mon, 21 Mar 2005 13:14:25 -0800, "John Smith"
wrote:

Yet, it seems like such a design would suggest itself to many minds and be a
good solution to many restricted spaces and, one does ponder why the math,
methods, formulas, software, etc. has not been created to make such a matter
of childs play--and well documented and explained.

Hi John,

In fact, nearly every "new" idea that hits this board can be found
described with utter simplicity - years ago (10, 20, 40, 80 years).
Very little math is demanded and the record is full of documentation.

The continuous length of coil you describe has been anticipated by one
in using a "slinky." The benefit there is that the springy form
allows one to collapse or extend the coil to find resonance. Use two
of them and you have a dipole.

It performs, and has performed for years. You can buy one too. Why
doesn't everyone use one? The reason goes back years ago to rather
simple terms: size v. wavelength and the number and separation of
nodes. It performs, but not as well as a larger antenna it attempts
to replace. Hence: size v. wavelength is a restriction, there is only
one node, and it has nothing (another separate node) to combine with.
Once you can get your arms around these simple concepts, then you
throw in loss - the numbers get ugly and the pain is real.

We get tons of small antennas touted here.

Many mobile whips seem centered around designs somewhat similiar to the one
proposed.

However, among the population of those many, when they are all
compared the longstanding traditional designs win hands down. They
win for very simple reasons. The list of rules, so to speak, is very
short.

Unfortunately there are too many simple reasons floating around as new
and improved theory. The test of the newcomer is to separate those
improved theories (noted for their baroque language, elaborate math
and lack of field work) from ages-old results nailed down in rather
ordinary terms.

The new-and-improved theories call upon
- separating the E and M fields;
- unique properties of fractal math;
- improved length efficiency;
- proofs of polygonal analysis;
- super gain;
- over/tight/critical coupling;
- faster than light transmission....

As you can see, the field of simple reasons abound. Some reasons have
their attractive features, but once you try to pull the conversation
into the realm of implementation, barriers to discussion bloom like
weeds.

73's
Richard Clark, KB7QHC

Well... Yes, that argument is made with most everything...
It has already been done... everything has been tried... all the answers are
known... there is nothing new to be found out...
(But, just on the outside chance that thinking is wrong: What about LDE
(long delay echo)? You got the answer to that?)
The fact is, most, if not all, of the formulas we deal with are crafted from
things we have first built--THEN we look for a mathmatical explanation to
explain the object we built. While this is better than nothing, it is
slow--exploration by first developing the theory and math--then the physical
object--is much more suited for really finding "something new" and the rapid
development of such objects. (i.e., computers design computers, however,
since antennas can't design antennas--we need computers to design the
antennas.)
Unfortuantly, if all we use are past "rules" and "laws" we can only find the
past!!! Anything REALLY NEW will break all the laws we are currently
slaving under (or, at the least, re-define these laws) with total disregard
to the high esteem we had held these faulty laws.... indeed, being too tied
to the past and "conventional thinking" may hold us to the past...
However, whenever there seems a danger of this happening, then someone comes
in from left field with a new idea, such as quantum physics, and all bets
are off, and the physists and mathematicians are sent off to develop new,
undenighable and final laws to explain it...

If it were all done, if there is nothing new to be found out, if all the
existing data and formulas are totally all there is... WHY THE HELL ARE WE
HERE? Let's go buy one, go home and have a beer...

Fact is, we hate to admit when we are wrong, so, when we are wrong we
quickly move on and say these NEW ideas are what we have really believed all
along!
I am not opposed to the possibility that all that can be known, is known...
however, some guy that doesn't know any better usually suddenly pops up and
you end up embarassed for your beliefs--one more time.

The fact is, I have built those "silly antennas", by hand, with real
materials--then modeled them on mathmatical models, evaluating what is
actual against what was predicted... few ever provide anything but
disappointment. But, I am convinced that while what the developers are
claiming may be "false reasoning" and improper models, there is something
here which has been overlooked and current conventional thinking and models
miss...

However, the antenna design I presented is simply a helical loaded 1/2 wave
which just happens to correspond to 1/4 wave physical length...
It really doesn't challenge any current antenna theory or present anything
new, other than perhaps an unconventional arrangement of wire...

Frankly, I take it as a "leap of faith", but as long as there are
discussions such as these... something new is comming our way right now, we
just won't be able to see it till it gets closer, then we will realize we
really "knew it all along!"
But then the harsh "reality" hits us, we realize and with some
disappointment--that once again it has happened, all the final answers and
laws are known--nothing to do but go home and grab a beer and wait for next
time... grin

Warmest regards

"Richard Clark" wrote in message
...
On Mon, 21 Mar 2005 13:14:25 -0800, "John Smith"
wrote:

Yet, it seems like such a design would suggest itself to many minds and be
a
good solution to many restricted spaces and, one does ponder why the math,
methods, formulas, software, etc. has not been created to make such a
matter
of childs play--and well documented and explained.

Hi John,

In fact, nearly every "new" idea that hits this board can be found
described with utter simplicity - years ago (10, 20, 40, 80 years).
Very little math is demanded and the record is full of documentation.

The continuous length of coil you describe has been anticipated by one
in using a "slinky." The benefit there is that the springy form
allows one to collapse or extend the coil to find resonance. Use two
of them and you have a dipole.

It performs, and has performed for years. You can buy one too. Why
doesn't everyone use one? The reason goes back years ago to rather
simple terms: size v. wavelength and the number and separation of
nodes. It performs, but not as well as a larger antenna it attempts
to replace. Hence: size v. wavelength is a restriction, there is only
one node, and it has nothing (another separate node) to combine with.
Once you can get your arms around these simple concepts, then you
throw in loss - the numbers get ugly and the pain is real.

We get tons of small antennas touted here.

Many mobile whips seem centered around designs somewhat similiar to the
one
proposed.

However, among the population of those many, when they are all
compared the longstanding traditional designs win hands down. They
win for very simple reasons. The list of rules, so to speak, is very
short.

Unfortunately there are too many simple reasons floating around as new
and improved theory. The test of the newcomer is to separate those
improved theories (noted for their baroque language, elaborate math
and lack of field work) from ages-old results nailed down in rather
ordinary terms.

The new-and-improved theories call upon
- separating the E and M fields;
- unique properties of fractal math;
- improved length efficiency;
- proofs of polygonal analysis;
- super gain;
- over/tight/critical coupling;
- faster than light transmission....

As you can see, the field of simple reasons abound. Some reasons have
their attractive features, but once you try to pull the conversation
into the realm of implementation, barriers to discussion bloom like
weeds.

73's
Richard Clark, KB7QHC

On Mon, 21 Mar 2005 14:58:51 -0800, "John Smith"
wrote:

Fact is, we hate to admit when we are wrong

Hi John,

That never fazed me as long as I was challenged by facts instead of
superstition. I have failed to many times to worry about it. As the
saying goes, if you haven't failed, you aren't trying hard enough.

... there is something
here which has been overlooked and current conventional thinking and models
miss...

I try those angles, and go the extra mile. Evidence some 300+ pages
of examining fractal antennas:
http://www.qsl.net/kb7qhc/antenna/fractal/index.htm

This work eventually boiled down to a simple conclusion (not that the
leading proponent would allow his mystical explanation to be nudged
into the corner of drab insight).

These days I usually put a filter into the process by asking the
"inventor" a simple question:
Does it bring more than 1dB gain with it?

73's
Richard Clark, KB7QHC

John Smith wrote:
Well... Yes, that argument is made with most everything...
It has already been done... everything has been tried... all the answers are
known... there is nothing new to be found out...

This post got me to thinking (always dangerous)


Whatever happened to that wunderantenna from the University of Rhode
Island?

ttp://tinyurl.com/5qn4d


Especially interesting is the comparison against a 5/8th wave antenna @
150 MHz. Presemably that antenna was matched by a 9 inch DLM.

The BW was apparently 1 MHz better than the 5/8th wave, although thte
sentence was a bit unclear with that respect.

I remain very skeptical.

Bogus or Bonanza?

- Mike KB3EIA -

John Smith wrote:
Well... Yes, that argument is made with most everything...
It has already been done... everything has been tried... all the answers are
known... there is nothing new to be found out...

Absolutely - someone wanted to close the US patent office
over 100 years ago because everything possible had already
been invented.
--
73, Cecil http://www.qsl.net/w5dxp


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On Sun, 20 Mar 2005 18:26:42 -0800, "John Smith"
wrote:





My question(s):

For an example, on the 10 meter band:
If I take a 28" whip and mount it at the end of helical wound coil (wound on
1" diameter form), where the "wire length" of the coil, PLUS, the length of
the whip (28" + coil wire length) is equal to 1/2 wavelength (electrical
length)--BUT, the overall physical length of the antenna (top, tip of whip
to base of helical wound coil) is 1/4 wavelength, what would the radiation
pattern of such an antenna be?

Would it favor the pattern of a 1/4 or 1/2 wave antenna--or, would the
pattern be a compromise between the two--or, would the pattern be totally
unrelated to either?

What could I expect the impedance of such an antenna be? Would the
reactance be capacitive or inductive? What would be the best way to provide
a match to 50 ohm coax from such an antenna?

What software is available to model such an antenna?

Thanks in advance,
warmest regards



EZNec will model your antenna. As for the antenna, I believe that the
shortened 1/2 wave antenna will radiate with less effect than a
stretched 1/2 wave, but possibly better than a 1/4 wave. How much?
That depends on the coil and the matching network pending losses.

Good luck,
Buck
N4PGW

--
73 for now
Buck
N4PGW

I should add that the antenna you described will be less efficient than
a plain wire of the same height. The use of the coil in place of a
straight piece of wi

1. Makes no substantial difference to the pattern shape.
2. Decreases the efficiency.
3. Potentially makes matching more difficult.
4. Unnecessarily increases cost and mechanical complexity.

But it might look groovy and impress the good buddies. And it might
*seem* to work better -- the placebo effect is genuine and quite
powerful and it's been the reason for a lot of satisfied customers.

Roy Lewallen, W7EL

Well, I have 3 test antennas on this project:
1) 1/4 wave stainless steel whip w/4 heavy 1/2 inch, aluminum ground plane
radials
2) 1/2 wave without any ground plane/counterpoise, lower 1/4 wave section is
3/4 copper pipe, upper 1/4 is a stainless whip, total of the combination is
1/2 wave... ferrite beads are used on the outer shield of the coax at the
point where it connects to the antenna, match is though a simple l-network
(ferrite beads are actually un-needed but used anyway, no real detectable
radiation from coax either way)
3) This is the antenna I described in the first post(s), I tend to refer to
as the "quarter/half", it is constructed on 3/4 ID pvc pipe, and has an OD
of just over an inch, the coil is constructed of #8 copper wire and the top
whip is the 28 inch stainless whip I mentioned. Is a resonate 1/2 wave and
physical 1/4 (whip + helical coil length.) Matching network is a l-network,
capactior is constructed of acrylic insulator plates (acrylic "window pane")
with copper sheet plates, coil is a 1.3 OD torroid. coil is approx. 1+ uh
(computed from toroid data)--I have not measured the capacitance of the
capacitor (probably somewhere from 20+ pf to 30+ pf), no
groundplane/counterpoise, ferrite beads as above.

Naturally, as the models predict, the 1/4 is lower in preformance than the
half 1/2, and very noticable in the most distant contacts.
However, the "quarter/half" out preforms the 1/4 but falls lower in
preformance than the 1/2. Contacts out at 30+ miles are where the
electrical 1/2 wave antennas differ most from each other (antennas 2 and 3
above.)
FSM measurements of the two 1/2 waves are very simuliar--however, these
measurements could have been taken at a greater distance to increase
accuracy (meters sensitivity I currently am using limited this.)
Franky, I was surprised by the preformance. As others have predicted--I
expected the preformance of the shortened 1/2 wave to be poorer than the 1/4
(mainly due to the helical coil skewing the radiation pattern and adding a
slight resistance to a physical 1/4 antenna.)
However, it seems to fall in the middle between the 1/4 and the 1/2 wave
(full length) antennas, favoring being closer to the 1/2 full length by 1/2
S-unit+
The biggest difference between the 1/4 and 1/2 wave full length is 2-3
s-units at stations in the 30+ mile distances.
The full 1/2 wave and the shortened 1/2 wave seem close to 1 s-unit on all
apparent distant stations.
I find this hard to believe, and the models I calculated did not reflect
what I had actually seen in s-units.

All three antennas were placed at the same height, on the same mast while
testing (32 ft above real ground.) And all other conditions the same.
The l-network match is the only difference between the two 1/2 wave
antennas, in the future I will correct this and finalize the tests... the
difference in the matches could be responsible for the difference in
expected results.
Right now, it actually looks to me, from the above--that the "1/4 physical,
1/2 wave electrical (quarter/half)" antenna was and is exhibiting properties
of both a 1/4 and a 1/2 wave antenna. This is the main reason I tossed out
this "antenna problem" here, to see others reactions and draw from their
experience.

Warmest regards

"Buck" wrote in message
...
On Sun, 20 Mar 2005 18:26:42 -0800, "John Smith"
wrote:





My question(s):

For an example, on the 10 meter band:
If I take a 28" whip and mount it at the end of helical wound coil (wound
on
1" diameter form), where the "wire length" of the coil, PLUS, the length
of
the whip (28" + coil wire length) is equal to 1/2 wavelength (electrical
length)--BUT, the overall physical length of the antenna (top, tip of whip
to base of helical wound coil) is 1/4 wavelength, what would the radiation
pattern of such an antenna be?

Would it favor the pattern of a 1/4 or 1/2 wave antenna--or, would the
pattern be a compromise between the two--or, would the pattern be totally
unrelated to either?

What could I expect the impedance of such an antenna be? Would the
reactance be capacitive or inductive? What would be the best way to
provide
a match to 50 ohm coax from such an antenna?

What software is available to model such an antenna?

Thanks in advance,
warmest regards



EZNec will model your antenna. As for the antenna, I believe that the
shortened 1/2 wave antenna will radiate with less effect than a
stretched 1/2 wave, but possibly better than a 1/4 wave. How much?
That depends on the coil and the matching network pending losses.

Good luck,
Buck
N4PGW

--
73 for now
Buck
N4PGW

If there's no ground system loss, a half wave vertical antenna has about
1.3 dB gain over a quarter wave vertical due to the sharper pattern
shape. This is the line-of-sight or surface wave gain difference. If
reflection from real ground is included in the analysis, the gain
difference is about 1 - 1.5 dB at lower angles, and the quarter wave
does much better, by 3 or 4 dB or so, at high angles (very roughly above
50 degrees or so).

Coil loading to achieve half wave resonance does have one potential
advantage, and that's to reduce ground loss when substantial ground
resistance is present. Because of the much higher base impedance, ground
current is much less with a half wave resonant base fed antenna than
with a quarter wave antenna, even when the resonance is achieved with
coil loading. Ground loss is typically pretty low on ten meters in
mobile applications, but in some other setups (such as ground mounting
over a buried radial system, or a hand-held radio), the reduction in
ground current could reduce ground loss more than enough to compensate
for coil loss.

I suspect this is the explanation for at least some of any advantage you
see in the coil loaded antenna over a straight wire of the same length.
However, there's a good sized handful of other possible factors. (Every
last one of them, incidentally, explainable perfectly well by "standard
theory".) If the measurement results don't agree with the model, it
nearly always means that the actual antenna -- that is, the "antenna",
the "ground" system, and everything connected to either one or in the
near field of either one -- differs from the model in some significant
way. Or the measurement system is faulty.

Someone interested in understanding the operation of an antenna will
commonly spend a great deal of time tracking down the factors that
differ between the model and real antenna, and it's just about always a
truly educational experience. When done, the result is usually a model
that really represents the antenna system, and that shows results very
close to careful and competent measurements. And an experimenter who
knows more about antennas, modeling, and the importance of some factors
he never before considered. You go through this exercise a few hundred
times, like professional engineers routinely do, and you come out with a
great respect for "standard theory" and an even greater level of
skepticism toward people who have a weak understanding of it and are
convinced they've witnessed a miracle. Those of us who have spent a
career using "standard theory" to design real, useful items that work as
designed haven't become skeptical because our brains have been petrified
by education; it's because we've seen "standard theory" work, over and
over and over, and every last miracle inevitably fall, one after
another, to careful scrutiny and understanding.

But we also eventually come to realize that astrology, homeopathy, and
feng shui(*) will be with us forever. People will simply believe what
suits them, and won't be bothered by evidence. Especially if the
evidence takes effort, knowledge, patience, and understanding to acquire.

The "S-Unit" is a nice homey amateur unit of measurement, but it has no
meaning. (Some people seem to think it's equal to 6 dB, but vast numbers
of others think it's the the size of the markings on their receivers' "S
Meter". The two can be very different.) dB, on the other hand, is a
universally defined and understood unit. Anyone unable to accurately
measure relative values in dB is unable to make quantitative gain
measurements at all.

(*) My spell checker didn't recognize this, so I did a quick google
search to see if I got it right. It came up with 2,180,000 hits. There's
no lack of believers.

Roy Lewallen, W7EL

John Smith wrote:
Well, I have 3 test antennas on this project:
1) 1/4 wave stainless steel whip w/4 heavy 1/2 inch, aluminum ground plane
radials
2) 1/2 wave without any ground plane/counterpoise, lower 1/4 wave section is
3/4 copper pipe, upper 1/4 is a stainless whip, total of the combination is
1/2 wave... ferrite beads are used on the outer shield of the coax at the
point where it connects to the antenna, match is though a simple l-network
(ferrite beads are actually un-needed but used anyway, no real detectable
radiation from coax either way)
3) This is the antenna I described in the first post(s), I tend to refer to
as the "quarter/half", it is constructed on 3/4 ID pvc pipe, and has an OD
of just over an inch, the coil is constructed of #8 copper wire and the top
whip is the 28 inch stainless whip I mentioned. Is a resonate 1/2 wave and
physical 1/4 (whip + helical coil length.) Matching network is a l-network,
capactior is constructed of acrylic insulator plates (acrylic "window pane")
with copper sheet plates, coil is a 1.3 OD torroid. coil is approx. 1+ uh
(computed from toroid data)--I have not measured the capacitance of the
capacitor (probably somewhere from 20+ pf to 30+ pf), no
groundplane/counterpoise, ferrite beads as above.

Naturally, as the models predict, the 1/4 is lower in preformance than the
half 1/2, and very noticable in the most distant contacts.
However, the "quarter/half" out preforms the 1/4 but falls lower in
preformance than the 1/2. Contacts out at 30+ miles are where the
electrical 1/2 wave antennas differ most from each other (antennas 2 and 3
above.)
FSM measurements of the two 1/2 waves are very simuliar--however, these
measurements could have been taken at a greater distance to increase
accuracy (meters sensitivity I currently am using limited this.)
Franky, I was surprised by the preformance. As others have predicted--I
expected the preformance of the shortened 1/2 wave to be poorer than the 1/4
(mainly due to the helical coil skewing the radiation pattern and adding a
slight resistance to a physical 1/4 antenna.)
However, it seems to fall in the middle between the 1/4 and the 1/2 wave
(full length) antennas, favoring being closer to the 1/2 full length by 1/2
S-unit+
The biggest difference between the 1/4 and 1/2 wave full length is 2-3
s-units at stations in the 30+ mile distances.
The full 1/2 wave and the shortened 1/2 wave seem close to 1 s-unit on all
apparent distant stations.
I find this hard to believe, and the models I calculated did not reflect
what I had actually seen in s-units.

All three antennas were placed at the same height, on the same mast while
testing (32 ft above real ground.) And all other conditions the same.
The l-network match is the only difference between the two 1/2 wave
antennas, in the future I will correct this and finalize the tests... the
difference in the matches could be responsible for the difference in
expected results.
Right now, it actually looks to me, from the above--that the "1/4 physical,
1/2 wave electrical (quarter/half)" antenna was and is exhibiting properties
of both a 1/4 and a 1/2 wave antenna. This is the main reason I tossed out
this "antenna problem" here, to see others reactions and draw from their
experience.

Warmest regards

"Buck" wrote in message
...

On Sun, 20 Mar 2005 18:26:42 -0800, "John Smith"
wrote:






My question(s):

For an example, on the 10 meter band:
If I take a 28" whip and mount it at the end of helical wound coil (wound
on
1" diameter form), where the "wire length" of the coil, PLUS, the length
of
the whip (28" + coil wire length) is equal to 1/2 wavelength (electrical
length)--BUT, the overall physical length of the antenna (top, tip of whip
to base of helical wound coil) is 1/4 wavelength, what would the radiation
pattern of such an antenna be?

Would it favor the pattern of a 1/4 or 1/2 wave antenna--or, would the
pattern be a compromise between the two--or, would the pattern be totally
unrelated to either?

What could I expect the impedance of such an antenna be? Would the
reactance be capacitive or inductive? What would be the best way to
provide
a match to 50 ohm coax from such an antenna?

What software is available to model such an antenna?

Thanks in advance,
warmest regards



EZNec will model your antenna. As for the antenna, I believe that the
shortened 1/2 wave antenna will radiate with less effect than a
stretched 1/2 wave, but possibly better than a 1/4 wave. How much?
That depends on the coil and the matching network pending losses.

Good luck,
Buck
N4PGW

--
73 for now
Buck
N4PGW

The "S-Unit" is a nice homey amateur unit of measurement, but it has
no
meaning. (Some people seem to think it's equal to 6 dB, but vast
numbers
of others think it's the the size of the markings on their
receivers' "S
Meter".
================================

And one million US housewives can't be wrong!