sigma4 article is online

[Marconi]

Bob, you had absolutely nothing to do with my disregarding common sense when it came to my cleaning that antenna. You can get that out of your head. That never crossed my mind. I don't want you feeling guilty about that.

Old age and 30+ years with diabetes just caught up with me Bob.

Again, the only reason that I requested that you tell us your secret for how you manipulate signals is pretty simple...because you keep bring the idea up and telling us the difference you clearly see on your radio's meter.

Our old buddy Freecell (Jack) told me once how he was able to talk into the big city...several thousand feet below his place on a mountain. He told me he hung a regular StarDuster upside down inside the top of his three story hay barn and it was the only way he was able to broadcast his signals down into the city...about 60 miles away. He said otherwise...his signals went right over their heads into the coast line area farther away.

Bob you might be right. It is possible that it was Jazzsinger that built that little circuit that did the fix. Maybe it was him that promised to send one to me to hookup to the meter on my radio. I also think he said there was a video over there on the subject and he was going to get me a link...but I don't recall having seen it yet.

I think Jazz and I just recently spoke about such a device as a matter of fact.

 

[HomerBB]

On my mind.
As simple as Henry's article is written, it is still above the heads of some. So a thing or two.
1. The claim is made for the cone being a simple quarter wave tuning device shaped differently than, but similar to a J-pole. It is suggested that one could eliminate the Gamma and find the 50 Ohm match point on the cone. That has not been real world demonstrated, yet. Furthermore, the antenna uses a capacitor (gamma match) to handle
match. This seems odd to even the novice antenna student - 2 matchers, stub and capacitor, when only one is needed?
2. The cone is said to contribute little to no significant contribution to the far field, yet is compared to the J-pole which in all models of a J-pole clearly shows a significant difference toward the side of the antenna the short side (or not connected to the upper radiator) of the lower stub. One J-pole contributes measurably to the antennas RF signature , but the other doesn't?
3. Although I understand the why of this one, it would serve everyone well to clearly say why this antenna does not send it's major lobe into the stratosphere but toward the horizon, unlike other antennas of 3/4 wavelength or longer. This is vague in the article, IMO, due to the claim that the cone is merely a matching device with the ability to capture most of the out of phase currents on the lowest 1/4 wave, yet does not add significantly to the signal on the far field. If your answer is what I suspect it is then this article claims the S4/V4k antennas are not electrical 3/4 wavelength antennas but over-sized EFHW's.
4. The current discussion is centering around the ability of this antenna when tuned to the proper extent to manipulate signals toward the earth at 0° or lower with some doubting the empirical evidence of years. Citing theory (which theory?) they refuse to embrace a challenge to attempt to repeat this phenomenon demanding the empiricist deny their practical real world experience is favor of theory.
I am a willing student, but an avid empiricist. i think it would be more profitable and more educational if the goal would center on reconciling the long evidenced real earth results to the theory as expressed somewhat in the article. Thank you to those who are trying to break away from stubborn debate to accomplish this. The article says the answer is new antenna excitement, a lousy old antenna system, or imagination, with the likelihood this antenna will out perform 5/8 wave antennas mounted at same bottom height. It does not address the professional use of the antenna where none of the above applies.

I think no one cares what the electrical size of the antenna actually is, but everyone wants the truth of the real world experience with this antenna explored and understood. Denying it occurs just obfuscates the issue and brings a will to dismiss the whole subject as unworthy of consideration, or, a waste of time for those who are not insane. The article may need a follow-up, IDK, but as it stands Henry has just called it a symmetrically more rounded out J-pole - a 1/2 wave sitting over a 1/4 wave matcher with a second capacitor/matcher thrown in for the fun of it. Confusing illogic to some folks.

Homer

 

[Henry HPSD]

Homer,

Thank you for your info, it is valued...!!! thumbs up !!
As writing something yourself, sometimes things seems logical where from another point of view it is not.

..just got home...wife at work need to pic up the kids etc..bit bussy hihi.

1 - is done allready..ill post some pics later
2- No, ill like to put a bit more "balance" in your words.
3-Oke..will read again..but think oke..
4-Not sure what it is you are asking...if your are asking me?...could you be so kind and try it again ? (sorry not native English)

Kind regards,
H>

 

[Shockwave]

The most important thing to remember is the proof is in the pudding, NOT the paperwork. I almost want to gag every time I hear a comment that suggests the models are the "proof" and the results from 15 years of professional broadcast use are simply "hearsay". Not even one of over 1500 clients has agreed with the "unity gain J-Pole" theory. The proof of that is every one had 30 days to analyze the antenna where it counts with all claims backed by a full refund policy.

I've offered in private to provide emails from Clear Channel engineers with names, job titles and contact info included but real world results don't seem to have an influence here. I'm told over and over again it's me that doesn't understand this theory and the only thing I don't understand is why more than 40 pages can't remotely describe the repeatable field results.

I'm still waiting for someone to show me a pair of dipoles in EZNEC with downward tilt below 0 degrees. We have heard the claim that since the Sigma model can't do that over real earth, it's not possible in the field. Try it on an array known to produce downward tilt and explain why you can't get EZNEC to show the effect with stacked dipoles either.

 

[Shockwave]

While Henry's test antenna was constructed without a gamma match, that certainly will not help the performance of the antenna in the field. You cannot extend the two radiator lengths in order to peak the far field gain without introducing capacitive reactance in the matching network. The test antenna I saw only used 3 radials to "confine" the out of phase field within the cone. Another case where the best proven results appeared to have been overlooked.

We have also heard theories that suggest currents present on the radials form rotating fields around the individual radials rather than seeing the structure as a single element forming a shield like coax. I've pointed out this can't be true because the antenna performs nearly identical when the radials are covered over in a tight wire mesh. How does the rotating field on individual radials circulate in and out of the cone structure rather than around the entire cone in this case?

Henry also backed W8JI's claim that this antenna would benefit from 4 horizontal radials added to the base. Good luck with that. You're going to find this just robs constructive currents off the cone and places them on horizontal radials where they add nothing to the far field gain. CMC has already been radiated off the outside of the cone where it is constructive.

 

[Henry HPSD]

Donald,

Please allow me to respond a bit later, its "kids" time now..

In the meanwhile, could you be so kind and share those results of clear channel?
That maybe done in private of course. I have never been offered those before, so obvious interested.

Thank you...
About diner time

Kind regards,

H>

 

[bob85]

Homer,
Using the gamma allows a simpler dc grounded construction needing no insulator at the base, it also allows monopole lengths other than 3/4wave,

We know EZNEC can model the j-pole and show the effects of common mode on the short leg,
I feel but can't prove it that there probably lies the answer to what i was manipulating,
The cone terminated with dummyloads has very little radiation,
a j-pole stub terminated with a dummyload and been perfectly parallel would have no radiation,

common mode can't flow only part way onto the mast as has been suggested with the CST animation and the sirio engineers words,
If there is common mode it will flow on the whole mast in a sinusoidal pattern,
That makes me question the sirio engineers understanding of antennas or the the interpretation of what he actually meant.

 

[Henry HPSD]

The most important thing to remember is the proof is in the pudding, NOT the paperwork. I almost want to gag every time I hear a comment that suggests the models are the "proof" and the results from 15 years of professional broadcast use are simply "hearsay". Not even one of over 1500 clients has agreed with the "unity gain J-Pole" theory. The proof of that is every one had 30 days to analyze the antenna where it counts with all claims backed by a full refund policy.

But donald I did the pudding as well ,In fact i constructed everything you want me to...but still NO additional gain.

And just because you sell those antennas for 15 years to low power FM stations
"professional" has two indications:
1- being done for money and 2-really well done
I think you understand what im trying to say.

Heck, i could say the say about antennas in the Military.
The forces in Afghanistan still have my antennas, the word "professional" ehm..
No i wouldnt use it. In this case its just a "word" to enhance value.

You know what, i worked with a lot of different antenna engineers.
The thing that strikes me most is that they can remember almost each word in from Balanis but often fail in "logical thinking.
If worked with guys who design antennas for a living.
The difference being: the client wants "x" as soon as "x" is achieved it is settled.
Where us enthusiast go beyond...we want "x and plus" then they look at me and ask why ?

You know what else is striking, often they are not that good outside their field of specific expertise.
Those whit who i speak, if they are HAM's as well the tend to be a lot better cause they have "enthusiasm"

Donald you construct a max 3 Kw version.
The term "professional broadcast" ...I believe the FCC has "classes".
I tend to think the majority of those stations are "low power" or educational ?
I don't think most of them will have the best engineers available.

You have given me a name over the personal mail, who i all ready forgot.
Wasn't that some sort of Christian low power radio station on ...Guam ?
With respect for the guy...he could be very good !
But its not really helping me to find some "proof"

Though i could imagine the FCC has done some "measurements"
If the antenna was able to produce whatever gain it is you say...wouldn't the low power stations be forced to turn the power down ? for sure that has happen to one of your 1500 clients ? Or doesnt it work that way if the ERP is too much ?


I've offered in private to provide emails from Clear Channel engineers with names, job titles and contact info included but real world results don't seem to have an influence here. I'm told over and over again it's me that doesn't understand this theory and the only thing I don't understand is why more than 40 pages can't remotely describe the repeatable field results.

I have never been offered any emails from clear channel.
I know you have mentioned CBC and i saw a picture on your site from a reporter vehicle. ...You said the engineers of CBC have measured the gain.
Hm..i just might give them a call, or clear channel if you are willing to share.

I'm still waiting for someone to show me a pair of dipoles in EZNEC with downward tilt below 0 degrees.

Oke:


please read the text underneath the plot...

We have heard the claim that since the Sigma model can't do that over real earth,

No, i never said that..the sigma can have downward tilt...and so can a dipole
Not accurate.

it's not possible in the field. Try it on an array known to produce downward tilt and explain why you can't get EZNEC to show the effect with stacked dipol

No, who says Eznec cant show that ...I told you all ready it can.
Not accurate

I said...the earth will have influence it sure can have downward tilt
But the effects wil be NEGATIVE for the CB user. NOT for direct wave communication as is the case with cell phones for example ..
ou CAN NOT transmit a signal below the earth surface (well you can..but that goes to deep)

 

[Henry HPSD]

While Henry's test antenna was constructed without a gamma match, that certainly will not help the performance of the antenna in the field.

Donald you have seen one test antenna in the beginning from that you draw a inaccurate conclusion that it is the only one.
Your claim that a gamma match will enhance performance...
Oke...imagine a single dipole...it can be direct fed as it it resonant (depending on a few things) but we could also feed it with a gamma-match...
That wont effect performance besides the possible loss of the matching unit.
So...Not accurate.

You cannot extend the two radiator lengths in order to peak the far field gain without introducing capacitive reactance in the matching network.

And guess what happens if we move the feed point on a center fed dipole.
We introduce reactance etc..
So yes you are RIGHT

The test antenna I saw only used 3 radials to "confine" the out of phase field within the cone. Another case where the best proven results appeared to have been overlooked.

Again you draw the wrong conclusion, im sure you still have some pictures if not I have and there are 4 ...
Not accurate.

We have also heard theories that suggest currents present on the radials form rotating fields around the individual radials rather than seeing the structure as a single element forming a shield like coax. I've pointed out this can't be true because the antenna performs nearly identical when the radials are covered over in a tight wire mesh. How does the rotating field on individual radials circulate in and out of the cone structure rather than around the entire cone in this case?

Ehm...oke...tell me... how do we feed a 2el cubical quad ?
Yes, with a piece of 1/4 wave coax line.
A transmission line and a coax cable can both be used to transform impedance.
So...not accurate.

Henry also backed W8JI's claim that this antenna would benefit from 4 horizontal radials added to the base. Good luck with that. You're going to find this just robs constructive currents off the cone and places them on horizontal radials where they add nothing to the far field gain.

No donald, they will not...the radials will enhance the ground verticals depend on but some can work without. And we allready provided proof they will help especially at large height...now..that is something you can test

CMC has already been radiated off the outside of the cone where it is constructive.

Actually CMC is a term used for currents NOT being constructive.
So...not accurate.

I cant help it Donald, I appreciate you cause you are one of the few manufacturers willing to come online !

But i see the tendency of being not accurate.
Neither have you done anything I have asked, for which i am disappointed.
Now, you can continue your search with something "new"
as i did mention yesterday....i would expect nothing else...

So...happy searching


Kind regards,

H>

 

[HomerBB]

Homer, . . .

4-Not sure what it is you are asking...if your are asking me?...could you be so kind and try it again ? (sorry not native English)

Kind regards,
H>

I'll try.

The current discussion seems to be centering around the ability of this antenna when it is properly tuned to manipulate signals toward the horizon at 0° or lower. Some seem to be doubting the evidence of years of seeing the proof of this occurring in the real world. The doubters seem to say that theory (or models) don't support this and refuse to accept a challenge to attempt to repeat this phenomenon, but instead are demanding the empiricist (those with experience in something) deny their practical real world experience is favor of theoretical arguments.

I am a willing student, but also an avid empiricist (believe that no one with an experience should bow to another with only an argument).

I think it would be more profitable and more educational if the goal would center on bringing together the long time evidence of real earth results with the theory as expressed somewhat in the article. In other words, instead of using arguments and theory to outright reject the hard evidence of those who have experienced the performance of this antenna for years we should try to find out why the antenna works in the way it does. Thank you to those who are trying to break away from stubborn debate to accomplish this. The article says the reason the antenna is said to work as well as it does is because {a} it is new shiny antenna causing excitement, {b} they had a lousy old antenna system so any new one would work better, or {c} just imagination. Yet, it is still said that it is likely this antenna will out perform 5/8 wave antennas mounted at same bottom height(??). The article does not address the professional use of the antenna where none of the above ideas apply.

 

[HomerBB]

Homer,
Using the gamma allows a simpler dc grounded construction needing no insulator at the base, it also allows monopole lengths other than 3/4wave,

We know EZNEC can model the j-pole and show the effects of common mode on the short leg,
I feel but can't prove it that there probably lies the answer to what i was manipulating,
The cone terminated with dummyloads has very little radiation,
a j-pole stub terminated with a dummyload and been perfectly parallel would have no radiation,

common mode can't flow only part way onto the mast as has been suggested with the CST animation and the sirio engineers words,
If there is common mode it will flow on the whole mast in a sinusoidal pattern,
That makes me question the sirio engineers understanding of antennas or the the interpretation of what he actually meant.

So, do I understand this answer says the antenna is NOT a J-Pole, but something else? Possibly because something unique may be going on with the cone section not explored in the discussion about Henry's article?

The J-pole reacts to common mode currents in a specific way, correct?
This antenna acts differently, correct? And whether this antenna is or is not a J-Pole it does not behave like one?

So once again, are we seeing what it isn't, but not discovering what it is?

Thanks for the answer.

Also, does a J-pole need a gamma match if we start extending the top radiator section beyond a half-wave?

I am not trying to be difficult. I'm just sorting through some questions some things discussed have raised for me.

 

[Marconi]

For a long time I’ve told my story basically to say: I don’t see much difference in the CB antennas that I’ve accumulated and compared over many years. And I have worked my real antennas repeatedly for years...long before I could model.

I am not scientifically minded by nature, and for that reason I have always tried to take a more simplistic approach in my considerations about things of interest to me. This was easier to do early on when nobody had much to show. Again this was before I learned to model antennas using Eznec, and then I began to see details that were hard to dispute concerning the words of other members as to their results. Here is a pretty simple concept: I'm willing to believe the words as long as I don't have other evidence that disputes the words. This is why I ask questions.

I am not always right, but I consider my niche to trend to try and always take a modest approach without a lot of scientific "mumbo jumbo" that is difficult to explain even if I could.

In most cases modeling helps me look at things closely while at the same time considering my own bias regarding the details I consider, against what I once believed or considered as fact or good ideas in some way.

I think with this S4/NV4K antenna issue…too many folks are trying to make too much of the idea that the Sigma4/New Vector 4K works in some veiled ways that allows only a few to understand.

IMO this antenna is nothing more than a raised up ½ wave radiator that happens to work very effectively. IMO, it is a fact that Avanti produced some very good antennas with their Co-Inductive idea.

I also think the idea of the J-Pole is directly related to the understanding for how the Sigma4/NV4K works in general. I think this is why we often hear it being referenced to as some form of coaxial J-Pole.

See attached references in the links I provide below:

Click here: http://k6mhe.com/files/ssfm.pdf

Click here: http://www.sirioantenne.it/prodotti_all.php?category=HF (3-30 MHz) Base Antenna&antenna= NEW VECTOR 4000&idc=1008171241&idg=1008171169&idp=66

Also check the link below and you will see a word description in Wikipedia. It describes some limitations and its seeming less than debilitating quirks that many tend to claim renders the J-Pole antenna virtually worthless.

Click here: http://en.wikipedia.org/wiki/J-pole_antenna

What is wrong with taking an already effective design and making it better in just about every way possible…for a new and developing novice hobby minded public back in those days when Avanti developed the Sigma4?

Back then the J-Pole idea was probably considered by ham operators as a suitable homemade, novel, cheap, and effective way to start getting a vertical Amateur radio signal on the air, and I still think it has utility for radio world today.

I see the success Avanti had in the Sigma4/NV4K design…as a big advantage with modestly better performance results…and for me that is enough.

I believe that Avanti was pretty much right on in their claims regarding performance in the Patent and other publications, but I’m dubious about the claims made by many today.

I have heard it claimed, seen it reported, but I have never been presented with a single thread of real evidence that indicates the Sigma4/NV4K will produce 4.15 dbi in a Free Space model, or 2 dbd of gain over a dipole.

IMO, most will probably agree that the reports in the past from Solarcon regarding the gain for their A99…were results base on smoke and mirrors reporting from the advertising department, and that is not science. IMO, some of the claims for the S4 are similar...even though I believe this antenna will show a bit more gain at a lower angle than most 5/8 wave antennas.

Henry is telling it like it is, and I’ve been reporting about the same for a while now.

 

[bob85]

Homer
Calling the vector a j-pole is like calling a chrysler pickup a ford sedan because they are motor vehicles and operate more or less the same way,

Plenty of 5/8 j-poles have been constructed without the need of a gamma, they don't work as well as a 1/2wave j-pole,
I think that's people getting caught up in the 5/8wave myth,

I used to think that extending the monopole caused more unbalance of current at the top of the cone which would increase radiation from the cone in a positive way in much the same way that the unbalance of currents at the top of the j-pole stub causes radiation from the short leg of the stub and more gain at a lower angle in the direction of the stub,

I believed this because the bottom of the extended radiator has lower end impedance than the bottom of a 1/2wave, while the top of the stub or cone still sees the very high impedance of air,

We can't fool with kirchhoff, any current flowing into the radiator at the top of the cone must be balanced with current on the short leg or cone, there is no free lunch,

What i failed to understand is that does not equate to better performance as i imagined,
http://www.hamradio.me/antennas/58-wave-j-pole-vs-12-wave-j-pole-eznec-shootout.html

So even though i can manipulate signals with incremental tuning adjustments, the cause imho can't be what i thought it probably was,

Maybe i underestimated the true electrical length of the monopole near to earth and surrounded by the cone which raises resonant frequency ( makes it look electrically shorter ),

Maybe i was reducing deconstructive mast currents since its not possible to have currents flowing part way down a conductor unless you break it and fit an isolator or use a resonance breaker etc
the same applies to your coax braid,

Whatever the exact nature of the signal manipulation i don't think i was making the antenna have more gain, reducing detrimental effect of mast or feed-line currents is more likely imho.

The sigma design antennas don't need any voodoo to outperform a 5/8wave, they are taller with a current maxima higher above ground and use a reasonably efficient feed system,
http://www.w8ji.com/omega_and_gama_matching.htm

A 5/8wave also take advantage of height of current maxima but they need some voodoo to have the claimed advantage over other antennas when not installed over an extensive ground system,
http://en.wikipedia.org/wiki/Trombone

Take that advantage away and a simple dipole will equal or outperform them all.

IF anybody can actually prove im wrong im interested in seeing the proof, Im always willing to learn.

 

[Henry HPSD]

@ Homer,

So, do I understand this answer says the antenna is NOT a J-Pole, but something else? Possibly because something unique may be going on with the cone section not explored in the discussion about Henry's article?

No,
You may look at it as you want.
The "thing" is one has to be precise. A J-pole is straigth. the Sigma 4 has a cone.
Normally the J-pole has one radial The cone version has either 3 or 3.
So yes...its a J pole with the differeneces mentioned.

A dipole is straigth...a inverted V is still a dipole...but we dont call it that way.
It is not MY job to decided at which point the antenna should be named otherwise.

The J-pole reacts to common mode currents in a specific way, correct?
This antenna acts differently, correct? And whether this antenna is or is not a J-Pole it does not behave like one?

No, it reacts to is the same...
Though i am tempted to say the S4 handles it better as it is more "symetrical due to extra vertical radials.

Also, does a J-pole need a gamma match if we start extending the top radiator section beyond a half-wave?

Yes, Or....you can move the feedpoint....or you can shorten or lenghten the bottom 1/4 wave. Or you can change the dimensions of it (distances between wires etc)
Any change in the "transmission line section" willl change its impedance and therefor the ability to "transfor.


I am not trying to be difficult. I'm just sorting through some questions some things discussed have raised for me.

Not difficult at all...and i do understand its difficult to understand.
If something is not understood its wise to ask.

 

[Henry HPSD]

The doubters seem to say that theory (or models) don't support this and refuse to accept a challenge to attempt to repeat this phenomenon, but instead are demanding the empiricist (those with experience in something) deny their practical real world experience is favor of theoretical arguments

Im not denying the real world results Donald has made...
Im absolutly positive in some cases he has noticed some advantage.
However im confident there are reasons for it which NOT are a "collinear" effect or the mentioned high gain.


I think it would be more profitable and more educational if the goal would center on bringing together the long time evidence of real earth results with the theory as expressed somewhat in the article. In other words, instead of using arguments and theory to outright reject the hard evidence of those who have experienced the performance of this antenna for years we should try to find out why the antenna works in the way it does.

I couldnt agree more.
However, I have done everything....really....everything...
Now i am asking those who think they have measured something to look where they went wrong...as it is clear that is the case.

Yet, it is still said that it is likely this antenna will out perform 5/8 wave antennas mounted at same bottom height(??). The article does not address the professional use of the antenna where none of the above ideas apply.

Yes,
Ehm, which professionall use ?
The 5/8 wave is commonlly seen on CB.
On this band its height is its main advantage.
Its popularity drops as soon as we go to "other" places...yes some in HAM use etc.
And you can see some on MW broadcast....For reasons given

Just ask yourself the question
....I would actually say:
why dont we see them that often in professionall applications.

Or are you asking about the professinal use of the Sigma 4?
Then .......there are maybe hundred of professinal dipole manufacturers but only one with a dominator. why ?

kind regards,

H>