New thread to debate V-4000

[HomerBB]

Anyone here brought an FM antenna to the discussion; that I believe we are talking about the Sigma 4 Sirio Vector 4000.
These antennas ever demonstrated in the real world that can overcome a 5/8 as the Penetrator 500.
If they were as good as their physical length looks, its use would be massive, but the more that are removed by inefficient that those who remain.
Must be the biggest antenna that gathers dust in the garage.

I have done just what you asked. I have built three CB sized models of this type antenna. It has proven to outperform the 5/8 groundplane antennas consistently for me.
The only reason I have seen that folks have replaced them is the fragility of the antenna as produced by the manufacturers. It takes special attention to the construction to make such a long antenna strong enough to survive strong winds and ice. This brings us to the second reason it isn't more widely used.

It is longer than most antennas used by CB operators. In many CB installs - get it up quick and easy - they choose to not use an antenna that may be more challenging to use. Its unorthodox appearance puts many off, too.

Reason three is that there is so much more hype associated with the 5/8 GP because of the many more of them made, bought, and used, all of which perform on a relative parity to each other.

The biggest reason of all is that most CB operators have been traditionally less interested in the theory of antenna performance than in the can-I-talk-and-hear-with-it type of thinking. If their buddy, or group of friends say it works, whether or not it works well, they buy that one.

Additionally, with the recent debate resurgence associated with this antenna I have noticed an attendant resurgence in interest in it, too. More are going up all the time.

 

[nosepc]

Several people here have tried to tell you that they have built them.
Read this Quote slowly and very carefully and try to understand, it has nothing to do with Antenna modeling and relates to direct experience with comparing the 1/2 wave, a 5/8 wave and the vector.
Please think a little bit before you dismiss Homers testing.

Posted by Homer, a man who has built many antennas and reported his testing here.



You ask
You ask for experience, but when it is presented to you, you simply post something using a program that will still see the antenna as a J-pole.

Several times I have told myself I will not respond to your posting again, but I can not help it. I can not understand why you are so determined to keep posting pictures made with software that still fails to model the antenna properly.
I am sorry it hurts your pride that your beloved modeling program is wrong, and a new, more advanced modeling program has come along and proved it wrong.

I hate to be rude and blunt but lets see if you understand if I word it this way:

NEC IS ******* WRONG IN THE WAY IT PRESENTS THE ANTENNA UP TO THIS POINT.


There is no better proof than this:

MANY BROADCAST STATIONS HAVE TAKEN DOWN THERE EXISTING ANTENNAS AND REPORTED BETTER COVERAGE WITH THIS STYLE OF ANTENNA, EVEN AFTER REDUCING THE NUMBER OF ANTENNAS USED.

How hard is it to understand the above words?

If all these guys that rely on the antenna working properly agree that they work better, how do you explain the real world experience that have reported?
They are station engineers for gods sake, not the guy selling the antenna, not the guy installing the antenna, but the guy whos ass is in the line if the station coverage does not improve after the switch.


Any more Plots and cartoons that you Post from this point on will be disregarded as garbage because about everyone here already knows that it will not model the antenna correctly.
Until you build and test the antenna for your self, your words here....will be meaningless and not worth any more replies.
It is not hard, I have seen them built with very little cost in materials.

73
Jeff

The Germans invented the j-pole in the early twentieth century. they never said it a radiant 3/4 wave.
To say that it is is that the Germans are stupid and know nothing of antennas??.
Even manufactured and sold even for VHF, but even as a 5/8 wave, but a simple half-wave.
The Germans are wrong?

Hallo Hajo,

die von Martin (DK7ZB) beschriebene Antenne ist eine Sperrtopfantenne. Der Lambda/2 lange Strahler wird am Ende eingespeist, also sehr hochohmig. Zur Anpassung an das 50 Ohm Koaxkabel dient der am unteren Ende kurzgeschlossene Sperrtopf (Lambda/4).
Diese Antenne ist ein Abkömmling der J-Antenne, wie oben schon Jürgen erwähnt hat.


http://forum.db3om.de/ftopic12247.html

http://der-bastelbunker.blogspot.com.ar/2010/11/70cm-sperrtopfantenne-aus-einfachstem.html

 

[HomerBB]

The Germans invented the j-pole in the early twentieth century. they never said it a radiant 3/4 wave.
To say that it is is that the Germans are stupid and know nothing of antennas??.
Even manufactured and sold even for VHF, but even as a 5/8 wave, but a simple half-wave.
The Germans are wrong?

So What?

Do us all a favor, Sir. Go to the public library. Ask if there is anyone there who can read and understand English. Ask them to read the reply you quoted and explain to you that there was absolutely nothing about a J-pole in the quote. Then have them read your own reply back to you and explain to you how absolute silly it is, and how it has nothing to do with what you quoted, nor your original question.


I really wish you were serious. You, sir, don't even try to be friendly.

 

[Shockwave]

At last I found some of these antennas for VHF, 2-meter, so I take back that "nobody does"*.

The Germans do, but sold as half-wave antenna.

Winkler CX-2 Sperrtopfantenne (2m)

Since you're always wrong, you might as well deal with this inaccuracy too. Here we have a 2 meter 3/4 wave Coaxial J-Pole. In fact it's the same antenna my local fire deparment uses on station 2. The Germans must have made a typo because you'll notice your link is for the same 3/4 wave CX-2 antenna made by Sirio with 2 dbd.

VHF (30-300 MHz) Base Antenna, CX 2 m series

 

[nosepc]

If then we will be guided by what marketers say, nobody can deny that effectively Solarcon A99 has 9.9 dBi of gain.
What makes the Sigma 4 a giant useless junk.

 

[Shockwave]

When Solarcon came out with that inaccurate statement we beat them up with the truth nearly as bad as you're getting here. Similiar to "Audio Gain" with Jo-CapGunn. The only difference is Solarcon eventually realized they were so wrong, it would not stand. You are another situation.

 

[ghz24]

Where did the extra gain I see in the model I posted come from?
Why does this show in phase radiation.

nosepc this jpg is "show phase as color." option see how all the radials are the same color. and it is only slightly out of phase with the main radiator.
Same color = same phase.

You must demand the software mimic what happens in the lab or field before you can argue it's right.

Gee I think the navy might have done that.
If nec cant accurately model this antenna it's one of very few.
Almost all the results I have seen match almost perfectly with expected results.
Yes it's old (1980's) but the laws of physics regarding HF radio were pretty well understood. The F-117 stealth fighter was flying when this code was written for the navy.
And I'll bet more tax money was spent developing NEC than was spent designing your CST.
I'm sure glad the Russians didn't know that our radar arrays were so flawed.
When they originally design this antenna they most likely used a slide rule.



At least quote the complete passage

The NEC engine provides support for modeling patch antennas as well, but the algorithm has not proven as robust or accurate when modeling solid structures such as parabolic antennas.

A patch? And I don't know who thinks parabolas don't model, but that is bull, as far as I can tell all the parabolas I have modeled (50+ of them) fall well within published values based on area of the reflector, frequency of operation, and imperfections in the surface.
Accurate biquads with solid reflectors have been tested as well.
The patch functions I can't attest to I've never tried a patch.
The important passage is actually :

Limitations
NEC-2 does not model tapered elements such as those made of telescoping aluminum.
NEC-2 does not model buried radials or ground stakes.

And I could add it wont model an antenna underwater.
Also the small frequency shift is well known and documented by a group modeling and testing VHF and UHF antennas with reflectors that are closely spaced enough to be considered solid
Under your definition all reflectors are solid surfaces
Maybe CST inflated the gain.
Maybe nec can't accurately model this antenna but, I think you protest to much.
Even leaving the modeling aside I don't see enough area to get your current maximums far enough apart to achieve 2 dB gain. Seems about 2 feet short I'd say.
Even if the radials current max is at the very bottom that's only 0.5 wavelengths
stacking antenna and broadside collinear gain increase
Maybe the mast is radiating ... or the coax?
Don't get me wrong I think this is likely the best omni available at this frequency.
And I'm not perfectly happy with the model in 4nec2.
2dBd just seems a little high for this antenna.
Maybe CST inflated the gain.
you doubt NEC well at least it's open source and the code can be checked for accuracy: then I can doubt your proprietary software.

 

[Shockwave]

Mentioning the CX design of antennas does bring me to a question I'd like to ask some of our other antenna thinking members. Having tested just about every type of omni directional antenna made, I noticed something different between the Vector and CX design. More CMC issues were noted with the CX. The CX tunes different when attached to a mast, the Vector does not. Changes in coax length and position are much more apparent in the CX I tested.

Differences in construction I noted include the fact I had to rescale the CX to a new band and it is possible an error was made here but I went over it twice. The obvious difference is the CX uses a solid cylinder as the sleeve. Anyone think that could have anything to do with more CMC? I'm leaning towards the fact it really doesn't have a gamma match. The match is shaped like a gamma but just made from solid wire with no DC isolation. Any thoughts on this?

 

[bob85]

cm current on the braid is the only thing i know of that changes vswr with coax length/position so id presume the cx series has more cmc if you notice they are more sensitive to coax length/position.

 

[Shockwave]

Gee I think the navy might have done that.

Not until you can test a model in that software with the 4 extra collinear wires that so few seem to understand prove how much of the original antenna radiates in phase. You can't convert an existing antenna into a collinear without understanding the radiation length and phase angles present in the existing antenna so you can make sure your new phase shift has placed the new 1/2 wave in a phase that is constructive with the entire antenna.

Remember, with the Sigma that new 1/2 wave top has to be in phase with the cone and first 50% of the vertical extending past the cone. It does not simply match the phase of the existing top half wave because it has already been delayed by 90 degrees with respect to the source, through the inside of the cone were it was not allowed to radiated during its first 1/4 wavelength.

If nec cant accurately model this antenna it's one of very few.

We are in absolute agreement here. I'm not aware of any other antenna in which I can prove NEC has miscalculated the constructive wavelength by 33%. Where it consistently misguides you to make the phase shift in collinear versions 100% more than the 90 degree shift that works in the field.

Almost all the results I have seen match almost perfectly with expected results.

I agree here too in every case other than the Vector design. I also have to conclude with such gross inaccuracies in this design, it is possible there are others it fails at too.

Yes it's old (1980's) but the laws of physics regarding HF radio were pretty well understood. The F-117 stealth fighter was flying when this code was written for the navy.
And I'll bet more tax money was spent developing NEC than was spent designing your CST.
I'm sure glad the Russians didn't know that our radar arrays were so flawed.
When they originally design this antenna they most likely used a slide rule.

The accuracy of Navy or Russian radar antennas is not in question here. I'm sure they confirmed the software was producing accurate results in the design they were working with. Just like I know Sirio and myself found NEC based programs were not showing what we saw in the field with the Vector. Identifying the limitations NEC has with this design is why CST was used.

I'm not sure dumping tax money into a project is good justification of a job well done. In any event you should recognize CST can do everything NEC does since it can switch to any one of 6 engines using different algorithms. Where you can search reviews and find most programs excel with specific types of antennas, CST has demonstrated an ability to accurately model whatever you can build in the field.

At least quote the complete passage
A patch? And I don't know who thinks parabolas don't model, but that is bull, as far as I can tell all the parabolas I have modeled (50+ of them) fall well within published values based on area of the reflector, frequency of operation, and imperfections in the surface.
Accurate biquads with solid reflectors have been tested as well.
The patch functions I can't attest to I've never tried a patch.
The important passage is actually :


And I could add it wont model an antenna underwater.
Also the small frequency shift is well known and documented by a group modeling and testing VHF and UHF antennas with reflectors that are closely spaced enough to be considered solid
Under your definition all reflectors are solid surfaces
Maybe CST inflated the gain.
Maybe nec can't accurately model this antenna but, I think you protest to much.
Even leaving the modeling aside I don't see enough area to get your current maximums far enough apart to achieve 2 dB gain. Seems about 2 feet short I'd say.
Even if the radials current max is at the very bottom that's only 0.5 wavelengths
stacking antenna and broadside collinear gain increase
Maybe the mast is radiating ... or the coax?
Don't get me wrong I think this is likely the best omni available at this frequency.
And I'm not perfectly happy with the model in 4nec2.
2dBd just seems a little high for this antenna.
Maybe CST inflated the gain.
you doubt NEC well at least it's open source and the code can be checked for accuracy: then I can doubt your proprietary software.

I can't comment on the accuracy of the quotes taken from the encyclopedia. That is the work of many that contribute to and scrutinize Wikipedia. If you have information that can contribute to a better explanation they will listen. The point is there are identified limitations NEC has that effect accuracy in this design. Cebik, Sirio, CST, myself and many others are in agreement here.

With respect to the 2dbd, it's not as unrealistic as you may think once you acknowledge that this gain is caused by more than just a longer antenna. The antenna is a 1/4 wave longer than a 1/2 wave and accepting the bottom is an effective 1/4 wave radiator is the first hurdle CST confirms. It's still a 1/4 wave too short to produce 3dbd but in phase radiation length is not the only factor.

Stacking one in phase radiation current over another in phase current also reshapes the pattern so that more of the existing gain is compressed on the distant horizon. This is a significant factor in the design. It's why 11 meter users don't say "I'm hearing Joe across town with an extra S-unit on the Vector". They say "I can hear that guy Joe talks to 60 miles away now that I've installed the Vector."

While all of my clients do not test the antennas gain, all of my clients who did test or pay to have the antenna tested all confirm nothing less than 2dbd and as high as 3dbd. My application offers unique advantages when using this design since I'm almost always replacing side mount antennas that have to be spaced lower on the tower and obstructed by the tower.

When I replace one side mounted dipole at the same location and mounting situation on the tower, stations are confirming 2dbd. When we remove 4 CP bays spread across 40 feet or more of tower and can place one of these antennas at the top, stations report 3dbd and a coverage contour that is now perfectly omni-directional (or distorted only by the terrain) without distortion and reflections from the tower. White noise on FM makes spotting these smaller differences in the fringe area possible with just a receiver.

 

[nosepc]

Mentioning the CX design of antennas does bring me to a question I'd like to ask some of our other antenna thinking members. Having tested just about every type of omni directional antenna made, I noticed something different between the Vector and CX design. More CMC issues were noted with the CX. The CX tunes different when attached to a mast, the Vector does not. Changes in coax length and position are much more apparent in the CX I tested.

Differences in construction I noted include the fact I had to rescale the CX to a new band and it is possible an error was made here but I went over it twice. The obvious difference is the CX uses a solid cylinder as the sleeve. Anyone think that could have anything to do with more CMC? I'm leaning towards the fact it really doesn't have a gamma match. The match is shaped like a gamma but just made from solid wire with no DC isolation. Any thoughts on this?

It is obvious that a device that does not need an adapter Gamma-match is more efficient.
The gamma-match adapters must avoid if you can not add heat lost by irradiation of an alien parasite to the antenna element is only an adapter.
This device adds lost to an antenna.

"no see".

 

[The DB]

Several times I have told myself I will not respond to your posting again, but I can not help it. I can not understand why you are so determined to keep posting pictures made with software that still fails to model the antenna properly.

I've tried the same thing, but some of the stuff he says...

I do have to give him one thing, some of the stuff he says is entertaining. Perhaps he is in the wrong line of work, he should have been a comedian...

If only he would direct the tenacity he has towards learning the truth about the Vector 4000, rather than attempting to prove a lie that he believes (or friends of his insist is true) with mis-information that I highly doubt he understands himself...


The DB

 

[Shockwave]

It is obvious that a device that does not need an adapter Gamma-match is more efficient.
The gamma-match adapters must avoid if you can not add heat lost by irradiation of an alien parasite to the antenna element is only an adapter.
This device adds lost to an antenna.

"no see".

Let me see if I got this right NoSee. Without the cap in the gamma I find the CX to have more CMC, more difficult to tune, and slightly less gain on the horizon since it can't be made longer than 3/4 wave without the cap, BECAUSE IT'S MORE EFFICIENT? Thanks, as I'm sure I would have never seen this without your misguiding me to it. I'll also begin to refer to the gamma match using the new updated term "alien parasite". It's so funny I love it.

 

[nosepc]

Let me see if I got this right NoSee. Without the cap in the gamma I find the CX to have more CMC, more difficult to tune, and slightly less gain on the horizon since it can't be made longer than 3/4 wave without the cap, BECAUSE IT'S MORE EFFICIENT? Thanks, as I'm sure I would have never seen this without your misguiding me to it. I'll also begin to refer to the gamma match using the new updated term "alien parasite". It's so funny I love it.

Matching the impedances isn't particularly efficient: it actually gives a 6dB loss in a ideal circuit. In a REAL WORLD is much more.

CST whitepaper

https://www.google.com.ar/url?sa=t&...oK4y8UHWqP5NoFU7z5c47yw&bvm=bv.56988011,d.cWc

 

[Shockwave]

Matching the impedances isn't particularly efficient: it actually gives a 6dB loss in a ideal circuit. In a REAL WORLD is much more.

CST whitepaper

https://www.google.com.ar/url?sa=t&...oK4y8UHWqP5NoFU7z5c47yw&bvm=bv.56988011,d.cWc

It's also not particularly inefficient as proven by the lack of even a little RF heating that would melt the hot glue inside the heatshrink tubing I use the seal the gammas in continuous use at multiple kilowatts on VHF frequencies. According to your 6 db loss figure, I'd have about 2000 watts of heating in my gammas. I sure am happy you're as far off on this figure as everything else you claim.

Notice NoSee didn't even attempt to make any sense and argue a tinny fraction of power might be lost in the matching network. He reached the impossible level of ridiculousness by suggesting the vast majority of power would be wasted with only a tiny fraction actually being radiated after matching losses.