New thread to debate V-4000

[nosepc]

I have already !!

 

[The DB]

CB, in my first year at the University of Texas in 1957, I took an advanced 1/2 credit elective course on Maxwell's World in Science. I had a youthful notion for science in my life in those days. I took that course at no cost for taking some advanced student testing. After that course...I changed to the school of business in economics, management, and accounting right fast.

I did learn some things about Maxwell's life and contributions however. I was lucky to have a down to Earth professor that was very hands-on and well skilled in his lab work. He taught his own class, and he could write and draw images that looked like art on the blackboards of those days. He also talk with a straight tongue, and that gave me confidence.

After that class however, I never had any more ideas that I would ever have any interest in the field of electromagnetic physics, science, or math however.

I asked the question, simply to see if you were thinking of the Maxwell I studied at UT, or the other Maxwell of modern day times that wrote on transmission lines and such.

Maxwell's equations are named after James Clerk Maxwell, and were originally published by him in 1861 and 1862. From what I understand the equations as they exist today are not necessarily the original equations, but they do continue to bear his name.


The DB

 

[Marconi]

Donald, hopefully we don't have long to wait until W6BYU is able to get back with some report from his testing of your ideas in his testing the S4 design.

I can't excuse all the petty back and forth going on in disagreement here, getting personal and all, but hopefully all that will soon be over. I think I've been respectfully disagreeing with your ideas about Eznec, and how it handles the S4 design for a while now, and for sure long before Nosepc came on the scene.

I don't even know why you guy's pay that any mind...excepting maybe the idea is to shut down all decent to a popular idea.

 

[Marconi]

Maxwell's equations are named after James Clerk Maxwell, and were originally published by him in 1861 and 1862. From what I understand the equations as they exist today are not necessarily the original equations, but they do continue to bear his name.

The DB

DB, when you find one example that fits your claim here, then please post it up with a source for the difference or an error claimed as well...please.

I put no faith in the fruits of man words alone, without some justification.

 

[The DB]

DB, when you find one example that fits your claim here, then please post it up with a source for the difference or an error claimed as well...please.

I put no faith in the fruits of man words alone, without some justification.

Are you talking about what I said about NEC? If you are I addressed that in my post before that one saying "I may have to eat those words"...


The DB

 

[Marconi]

Are you talking about what I said about NEC? If you are I addressed that in my post before that one saying "I may have to eat those words"...


The DB

No DB, I'm talking about your remark:

From what I understand the equations as they exist today are not necessarily the original equations, but they do continue to bear his name.

 

[The DB]

Ahh ok... How about this...

In electromagnetism, one of the fundamental fields of physics, the introduction of Maxwell's equations (mainly in "A Dynamical Theory of the Electromagnetic Field") was one of the most important aggregation of empirical facts in the history of physics that took place in the nineteenth century, starting from basic experimental observations to the formulations of numerous mathematical equations, notably by Charles-Augustin de Coulomb, Hans Christian Ørsted, Carl Freidrich Gauss, Jean-Baptiste Biot, Félix Savart, André-Marie Ampère, and Michael Faraday. The apparently separate laws and phenomena of electricity and magnetism culminated by James Clerk Maxwell, who published an early form of the equations completing Ampère's circuital law by introducing the displacement current term, and showed these equations predict light to propagate as electromagnetic waves. They were rewritten in by Oliver Heaviside in the more modern and compact vector calculus formalism he independently developed. Increasingly more powerful mathematical descriptions of the electromagnetic field were developed into the twentieth century, enabling the equations to take simpler forms using more advanced mathematics.

Source: History of Maxwell's equations - Wikipedia, the free encyclopedia


The DB

 

[Shockwave]

DB, I'm impressed with the extent of you awareness. Can you post something, a reliable link maybe, that supports such ideas regarding the Nec engine being so antiquated?

Did you find something yet...I'm sitting here with nothing to do.

The Numerical Electromagnetics Code (NEC) is a popular antenna modeling software package for wire and surface antennas. It is credited to Gerald J. Burke and Andrew J. Poggio, and was originally written in FORTRAN in the 1970s. Numerical Electromagnetics Code - Wikipedia, the free encyclopedia

Don't eat any words yet DB. I've got the backs of those who stand up for accuracy when I can support the subject at hand based from first hand experience. Not opinion or hearsay. We have others here with full plates about to get served. From what my educators told me, NEC dates back long before the computer age to books, pen, paper and things like the slide rule.

 

[Marconi]

That's good DB. Thanks

 

[Shockwave]

Interesting highlights from the encyclopedia that show we are not alone in identifying limitations impacting accuracy using this software in these designs.

the implementation has many practical limits.

the algorithm has not proven robust or accurate when modeling solid structures

This is partly due to known limitations of the method of moments technique and partly due to inaccuracies that result from modeling 'solid' conducting structures with a mesh of wire elements

If you think this low end software still gets anywhere close to being accurate on this antenna, remember that those multiple upswept radials mimic a solid structure (that confines out of phase current) at RF frequencies in the field. If you think that's not the case remember that Sirio also calls the CX line of antennas a Coaxial J-Pole and that clearly has a solid bottom section. You must demand the software mimic what happens in the lab or field before you can argue it's right.

 

[Shockwave]

Donald, hopefully we don't have long to wait until W6BYU is able to get back with some report from his testing of your ideas in his testing the S4 design.

I can't excuse all the petty back and forth going on in disagreement here, getting personal and all, but hopefully all that will soon be over. I think I've been respectfully disagreeing with your ideas about Eznec, and how it handles the S4 design for a while now, and for sure long before Nosepc came on the scene.

It's odd that you would hold out hope that this persons results alone would prove CST, the 4 wire phase test, Cebik's analysis, engineers from broadcast stations and them filing it with the FCC under antenna ID number 86494 all so wrong. You sure don't sound like that guy who told me "I hope you're right". You sound like you'll take any words, right or wrong and use them to dispute everything else.

Keep in mind the guy you're waiting on has lots going on to invest the time truly needed to conduct an accurate field test and is why I offered to send him an antenna so he would not take the shortcuts building one and testing it like I pointed out to him. We are also coming up on a year since that thread began. Sometimes you need a "dog in the race" to invest the time, money and effort into getting the job done right.

Since you already recognize I'm going to say his results are inaccurate if they don't match the many other field tests, you might as well recognize why. I don't like the idea of feeding it like a J-Pole or isolating the base of the vertical from DC ground and the cone so he can feed it in a different location directly across the base. Bypassing the shunt fed gamma match in both cases and forcing the only method of tuning for a 50 ohm impedance to become juggling the critical element lengths around. That comes at the expense of gain on the horizon. Notice how using no capacitor in a gamma always makes the Vector design shorter in NEC than in real life? I'd like to see you try and get a .82 wave or 7/8 wave to match in the field without a gamma or with even less loss. I'm against using less than four radials forming the cone to confine the inside current and evenly distribute the outside one. I don't buy the idea that laying the antenna on its side parallel to the ground in a horizontal plane will increase testing accuracy. That's nothing like how we use the antenna and will introduce a different set of ground reflections at both ends of his test link. I don't like the fact he's going to measure field strength across his backyard when we have clearly said the advantage is not all related to more gain but partially related to focusing existing gain on the distant horizon. Should I go on? How many variables do you need before you can validate my doubt? This paragraph is getting long.

 

[Shockwave]

That FCC antenna ID number has some history too. I worked my butt off trying to get that golden egg recognized with no results from the FCC other than getting passed from one department to another before I gave up. The result I'm certain they were holding out on.

It took a flood of simultaneous CP permits being filed with the FCC from multiple station engineers at LPFM, Translators and temporary permits, two of which were from Clear Channel filing on different stations in different states to get the ball rolling. Engineers in Canada at the CBC were also doing the same thing at the same time with Industry Canada.

When I got an email one day informing me about 86494, I researched the FCC public CDBS database and to my surprise my antenna had earned 3 different ID numbers on their database that I had nothing to do with. That happened because when they filed the CP they all didn't use the same exact info.

Some filed the model as NE-34 rather than the correct NWE-34. Others included the change in model number that reflected the use of different connectors such as NWE-34N or NWE-34D for 7/16 DIN. Each received a different antenna ID number from the FCC.

 

[nosepc]

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.

 

[nosepc]

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)

 

[AudioShockwav]

These antennas ever demonstrated in the real world that can overcome a 5/8

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.

If my V4k antenna works better at 37' tip height than my 1/2 wave or 5/8 wave (which it does), then I attribute this to the antenna design, not height over objects or raised current maximum due to length. This is also a piece of your argument that is not being factored into the discussion you present.

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