Base Open Sleeve EFD

[Marconi]

I posted models supporting my opinions and ideas about this stuff above, and I don't think either of you could have possibly considered all that out yet. It is just my ideas at work.

Have you considered that I was alone in my efforts for years trying to convince the "No J-Pole Group" that was in private conversation back at the time Henry did his work?

There was at least some merit in my words and ideas at the time. Bob confirmed that to me when he contacted me several days before Bob posted the link to Henry's report.

I have learned a thing or two since then too.

I'm just trying to express my opinions about the J-Pole of late, and of course, things get all connected again.

Steve, I'm not sure I knew that you were part of that group at the time, but I probably wasn't surprised either. I remember, at some point, hearing about the group considering modeling additional attached or not attached wires to the radial cone...to see if there might be common mode currents flowing. I simply mention that the Eznec manual suggests to users that want to add a feed line to their model, they must add a wire. I think this idea might be one of the things that lead you and me to ever get crosswise, seeing as you were likely the one doing that modeling.

I don't like holding grudges except in rare cases. To me, that situation was not the case...because I did try and explain any misunderstanding my words inferred. That said, however, I'd be a fool to forget.

I have a sense you two guys just don't like it...and that is not a problem. I can understand.

I admit that Henry's report was far more comprehensive than my little presentation here. I only considered the basic question about the J-Pole vs the Sigma4 design as that was in question by Homer, and I was trying to give him my opinion just like he gave us his opinion. I posted the document Henry published in his report...as a conclusion noted under his Real Live Testing heading.

Now, if we can, could we get back to the discussion? I will address your concerns above as I have time.

Homer, you mentioned you have a two-meter J-Pole...can you detect the skewing we've talked about here?

I welcome specific question, but if it concerns a particular model that I posted...please give me a link...so I can respond accordingly. These models are numerous and of late I've tried to code the titles so I can at least have a little information to know what the model might look like...in my index list of titles.

There are two selections on my computer for that cut/paste linking feature to a particular post. I use the bottom selection. Just select the whole address in the box and type CTRL/C to copy...in case you didn't know.

If that is not convenient, then when you see a model I did that you have a question on...give me the correct and complete title. please.

Again, I have not had time to digest the post for either of you, but I'm not here to fight either. Again, I'm here hoping to exchange ideas whether I agree or not.

 

[Marconi]

I'de like to discuss two things about this discussion, starting with Henry's report. It may be just me, but when people refer to said report, I get the impression that they limit themselves to the parts of it that support the claims they once made (and still make), but not taking the report as a whole.

I can't argue the whole report, Steve. I don't think anybody could. I don't know how much time it took Henry to get to the end and publish. I was not a part of any of it until maybe two weeks prior to Bob posting the link. Henry told me some things, and I think he was tempted to stop. I'm not sure, but I think Bob told me the same thing a few days prior to publishing. Even though we disagree on some things, I encouraged him to continue and finsish.

The one thing that said report removed from the discussion was the collinear idea.

How would I know Steve, I was not a part of the group hashing out the truth. I'm not sure, but I don't think this was part of the report, but here you are referencing a situation that probably helped convince Bob of something new as part of the group. On that issue, all I recall is what I think Bob told me. That said, I never went along with Donald's two or three wire test. I couldn't tell you why he was wrong, but I modeled the idea with no more success. I had no more success than the idea of adding wires to the radail-cone...trying to check if there were RF currents on the outside of the radials and if they were common mode currents.

How would I know, otherwise, that Bob fleshed out the truth on that matter?

That was it.

What about the issue, that was in the report, concerning the reported untruth that Eznec was junk science and could not model the Sigma4 or would be very difficult to impossible, because of a non-apparent colinear effect.

It supported both Marconi's far field plots that never once showed 2 dBd gain figures, as well as Shockeave's real life measurements that showed 2 dBd gain over a dipole, and even suggested more was possible.

You're right, my models never did report dBd gain on any model.

In addition, I can easily go back to when the report was released, their was more than one topic I discussed with Henry that no one payed any mind to, like said discussions were irrelevant.

I've tried to read everything you post Steve. I respect your ability to model even though you repeatedly tell us you and I do things differently. As far as I know, you are the only one I can talk to at present regarding modeling process. It doesn't make sense for me to piss you off, just because I might not agree.

Seriously go back and read the thread and see for yourself.

Yep, you can bet I'm going straight away to the "Search" feature and read the 1000's of words you've made.

I find it sad that so much in that report is worthy of discussion, some pretty advanced stuff, and it seems to be ignored.

I think it might be a good idea, but I would feel more comfortable if Henry was around to defend his report.

That said, why don't you pick a topic from the report and we will see where the discussion goes.

Even when I brought part of it up, I got a like from Henry, but no one really said anything.

Give me the link and I will go there and give you a like if it will make you feel better. Here is a heads-up...please don't pick that topic Henry showed you on 6-Real and Ideal, page 33-34. I asked questions to and I recall a suggestion I read the latest ARRL Antenna Hanbook for a start.

 

[bob85]

DB
i don't think all the different length versions act just like a stock j-pole,
when you increase the length the unbalance at the top of the radials increases so cmc on the radials must increase imho,

you have currents in the gamma section not included in nec if you omit the gamma & stick a source somewhere near to the gamma strap, its not gamma fed,

there is no shorted transmission-line, no transmission-line currents, no gamma loss, no capacitor cancelling the inductance of the gamma rod,

it may be why we are not seeing any difference in loss between direct & gamma feed,

i could be wrong but i don't think it is so easy modeling the gamma as found on the vector, its not parallel to the radiator & uses dissimilar tube size.

 

[The DB]

Have you considered that I was alone in my efforts for years trying to convince the "No J-Pole Group" that was in private conversation back at the time Henry did his work?

I'm not looking to relive the past. All I'll say is if its the group I was thinking of, their are reasons you weren't in that group, and those reasons were brought to the forefront when the existence of the model that was being worked on came out (before I was ready to bring it out I might add). This is all water under the bridge to me, I have moved past that.

I have learned a thing or two since then too.

I have no doubt about this, I have seen it. I have learned a lot as well. I just think referring to certain events in the past is stifling conversation over a very interesting antenna, although I don't think it is intentional.

Steve, I'm not sure I knew that you were part of that group at the time, but I probably wasn't surprised either. I remember, at some point, hearing about the group considering modeling additional attached or not attached wires to the radial cone...to see if there might be common mode currents flowing. I simply mention that the Eznec manual suggests to users that want to add a feed line to their model, they must add a wire. I think this idea might be one of the things that lead you and me to ever get crosswise, seeing as you were likely the one doing that modeling.

I was an original member of that private group. I am the one who did all the modeling. The concept, at least as far as I was concerned, was to see what would happen if we made a model that would explicitly duplicate what Bob and Shockwave were saying was happening at the time. The model did exactly what we would have expected, and showed that if the ideas being presented at the time were accurate what was being said was true. That was the most interesting model I've ever made, and this goes beyond the Vector discussion. Their were a bunch of oddities with that antenna model that due to circumstances were never discussed, because of this I learned from them on my own.

I don't like holding grudges except in rare cases. To me, that situation was not the case...because I did try and explain any misunderstanding my words inferred. That said, however, I'd be a fool to forget.

I'm not asking you to forget, however every time its brought up their seems to be a disruption in the conversation on some level, or perhaps that is just my perception?

What about the issue, that was in the report, concerning the reported untruth that Eznec was junk science and could not model the Sigma4 or would be very difficult to impossible, because of a non-apparent colinear effect.

OK, so I might have missed something. While I have read the report several times, it has been a while since I last read it. As this wasn't talking about the technical aspects of the antenna I likely just glossed over it. If you haven't figured this part of me out yet, I am interested in the technical aspects of antennas, where I limit myself unless an accusation was made against me personally. IMHO this aspect was more a he said/she said anyway. I really didn't care about this aspect of the discussion and saw it as little more than fluff, as I said I'm more interested in the intricacies of the antenna itself.

I've tried to read everything you post Steve. I respect your ability to model even though you repeatedly tell us you and I do things differently. As far as I know, you are the only one I can talk to at present regarding modeling process. It doesn't make sense for me to piss you off, just because I might not agree.

Based on the models we make, we do model very differently. Their are several reasons as to why that might be, not the least of which is the different software being used. I don't see this as a bad thing as our models consistently show similar results. I have said this on the forum before, that two people with at least a certain amount of knowledge will consistently get to very similar conclusions even if using two completely different "paths" to get to said conclusions. That isn't my thought, I read it somewhere and forget the name of the guy that came up with it. This happens with our models, and I see this as a good thing. It tells me we are both doing something right.

I also think we look at the models we make differently. I'm a bit touchy with you because you have a history of discounting (and even trying to discredit) some little things I have noticed from various models. Saying you disagree with something is fine, saying why you disagree with it is better. The problem is, many times in the past I got the distinct impression that you clearly didn't understand what it was I was trying to say yet saying it was wrong anyway.

i don't think all the different length versions act just like a stock j-pole,
when you increase the length the unbalance at the top of the radials increases so cmc on the radials must increase imho,

I agree with this assessment. For significant cancellation to occur the currents on the basket and the part of the vertical inside the basket the currents need to be close to equal and opposite. Change the vertical from an electrical 1/2 wavelength longer than the electrical length of the basket and that changes, and this change can be drastic. I'm not saying that no cancellation is happening, but the further away from 180 degrees out of phase these currents are the less cancellation will happen. The radials in the basket area being angled away from the central vertical will also cause less cancellation, although admittedly this difference is small.

you have currents in the gamma section not included in nec if you omit the gamma & stick a source somewhere near to the gamma strap, its not gamma fed,

there is no shorted transmission-line, no transmission-line currents, no gamma loss, no capacitor canceling the inductance of the gamma rod,

it may be why we are not seeing any difference in loss between direct & gamma feed,

i could be wrong but i don't think it is so easy modeling the gamma as found on the vector, its not parallel to the radiator & uses dissimilar tube size.

With 4nec2 I can put an actual gamma in, capacitance and everything. I can measure a difference in loss, at least to some degree. With the recent discussion between you and Marconi on the gamma, I modeled three different antenna designs with and without gammas and was going to post the results, however with my new ISP, they won't let me host pictures on my home network and share them out, so I am at the point of having to create a video, which takes more time that I have been so short on lately. In one of the three cases antenna efficiency actually went up which surprised me, although at the cost of the gains being in a non-beneficial direction...

I agree, there is more to adding a gamma than moving the feed point, although I don't see a problem with using that if you don't have the ability to actually build the gamma into the model itself, as long as you realize its limits. Also a note, I didn't use the Vector as any of the antennas I modeled with a gamma. I have modeled a Vector with a gamma in the past, although that was before I lost all of my models with a hard drive crash. I'm sure I'll do it again at some point.

Hey Homer, the version of the Vector you built that you once gave me the dimensions on, would you mind posting those dimensions again for me? I think it was the one you had the most success with.


The DB

 

[Marconi]

I hear you.
Yet, what I was referring to is your models with the three antennas overlayed. In each case it is your models, not my real world experience, to which I was commenting.

Can you give me a clue to what overlay you are considering here?

Some things I've learned over time.
Antenna aperture matters, but tip height really matters.
In your models all three are of equal aperture, and at the same tip height.

Homer I've read similar claims and common sense tells me aperture has an effect. I have lots of models that test the ideas for various tip heights. Do you have a question about a particular model I posted on the subject?

My clear colored glasses see better over all patterns and slightly more gain from the Nv4k than the other two.

You have told us before, but can you share any details relative to a model I posted or some comments I've made in this regard? Hang onto those glasses.

I do have a j pole on my 2m radio.
Seems to work well. I need to get it up higher to see how it compares to the homebrew 5/8 GP I was running. It did very well.

I would be interested in any information on such a comparison. I think I've asked you already...if you can detect any skewing on your 2-meter J-Pole by sound or signal.

 

[Marconi]

Personally, I was ready to let things cool off, too. However, the cooling off came a little late to save some well informed folks from abandoning a very good topic. Friendships and trusts seemed to have gone from warm, to cool, to cold...

Homer, over time I can't tell you for sure that I have never discussed the period since Henry published his report. After that and early-on, there were questions asked and few answers forthcoming...just like Steve recently noted here in this thread.

Folks, come and go on these forums all the time Homer. Among others, I regret seeing the guys that produce modeling they've done...they just seem to disappear. I don't think our talking about the report had anything to do with folks leaving. Other than maybe Donald and Henry...they may be an exception.

I never changed my point of view. I said all along that my experience with the Nv4k gave me better results than other monopole antennas. I said I did not believe it was "just a j pole" meaning it was only a baseline 1/2^ with a really large matching section. To that end perhaps Eddie's sense of the j pole's "sleeper" status needs exploration, however, that the j pole is just an unremarkable okay antenna is how it is generally presented to be as if the S4/V4k are nothing special because they are 'just jpoles".

Well, Homer, you raise a good point here. I have lamented numerous times that it is a shame that more folks don't come on the forum and tell us about their experiences with their S4/NV4.

Below is a model of the J-Pole that has a mast directly connected to the antenna. The pattern is an ugly site. I also posted another model of an NV4k mode with a similar setup. See if this is close to a pattern you could predict.

If Marconi wishes to call it a j pole, then when his own models show it is better than either the j pole or the skeleton sleeved monopole decide to explore whether the j pole is under appreciated, I'm okay with that, too. If it's, back under examination from any angle I enjoy the conversation.

Saying it performs as it does only because it is sticking up higher in the air does not explain what is going on in Marconi's models.

There are potential reasons for why one antenna can do noticeably better for one person than another - topography, soil conductivity, interaction with structures, feed line losses, etc.

BUT, none of those exist in the models of the three antennas compared by Marconi.
To bring them up now whether directly or by inference is only a subterfuge and distraction.

Homer, that is pretty strong, but maybe I said something that upset up. I hope it is not just my opinion.

I would be interested in more knowledgeable people than me discussing other aspects of Henry's thesis. Git ur dun.

I would like to see this discussed too. Maybe over on eHam would get some action...similar to Booty Monsters showing them his homemade Vector.

Maybe the idea for why these models respond to a mast directly connected to the antenna appears so different in the patter images. I have an idea, but maybe you have questions or comments.

 

[Marconi]

I'm not looking to relive the past. All I'll say is if its the group I was thinking of, their are reasons you weren't in that group, and those reasons were brought to the forefront when the existence of the model that was being worked on came out (before I was ready to bring it out I might add).

I was told you were in the group because you could model with 4Nec2.

That's it!

I also recall, you telling me, yourself, that there was lot's of tension going on in that group...and that you consider stepping aside, just like I also heard Henry did. I suspect Henry's frustration was mostly with Donald. And later with me...after he contacted me several weeks before publishing his report.

I can tell you a very simple reason I was not a part of that group...what better reason...you guys were of one opinion and I was of another.

I also heard the group had quite enough disagreements without me in there too. Does that make sense to a clever guy like you?

This is all water under the bridge to me, I have moved past that.

That maybe Steve, but you left lots of insinuations as you passed on by, figuratively speaking of course.

 

[Marconi]

I have no doubt about this, I have seen it. I have learned a lot as well. I just think referring to certain events in the past is stifling conversation over a very interesting antenna, although I don't think it is intentional.

I thank you for that Steve.

 

[Marconi]

I was an original member of that private group. I am the one who did all the modeling. The concept, at least as far as I was concerned, was to see what would happen if we made a model that would explicitly duplicate what Bob and Shockwave were saying was happening at the time.

That is a coincidences Steve. Those words are very similar to words I said to Bob many years ago...when I asked him to join me in another attempt at learning to model...so maybe we together might be able to prove what Bob had been telling us about his Vector Hybrid using modeling as evidence. At this point it would seem that was all just Pie in the Sky on my part.

The model did exactly what we would have expected, and showed that if the ideas being presented at the time were accurate what was being said was true.

This the first time I realized there was such a model.

Was the model included in Henry's report?

Can I see the details for this model?

That was the most interesting model I've ever made, and this goes beyond the Vector discussion. Their were a bunch of oddities with that antenna model that due to circumstances were never discussed, because of this I learned from them on my own.

Steve, this sounds pretty important. Would it be fair for me to ask you to discuss this new information that was reveled to you?

 

[Marconi]

The model did exactly what we would have expected, and showed that if the ideas being presented at the time were accurate what was being said was true. That was the most interesting model I've ever made, and this goes beyond the Vector discussion. Their were a bunch of oddities with that antenna model that due to circumstances were never discussed, because of this I learned from them on my own.

Steve, I've address another idea in this post already, but I would like some more details if possible.

What were your expectations going in and specifically what did this model reveal in the end?

What was being said and what was then said to be true?

I can't recall the most interesting model I ever did,

Can you give me a clue what the idea or revelation was that went beyond the Vector discussion?

What were the oddities and why do you say it was never discussed?

What specifically did you learn on you own?

This is a lot of questions, but I'm trying to get back on track with a discussion of the topic at hand. No rush, I know you're busy.

 

[Marconi]

Based on the models we make, we do model very differently. Their are several reasons as to why that might be, not the least of which is the different software being used. I don't see this as a bad thing as our models consistently show similar results.

Steve, I say who cares which software we use to model the information we post.

 

[The DB]

I was told you were in the group because you could model with 4Nec2.

That's it!

I also recall, you telling me, yourself, that there was lot's of tension going on in that group...and that you consider stepping aside, just like I also heard Henry did. I suspect Henry's frustration was mostly with Donald. And later with me...after he contacted me several weeks before publishing his report.

The group started when Bob came to me in a private conversation. The others were added later, and Henry was added last of all. The tensions were not from when I was working on that model, but after that when Henry was working on his document. I'm pretty sure I didn't mention that tension to anyone as it id unrelated to antennas, which is the limit of where my interests are.

That model was a pain in my backside to work on, if only I knew when some of the things I know now I would have made it very differently... Anyway...

I can tell you a very simple reason I was not a part of that group...what better reason...you guys were of one opinion and I was of another.

I also heard the group had quite enough disagreements without me in there too. Does that make sense to a clever guy like you?

First off, don't put me as a definite on the opinion that Bob and Donald were presenting. I was just a guy trying to figure out the antenna, and trying to find some explanation to the reports people were making with it. It would be fair to say I favored their idea, but to say I was fully on board with it would not be true. That is why I built the model, so I could experiment with it and test the validity of their claims.

That maybe Steve, but you left lots of insinuations as you passed on by, figuratively speaking of course.

I left insinuations? Perhaps I did even if unintended, but if that is the case, please don't act like that was a one way thing. I can say this, I was genuinely frustrated with you.

This the first time I realized there was such a model.

Was the model included in Henry's report?

Can I see this model?

This is the first time you realized their was such a model? You fought against it so hard back then, even making claims such as I modeled the antenna over a perfect ground and such. I posted the dimensions, and you made some changes, which broke the model, which you then tried to use against the model.

What were your expectations going in and specifically what did this model reveal in the end?

I had none, I didn't know what to expect. It was an experiment. It was the model that, before conversion to aluminum, showed more than 2 dB gain over a dipole mounted at the same tip height, and after converting it to aluminum it still had 1.8 dB gain over said dipole.

What was being said and what was then said to be true?

It was a while ago, and I would have to go back and find the thread.

What were the oddities and why do you say it was never discussed?

What specifically did you learn on you own?

I'm not going into all of them, I would have to remake the antenna model again to get most of them. One of the oddities I mentioned above, the antenna, when tuned to perform at its best, matched the dimensions of the Vector almost perfectly, and this is down to the length of the mounting tube under the radial cone. Another was that it was the first of the antenna models that had a significant amount of what 4nec2 called "Current imaginary", which can me measured separately from "Current real". Yes, this is referring to real and imaginary in exactly the same way as a complex impedance's R and X are real and imaginary portions of the feed point match. Because of this, if I looked at "Current magnitude" on that antenna model, their were large areas where the current didn't appear to change much where I would have expected it to. I have found very little information in regards to these aspects of current on-line, or in any of my other resources. If anyone happens to know anything about these, especially "Current imaginary" you have my undivided attention. It was also a very sensitive model, changing a part of it by no more than an inch would sometimes throw its output way off.

Steve, I say who cares which software we use to model the information we post.

That was just an example of where some of the differences come from. You've seen my video where I show how I model, and the heavy use of variables, as well as my use of auto-segmentation. The software is only part of this difference between our "styles" if you will. Our approaches are completely different, and part of that I think is represented with what and how our different software programs allows us to operate. I don't see it as a bad thing, just different. When we make models that have similar results, those differences actually becomes a sort of strength.


The DB

 

[Marconi]

I also think we look at the models we make differently. I'm a bit touchy with you because you have a history of discounting (and even trying to discredit) some little things I have noticed from various models.

This is not unusual to me. You comment the same thing over and over again...like it is a badge of honor. I think it is basically human nature. Are you still talking about my arguing with the group on the situation where you guys were trying to add wires to the S4 radial cone, etc............?

Saying you disagree with something is fine, saying why you disagree with it is better.

Say what? IMO, this is like you and Henry complaining about my using the word "Trick." Also reminds me of Bill Clintion's declaration, say..."...it depends on what is...is."

The problem is, many times in the past I got the distinct impression that you clearly didn't understand what it was I was trying to say yet saying it was wrong anyway.

I don't remember that specifically but I probably was simply disagreeing with something and I've been known to be wrong and I'll probably be wrong again down the road.

Maybe I should ask you "May I" before I post my ideas.

 

[The DB]

This is not unusual to me. You comment the same thing over and over again...like it is a badge of honor. I think it is basically human nature. Are you still talking about my arguing with the group on the situation where you guys were trying to add wires to the S4 radial cone, etc............?

Say what? IMO, this is like you and Henry complaining about my using the word "Trick." Also reminds me of Bill Clintion's declaration, say..."...it depends on what is...is."

I don't remember that specifically but I probably was simply disagreeing with something and I've been known to be wrong and I'll probably be wrong again down the road.

Maybe I should ask you "May I" before I post my ideas.

So you are still playing these games...

I rescinded what you mistook for criticism of the use of the word "trick". I also admitted that I have used said word myself, and explained why I used it and why I didn't like that use of that word. Or have you forgotten? Do we really want to play the gotcha game?

Its not your ideas I have a problem with, and its not even you disagreeing with me. Its when you say I am wrong, flat out, (rather than simply disagreeing) and then demonstrate that you don't even grasp what it is I am trying to say or show that I get frustrated. This is often why you may find me repeating myself, I am trying to get you to see something that you are missing. The only person I recall repeating myself with is you (and maybe one or two others at most), and for this reason.

But I digress, we are way off topic, and way off of what I intended this to be. I am tired of this diversion, and the attempt at turning it into a gotcha game. You are very good at diversions like this, and the amazing thing is, I am not even sure you realize you are doing it... However if you want to drag me back to the past with this childish gotcha game you seem to be turning this in to, you can go play by yourself.

Back to antennas.


The DB

 

[bob85]

Eddie,
the idea of adding a parallel wires to the radials came from me reading about having to add a wire to coax if you want it to radiate in the model like the real world,

at the time seemed to me that if the cone is just a flared extension of the feed-line it would also need the extra wires,

apparently that is not the case,
j-poles & skeleton sleeve antennas don't need extra wires for the radiation to show up in the pattern so why would the vector,

Homer,
Don't under estimate the importance of height of current maxima, especially when a few extra feet means it sees over obstructions the shorter antennas can't,