Battle of the Ground plane #2

[Marconi]

Donald that was an after thought I had in looking to see if I made any mistakes. Do I have to get permission to edit now. How does showing my gratitude to 211, possibly effect you or even this thread?

This is not discussing the issues in this thread, but these discussion about the Sigma4 design always seem to come to the same demise, no agreement made, no considerations made, only personal feeling affected, and as long as that result remains, no answers to how the S4 design works, every thing is fine and dandy with the status qoe.

You know that I commented to Bob the other day, when he said "...nothing has changed in the debate since maybe even the beginning." I told him, yes something has changed...and I mentioned the image you posted for the CST pattern. At first I accepted the words back then, that this describe how the bottom radial basket worked and it was in-phase with the RF for the top 1/2 wave, and I think my Eznec also shows that to be true too. The only difference that I argue here is something that you Donald tell us that that RF from the bottom cone is significant, and I say there is current there and it is in-phase, but I draw a distinction...that the magnitude of the current that affects the far field looks to be minor, almost to the extent of being insignificant.

It is you guys that ignore what I have said...and all you have to do is to go back and find where I said different...copy the link address of that information, past to a comment here and you will prove your point with little effort.

I have am Eznec project finished that I think demonstrates this. I sent Bob and email of the recap for 4 models if I recall correctly, however I did not send all the details, because I was trying to concentrate on this subject with you...in hopes we could find some common ground.

I wanted to try again and make notations for Bob, to try once again to demonstrate to him how I saw the currents using Eznec. It is a complicated issue and I'm not sure I'm up to the challenge, nor that I'm even right, but I want to try.

You see Donald, I consider myself a humble man, and when I admit my limitations that just feeds you using that admission against me to try an prove without even considering the work...how I see Eznec currents working.

You didn't bother to answer my question at the end of my last post here, and that gives me assurance that you are not considering one word I say in defense of my argument either.

So Donald, I too feel ignored at times, but I have say that here only in response to your similar comment. I choose not to think you do it on purpose however and I hope you feel the same. When this happens among friends, it generally just happens due to the circumstance of life. I still hold out hope that we can still be friends that...just disagree somewhat.

We got along fine, I thought, yesterday when I was glad to try and follow your suggestions and model you idea for a real collinear Sigma4, albeit I have not gotten back to that project this day.

I don't think we were finished, because I still have questions. I want to try any ideas or changes you might want to explore doing that model too.

Here is the recap I sent to Bob on the 19th. This is so, that if and when I do the full report we can see if anything has changed in my work that I did before this ordeal of words started about the same time.

I am sorry for the ill feelings between us.

The following is a recap that demonstrates the math from the article in ARRL "The Open Sleeve Antenna" as applied to the Vector 4000 with different lengths. As noted I used radiator lengths for a .75 wave antenna using the 3:1 ratio, a model at .82, over the maximum length limit as noted in the article where the antenna starts to fail in performance and match, and one at .797 where I determined the maximum gain was possible.



Now Bob comments back that I misunderstood the meaning and intent for the formulas and math in this article and that could be true, but he will have to show me the error of my understanding by example and word if possible.

I'm sure Bob is well meaning in his accretion, and will be able to satisfy everyone's better understanding on the matter as noted above.

You guys remember, I'm from Missouri and I need to be shown proof <gotproof>.

 

[Marconi]

Being disappointed is not the issue. It's how one handles disappointment that matters.

I also fully remember all of our past correspondence and the very issue you spotted about the orientation of a given wire in EZNEC. That just reversing the start and end positions of the wire caused discrepancies with the currents even though the wire was the same exact length and in the same position.

Don't think I ignored you just because I didn't have the answer. You did the same thing I did with the phase problems regarding the Sigma. We informed Roy, he decided to ignore the issue because his EZNEC can't make mistakes.

Thanks for confirming this. I was confident you could support my recollections.

That is an important matter, but we see it makes no difference to results. When I get back to our work on yesterday regarding your stacked collinear Sigma4 with a top 1/2 wave radiator or the Sigma4 on top, I will show everybody how that to is important here as well...but I will emphasize that there is no difference in any details in performance and status for the model.

Donald, I've thought about that comment from Roy to both of us, but I have to assume he was correct, and that we both took his remarks incorrectly.

Personally I think very few users ever consider the currents log information, and in a math and computer process sense the fact that the ends of the wire allocations might make some difference to the image we see, probably is explained by the fact the image defaults to not in phase.

IMO, the only problem is our misunderstanding. I cannot state however that is affects you idea about the Sigma 4 in any way as per your theory on the matter. Just my opinion.

Donald, we are making progress I think. I hope we can continue.

 

[Shockwave]

Donald that was an after thought I had in looking to see if I made any mistakes. Do I have to get permission to edit now. How does showing my gratitude to 211, possibly effect you or even this thread?

This is not discussing the issues in this thread, but these discussion about the Sigma4 design always seem to come to the same demise, no agreement made, no considerations made, only personal feeling affected, and as long as that result remains, no answers to how the S4 design works, every thing is fine and dandy with the status qoe.

You know that I commented to Bob the other day, when he said "...nothing has changed in the debate since maybe even the beginning." I told him, yes something has changed...and I mentioned the image you posted for the CST pattern. At first I accepted the words back then, that this describe how the bottom radial basket worked and it was in-phase with the RF for the top 1/2 wave, and I think my Eznec also shows that to be true too. The only difference that I argue here is something that you Donald tell us that that RF from the bottom cone is significant, and I say there is current there and it is in-phase, but I draw a distinction...that the magnitude of the current that affects the far field looks to be minor, almost to the extent of being insignificant.

It is you guys that ignore what I have said...and all you have to do is to go back and find where I said different...copy the link address of that information, past to a comment here and you will prove your point with little effort.

I have am Eznec project finished that I think demonstrates this. I sent Bob and email of the recap for 4 models if I recall correctly, however I did not send all the details, because I was trying to concentrate on this subject with you...in hopes we could find some common ground.

I wanted to try again and make notations for Bob, to try once again to demonstrate to him how I saw the currents using Eznec. It is a complicated issue and I'm not sure I'm up to the challenge, nor that I'm even right, but I want to try.

You see Donald, I consider myself a humble man, and when I admit my limitations that just feeds you using that admission against me to try an prove without even considering the work...how I see Eznec currents working.

You didn't bother to answer my question at the end of my last post here, and that gives me assurance that you are not considering one word I say in defense of my argument either.

So Donald, I too feel ignored at times, but I have say that here only in response to your similar comment. I choose not to think you do it on purpose however and I hope you feel the same. When this happens among friends, it generally just happens due to the circumstance of life. I still hold out hope that we can still be friends that...just disagree somewhat.

We got along fine, I thought, yesterday when I was glad to try and follow your suggestions and model you idea for a real collinear Sigma4, albeit I have not gotten back to that project this day.

I don't think we were finished, because I still have questions. I want to try any ideas or changes you might want to explore doing that model too.

Here is the recap I sent to Bob on the 19th. This is so, that if and when I do the full report we can see if anything has changed in my work that I did before this ordeal of words started about the same time.

I am sorry for the ill feelings between us.

The following is a recap that demonstrates the math from the article in ARRL "The Open Sleeve Antenna" as applied to the Vector 4000 with different lengths. As noted I used radiator lengths for a .75 wave antenna using the 3:1 ratio, a model at .82, over the maximum length limit as noted in the article where the antenna starts to fail in performance and match, and one at .797 where I determined the maximum gain was possible.

View attachment 11219

Now Bob comments back that I misunderstood the meaning and intent for the formulas and math in this article and that could be true, but he will have to show me the error of my understanding by example and word if possible.

I'm sure Bob is well meaning in his accretion, and will be able to satisfy everyone's better understanding on the matter as noted above.

You guys remember, I'm from Missouri and I need to be shown proof <gotproof>.

I thought the tone of this debate had softened too until your "lecture of the day" post indicated otherwise. When you use EZNEC to try and discredit the .82 wavelength I've been promoting for years, I do ignore that for good reason.

I try to keep my business separate from my posting here but unfortunately it is mostly my experience in that field that unequivocally debunks the notion that the cones radiation is not significant.

After 15 years we now have over 1000 antennas of the Sigma design in use at broadcast stations worldwide. Every one of those antennas was sold with an unconditional guarantee it would provide more gain per bay than anything it replaced regardless of cost.

One customer out of all of them requested a refund and was given the refund even though the antenna was returned with a burnt up matching network. The vast majority of antennas it replaced were dipoles or CP bays with well established gain figures for comparison.

Now, do you really think there is something you're going to do in the modeling realm that would alter the performance characteristics noted at over 1000 real life commercial broadcast installations? Many of these station engineers have shared the impressive results with me.

Rather than putting so much useless effort into convincing me that green is red, put a little more effort into bringing your results inline with reality. Sorry if that sounds cocky but those are the reasons your conflicting opinions don't hold much water with me in these areas.

 

[Marconi]

I thought the tone of this debate had softened too until your "lecture of the day" post indicated otherwise. When you use EZNEC to try and discredit the .82 wavelength I've been promoting for years, I do ignore that for good reason.

I try to keep my business separate from my posting here but unfortunately it is mostly my experience in that field that unequivocally debunks the notion that the cones radiation is not significant.

After 15 years we now have over 1000 antennas of the Sigma design in use at broadcast stations worldwide. Every one of those antennas was sold with an unconditional guarantee it would provide more gain per bay than anything it replaced regardless of cost.

One customer out of all of them requested a refund and was given the refund even though the antenna was returned with a burnt up matching network. The vast majority of antennas it replaced were dipoles or CP bays with well established gain figures for comparison.

Now, do you really think there is something you're going to do in the modeling realm that would alter the performance characteristics noted at over 1000 real life commercial broadcast installations? Many of these station engineers have shared the impressive results with me.

Rather than putting so much useless effort into convincing me that green is red, put a little more effort into bringing your results inline with reality. Sorry if that sounds cocky but those are the reasons your conflicting opinions don't hold much water with me in these areas.

Well Donald, that was an another edit remark that was meant trying to be cute with a little slant toward humor for me. It was not meant to be serious, because I am more unassuming than that...I think.

Donald, your business is of concern to you with anything you do...I realize that. But, how can I avoid asking questions that might never trespass on that relationship you have?

I don't think about your antenna when I consider my thinking or questions I have regarding the Sigma 4, and you obviously can't discuss this subject without considering your antenna instead of the Sigma4, so how will we ever get past that unless I acquiesce to your claims in the discussion.

In the case of my testing the math project, I think that is plausible because Bob made it out as the requisite answer regarding the Sigma4. I say if the article doesn't prove the situation claimed then the article is either wrong, the interpretation is wrong, or the idea at test in a bad idea.

Bob, tells me that I read the article wrong, but I doubt he will try and back that up claiming the math is wrong, and he won't try and use words to better describe what he sees. Bob is good about posting a reference, and saying a little about it as possible in order to safeguard him being wrong.

I on the other had put my stuff out there for all to test, and wait for that to happen, I even sometimes ask for that to happen. You guys can try and prove my ideas wrong at any the time. That is why I post my stuff, and if I find I'm wrong...then I'm one that benefits...I've learned something different than what I previously thought true. How better can that get unless you don't want something to shine the light of truth on your own beliefs.

Donald, you and Bob might just be right on the money in your ideas on this subject, but you can't or won't prove anything either. Only difference here is I'm trying.

You tell me to bring my ideas into reality, but respectfully I think you mean something else...that I have to have faith only in what you say here...and I'm just not persuaded yet.

Does this mean we can't proceed with your ideas for the stacked Sigma4 with a 1/2 wave collinear model.

BTW, I don't consider that you were being cocky, to me it is just another way of stating your position on the matter. I have feelings too, but I would rather get to the truth of the matter, and how all this impacts how we think about Ezenc modeling if possible.

Here is a section on Currents in the Eznec Manual that I think has some important info in the highlighted area. I hope you will read and hopefully we can discuss what this all means sensibly. There is more to this complication that I say developed due to Roy trying to make Eznec more user friendly.

Maybe this occurrence we both see happen here is not the way Method of Moments handles things in it processing, but maybe there are options available. I have read that CST has Incorporated many features that allow it to work and use more of the scientific type features available with the MOM system.

 

[Shockwave]

My comments at this point are only going to be useful with regards to the EZNEC instructions since we obviously have had much different experiences with the basic Sigma design.

I see these instructions as acknowledging the fact currents can be inaccurate depending on how you define the ends of a given wire. I also see this as an attempt to assure one that this is nothing to be alarmed about as though it doesn't make a big difference.

Perhaps that is true but it does not take into account what is happening in the Sigma model. Here we have a situation where current phase is critically important to the electrical length of a phasing network and causes a difference in length that is 100% greater.

That strongly supports the possibility that the stock antenna modeled in EZNEC may not be interpreting the fact that the cone is a 1/4 wave radiator in itself and that it physically causes a 90 degree phase delay in the currents radiated on the vertical radiator.

 

[bob85]

eddie if you read the open sleeve article again you should be able to figure out what antenna mode and transmissionline mode currents are,

model a 1/4wave and a 1/2wave over ground, you see the 1/4wave has more current at the base than the 1/2wave due to the high end impedance of the 1/2wave, antenna mode impedance is high for the 1/2wave and low for the 1/4wave, a 3/4wave would have low antenna mode impedance and high antenna mode current,

when you bring the 1/4wave radials beside the monopole you create a second impedance seen in parallel with the antenna mode impedance, when the spacing gets close enough for the frequency and tube diameters significant current flows in transmissionline mode,
these currents flow the opposite direction to antenna mode currents, they are the only possible source of radiation i know of for the outside of the sleeve to be in phase with the upper 1/2wave,

before we judge the cst plot we need to know how it handles mutiple conductors,
model a single conductor vertical with say 1amp of current then a 4 wire cage vertical and compare current logs, does the program show 1amp in each cage wire or does it show 250ma for each wire?,
we already know it acts like a fatter single wire with regards to radiation but what would cst show.

 

[211inthamag]

The band opened up very nice today, the gain master did a fantastic job and got to talk to a lot of people on 400 I have not heard in a while!

 

[Shockwave]

before we judge the cst plot we need to know how it handles mutiple conductors,
model a single conductor vertical with say 1amp of current then a 4 wire cage vertical and compare current logs, does the program show 1amp in each cage wire or does it show 250ma for each wire?,
we already know it acts like a fatter single wire with regards to radiation but what would cst show.

These are good questions that I can't provide a definitive answer to. Just to be clear to those following who may not know, the CST plots were given to me by Sirio. I don't have the CST program and really can't justify its cost at thousands of dollars for my applications.

What I can say is there are many strong indicators that CST is interpreting the currents in the cone properly. The fact it reports gains around 2 dbd while EZNEC struggles to show much better than unity gain tells me it recognizes the cone as a 1/4 wave radiator.

There has to be some good reason Sirio splurged for this software. If I can spot problems with EZNEC modeling this design and Cebik said the same too, why wouldn't we suspect the engineers at Sirio discovered the same?

They also designed the entire CX line of VHF antennas with CST and have some very detailed info about them as a result. Having had the opportunity to speak with one of their engineers, I can tell you he impressed me and taught me much about this design in less than 15 minuets.

 

[Marconi]

eddie if you read the open sleeve article again you should be able to figure out what antenna mode and transmissionline mode currents are,

model a 1/4wave and a 1/2wave over ground, you see the 1/4wave has more current at the base than the 1/2wave due to the high end impedance of the 1/2wave, antenna mode impedance is high for the 1/2wave and low for the 1/4wave, a 3/4wave would have low antenna mode impedance and high antenna mode current,

when you bring the 1/4wave radials beside the monopole you create a second impedance seen in parallel with the antenna mode impedance, when the spacing gets close enough for the frequency and tube diameters significant current flows in transmissionline mode,
these currents flow the opposite direction to antenna mode currents, they are the only possible source of radiation i know of for the outside of the sleeve to be in phase with the upper 1/2wave,

before we judge the cst plot we need to know how it handles mutiple conductors,
model a single conductor vertical with say 1amp of current then a 4 wire cage vertical and compare current logs, does the program show 1amp in each cage wire or does it show 250ma for each wire?,
we already know it acts like a fatter single wire with regards to radiation but what would cst show.

I can show what my Eznec model does, but we can't compare that to what CST shows, because we have no access to that product except by the image.

I've described to you both that I see the same thing you both see in the CST pattern for the NV4, and when I further describe what else I see in detail, the part you guys fail to even descibe, then I think you both ignore what I say. I won't repeat what I see. I just did that in a previous post here.

If you want to really put this to the test, please descibe in approximate detail how you physically see these two antennas with approx dimensions. Lets assume that a 1/4 wave is 102" just for grins. I don't want to do this and then you tell me I got it all wrong, because it is not what you were describing. Is that fair?

Donald, if Bob is gone and you have a clear idea of the design he was suggesting, please help me out and I'll do the model right now.

Also note that I can't control the amps, perse. But I can control the watts, and that produces whatever the software determines for the amps. Is that fair enough?

 

[Marconi]

Donald, since Bob is gone, if you have a clear idea for what he briefly described, could you help me out and I'll to this right now?

 

[Shockwave]

I can show what my Eznec model does, but we can't compare that to what CST shows, because we have no access to that product except by the image.

I've described to you both that I see the same thing you both see in the CST pattern for the NV4, and when I further describe what else I see in detail, the part you guys fail to even descibe, then I think you both ignore what I say. I won't repeat what I see. I just did that in a previous post here.

If you want to really put this to the test, please descibe in approximate detail how you physically see these two antennas with approx dimensions. Lets assume that a 1/4 wave is 102" just for grins. I don't want to do this and then you tell me I got it all wrong, because it is not what you were describing. Is that fair?

Donald, if Bob is gone and you have a clear idea of the design he was suggesting, please help me out and I'll do the model right now.

I think what Bob is trying to demonstrate is how the characteristic feedpoint impedance of a given end fed vertical effects the currents within its radial system. That antennas with a low characteristic impedance like a 1/4 or 3/4 wave would have stronger currents here than a 1/2 wave. That when you fold the radials upwards a second current will flow in the opposite direction.

You'll probably want to confirm with him exactly the points he is trying to make but in any event, I can help you with the models he suggests. You're 1/4 wave should be closer to a 108 inch vertical radiator with 4 radials of the same length on a 45 degree angle.

For the 1/2 wave model, extend the vertical to 18 feet, Take the same radials you used on the 1/4 wave and position them at 90 degrees out from the feedpoint. I don't think being 100% accurate with your element lengths here is going to make a big difference. As long as the models are close to resonance they should display the points he's trying to make.

Also note that I can't control the amps, perse. But I can control the watts, and that produces whatever the software determines for the amps. Is that fair enough?

Agreed, changing the watt level will change the current level.

 

[Marconi]

I think what Bob is trying to demonstrate is how the characteristic feedpoint impedance of a given end fed vertical effects the currents within its radial system. That antennas with a low characteristic impedance like a 1/4 or 3/4 wave would have stronger currents here than a 1/2 wave. That when you fold the radials upwards a second current will flow in the opposite direction.

You'll probably want to confirm with him exactly the points he is trying to make but in any event, I can help you with the models he suggests. You're 1/4 wave should be closer to a 108 inch vertical radiator with 4 radials of the same length on a 45 degree angle.

For the 1/2 wave model, extend the vertical to 18 feet, Take the same radials you used on the 1/4 wave and position them at 90 degrees out from the feedpoint.

Agreed, changing the watt level will change the current level.

Well, Donald if you are right, I missed that one by a mile.

You know now why I asked him the questions. I just hope Bob doesn't read stuff like he gives his instructional ideas.

Here is what I did trying to follow is instructions to the "T".

View attachment Bob's .25w ideas I think..pdf

 

[Marconi]

The band opened up very nice today, the gain master did a fantastic job and got to talk to a lot of people on 400 I have not heard in a while!

Here is my good report about my Gain Master today 211, we had terrible thunder storms rolling thru about every 45 minutes most of the day yesterday. I got over 5" of rain here at my place. I don't have an indicator for the wind any more, the wind blew it off, but I figure at times we had maybe 50 mph and more. It was scary, but my GM just spit in the face of the wind.

I check the match and it still looks a bit higher that it did in the beginning, but it looked the same as before the storm.

BTW, I didn't measure the storm according to the best scientific measurements available, so you guys hold off getin' on my case for that OK?

 

[Shockwave]

Well, Donald if you are right, I missed that one by a mile.

You know now why I asked him the questions. I just hope Bob doesn't read stuff like he gives his instructional ideas.

Here is what I did trying to follow is instructions to the "T".

View attachment 11224

As I read Bob's post, he speaks about two different modeling scenarios. I think the one you responded to was the one he wanted to see in the CST program, not EZNEC. The second set of models are what I discussed and what I think he wanted you to see.

 

[bob85]

what im wondering is are the currents in the lower 1/4wave shown at 1/4 their effective current with the 4 radial vector, or is the cst plot showing total field strength of the combined radiation from the 4 radials,

that would make a significant difference to how impressive radiation from the lower 1/4wave looks compared to the upper 1/2wave on the cst animation.