I-10K/Sockwave model first run

[Marconi]

A thought I had and something I just noticed.

I noticed that in my models above the pattern is being shown along the X axis. If I show the pattern along the Y axis for both of them, their is no skewing. This is with both with your model and mine. I could be wrong, but do you know if EZNEC defaults to showing gain along the Y axis? I think 4NEC2 shows the direction with the most gain by default. I do know some models it doesn't default to the X axis...

DB, I forgot to address these issues...I hope this does not create confusion between us. I agree you started talking about another model design of the I-10K, and I was aware there was an angle difference between the trombone design on Jay's antenna and the Shockwave model. Without any discussion on this issue...I just figured they worked similar, but that may be the difference you see with the skewing you get.

That said however, IMO the actual performance results should still be about the same. I did not consider the Shockwave pattern might be skewed a bit.

BTW, Jay's antenna does come with radials asymmetrically mounted on his antenna, but my model is symmetrical just like your Shockwave model is symmetrical. And the Shockwave radials come symmetrically mounted, but the trombone matcher is set at an angle.

I hope we do not get into the weeds over this seemingly insignificant difference.

Something else I noticed between our models. Your trombone section is in line with one set of radials, while mine is not. Looking at pictures of the antennas online, I think the I-10K design is more like your model layout, while the Shockwave appears to be more like mine.

I agree, but IMO both of our models are still made with the radials symmetrically mounted in the our model. The trombone matchers are just a installed a little different in the angel. Am I talking in a circle?

Also, the Shockwave antenna has its radials directly in line with the mast, they are not offset any, again more like my model than yours.

I wonder if these two differences are part of the difference in our models...

IMO NO, the skewing you see in your Shockwave model is not the difference you just brought up about our models being different. Your are right, however, there is a design difference, but little performance difference.

I have questioned how Eznec defaults the power lobe on a beam model...but I'm not sure I know the answer. With a Omni direction antenna I understand how skewing can have some effect in this regard, but I don't no how NEC handles that either. I'm just sure that the NEC engine does do something to the pattern however, but the performance results always look to be the same.

Does this make sense...or am I talking in circles again.

DB, at this very moment my eyes are giving me problems, maybe my blood sugar is high, and I don't feel like proof reading these words, but I tried, OK?

 

[The DB]

DB, fix the 5 errors noted and hopefully the model will work right.

To be fair they weren't all errors, some were warnings. I did fix them, but I had to modify the model to do it. It did fix AGT, that came into line, the gain and pattern didn't change much though.

Playing with the model I was able to get SWR down from 1.8 and 1.9 range to the 1.5 to 1.6 range while maintaining resonance, but pushing further only introduces more warnings. This didn't have any significant effect on gain.

Playing with your model, the differences in our modeling techniques are clear. The how of what you do and what I do are very different, yet often we get very similar results...

I think part of those differences arise from the modeling software we use, and part from different concepts of how things work. I'm also sure that EZNEC if more forgiving than 4NEC2 on some things, hence I had to modify the model you posted the dimensions to to make it work without warnings or errors...


The DB

 

[The DB]

DB, I forgot to address these issues...I hope this does not create confusion between us. I agree you started talking about another model design of the I-10K, and I was aware there was an angle difference between the trombone design on Jay's antenna and the Shockwave model. Without any discussion on this issue...I just figured they worked similar, but that may be the difference you see with the skewing you get.

That said however, IMO the actual performance results should still be about the same. I did not consider the Shockwave pattern might be skewed a bit.

I would agree with this.

BTW, Jay's antenna does come with radials asymmetrically mounted on his antenna, but my model is symmetrical just like your Shockwave model is symmetrical. And the Shockwave radials come symmetrically mounted, but the trombone matcher is set at an angle.

Looking at your model, I see this.

I have questioned how Eznec defaults the power lobe on a beam model...but I'm not sure I know the answer. With a Omni direction antenna I understand how skewing can have some effect in this regard, but I don't no how NEC handles that either. I'm just sure that the NEC engine does do something to the pattern however, but the performance results always look to be the same.

I don't think this is a function of the NEC2 engine, all that does is provide the results. How those results are displayed are more of a function of the software that is showing them. 4NEC2 always shows the direction of maximum gain, but I can see other directions as well, even a 3d image the the pattern if I desire. I asked that question because I know that there is a direction where there was no skew, and I didn't know how EZNEC chooses which data to show by default. It may just be showing you a non-skewed pattern by default, but there is definitely some skewing with our designs, both of them.

When it comes to the I-10K and the Shoclwave designs, yes they will be similar. Honestly, the biggest difference in our models is how we incorporate the feed point. We clearly have very different ideas about how it is supposed to work. I think if I incorporated the feed point into your model as I did with mine it would be much more tune-able.


The DB

 

[Marconi]

When it comes to the I-10K and the Shoclwave designs, yes they will be similar.

Well DB, I can't argue with your conclusions here, it just seems to make sense that Jay's I-10K and the Shockwave are similar, but still different in design only.

. Honestly, the biggest difference in our models is how we incorporate the feed point.

We have discussed this already, but I don't understand your application and I don't know how I could apply my source differently, but you could be right. I would feel better about my model if it produced results that are closer in the match to what I see with my real antenna.

We clearly have very different ideas about how it is supposed to work.

IMO, it makes little difference my using Eznec and you using 4NEC2. The software should show us all that...results can be very still similar. So I'm not so sure, as you that we would see differences in results. I will give you credit for the fact that you understand how this software works.

I think if I incorporated the feed point into your model as I did with mine it would be much more tune-able.

If you figure out how I could do what you did with your source...then let me know, and I will attempt to fix my model accordingly. I would love to have my model show the nice match that you get. I would also like to see a better bandwidth than my model currently shows.

I'm open to discussing how Eznec applies the feature that inserts the source on my end, but I'm not pressing for that to happen, so don't get upset with me over this issue.

IMPO, I would expect our source to be located at the same point in our models, the AG results be close to the same, and of course the performance results be close to the same, but I don't know the science or math.

Thanks for your discussion on the subject.

 

[The DB]

Can we get a plot for the Sirio vector 4000 The DB? Or is it just about the same as the others shown? I am just curious and if it's the same then no need to mess about with it. But it would be nice to see what it looks like. Thanks for any and all responses. Much appreciated!!!

I did this for you but there are considerations I need to talk about.

First the plot. Unfortunately I modified the file for the I-10K/Shockwave antenna model and didn't make a backup first. Some things are different, but it is close. Unfortunately this version has slightly less gain...

Both antennas are matched to 1.05:1 or better SWR. Both antennas have an X of less than 1. Both antennas are made out of T6 aluminum, and have a base height of 11 meters. These antennas are not at the same tip height. I am also not done with the vector model, this was an early run with almost no tweaking done. I think I can get its gain figure while matched up some more. I still have variables like ring height to apply as see what happens.

There is also a difference in how I had to match these antennas. While the i10k-2 model is entirely matched using elements, I had to add capacitance to mimic the gamma match on the vector model. Because of this, I would expect the Vector model to actually have slightly less gain in reality, although not much less. How much is hard to say, unfortunately, as I have no other way with 4NEC2 to simulate the effects of one tube inside of another, at least none that I am aware of, this is the best I can do at the moment.


The DB

 

[222DBFL]

I appreciate anything you post DB! Truly I do! At the moment I am preparing for the hurricane as I live in Daytona Beach, FL. Hopefully the vector will survive! My fingers are crossed and the antenna mast has been guy roped off as best as I can get it. Much time went into getting it guyed off!! Wish me luck!!

 

[543_Dallas]

I downloaded eznec recently but haven't really learned to use it effectively yet. Hats off to the guys that take the time and post their results here.

 

[The DB]

I downloaded eznec recently but haven't really learned to use it effectively yet. Hats off to the guys that take the time and post their results here.

I'm not saying to not use EZNEC, but I do recommend at least looking at 4NEC2, which is what my models above are all made with, as well. It is also completely free, unless you want to spend money on more capability (such as more segments) like with EZNEC...

There are also things I can do that I haven't seen done with EZNEC, for example, the capacitor included on the imax antenna model in another thread...

Yes, I am biased, can you tell?

I had considered making a video series showing how I make models, how to test for accuracy, what to watch out for, ect. and posting it to youtube. The idea was to help others while shoring up what I think I know about modeling... Unfortunately I really haven't had the time...

If you have any questions with either of these programs, don't hesitate to ask. I'm willing to help you learn, and I'm sure Eddie is as well.


The DB

 

[Marconi]

When it comes to the I-10K and the Shoclwave designs, yes they will be similar. Honestly, the biggest difference in our models is how we incorporate the feed point. We clearly have very different ideas about how it is supposed to work. I think if I incorporated the feed point into your model as I did with mine it would be much more tune-able.

A while back I posted the following image of my I-10K model beside yours.


Here we see our models with matchers included showing very similar results. I agreed with you that your feed point connection idea incorporated into my model could possibly improve my match.

Then after I posted my wires description, and you applied my wire description to 4Nec2. You reported that your model returned errors and warnings, and I checked you wires and found 5 wires with typos.

After you fixed the errors you come back still claiming you had to modify my model to get it to work, and that due to the error reports popping up you posted an idea that 4Nec2 and Eznec are different, which is obvious. Could the problem be that the source data did not cross over in duplicating the wires...and you have to fix the source?

You said in part:

That is also why I wondered if there was a difference between out programs...

Then you went on to talk about the different approach we made in the way we set the feed point and match the antenna.

DB all that I did to my model is insert the source (feed point) just like I always do with most models, and I asked you if what you did was apply your source using a split feed point feature in 4Nec2. I do not recall your answer to the split feed point question, but I know that 4Nec2 has such a feature, I think I called it to your attention way back when we first started using our software. I was lost in your describing what you did...and here we are.

I was curious though, and had an idea to set my FP in several different points on the trombone tuner and including the base of the radiator...which is where I see you FP set in the model that started this thread.

On moving the feed point around to different point on the tuner...I found moderate to very good match points at different places and none of them broke the NEC code...until I use the tuner part that is beyond the ground connection for the tuner, or like the typo errors your Geometry and Segment check program reported.

When I fixed the 5 wires I noted on you wires description all of the Geo/Seg errors and warnings went away. You say you had to fix other parts of my model, can you tell me what else you had to do?

Here is your editor with my wire descriptions you posted for me.



Here is the file I sent you with the correct wire descriptions. Look DB, I know how difficult it is to type all those little number values down in the right column, and if you get one wrong in will mess the model up:



Could you help me with what you had to fix?

I also posted your antenna view at post #1 above, and my antenna view of the matching devices on my model and from the I-10K manual for comparison. You will see the real antenna has angles below the radiator mast among other dimensions that are not in the same plane like you matcher.

So, I conclude that even though our matchers look different, they still produce similar results, and IMHO has nothing to do with 4Nec2 working differently than Eznec...even though there are differences in features which were created by the developers of the antenna software to make operator handling easier for the user to use the Nec engine.

 

[Marconi]

Well I designed a working gamma for my Vector 4K. I called the son of my old antenna mentor, and he gladly came over and help me thru the hoops. He made it look easy, but he used some Maxwell math which will be over the heads of most and I won't be getting into that.

DB, the problem with this hidden gamma thing is not what we, or I for sure originally thought.

The antenna does not have a good bandwidth, but it shows a near perfect match. I could not make any more gain to speak of.



The model also works fine when I create it in Free Space, and I added the pattern and match for it without the mast in the PDF file below.

The Average gain is 1.001 = 0.01 dB for the FS model.

As I've said before, adding matching to a model either makes the gain drop a little, due loss and or improving the actual model...that is my best guess. Or matching has little to nothing to do with adding gain in most cases.

I asked Martin about the I-10K model and the funny looking pattern that I and another buddy on the Internet saw after adding a matching device to a model. He said large matching networks can do that, and he gave me a specific reference to study on the subject.

I spent all day and 1/2 the night on this project.

 

[Marconi]

Here is my New V4K model with a gamma over very poor Earth.

 

[The DB]

Then after I posted my wires description, and you applied my wire description to 4Nec2. You reported that your model returned errors and warnings, and I checked you wires and found 5 wires with typos.

I thought you were talking about the warning and error data that came up. I didn't realize I had those typos until you circled them in this post. As I assumed you were referring to something else, and my quick scans over the data didn't pick up on the transposed numbers, they were still transposed this morning, all models I have made with your data had those transposed numbers. When I get time I will have to rerun the models...

DB all that I did to my model is insert the source (feed point) just like I always do with most models, and I asked you if what you did was apply your source using a split feed point feature in 4Nec2. I do not recall your answer to the split feed point question, but I know that 4Nec2 has such a feature, I think I called it to your attention way back when we first started using our software. I was lost in your describing what you did...and here we are.

Yes, I can put multiple feed points on an antenna. I don't really like having to do that as antennas don't actually have multiple feed points.

How I do feed points is simple. When connecting a coax to to an antenna, how many wires are attached? I simply position my feed point so one wire is where the center wire connects, and the other is where the shield connects. That is how the feed point is attached in the "real world", and I don't have any reason to treat modeling any different. It is really nothing more than envisioning where the two wires go and using that segment on the model to place the feed point.

For example, on the I-10K/Shockwave model I made, the center conductor is attached to the center part of the trombone section, and the shield is attached to the bottom of the trombone section. I simply added a single segment wire across those two points and made that segment the feed point.

I was curious though, and had an idea to set my FP in several different points on the trombone tuner and including the base of the radiator...which is where I see you FP set in the model that started this thread.

Neither the feed points I used in my model and my attempted reproduction of your model has the feed point at the base of the radiator. As I mentioned above, in my model there is a single segment tap between the bottom part of the trombone section, and the middle section. This tap is directly across the trombone section like the actual antennas. That is where my feed point is. The radiator doesn't start until the top trombone section. In my reproduction of your model the feed point is on wire 8, which is on the middle of the middle trombone section wire.

As you can see, there is no direct connection between the feed point and the radiator above it.

When I fixed the 5 wires I noted on you wires description all of the Geo/Seg errors and warnings went away. You say you had to fix other parts of my model, can you tell me what else you had to do?

As I didn't directly fix those numbers, I don't know if they would have fixed all of the problems. There were several warnings that I fixed by adjusting some of the segment's diameters. Those were warnings and not errors. I think I may have also changed a segment count on one of the wires as well. I modified the model again since then, and removed/adjusted some of the wires so I could use my tuning methods when working with the model. This essentially was combining some of the wires that were inline with each other into a single wire. I did make sure to keep the feed point segment in the same position as wire 8, at least initially. That version of the model had only one of those typos as I combined those four wires.

The working different question had to do with the errors and warnings I got for the model. You didn't get any, and I did and I was looking for an explanation. The results, in spite of the errors, were very similar.

As I said above, when I get some time I will remake your model (I modified it some what and want to make one fresh from scratch).

When it comes to the Vector, I did my gamma a little differently.

I started with the ghz24 model I modified back when Henry released his report. I didn't have specific data offhand and I wasn't sure which ones of my older models were for which data, bad notes on my part, so I used some estimates. I brought the gamma out at a 45 degree angle between the base of two of the radials, added an upper segment that does the same, and added a vertical element. There was already a small vertical wire as part of the main vertical element in this model, so I used that. On the vertical element I have a capacitor. I put the feed point on the bottom segment part of the gamma. I have the ability to change the height of the top of the gamma and the capacitance in the gamma with variables. That capacitance is required for this to function and tune. I have also adjusted the tip height of the main vertical element, I believe the maximum gain with this ring height was at .78 wavelength between the base and the tip of the antenna. I still have more playing to do with the antenna.

This model is designed in such a way that if someone gives me data for antenna length, ring height, ring diameter, antenna height, ect, I can simply drop those numbers in as variables. I simply added my gamma match to that antenna model.

This is also the first model that I've successfully used the 4NEC2 optimizer, and I used that specifically for tuning purposes. It really did speed up the process, and seemed to work better than trying to tune the antenna for maximum gain with the optimizer.

Still, it isn't to far off from the pattern your model is making, if not a little less gain.


The DB

 

[Marconi]

Yes, I can put multiple feed points on an antenna. I don't really like having to do that as antennas don't actually have multiple feed points.

The split feature is not the same as using multiple feed points. I can do multiples too, but I don't know the dynamics or the technique.

How I do feed points is simple. When connecting a coax to to an antenna, how many wires are attached? I simply position my feed point so one wire is where the center wire connects, and the other is where the shield connects.

Eznec is slicker than that. On setting the source a window pops up and you just enter the wire #, where on the wire (as a %) you want the FP, the amplitude, phase, and type, and hit the enter key. To do the split, you select split in the type field of the window noted above, and the hit the enter key.
WaLa!!!! you have a FP port.

That is how the feed point is attached in the "real world", and I don't have any reason to treat modeling any different. It is really nothing more than envisioning where the two wires go and using that segment on the model to place the feed point.

I would describe Eznec's source feature doing the same, envision where you want the feed point and set it.

For example, on the I-10K/Shockwave model I made, the center conductor is attached to the center part of the trombone section, and the shield is attached to the bottom of the trombone section. I simply added a single segment wire across those two points and made that segment the feed point.

I suspect, the way I sent you the earlier model with the wires description only, the source would not been included. You would have to add the source in 4Nec2. I think your 4Nec2 source coded is included in the wires description. I just think Eznec does it different as I've noted above.

As you can see, there is no direct connection between the feed point and the radiator above it.

That may be DB, but the red circle was showing to be on the base of the radiator between two sections of the trombone tuner. That is all I could see, and it just looked different that my connection. I don't doubt your clarification however and it make sense.

As I didn't directly fix those numbers, I don't know if they would have fixed all of the problems. There were several warnings that I fixed by adjusting some of the segment's diameters. Those were warnings and not errors.

Well we both learned something I guess. You see an apple and I see an orange.

I think I may have also changed a segment count on one of the wires as well. I modified the model again since then, and removed/adjusted some of the wires so I could use my tuning methods when working with the model.

I just typed in the 5 errors on my Eznec spreadsheet, and I saw the same error reporting as you. I fixed the numbers back right, and all the errors and warnings went away. These to programs work the same in this regard, believe me. I work in the box until I feel comfortable out of the box. I'm not comfortable with my model skills just yet.

This essentially was combining some of the wires that were inline with each other into a single wire. I did make sure to keep the feed point segment in the same position as wire 8, at least initially. That version of the model had only one of those typos as I combined those four wires.

I also think the problem with my model (the one I posted) I had tapper in the trombone tuner and when I first thought to add the series type matcher to a model some time back...I figured I really need
the wire intersection points to be in the same exact location, for the antenna to be tunable. I also realized early on the Eznec does not like tapper, but I forgotttttttttt.

I always thought tapper was a function of NEC that forced the limitation. So, you could be right...NEC is not the controlling factor in these designs, and it's old Roy's fault.

I have also adjusted the tip height of the main vertical element, I believe the maximum gain with this ring height was at .78 wavelength between the base and the tip of the antenna. I still have more playing to do with the antenna.

I figure now you are talking about the Vector, right?

I tried doing the same thing after Martin left, but I failed in the gamma design somewhere in the process of modifying. I think the load needs better or different info, but I'm not sure exactly how or what was done. At the time I thought I had it all down pat. I still have more to try and grasp.

This model is designed in such a way that if someone gives me data for antenna length, ring height, ring diameter, antenna height, ect, I can simply drop those numbers in as variables. I simply added my gamma match to that antenna model.

I don't fully understand any of this, but I think I understand the idea, and that is maybe how the optimizer is best used. I sure can't make such a claim. I guess that is why I'm still in the box.

This is also the first model that I've successfully used the 4NEC2 optimizer, and I used that specifically for tuning purposes. It really did speed up the process, and seemed to work better than trying to tune the antenna for maximum gain with the optimizer.

I think I accused you of saying this before...all to find out much later it as GZ24 as best I recall.

Still, it isn't to far off from the pattern your model is making, if not a little less gain.

Well about gain, the model I original posted here was probably at 32' feet, again I had tapper in the trombone tuner, and the model was set of Average Earth. All those situation had an effect. IBME as I improved these failings in my models in the past (and this is not the only model like I'm describing here) the model improved...but I seldom fine that improvement as a + or > than...gain in the pattern.

But that is just me I think, and maybe it is backward and wrong headed.

Maybe after this you can help me in areas...I think now we can possibly work together and make headway...instead of playing bumper cars.

How say you?

 

[Marconi]

I like the nice low angle gain shown above, but I like my old pattern below much better. To me it seems it would cover a lot more signals coming into the antenna and maybe going out as well.



Maybe the model is set lower and over Average Earth, and it fixed would show more gain. IMO these are the areas where we can expect to get increased gain.

 

[The DB]

The split feature is not the same as using multiple feed points. I can do multiples too, but I don't know the dynamics or the technique.

I haven't seen or heard of anything related to that in 4NEC2. When I tell it where a feed point is it just marks a segment as a feed point. To be fair, I haven't really looked either. It is possible that that is a feature you have access to that I do not. That would potentially be a difference we both had with your model that we may have to account for in the future as, as far as I know, I have to have a segment in the spot of the feed point.

Well we both learned something I guess. You see an apple and I see an orange.

That isn't the first time that has happened between us, and it likely won't be the last. As long as we are aware of the possibility.

I always thought tapper was a function of NEC that forced the limitation. So, you could be right...NEC is not the controlling factor in these designs, and it's old Roy's fault.

Actually it isn't. NEC2 never really handled taper very well, even before the days of EZNec and 4Nec2. Some programs have inbuilt calculators for said taper, I know the one in 4Nec2 was tested directly against the taper feature in MiniNec, as that was was known to be very accurate. That being said, I have never used the taper feature of 4Nec2. I never felt the need to use it. I can say the 4Nec2 version of this uses some formula to set the entire length of an element to a single diameter that will act like the taper. Through my own experimenting, I don't see this making a significant difference, although now that I am including things like the material the antenna was made from, and beginning to include matching circuits that are actually tunable while on the antenna, and other ideas I might come up with to increase accuracy, this may one day change.

I figure now you are talking about the Vector, right?

Yes I was.

I tried doing the same thing after Martin left, but I failed in the gamma design somewhere in the process of modifying. I think the load needs better or different info, but I'm not sure exactly how or what was done. At the time I thought I had it all down pat. I still have more to try and grasp.

The thing about the gamma match, it requires added capacitance to be added to an element. I don't know if EZNec can do that or not. On that the ball is in your court.

I don't fully understand any of this, but I think I understand the idea, and that is maybe how the optimizer is best used. I sure can't make such a claim. I guess that is why I'm still in the box.

This was a response to me talking about variables. In 4Nec2 I can create a variable called height. I can then use that in place of an actual height measurement when putting data into the wire data screen. I can make another variable called length, and use that as a way to define the length of the vertical element on the antenna. For the tip of the antenna in the Z coordinate I can type height+length, and the program adds them together. I can then simply change the height variable if I want to change the entire height of the antenna, instead of having to enter the new info in for every Z coordinate point.

That is a feature built into Nec2 that 4Nec2 takes advantage of. It is actually a pretty powerful feature once you figure it out, as I used it in the Vector model above to define the ring radius on both the X and Y axis, but I included a formula to calculate 12 other points on the ring. If I want a ring of 19 inches, it gives me a circle of 16 points and the wires between them for 19 inches. If I want a different sized ring I just change the 19 inches to whatever radius I want to use. With this use, think of it as a means of automating a process that I would have to calculate by hand every time I wanted to change the diameter of said ring. That is what I have used it for in the past and I still use the feature mainly the same today.

I think I accused you of saying this before...all to find out much later it as GZ24 as best I recall.

Yes, those were Ghz24's words, although I generally agreed, I didn't really understand how said feature worked, I have learned more about it since, and still have a ways to go.

The optimization feature also uses those variables we talked about above. It does seem to be a bit touchy about them though.

Maybe after this you can help me in areas...I think now we can possibly work together and make headway...instead of playing bumper cars.

How say you?

If you need help ask. Just be aware that when you say apple I might hear orange, I'll keep that in mind as well.

Maybe the model is set lower and over Average Earth, and it fixed would show more gain. IMO these are the areas where we can expect to get increased gain.

You know what, when I made that Vector model, I didn't check the ground type it used... Hmm... Well, when I get time I'll double check and retune if necessary. Its not a total loss as I wasn't finished toying with it anyway...

I just did that real quick. The pattern looks pretty much the same, the tune still meets my requirements, but the gain dropped some, it now has 4.94 dBi gain.

I'm just busy right now, maybe next week I'll get a chance to play with these models again...


The DB