Marconi's I-10K with trombone matcher that works.

[Marconi]

I got out of that page that when he went to the shortened .528 version he lost 1.03db but eliminated the cancellation at 35 degrees.

And the 5/8 thing, well .625 is real close to .6346 so I can see why they would give it the nickname of a 5/8. I just wonder if there is much of a difference at greater distances using the .6346 versus a .625 aside from the models, in the real world.
Maybe I can build a home made version of it so I can test different lengths.
Still it seems kind of like a moot point now with the Sirio Gainmaster on the market.

I'm surprised we don't hear CB manufactures making claims about their .528 wl model antennas, and/or making negative counter claims about the fading problems for users of their competition's 5/8 and .64 wave model CB antennas.

I also noticed that Maxwell used the word "only" in his closing remarks for this topic, while describing the 1.03 db reduction in gain, in telling us that Broadcasters maintained their standard...using 1/2 wave antennas.

This too might be said to be a distinction...worthy of note.

I miss a good understanding of some of these "Elmer" type guys from time to time, and I've commented as such. But, like I've said before, "...we don't always get much out of just looking at the pictures."

 

[Needle Bender]

I'm surprised we don't hear CB manufactures making claims about their .528 wl model antennas, and/or making negative counter claims about the fading problems for users of their competition's 5/8 and .64 wave model CB antennas.

I'm thinking that might be more of an issue with ground mounted antennas on low AM band at night as the D layer becomes porous and the E layer becomes like a mirror. It might not be an issue at all on 11m but I haven't read much about that yet.

 

[Marconi]

Sorry, I guess I drank too much of that cough syrup-

In the first paragraph of the pdf you posted a link to of Maxwell he says it's not .64 but actually .6346:
"I have performed a computer analysis
of the 0.64-l' vertieal radiator; a pattern
integration yields 0. 6346 L (228.45" .)
as the true optimum height, furnishing a
gain of 8.1898 dBi, or 3.029 dB over the
?Jfvertical."

I was hoping you would try a model of the 276" x 1" dia radiator(no top hat) with 107" x 1/2" dia radials just to see what the gain and pattern look like.

Then I was wondering if you had interest in putting it up with the top hat at 261" for 27.385 or whatever freq you usually use to test them out to see how it did on your hand-written s-units sheet/ chart as a .64.

I guess I better stop buying *hic* the cherry flavor

I think this is the model you requested in red above. I changed the dimensions for the model I posted earlier, "NB idea for extending top hat" with no Top Hat, which I did for a report on current distribution. Because the project was to show the current data for wire #3, I reduced the segments to 20, just for convenience in showing the report. That likely reduced the gain a bit. I fixed the model back to its normal segment count for wire #3, which is 100, so that may make a little increase in the model you requested.

View attachment NB idea 011612.pdf

 

[Marconi]

I'm thinking that might be more of an issue with ground mounted antennas on low AM band at night as the D layer becomes porous and the E layer becomes like a mirror. It might not be an issue at all on 11m but I haven't read much about that yet.

I would agree, but if I'm right about the source of this idea about .64 wave being better than .625........who knows? I hope I'm being clear in my words.

 

[Needle Bender]

OK thank you for the model.
Why have they all been so high on the TOA when I recall some a while back which showed the TOA more like 15 degrees. Were those in free space and these are over ground?

 

[Marconi]

OK thank you for the model.
Why have they all been so high on the TOA when I recall some a while back which showed the TOA more like 15 degrees. Were those in free space and these are over ground?

If you will go back and read my original post, you'll see in the text and in the hand written images...these models were only 18' feet high. There was a reason for that, but I'll wait for another day to explain.

 

[Needle Bender]

If you will go back and read my original post, you'll see in the text and in the hand written images...these models were only 18' feet high. There was a reason for that, but I'll wait for another day to explain.

- Which raises the question of what height above ground does eznic show as best for the lowest TOA for a 5/8 and is there a different ideal height for a .64? How do those ideal height models compare to free space models?

 

[Marconi]

OK thank you for the model.
Why have they all been so high on the TOA when I recall some a while back which showed the TOA more like 15 degrees. Were those in free space and these are over ground?

I forgot to answer your last question. I can't remember for sure, but I think all my models in this thread used Eznec's real Earth feature.

Like I said above, there was a reasons I made the models at 18' feet, and that had to do with a project I have not posted as yet. The reason for the project was to try and show you why I disagree with your idea that it's possible to tune low and raise the antenna up higher, and expect the match to stay the same...without being real lucky. I don't know where you posted this claim, but I believe it was on this forum just recently, and I was amazed that you could say that and ask if you can explain? I think you also stated something to the affect that you though your Penetrator's ground plane was an example of your idea, that the ground plane was more or less invisible to the antenna, and to the Earth so the match did not change on raising. Maybe such ideas are connected in your thinking, and maybe you can explain a little more. Did you observe such results on an analyzer?

I got my idea back when I use to see this happen testing changes in height with an A99 several years ago...after I got my Autek VA1 analyzer. I never did understand fully what I was seeing, but when I started modeling, I got the feeling I was seeing the same thing happen with the match on some of my models. I felt I couldn't show modeling proof unless I had at least two different antennas, tunable, where I could control the match, and here we are. The genesis of my idea originated with a tuning claim that JoGunn makes in their manual for one of their beam antennas. That claim flat contradicts your idea too. I read in their claim that raising the antenna is linear, and I don't believe that either, but this is where I got my original idea.

IMO, raising an antenna higher does not produce a linear curve with the match...like most probably believe. The matching curve seems to follow a sinuous type curve that appears to repeat with very similar results at 1/2 wave intervals. If true, this may be the lucky part I noted for you above. On the other hand, you claim you can raise an antenna with no change in the feed point match. :thumbdown:

In between these 1/2 wave end points in height, the match is changing all over the place for R and X values on my VA1. The complex impedance value for Z on my analyzer, might not be changing that much, but the components for the match, resistance (R) and (X) reactance seem to change dramatically, to and fro.

NB, this is not to say that my idea is correct and that your's is not. I'm just trying to understand.


Last week I did another project using this model of the I-10K vs. Starduster. Finally, after seeing my model I-10K matcher working to produce a good match for a 5/8 wave radiator, I was able to do such a project. The models were each set at 18', 36', 54'. So, this is why I used the 18' model for this thread. I have not posted that project yet, because I'm still studying the results and trying to figure out a simple way to try and explain what I see.

 

[Needle Bender]

Well Marconi, I had a 5' pole I hammered into the ground about a foot to hold the Penetrator while I built it. Once on the roof it was about 40' to the radials.
Maybe being 4' off the ground and one wave length plus 4' in the air saw similar ground influence but all I know is I tuned it with the MFJ259 at 4' and simply straightened out the match wire once in the air to regain my almost zero reactance and 1:1 swr.
I would be surprised if the elevation above ground didn't have a much more significant effect on horizontal antennas, but the radials are there for a reason, to elevate ground and decouple the coax, and perhaps the specific match and radial placement design may be even more oblivious to earth ground, or perhaps my ground isn't nearly as conductive, or all of the above.
Remember that post on copper forum where tech833 tested it and saw a pattern that sharply cut off all downward radiation below the radials?
Maybe it works both ways.

 

[Marconi]

- Which raises the question of what height above ground does eznic show as best for the lowest TOA for a 5/8 and is there a different ideal height for a .64? How do those ideal height models compare to free space models?

Height is of no matter to free space models. I don't know of any ideal height for a 5/8 wave, unless I had a perfect model and could raise it and check to see if the magnitude of current flows on the attached mast made a difference in the gain and pattern and even then it would be a stretch to determine because height itself affects the gain and angle. This business of determining cause and effect is a very illusive subject.

Right now, I suspect that models with more current on the mast may show more gain as a result, and this current difference may be due, more or less, to different heights, but I was surprised to see your most recent idea, 274" x 107" without a top hat, show far less current flow on the mast of the antenna model I started with, and that was without any change in height. So, I could be all wrong. There is far more to what goes on here than just trying to see a difference between .625/.64, and that is why I'm trying to check things out.

If you will compare the model "NB idea no top hat 011612" that I just posted for you, to the first model "I-10K w matcher 18' mast #2" you will note, checking out the red line currents on these two masts, that the magnitudes are different, and so is the gain and angle. Which looks best to you?

It is my opinion that this magnitude of currents on the mast is significant to the gain, angle, and pattern shown. So, we can't always just go by the max gain and/or angle a model might show us, the currents indicated are important also. This might also account for some of why Bob85 tells us about modeling antennas without including the mast and feed line is problematic.

I guess I'm safe in claiming this much, changes in height are more significant that most realize. Increasing height is not just improving the range of your antenna. At some heights the match might be right on, and at other heights things might go to hell in a hand basket.

Maybe this is why we hear so many complaints from guys installing antennas like the Imax/A99 and maybe others, that should be about as close to match set as you're likely to get working CB. So, maybe all this complaining about the poor workmanship is not always the answer. Could it also have to do with the worst case scenario for the installed height?

 

[Needle Bender]

Marconi, you're right about different mast lengths on varying roof heights changing the playing field.
Now you have me wondering what performance I'd get if I used a few feet of fiberglass rod to insulate the Penetrator from the mast and wound a choke around the fiberglass rod to remove most all feed line radiation?
Maybe those free space models might reveal more considering the antennas could be isolated.
I'm really tempted to put the Penetrator back up, fully isolated from the mast, and try it out for a few weeks.

 

[gamegetter]

Yea, I understand NB, but it's hard to fully consider guys that probably use just one incident in their radio work to try and set their ideas in granite...like God did for Moses.

If I could find the test report that set this original idea for a .64 wavelength for a Broadcast monopole being better than a .625, you likely wouldn't believe that either. Could someone go thru the steps of doing such a thing and see the results you imagine? Yep! I suppose so, anything is possible.

I use the old "Take a minute, stand back, and think about this." formula to just try and get close, then I tune as best I can. I know on thing for sure, I've never gotten it totally perfect, as you might suggest.

I would also like to understand more about the HyGain idea for raising the radials in their ground plane mounts. I think they still produce some antennas with this design. That said however, I don't believe for one minute that this design will fully and completely decouple the antenna from the Earth affects like you claim, but it is an idea to consider and try to prove.

Regardless of what we hear, there are just too many variables to handle for this antenna business to be and easy process that always can give us perfect results, and for sure in CB.

I'll get off my soap box for now, I posted an image of the I-10K, section 6, on the Top Hat. I guess this section could have changed however. My antenna is pretty old.

I also post an image from Maxwell's 2001, Second edition of Reflections II, page 20-16, Chapter 20. Read this, it may be enlightening on the subject and supports what I been saying since back in the late 80's or early 90's when I originally read the Ballantine report to the newly forming US Broadcast Industry, and the counter report by Japanese engineers that the .64 produced the most gain. There is a distinction to be had here, that only understanding can provide. ^^ ab v c^^

View attachment 6403

View attachment 6404

Greetings Marconi: I hope all is good your way. I have a few thoughts on the Maxwell/Ballantine page you posted.

Although I do not have the Maxwell literature, I believe he is talking about the medium wave frequencies of am broadcasting, and there may be differences in radio wave propogation from them to the hf frequencies. I put this out there and perhaps the more advanced antenna guys can comment on the technicalities.

Regarding the text on Ballantine's discovery. Is Maxwell saying that the length of the radiator remained constant, while the tower height is what is changing?
This would seem more likely to me to be what he is discussing,,,That is the elevated vertical attempt of a dipole resulting in what is commonly known as the 5/8th wave length vertical.

 

[Marconi]

Greetings Marconi: I hope all is good your way. I have a few thoughts on the Maxwell/Ballantine page you posted.

Although I do not have the Maxwell literature, I believe he is talking about the medium wave frequencies of am broadcasting, and there may be differences in radio wave propogation from them to the hf frequencies. I put this out there and perhaps the more advanced antenna guys can comment on the technicalities.

Regarding the text on Ballantine's discovery. Is Maxwell saying that the length of the radiator remained constant, while the tower height is what is changing?
This would seem more likely to me to be what he is discussing,,,That is the elevated vertical attempt of a dipole resulting in what is commonly known as the 5/8th wave length vertical.

Thanks Gamegetter, and greetings to you too.

I don't know what medium or frequency they're talking about, except they refer to Broadcast, and I assume it was back at that time in 1923. I think they were talking about ground mounted verticals, and I think I recall Maxwell saying low frequency.

I also think Bob read it this way too.

I see it that Maxwell did not referred to height per se, he used degrees. IMO this seems to isolate the descriptive height of the radiating element to a specific length, and not to suggest height above the Earth. However, I think they are talking about a ground mounted radiator and comparing it to two towers with a radiating wire between them. So........

My point is the old mixing of apples and oranges debate that I believe the CB world seems to do all the time, trying to persuade or come up with something new...based on some science report or discovery.

I think your comment on propogation differences is probably on point as well.

 

[Marconi]

Marconi, you're right about different mast lengths on varying roof heights changing the playing field.
Now you have me wondering what performance I'd get if I used a few feet of fiberglass rod to insulate the Penetrator from the mast and wound a choke around the fiberglass rod to remove most all feed line radiation?

Maybe those free space models might reveal more considering the antennas could be isolated.

I'm really tempted to put the Penetrator back up, fully isolated from the mast, and try it out for a few weeks.

NB, your suggestion above is about what I'm thinking, but I have some reservations still. On completing your last request for a model, which did not change the height, I saw a change in the current flow on the mast...that I did not expect. So, I asked for more study time.

Your next idea, using an insulator, is another complex consideration as well. I can't hardly describe, in words, what I'm think sometimes, and now you're throwing another monkey wrench into the mix.

BTW, I think 4"-6" inches will do just fine.

Based on some modeling I've done using isolation, and some models that I've already posted, I think the choke and isolation idea could help eliminate RF on the mast below, and that is a good thing. This idea also seems to make sense to me, but to be honest I've not experienced any telling results...in my limited and possibly incorrect application for this idea. The particular isolation application may mean everything to the sucess or lack of sucess.

I know that Bob85 and Multimode200 have done it, and I think they will say the results were rather remarkable.

My Eznec somehow uses a Mininec algorithm, that I have to select, in order to handle a mast attached to Earth. When I do a free space model, I have to delete the mast, set the model to free space, set wire loss to zero, and the pattern plot type to 3 dimension. If you don't remove all the losses from the model, free space either won't work, or it gives wrong results warning that the model has losses.

No losses are the magic that free space models operate on, and for me this is why it's the best model for comparing antennas.

If my understanding of a free space process is correct, there needs to be no connection to the Earth, no environmental effects, no Earth effects, no resistance loss, and matching issues are not a consideration. It is just metal vs. metal, and design vs. design.

If I get into isolating some of the models in this thread and or doing free space models, things including my production and posting will get complicated fast.

I still have not heard from 954's Elmer buddy that was going to get back with an important aspect of my modeling procedures. So I still don't have, what I consider, near enough accurate model to really depend on this I-10K model. I made a post showing, in hand written notes, all the questions I have in this model already. So allow me some more time and maybe he'll answer.