Marconi comparing his Sigma4 vs. Marconi 7x

[Marconi]

Here is a video with a two way report of the transmitted results.

YouTube - Marconi comparing Sigma4 @ 34' vs. Marconi 7x @ 38' to bottoms

Here is an image of the two antennas.



Here is the BW curve for the Marconi 7x

View attachment Marconi 7x Bandwidth curve 021611.pdf

Here is my Eznec5 model of the Marconi 7x with modifications requested by MrS. which includeds the 7x model, a version with no horizontal radials, then two models with only horizontal radials, with the last one being 108" radials all the way around. I did not bother to fix the captions on each, so if you have questions about the order, leave a message.

Sorry about this, I scanned the wrong SWR bandwidth curve and then I rechecked it before posting. I could not figure out why it was so low in frequency, so I did the scan again. I also did a video of the process of making the SWR Bandwidth Curve which is on my YouTube page.

View attachment Marconi 7x Eznec5 Model 021611.pdf

 

[HomerBB]

You are an intrepid soul.

 

[Marconi]

You are an intrepid soul.

Yep Homer, I've always tried to show some evidence to support my words, just like you. How much of that do you see from all these other talking head's.

I can't claim any truth in my ideas and I try not to be categorical in my words, but if their heads are not full of mush, then this at least gives them something to think about. I'm just not sure it helps much though.

Go back and check out the modeling example I just posted. I made it try and support my idea for the Marconi 7x. I had no idea it would be so close, and that amazed me that even the match for resistance and reactance is close.

Cebik talks about the importance in modeling after the fact, and the real model work begins...where it really counts.

 

[MrSuburban]

Do you guys see and similarities?

View attachment 4166

In your testing methods? Yes Antenna #1 to close to #2, bar graph meter, ssb signals. J/K lol

Do you think that radials sloped down help while you have 3 out horizontal? Or vice versa. what does your model show as far as gain and toa with the sloped radials and what does it show with the horizontal only radials? I think over the spring i will rebuild my old penetrator

 

[Marconi]

In your testing methods? Yes Antenna #1 to close to #2, bar graph meter, ssb signals. J/K lol

Do you think that radials sloped down help while you have 3 out horizontal? Or vice versa. what does your model show as far as gain and toa with the sloped radials and what does it show with the horizontal only radials? I think over the spring i will rebuild my old penetrator

MrS, my experience while adding more radials using a Field Strength Meter at about 40' showed me notable increases while adding one radial at a time, while taking averages from a rotating test antenna. I think I've posted my results in my albums from back in 2006, where I did my work with the 1/4 wave. Most of that was just notes I kept, so I'm not sure without looking back. I tried again to duplicate the results back in 2009, before I got sick. At that time I was unsuccessful in gaining much reliable results however, so my findings from 2006, have not be duplicated as yet. Again, I just reported what I saw, right or wrong.

I learned a lot about what I had previously done wrong from the experience however. My current experiences have also given my some new ideas as well. With you guys help, I continue to learn new things to watch for and consider. The more I see the more I disbelieve among most previous reports generated on the Internet. It is not a matter of guy's telling lies either, cause I tend to believe the stories we hear. But, I know these guys don't consider everything and probably nobody ever will. We just do the best we can and I try hard not to discourage work and effort.

This is not to say that I consider everything either, and again I realize there is much more to testing than many of us ever thought.

This may be the only thing we can all agree on.

 

[MrSuburban]

MrS, my experience while adding more radials using a Field Strength Meter at about 40' showed me notable increases while adding one radial at a time, while taking averages from a rotating test antenna. I think I've posted my results in my albums from back in 2006, where I did my work with the 1/4 wave. Most of that was just notes I kept, so I'm not sure without looking back. I tried again to duplicate the results back in 2009, before I got sick. At that time I was unsuccessful in gaining much reliable results however, so my findings from 2006, have not be duplicated as yet. Again, I just reported what I saw, right or wrong.

I learned a lot about what I had previously done wrong from the experience however. My current experiences have also given my some new ideas as well. With you guys help, I continue to learn new things to watch for and consider. The more I see the more I disbelieve among most previous reports generated on the Internet. It is not a matter of guy's telling lies either, cause I tend to believe the stories we hear. But, I know these guys don't consider everything and probably nobody ever will. We just do the best we can and I try hard not to discourage work and effort.

This is not to say that I consider everything either, and again I realize there is much more to testing than many of us ever thought.

This may be the only thing we can all agree on.

Your doing what you love Grandpa playing on radio and testing antennas, you got the life. I am wondering if you added a 4th radial and removed the downward slope what you would see. Now I gotta open up Eznec ... :w00t:

 

[Marconi]

Mr.S, here are three 1/4 wave models.

This model has 4 horizontal radials and it has a very low resistive match and will work if some form of matching is provided. It also indicates nice gain at a low angle. However the gain advantage will probably go away trying to get a good match.
View attachment .25 wave model with 4 horizontal radials.pdf

This model has 4 slanted down radials. This antenna shows a nearly perfect match without any lossy matching.
View attachment .25 wave with 4 slanted down radials.pdf

This model has no radials at all. This model shows a very poor almost impossible match and even though it shows a nice gain at a low angle, matching would likely eat up much of the gain in the process of trying to match, so this would probably be a poor antenna.
View attachment .25 wave with no radials.pdf

With all this said I think the issue that is important to note with these models are the patterns. You see a whole range of matching and totally different configurations, with some difference in gain, but there is very little difference to be noted with each pattern and the associated angles. So, considering this what should we think when folks tell us that in order for an antenna to word really great the match and tune has to be almost perfect. I have personally tuned both my Sigma4 and my I-10K so that the tune is bad and then done signal reports and I find little to no difference in the comparative results or performance. I guess this too will twist everyone's thinking as well.

 

[HomerBB]

Grandpa, I'm beginning to feel like a school boy who, when I've finally manged a good grade and feel it is time for celebration, the teacher ruins it all by assigning a yet harder lesson.

I pick the 4 angled GP radials for best match with the near identical gain. No matching device necessary - no loss there.

 

[HomerBB]

I think I'll try putting up my 1/4 wave GP this Spring, and after reworking my Qv4k see what I hear and see from my QTH.

 

[unit_399]

 

[Marconi]

I think I'll try putting up my 1/4 wave GP this Spring, and after reworking my Qv4k see what I hear and see from my QTH.

Homer I have a simple idea in mind for why the 1/4 ground plan (Starduster type design) works so well compared to our AstroPlanes. In my mind they are both effectively matched 1/2 wave center fed vertical radiators, with a slight advantage for the SD'r due to an approximate 6' foot advantage in capture area, better balance, and in addition to showing a tad better symmetry, by not having an 8' tuning stub running close and parallel with the lower 1/2 of the AstroPlane's radiator.

What I see in my minds eye may really be very little difference however, but I think that Avanti demonstrates in their Patent that there is an affect by this tuning element that skews the pattern just a bit. You can see this in their Patent. Look for the little dimple type lobe to one side of the AT, in their depiction of the AP's pattern.

Otherwise a center fed 1/2 wave is a center fed 1/2 wave and this length at resonance is the bases of all radiating elements, shorter or longer...just like FreeCell use to tell us all the time.

You might remember my poll thread about the best way to test. In that thread I posted that I thought the best way to compare everything else different among the CB vertical antennas we often discuss was to set each antenna's current maximum at the same height. Over time my testing and my words describing such always seem to bear out my penchant to testing this way, so for me this kind of explains why I tend to see my antennas produce similar results...which by the way gives every other CB'er that I know in the world---some serious type hemorrhoids.

 

[Marconi]

Thanks for the kind reference 399, even though a protagonists can be a two edged sword.

Were you broadcasting into the States yesterday? I didn't get the chance to connect due to some bad weather in Columbia, but if that was you up high in the mountains on your coffee plantation, then Marconi or Grampa---CDX39zero says, "hello and hang loose."

You were clear, 5/9+ and counting.

 

[HomerBB]

Well, I believe there is merit to a variety of testing methods. If all you want to know is which antenna works best at 1ƛ high, then by all means put them all on the same 1ƛ pole and get the results everyone already knew before you tested, the longer one works best. If you want to see what the maximum potential of a given antenna design is, then test the antenna at a variety of heights, in a variety of locations to see where and how it behaves. And if you want to see how another does under a variety of conditions, do so. And just for the fun of it if you want to compare them, do it. So I have no problem with trying antennas out different ways.

There is something I will prove to myself when I get the Qv4k back into the air after taking it apart and rebuilding it for best integrity this Spring. It pertains to the irony of what I believe I've seen so far, which is that in spite of the fact that I raised the AP feed point up several feet above where the 5/8ƛ and Qv4k were fed, it is still 7.5' shorter than the tip height of the Qv4k when it was mounted lower, and appears to be out performing the Qv4k and 5/8ƛ.

Mount height for 5/8ƛ and Qv4k was:

35'
add 27' for 3/4ƛ Qv4k for a tip height of 62'
add 22.5' for 5/8ƛ for a tip height of 57.5'
the AP is a tip height of 54.5'

62 - 54.5 = 7.5' lower than Qv4k
57.5 - 54.5 = 3' lower than 5/8ƛ

And, yet, the AP appears, without further cross-checking, to best the others in my area. I have heard stations in these Ozarks with the AP that never were copied when I mounted the other two. In fairness, I believe there may be errors in the construction of my two homebrews, so I will be meticulously going over them optimizing their construction in every detail I can affect.

We'll see.

 

[Marconi]

Well, I believe there is merit to a variety of testing methods. If all you want to know is which antenna works best at 1ƛ high, then by all means put them all on the same 1ƛ pole and get the results everyone already knew before you tested, the longer one works best. If you want to see what the maximum potential of a given antenna design is, then test the antenna at a variety of heights, in a variety of locations to see where and how it behaves. And if you want to see how another does under a variety of conditions, do so. And just for the fun of it if you want to compare them, do it. So I have no problem with trying antennas out different ways.

There is something I will prove to myself when I get the Qv4k back into the air after taking it apart and rebuilding it for best integrity this Spring. It pertains to the irony of what I believe I've seen so far, which is that in spite of the fact that I raised the AP feed point up several feet above where the 5/8ƛ and Qv4k were fed, it is still 7.5' shorter than the tip height of the Qv4k when it was mounted lower, and appears to be out performing the Qv4k and 5/8ƛ.

Mount height for 5/8ƛ and Qv4k was:

35'
add 27' for 3/4ƛ Qv4k for a tip height of 62'
add 22.5' for 5/8ƛ for a tip height of 57.5'
the AP is a tip height of 54.5'

62 - 54.5 = 7.5' lower than Qv4k
57.5 - 54.5 = 3' lower than 5/8ƛ

And, yet, the AP appears, without further cross-checking, to best the others in my area. I have heard stations in these Ozarks with the AP that never were copied when I mounted the other two. In fairness, I believe there may be errors in the construction of my two homebrews, so I will be meticulously going over them optimizing their construction in every detail I can affect.

We'll see.

I agree Homer you are wise to question this result until you are sure your homebrews are performing as intended. Without checking the details of my installs, I think my results for both the Old Top One and the New one were pretty close to similar as to what you're seeing. I've probably said this before, but you are the first ever to confirm to some degree anything I've ever claimed. So I thank you for trying out the AstroPlane an unappreciated, but great little vertical antenna, with a lot of very good characteristics, and in my mind the New Top One is a tad-bit better than the old model.

I will add this note however for all you other guys. To be honest I also sense similar events like Homer suggested, where the audio portion of a signal may pick up to the copy level using my antennas while another antenna I have up at the same time remains in the mud. When side-by-side I can hear this happen just like you describe Homer and it may take some very special care to note this with only one antenna up at a different point in time.

However, my results are not always so well defined as to just one antenna. My reports vary as they should, and at-times I see or hear this distinction possibly with all of my antennas. I haven't recorded such responses on my reports...except maybe in rare occasions, but it happens.

On the local scene with channel 19 traffic, which surrounds me within a couple of miles on three sides, I also see signals vary a bit, first one antenna and then the other. As these guys move about, I often see their signals change with the opposite responses. So, nothing is ever really 100% - 100% of the time. I know when ya'll look at my professionally produced videos within a margin of 1% error, you see this same 100% rock steady signal report, but those are typically just one split moment in time, and if you don't see this variation at times from your own station, then you're just not watching very close.:headbang

Homer, I have a request. If you think about it when your fixing your longer antennas in the spring, and if you first end up with any sign of a bad tune, considering the rest of the antenna looks to be close, try working it for a bit even if only using RX signals. Do a few signal checks and see if you get similar results to mine...where I find the actual tune, within some degree of reason, does not notably affect performance in some remarkable way as you can tell working your radio, OK?op:

NOTE: I'm NOT suggesting you abuse your rig and TX with a sever mismatch however.

I had a guy once tell me a story about the top section of his antenna coming loose and sliding down, and he didn't notice the difference until he took the antenna down...even though otherwise he would proclaim loudly - "...that an antenna must be tuned perfectly in order to perform up to snuff." This is an embellished joke of sorts, but is based more-or-less on a true account and the rest of the story will never leave my lips.

 

[Marconi]

Well, I believe there is merit to a variety of testing methods. If all you want to know is which antenna works best at 1ƛ high, then by all means put them all on the same 1ƛ pole and get the results everyone already knew before you tested, the longer one works best. If you want to see what the maximum potential of a given antenna design is, then test the antenna at a variety of heights, in a variety of locations to see where and how it behaves. And if you want to see how another does under a variety of conditions, do so. And just for the fun of it if you want to compare them, do it. So I have no problem with trying antennas out different ways.

There is something I will prove to myself when I get the Qv4k back into the air after taking it apart and rebuilding it for best integrity this Spring. It pertains to the irony of what I believe I've seen so far, which is that in spite of the fact that I raised the AP feed point up several feet above where the 5/8ƛ and Qv4k were fed, it is still 7.5' shorter than the tip height of the Qv4k when it was mounted lower, and appears to be out performing the Qv4k and 5/8ƛ.

Mount height for 5/8ƛ and Qv4k was:

35'
add 27' for 3/4ƛ Qv4k for a tip height of 62'
add 22.5' for 5/8ƛ for a tip height of 57.5'
the AP is a tip height of 54.5'

62 - 54.5 = 7.5' lower than Qv4k
57.5 - 54.5 = 3' lower than 5/8ƛ

And, yet, the AP appears, without further cross-checking, to best the others in my area. I have heard stations in these Ozarks with the AP that never were copied when I mounted the other two. In fairness, I believe there may be errors in the construction of my two homebrews, so I will be meticulously going over them optimizing their construction in every detail I can affect.

We'll see.

I agree Homer you are wise to question this result until you are sure your homebrews are performing as intended. Without checking the details of my installs, I think my results for both the Old Top One and the New one were pretty close to similar as to what you're seeing. I've probably said this before, but you are the first ever to confirm to some degree anything I've ever claimed. So I thank you for trying out the AstroPlane an unappreciated, but great little vertical antenna, with a lot of very good characteristics, and in my mind the New Top One is a tad-bit better than the old model.

I will add this note however for all you other guys. To be honest I also sense similar events like Homer suggested, where the audio portion of a signal may pick up to the copy level using my antennas while another antenna I have up at the same time remains in the mud. When side-by-side I can hear this happen just like you describe Homer.

However, my results are not always so well defined as to just one antenna. My reports vary as they should, and at-times I see or hear this distinction possibly with all of my antennas. I haven't recorded such responses on my reports...except maybe in rare occasions, but it happens.

On the local scene with channel 19 traffic, which surrounds me within a couple of miles on three sides, I also see signals vary a bit, first one antenna and then the other. As these guys move about, I often see their signals change with the opposite responses. So, nothing is ever really 100% - 100% of the time. I know when ya'll look at my professionally produced videos within a margin of 1% error, you see this same 100% rock steady signal report, but those are typically just one split moment in time, and if you don't see this variation at times from your own station, then you're just not watching very close.:headbang

Homer, I have a request. If you think about it when your fixing your longer antennas in the spring, and if you first end up with any sign of a bad tune, considering the rest of the antenna looks to be close, try working it for a bit even if only using RX signals. Do a few signal checks and see if you get similar results to mine...where I find the actual tune, within some degree of reason, does not notably affect performance in some remarkable way as you can tell working your radio, OK?op:

NOTE: I'm NOT suggesting you abuse your rig and TX with a sever mismatch however.

I had a guy once tell me a story about the top section of his antenna coming loose and sliding down, and he didn't notice the difference until he took the antenna down...even though otherwise he would proclaim loudly - "...that an antenna must be tuned perfectly in order to perform up to snuff." This is an embellished joke of sorts, but is based more-or-less on a true account and the rest of the story will never leave my lips.

I just wish Starduster would come back and finish his work with his AstroPlane. He was going to test his antenna using a full length stinger in the top and then construct and test his AstroBeam. I was hoping someone would someday test my results when I fixed my TopOne with a full length 1/4 wave radiator.