Marconi testing an original Starduster vs. Gain Master

[gamegetter]

i agree with the slanting of the radials, after hurricane beulah came ashore back in '67 i think it was, i had some damage to a radial and i brought the 1/4 wave down to repair it and decided to slant the radials, i don't remember the exact bend i put on them but i do believe it was more than 55's has on his current merlin 55 antenna, but it definitely improved the match.

 

[Marconi]

http://www.worldwidedx.com/cb-antennas/102534-what-w8ji-says-about-1-4-wave-vs-5-8-wave.html

i believe there are 1/4 wave antennas that can out perform 5/8 wave antennas especially if the 5/8 has no ground plane. see above thread. the problem i have as well as other's is that the merlin 55 has both a capacitance hat as well as a coil...but i have not personally ran that merlin 55, model, but i have run a a 1/4 wave ground plane i constructed back in the early 70's that gave me very good performance. between my 3 element and my 1/4 wave gp i enjoyed many many hours of fun on the air waves.

hope i'm not :bdh:

Well gamegetter, I can't disagree with you much, I too have high regard for my Starduster and Starduster styled Marcon X antennas. I can't convince anyone what I see, but I think I'm close with my observations. I can't always claim that my SD'r models will produce the best signal RX/TX, but I don't think I've ever lost a contact, local or DX, while switching from one to another.

Regarding the Merlin, if it has radials that are slanted down near the same as my SD'r or my Marconi, then I think it should work about the same.

For me, both of these antennas operate at or near the center of CB with a little reactance at the feed point. On the other hand the resistance for both is pretty steady at around 50 ohms so the match is pretty good and the bandwidth is excellent, so they work well for me.

My thinking is, however, that maybe the Merlin, with the matching coil right below the top hat, is able to provide and even better reactive match and maybe show a little extra gain as a result. If so, will it be enough to see operating my radio? I DON'T KNOW!

But I hope one day to be able to test that idea that Terry uses in his design with my ground plane design below it...and see. IMO, the radials really must be slanted down more than 55 makes his on the Merlin, so I would like to be able to place his top radiator over my radials slanted down at about 27* degrees or more using my custom made A99 styled GPK hub, and see just how if works in that configuration.

 

[Blue_Max]

Thank you Blue Max, I'm a Starduster fan, an antenna nut if you will.

The shortened SD'r sounds interesting, how about a picture or two and tell us why and how you came about that design. I'm always interested in hearing about other guy's ideas and to see how and why they do what they do. Is what you have similar to the old Starduster 800? I've only see pictures of it, but I read that it was produced at one time. I don't think it was shortened very much however, but I'm not sure either.

Welcome to the forum.

I didn´t mean that I shortened the radials by myself. I only thought that there is also a model existing, where the radials have the same length than the beam. I bought it like this, here is a picture of mine:

I own this antenna now since nearly 20 years and I can´t remember the exact name or type. For about the last 10 years it was installed on the roof of my parent´s house without beam, because it felt off during a storm and I couldn´t reinstall it because I had no time.

This year´s spring I did mount it now on the roof of my house. Also if it doesn´t look like from this position, the bottom of the beam is 10cm higher than the top-end of the chimney...

The only modification I did to the antenna was that I reinforced it a little. As you know the beam consists of two parts, the lower aluminium hose with an outer diameter of 11mm that includes at the bottom the brass-bush with the thread and the upper aluminum hose with an outer diameter of 9mm. The lower part of the beam has a length of about 150cm. I got now a aluminum hose that had an inner diameter of 11mm and an outer diameter of 15mm and a length of 75cm. For the first 2cm of this hose, I increase the inner diameter on the lathe to 14mm, so that the brass-bush fits inside an then I fitted it over the lower part. Then I fixed everything with a small grub-screw at the bottom. The little gab between the two hoses I sealed with aluminum-fluid.
So now I have much less bending and vibrations. Here is a photo in bigger size maybe it´s visible... http://my.twingo.rs/d/2962-1/Starduster_M400.jpg

I can´t say if this has any effect on electrical behaviour.

 

[jazzsinger]

Thank you Blue Max, I'm a Starduster fan, an antenna nut if you will.

The shortened SD'r sounds interesting, how about a picture or two and tell us why and how you came about that design. I'm always interested in hearing about other guy's ideas and to see how and why they do what they do. Is what you have similar to the old Starduster 800? I've only see pictures of it, but I read that it was produced at one time. I don't think it was shortened very much however, but I'm not sure either.

Welcome to the forum.

the coils on the starduster 800 served a similar purpose to the traps on multiband antennas, to allow it to be used on more than one band, in the starduster m800's case 27 mhz and 88-108 mhz fm stereo. i think they would have only shortened the radials by a short amount as you say.

i doubt the starduster with coil loaded radials would be much less efficient than the full size version, when uk cb was first legalised the thunderpole antenna was the reverse of the shortened radial starduster in that the radials were full sized but the radiator was shortened, anyway to cut a long story short it was a very much underrated and very effective antenna here, efficiency wasn't hugely or even noticeably down on a standard starduster m400.

funnily enough the sirio tornado 27 or 827 with shortened
radials ain't that far down on antennas with full sized radials either. i think once you go by a certain length of radial,approx 1/8 of a wave then the gain becomes less and less, but the benefit that its less of an eyesore may well outweigh any performance gains, especially if you have retarded neighbours.

 

[Blue_Max]

.... in the starduster m800's case 27 mhz and 88-108 mhz fm stereo. ...

My antenna isn´t a multi-band, it wasn´t sold as one. It also wouldn´t make sense (here in Germany) as UKW-radio is allways horizontally polarised and not vertically.

....
i doubt the starduster with coil loaded radials would be much less efficient than the full size version, when uk cb was first legalised the thunderpole antenna was the reverse of the shortened radial starduster in that the radials were full sized but the radiator was shortened, anyway to cut a long story short it was a very much underrated and very effective antenna here, efficiency wasn't hugely or even noticeably down on a standard starduster m400.

funnily enough the sirio tornado 27 or 827 with shortened
radials ain't that far down on antennas with full sized radials either. i think once you go by a certain length of radial,approx 1/8 of a wave then the gain becomes less and less, but the benefit that its less of an eyesore may well outweigh any performance gains, especially if you have retarded neighbours.

I can´t imagine that the physical shortening of the radials has such a big impact on its performance. Electrically they are long enough and there is still the long pole in the middle that is, like the radials, connected to the ground. Maybe the band-with is shorter. All im all it´s a good antenna for its size and it looks good...

 

[Marconi]

Blue Max can you tell us what is going on at the ends of the radials that look to be black?

Can you tell us the top element and radial lengths for your antenna?

 

[Blue_Max]

The black ends are coils. The top-element has a length of about 2.70m (depending on SWR-adjustment) the radials about 1.60m.

Here is a better photos to see the length-ratios:

 

[Shockwave]

http://www.worldwidedx.com/cb-antennas/102534-what-w8ji-says-about-1-4-wave-vs-5-8-wave.html

i believe there are 1/4 wave antennas that can out perform 5/8 wave antennas especially if the 5/8 has no ground plane. see above thread. the problem i have as well as other's is that the merlin 55 has both a capacitance hat as well as a coil...but i have not personally ran that merlin 55, model, but i have run a a 1/4 wave ground plane i constructed back in the early 70's that gave me very good performance. between my 3 element and my 1/4 wave gp i enjoyed many many hours of fun on the air waves.

hope i'm not :bdh:

Many of W8JI's posts are designed to make you think to get your answer. What he really says is that there are applications where a 1/4 wave will perform as good as a 5/8 wave. He goes on to say that the 1/4 wave will not really outperform the 5/8 wave but it could equal the performance in some cases.

 

[gamegetter]

interesting comment

i post w8ji's thread here.

"Originally Posted by KA7NIQ
If you tried to tell most any CB Operator that a Starduster will outperform a full size 5/8 wave antenna for local or DX, you will get little agreement.
IS it possible the computer model is incorrect, and/or something else is going on that makes the big 5/8 wave vertical out play the 1/4 wave ground plane with sloping radials in actual practice ?"

"Nope.

The 5/8th wave depends heavily on a large highly conductive reasonably flat groundplane at the BASE height of the antenna. That groundplane has to extend out in all directions for a considerable distance. The reflection out some distance is how the antenna works and gets gain. Without that groundplane at base height for some distance, the feedline will radiate and the pattern also will not form properly. You ALWAYS wind up with an unpredictable mess because key parts of the system are missing.

The 1/4 wave with sloping radials acts as a vertical dipole. It decouples a bit better from the feedline shield, and it has no area carrying out-of-phase currents.

What you will find is the 5/8th wave can vary from being just slightly better than a 1/4 wave with three or more sloping radials to being much worse at low angles. Statistically the 1/4 wave is more reliable.

The reason you won't find CB'ers who support that is they:

1.) Generally don't understand antennas

2.) Generally don't do valid A-B tests, just like Hams don't.

3.) Like Hams, they are trained to think a 5/8th wave antenna universally has 3 dB gain.

4.) Went through the work of installing the 5/8th wave, so like a Ham it makes them "feel" it is better.

Models are, within known limits of the model, very good. When given the right input they are much better and more accurate than most people are."



I am sure everyone can understand why i would be reluctant to shell out $200 bucks for a new antenna when like most other old operators already have spent a lifetime tweaking dipoles, 1/4, 5/8, and beam antennas to work well for me, ie give me the coverage I need for my situation. I guess if i was new to the hobby I would prolly go the gm route as a good all around antenna. But I understand that no one single antenna does it all. And folks need to understand that, because sometimes they think that they can have one "best" antenna and then encounter situations where they don't have coverage and become upset or disillusioned with that product. So many variables, so little time..........Any way thanks for the observation and opportunity to share views.

 

[Shockwave]

i post w8ji's thread here.

"Originally Posted by KA7NIQ
If you tried to tell most any CB Operator that a Starduster will outperform a full size 5/8 wave antenna for local or DX, you will get little agreement.
IS it possible the computer model is incorrect, and/or something else is going on that makes the big 5/8 wave vertical out play the 1/4 wave ground plane with sloping radials in actual practice ?"

"Nope.

The 5/8th wave depends heavily on a large highly conductive reasonably flat groundplane at the BASE height of the antenna. That groundplane has to extend out in all directions for a considerable distance. The reflection out some distance is how the antenna works and gets gain. Without that groundplane at base height for some distance, the feedline will radiate and the pattern also will not form properly. You ALWAYS wind up with an unpredictable mess because key parts of the system are missing.

The 1/4 wave with sloping radials acts as a vertical dipole. It decouples a bit better from the feedline shield, and it has no area carrying out-of-phase currents.

What you will find is the 5/8th wave can vary from being just slightly better than a 1/4 wave with three or more sloping radials to being much worse at low angles. Statistically the 1/4 wave is more reliable.

The reason you won't find CB'ers who support that is they:

1.) Generally don't understand antennas

2.) Generally don't do valid A-B tests, just like Hams don't.

3.) Like Hams, they are trained to think a 5/8th wave antenna universally has 3 dB gain.

4.) Went through the work of installing the 5/8th wave, so like a Ham it makes them "feel" it is better.

Models are, within known limits of the model, very good. When given the right input they are much better and more accurate than most people are."



I am sure everyone can understand why i would be reluctant to shell out $200 bucks for a new antenna when like most other old operators already have spent a lifetime tweaking dipoles, 1/4, 5/8, and beam antennas to work well for me, ie give me the coverage I need for my situation. I guess if i was new to the hobby I would prolly go the gm route as a good all around antenna. But I understand that no one single antenna does it all. And folks need to understand that, because sometimes they think that they can have one "best" antenna and then encounter situations where they don't have coverage and become upset or disillusioned with that product. So many variables, so little time..........Any way thanks for the observation and opportunity to share views.

You have to read his entire article on this topic, not just the parts someone else quoted from his links. Someone posted the original links on this site to Tom's site and I spent some time reading the whole thing. He does step back from the comments quoted here and basically contradicts himself saying that the 5/8 wave is not worse then the 1/4 wave but that there are examples of where the 1/4 can equal the 5/8 wave. The real point Tom is trying to make deals with "reliability" and how that relates to many variables with the 5/8 wave. This requires a good understanding of typical radiation patterns of the antennas in question. Dealling with how the groundplane radials and height above ground will impact the secondary lobes, their beamwidth, and the elevation angle of the primary lobe that's hopefully on the horizon.

W8JI is saying that the 5/8 wave depends heavily on a good groundplane under the vertical and that its narrower beamwidth will be more affected by height above ground. The 1/4 wave also needs its groundplane under the vertical and its peak elevation angle will change with height too. The big difference is when you have the huge beamwidth of the 1/4 wave, you're literally sending out a radiation pattern that looks like a big ball in free space. That increases reliability by being able to target different angles regardless of the variables in the installation. It sure does not maximize signal in any key target area where you might want the benefits of antenna gain.

 

[Marconi]

Many of W8JI's posts are designed to make you think to get your answer. What he really says is that there are applications where a 1/4 wave will perform as good as a 5/8 wave. He goes on to say that the 1/4 wave will not really outperform the 5/8 wave but it could equal the performance in some cases.

Shockwave, I've re-read this linked thread again and I don't find anywhere that W8JI says or alludes to your idea:

"...that the 1/4 wave will not really outperform the 5/8 wave but it could equal the performance in some cases."

He may have said so in some other writing, but I don't see it here. If you have a link to such a conclusion by him, I would like to see it, cause I believe W8JI would suggest the very opposite and in particular according to his words, "...as determined in the minds of CB'ers and Hams." I think I've also read Cebik's ideas on this matter, and I think he too does not support the idea that the 5/8 wave antenna shows 3db advantage over a 1/4 wave, when tested over real Earth.

You know for some years I also believed that the longer antennas were so much better than the little "jobbers" that I was use to using, albeit I never felt inadequate in my radio operations at my location or in the mobile.

At some point when Jay first produced his new I-10K I decided it was time to try and compare test one of those longer styled antennas, and after a while testing my SD'r vs. I-10K, at differing heights, I really questioned what all the hop-la was all about.

So, I bought or was given some other antennas, and I tested and compared them as well. This started about 10 years ago, and since then I've taken the I-10K out and installed it and re-tuned it, but nothing has ever changed my mind that my SD'r couldn't perform just as well, even while set with the tip in the middle and higher...compared to the I-10K.

I know, I get the idea about side by side testing, but as you can tell I do a lot of signal recording, and even when I set these antennas out there all alone, the signals I record are always about the same, baring conditions of course or guys changing something with their radio systems.

I don't argue, that in theory, it is stated that the 5/8 wave shows a bit less than 3db gain over a 1/4 wave, but it also notes this occurs when compared over an infinite and conductive ground plane.

Simply put, had I never been able to see a 3db improvement by using Jay's I-10K over my Starduster, else I would be right there with you guys arguing the same issue while using my I-10K.

 

[gamegetter]

Simply put, had I never been able to see a 3db improvement by using Jay's I-10K over my Starduster, else I would be right there with you guys arguing the same issue while using my I-10K.[/QUOTE]

greetings old granpa,

can you rephrase the above? i not sure i follow!

 

[Marconi]

Simply put, had I never been able to see a 3db improvement by using Jay's I-10K over my Starduster, else I would be right there with you guys arguing the same issue while using my I-10K.

greetings old granpa,

can you rephrase the above? i not sure i follow!

You're right gamegetter, I should have said ever been instead of never been.

I was trying to say, that if my I-10K had produced 3db better performance than my SD'r, then I would not be here arguing the merits of an antenna with only a 1/4 wave radiator. I can say the same for my Top One or my New Top One as well. You can look at some of the videos I've made and see how close these antennas really are.

Can I see exceptions, Yes, but I see small exceptions in both directions all the time and I seldom see a remarkable difference. On-the-other-hand when I read comments from folks talking about their comparisons, I often hear them claiming 1-3 Sunits difference...which is a big difference as I understand it.

I will also acknowledge that all of my comparison signals are RX signals, so if I took the opportunity to always ask and get reliable info back regarding my antenna's TX signal, that might just be a horse of a different color. My issue with getting TX signals is also simple, I can depend on what I see on my meter, but I never know for sure what other's tell me.

If I was a well informed professional, testing antennas, I would probably want to test the TX signals in as controlled setup as possible, but my not having the setup to do so, I depend somewhat on the fact that antenna performance is supposed to be reciprocal and I feel more comfortable relying on the RX signals and my own observations of such.

 

[gamegetter]

thanks, i follow now...yes 1-3 s units is a big gain, comparable to 6 and 12 db, the gain expected of a 3 and 10 element yagi beam respectively. i have followed your reviews and reports and have commented before that differences in signal are negligible. I really have to sit down and do a cost versus performance trade off analysis when looking at gain and signal strength and changing antennas. remembering that to make your signal sound twice as loud requires increasing output power by 9 db. sometimes it makes more sense in my case to keep what i have and upgrade coax cable.

 

[Marconi]

thanks, i follow now...yes 1-3 s units is a big gain, comparable to 6 and 12 db, the gain expected of a 3 and 10 element yagi beam respectively. i have followed your reviews and reports and have commented before that differences in signal are negligible. I really have to sit down and do a cost versus performance trade off analysis when looking at gain and signal strength and changing antennas. remembering that to make your signal sound twice as loud requires increasing output power by 9 db. sometimes it makes more sense in my case to keep what i have and upgrade coax cable.

I agree adding power seems to do what you suggest. However, and this is just a guess gamegetter, since I can't see RF signals. But, you could also notice a difference in audio between two antennas at one moment in time simply due to conditions where signals arrived as line of site signals on one antenna, and with the other antenna the signals were reinforced by the addition of some reflection on the Earth's surface or objects, or from high angle reflections from the sky.

IMO, we are not likely to be able to observe such responses...unless at least one of the stations has two antennas up, connected thru a switch box for rapid switching, and the conditions are just right. To be fair, Bob85 recently posted information in another thread on this forum about their setting the radio's RFG back, in order to see better responses, and I believe that is possible in many cases. So, that too must be considered as a possible "cause" or "NO," in all such cases as I described above.

Otherwise I agree, it probably takes a lot of added power to produce a noticeably stronger audio signal in a general sense, and of course distance probably has much to do with such a phenomena being noticable. However, I might believe the responses are similar, IMO the causes are different.