The 5/8-Wavelength Antenna Mystique

[The DB]

What do you want me to prove? I didn't state a belief but rather a fact, Eznec cannot emulate real life. It cannot take into account attenuation, it cannot take into account the difference between the materials our houses are made out of, coax differences, differences in soldering techniques, antenna switches that Marconi uses that are poor quality, flat ground as apposed to hilly ground. Its a free space emulator which isn't valid in the real world.
In the real world where I live, quarter wave GP's do not perform as good as 5/8th waves, .64 or open sleeve antenna's. How do I know? Because I've had 2. Besides that I know people that have had them and they also believe they don't perform as good. Not saying they don't work just saying they don't perform as good as a 5/8th wave. If they did then everyone would have one because they take up very little space.
With antennae, the money is where the performance is around these parts and no matter what Eznec says that will always be the case.

First about EzNEC accurately duplicating reality... I never said it was just like reality. On multiple times in this very thread I said that it has its limitations. The part of your statement that I was challenging was you claiming it was a single persons attempt to duplicate what happens in reality, which is *NOT TRUE*. NEC2, which is used by EzNEC was developed in 1981 at Lawrence Livermore Labs under contract for the US Navy. There goes the one person's version of how the world works theory you presented. Also, being developed for the Navy, I would expect it to be pretty accurate, definitely more accurate than you obviously think. Again, this does not mean it doesn't have its limitations.

As far as what it can and cannot simulate, I myself, in this very thread, said that its results were akin to a "lab environment". The last time I checked, a lab environment is not the same as the real world. Weather or not EzNEC matched up to the real world was never in question, and definitely not part of *ANY* of my claims, and any assumptions of that on your part *ARE IN ERROR*. All I was trying to say is EzNEC is a tool, and its information as well as that of *ANY* modeling program needs to be taken in context. This was in response to you claiming that anything generated from EzNEC is effectively irrelevant, which again is also clearly not true.

Also, no one here ever once made the claim that a 1/4 wave groundplane antenna was always better than a 5/8 wave groundplane antenna. If that is what you thought was being said or assumed, then you misread everything in this thread. The claim that has been made, and backed up with two separate documents, is that the gain many people think they are getting with a 5/8 wave groundplane antenna over a 1/4 wave groundplane antenna is *NOT AS MUCH AS THEY THINK IT IS*. Often the difference between the two is so small that you can't tell the difference. One of the studies actually shows more of a gain for the 5/8 wave antenna when it is over poor soil conditions, which is counter to what many believe. That being said some of the modeling was done with EzNEC, so the whole article must be irrelevant to you. I suppose you expect me to fall in line with your version of reality over Cebik's study, good luck with that.

Also, when it comes to CB antennas and performance being where the money is, all to often the money is where the snake oil is and the people that fall for it don't know they aren't getting as much performance as they think. That being said, quite often when it comes to CB antennas the money is where the low price is. How many threads on this and other forums are people settling for an Imax 2000 over any number of other more expensive antennas.

How about this real world experience from me. There are two friends of mine that live on the same block with each other, and both are about 25 miles away. One of them has a 102" whip with homemade angled radial wires made of 14 AWG wire on his house, the other has a new version of the Hy-Gain Super Penetrator. They run the same power output from identical radios which were tuned by the same tech (also a friend of mine). I cannot tell the difference between their signals and the S-meter moves to exactly the same point on the scale (not that I trust s-meter reading, which I don't).

In your case the 5/8 wave antenna may in fact be superior, but elsewhere in the world where there are other environmental conditions at play (different hills, different soil conductivity/permeability, etc., you know the same environmental conditions that you mentioned that modeling programs cannot account for) you can expect a far different result.


The DB

 

[nav2010]

For that test between your two friends to be valid both antennae need to be on the same pole and in the same location with the same radio and coax otherwise it is a totally pointless exercise.
So you don't think Marconi is going to suggest later on in this thread that a quarter wave is better than a 5/8ths wave?
Been here before and bought the t-shirt, Marconi once stated that his A99 is the best antenna he has including his i10k and I know exactly where this is leading DB.
Anyone coming out with an opening statement 'or are we destined to ignore the truth?' already has an outcome on his mind.
He's going to suggest his Starduster is the best kick ass antenna in town, sorry but I already see this train coming.

 

[ghz24]

Eznec cannot emulate real life. It cannot take into account attenuation, it cannot take into account the difference between the materials our houses are made out of, coax differences, differences in soldering techniques, antenna switches that Marconi uses that are poor quality, flat ground as apposed to hilly ground. Its a free space emulator which isn't valid in the real world..

Of course NEC can't emulate real life. It was never meant to besides real life emulates real life perfectly Houses ,terrain, coax, relative soldering skills and any other real world interferences are what's irrelevant to simple antenna comparisons.

In the real world where I live, quarter wave GP's do not perform as good as 5/8th waves, .64 or open sleeve antenna's. How do I know? Because I've had 2.

But you haven't lived in all terrain types in every neighborhood (next to the guy with the bed spring mattress antenna) ect. ect. So how is your experience more relevant to people who live elsewhere in the real world

Besides that I know people that have had them and they also believe they don't perform as good.

<gotproof> well that's compelling evidence :headbang

With antennae, the money is where the performance is around these parts and no matter what Eznec says that will always be the case

Most places the money follows the well hyped snake oil leaving most of us at the mercy of all sorts of "works good for me" endorsements of (no offense) questionable quality.
I'm not saying you should blindly believe every model you see posted.
It is possible to miss lead with them (even yourself ).
It was good enough for the navy I think it's accurate enough to compare a few CB antennas.
The techs aren't arguing it doesn't work.

 

[nav2010]

Of course NEC can't emulate real life. It was never meant to besides real life emulates real life perfectly Houses ,terrain, coax, relative soldering skills and any other real world interferences are what's irrelevant to simple antenna comparisons.

But you haven't lived in all terrain types in every neighborhood (next to the guy with the bed spring mattress antenna) ect. ect. So how is your experience more relevant to people who live elsewhere in the real world


<gotproof> well that's compelling evidence :headbang

Most places the money follows the well hyped snake oil leaving most of us at the mercy of all sorts of "works good for me" endorsements of (no offense) questionable quality.
I'm not saying you should blindly believe every model you see posted.
It is possible to miss lead with them (even yourself ).
It was good enough for the navy I think it's accurate enough to compare a few CB antennas.
The techs aren't arguing it doesn't work.

Houses ,terrain, coax, relative soldering skills and any other real world interferences are what's irrelevant to simple antenna comparisons.
So if Marconi has the most conductive soil in the US what does that say about his antenna tests?
But you haven't lived in all terrain types in every neighborhood (next to the guy with the bed spring mattress antenna) ect. ect. So how is your experience more relevant to people who live elsewhere in the real world
Because its not just my experience, different people, different locations, different surroundings and 5/8ths wave wins.
It was good enough for the navy I think it's accurate enough to compare a few CB antennas.
I've got some news for you which you may not know. The navy is out in boats on an ocean not on land.
Most places the money follows the well hyped snake oil leaving most of us at the mercy of all sorts of "works good for me" endorsements of (no offense) questionable quality.
Depends who they are trying to kid doesn't it.

 

[The DB]

For that test between your two friends to be valid both antennae need to be on the same pole and in the same location with the same radio and coax otherwise it is a totally pointless exercise.

I don't own the antennas, and I doubt they would go for the hassle of that type of test when both of their antenna systems is properly tuned and working well. Therefore I am limited to what I have...

So you don't think Marconi is going to suggest later on in this thread that a quarter wave is better than a 5/8ths wave?

I think Marconi will stick to his line that he has stuck with since before this thread started, which I think is very close to being the same opinion as mine. Never once did I see him emphatically say that a 1/4 wave antenna was always better than a 5/8 wave antenna. I do remember him saying that it depends on various environmental factors.

Been here before and bought the t-shirt, Marconi once stated that his A99 is the best antenna he has including his i10k and I know exactly where this is leading DB.

I can't say I recall him ever saying that. I do know of several other people that have tried to make that very claim, although I don't recall seeing that on this forum. You wouldn't happen to have a link for that for verification purposes would you?

Anyone coming out with an opening statement 'or are we destined to ignore the truth?' already has an outcome on his mind.
He's going to suggest his Starduster is the best kick ass antenna in town, sorry but I already see this train coming.

I went back to the first post to get the full context of what was being said:

So, what is the truth, is the 5/8 wave idea as good as many in the CB World claim, or are we destined to ignore the truth?

I think this line could have been worded better. It is two separate questions in the form of a single question, and I think it is a bit confusing myself. It definitely can give the impression that a decision has been made, but it can be read to mean something else entirely. Only Marconi can narrow down the meaning any here. Having read his posts on this and other forums, I think I have a pretty good read on what he meant, but even that is subjective.


The DB

 

[ghz24]

The navy is out in boats on an ocean not on land.

oh.. all the navys resources are on the sea no land based antennas right?
Scientists try to limit the variables they must deal with , the less variables there are the more likely a correlation (and maybe a cause and effect)can be observed.
Unless you want any data to only pertain to you then your neighbors house is irrelevant to a good antennas design.
Getting your neighbors house out of the picture is the whole point.
Oddly the NEC results are exactly on or so close to what the ARRL handbook reports that I'd bet few here have equipment that could measure the difference.
As far as

If they made a mistake or two then its a pile of horse manure

It's open source you can check for mistakes yourself like I'm sure hundreds of EEs have already. When they are discussing it's limitations.
There are whole groups of amateurs building complicated antennas from models and comparing the real antenna to the models prediction and documenting every minute discrepancy.
There is a reason ham publications require gain claims to be backed up by modeling. It cuts out the real horse manure.
Not that the advertisers don't always try to push the truth to make their product look better.

So if Marconi has the most conductive soil in the US what does that say about his antenna tests?

Without actually studying the data in question I'd say they are equal in relevance to any other tests of equal accuracy (skill in collecting the data and quality of equipment) But they are most relevant to him at his local just like everyone's are most relevant to them.
If we could get enough equal quality tests at hundreds or better thousands of places then statistics could be used to get usable quantitative results.
But with the variations of skill and equipment I would be still at least somewhat skeptical of sample sizes in the hundreds vs thousands.
Maybe a network of thousands of identical internet connected receiver units.

 

[Henry HPSD]

Frequently we see the CB community questioning NEC.

Anyone, who investigate that subject a bit futher will found out those "tests" are already done quite some times by far more knowledgable people.

NEC is accurate. (within its limitation).
NEC is more accurate than people can "notice".(just give it a shot.. 0,5 dB on ear

The biggest "error" (as always) would be the human interpertating/providing the data.

Regards,

Henry

 

[Marconi]

It is easy to argue that I might get something wrong that I've said over time or what I think, my opinion. It might even be fair to argue that Eznec is not perfect...even though I doubt Nav2010 knows enough about the program to make a reasonable judgment on the difference between what theory might suggest and real Earth situations. His opinion maybe be warranted, but his personal condemnation of me or Eznec, as an argument is not...unless he has some real evidence he can produce...instead of just words.

I consider Cebik a good source of information, so check out his comparison report below, which is in the following article: The 5/8-Wavelength Mystique

There you will find what Cebik indicates, as a practical matter, as he compares a 10 meter 1/4 wave at various heights, configurations, and soil conditions to a 5/8 wave.

Now, based on the theory in the original review I posted for this thread, see if you can find a situation at the 25' foot height where Cebik indicates the 5/8 wave setup is 3 db better than the 1/4 wave, as is clearly noted for the theoretical gain in Fig. #2, of the article.

This review also has nothing to do with Eznec or modeling as we know it today.

This is all I intended to show, if one makes an effort to read this review carefully. With that said Nav2010, it would be more productive to make your point about the article and not me personally. I'm not the subject of this thread, but I do have my opinions.

Table 15. 10-Meter 1/4-wl monopoles over various soils.

Soil Type Gain TO Angle Lobe Feedpoint Impedance
dBi degrees No. R +/- jX Ohms

1/4-wl Monopole, 90-degree radials, 1' above ground
Very Poor..0.66....27...1....33.4 + j 4.2
Poor.......0.23....25...1....36.1 + j 6.1
Good.......0.07....25...1....36.4 + j 5.8
Very Good..0.43....23...1....38.8 + j 6.2

1/4-wl Monopole, 90-degree radials, 5' above ground
Very Poor..0.43....22...1....25.2 + j 1.3
Poor.......0.95....19...1....26.1 + j 0.5
Good.......0.75....20...1....26.0 + j 0.3
Very Good..0.81....17...1....26.5 - j 0.5

1/4-wl Monopole, 90-degree radials, 25' above ground
Very Poor..2.99....13...1....24.1 + j 4.0
Poor.......2.67....35...2....24.2 + j 3.9
Good.......2.73....34...2....24.2 + j 3.9
Very Good..3.78....33...2....24.1 + j 3.8

1/4-wl Monopole, 45-degree radials, 25' above ground
Very Poor..3.11....13...1....59.3 + j 38.3
Poor.......2.42....38...2....59.6 + j 38.2
Good.......2.51....37...2....59.6 + j 38.1
Very Good..3.52....36...2....59.8 + j 38.0
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table 16. 10-Meter 5/8-wl monopoles over various soils.

Soil Type Gain TO Angle Lobe Feedpoint Impedance
dBi degrees No. R +/- jX Ohms

5/8-wl Monopole, 90-degree radials, 1' above ground
Very Poor..2.13....19...1....82 - j 307
Poor.......1.97....16...1....82 - j 307
Good.......1.72....16...1....82 - j 307
Very Good..1.05....13...1....82 - j 308

5/8-wl Monopole, 90-degree radials, 5' above ground
Very Poor..2.43....17...1....83 - j 307
Poor.......1.88....14...1....83 - j 307
Good.......1.63....14...1....83 - j 307
Very Good..2.21....46...2....83 - j 307

5/8-wl Monopole, 90-degree radials, 25' above ground
Very Poor..4.13....10...1....84 - j 308
Poor.......3.16....26...2....84 - j 308
Good.......3.19....25...2....84 - j 308
Very Good..4.19....24...2....84 - j 308

5/8-wl Monopole, 45-degree radials, 25' above ground
Very Poor..3.02....10...1....83 - j 283
Poor.......3.57....25...2....84 - j 283
Good.......3.54....25...2....84 - j 283
Very Good..4.26....23...2....84 - j 282

Also pay close attention to the captioned section in the original link that I posted for this review, entitled: "Measurement Techniques," where it describes specifically how the real world testing was done as compared to what theory predicted.

 

[nav2010]

Eddie, my experience is that a 5/8ths wave performs better than a 1/4 wave GP, this is my real world experience. I don't care whether Eznec says a quarter wave can work wonders and shit cucumbers it will not change that fact.
No matter how much you twiddle and manipulate Eznec to say otherwise the fact will always remain for me that 5/8th wave are better. Where I live there are about 30 CB breakers who have homebase antennae, out of those 30 people none have a quarter wave GP and i'd say probably more than half have 5/8th waves, the rest a mixture of half waves, vector 4000's and Gainmasters.
The price of a Starduster is £51 delivered, the price of a Vector or an 827 is 90-£100, a Gainmaster about £120. As you can see the cheapest option is the quarter wave aswell as being less space consuming, people prefer to pay double that of the Starduster so this is not a cost issue as someone pointed out. The real reason is because several local Cb'ers have bought quarter waves, mounted them on the same pole as they had their 5/8ths wave and found it didn't cut the mustard. Now you either except that or spend the rest of your life twiddling with pointless silly software. The proof is in the real world.

 

[northern35s]

30 CBers could never be wrong eh?

With a closed mind it's impossible to see what's in front if your face, your comment; "Pointless silly software" tells me all I need to know about the information you present here, rather than back up any of your claims with rigorous testing, you instead back up your claims with ad hominem attacks on anyone who you disagree with.

If you study the theory, read the peer tested articles, then you are on your way to a better understanding of the subject, there are some very clever people behind the articles linked to or posted on this and many other threads like it, discounting their findings in favour of your 30 CBers just reinforces your closed mind thinking.

 

[nav2010]

30 CBers could never be wrong eh?

With a closed mind it's impossible to see what's in front if your face, your comment; "Pointless silly software" tells me all I need to know about the information you present here, rather than back up any of your claims with rigorous testing, you instead back up your claims with ad hominem attacks on anyone who you disagree with.

If you study the theory, read the peer tested articles, then you are on your way to a better understanding of the subject, there are some very clever people behind the articles linked to or posted on this and many other threads like it, discounting their findings in favour of your 30 CBers just reinforces your closed mind thinking.

I don't care if the Queen of England wrote the software and Isaac Newton designed the quarter wave, it ain't as good as a 5/8ths wave.
My mind isn't closed, I've had 2 quarter waves up on my pole and they are on a par with a half wave or maybe just under, my tests were done on the same coax, same pole, same radio with reliable signal reports.
What will be your next claim? Quarter wave is better than a Vector 4000?:bdh:
edit:
Mind you, that is not off the cards because I remember Marconi claiming that his Antron99 was better than a Vector, an Imax 2000, i10K and a Gainmaster. May the misinformation super highway continue...............

 

[ghz24]

my tests were done on the same coax, same pole, same radio with reliable signal reports.

Same pole as in no higher? So the tip of the smaller antenna was lower than the tip of the 5/8 is that right?
How did you determine the reliability of those signal reports?

 

[nav2010]

Here is my list of best performing antennae including modded versions.
1. Open sleeve types (Vector, siggy4 etc)
2. 5/8ths with full quarter wave radials (i10k, Mr coily etc)
3. 5/8ths/.64 wave dipole (Gainmaster)
4. 5/8th wave with radial kits or shorter radials (Sirio 827, Imax with GP kit)
5. Half wave with full quarter wave radials
6. Standard 5/8ths wave no radials
7. Standard half wave
8. Quarter wave.

 

[nav2010]

Same pole as in no higher? So the tip of the smaller antenna was lower than the tip of the 5/8 is that right?
How did you determine the reliability of those signal reports?

I've had the tips at the same height as an half and 5/8ths wave and i've had them ever higher than a 5/8ths wave, still not as good.
I have a mast that is on a winch system and I could get an antenna on and off within 30 minutes and set the height where ever I like.
I have good friends all over this district who I have met and worked with on antenna projects at various times. People that I have gone CB fox hunting with for years who I know are good people. This is a tight nit CB community and we all help each other all the time, not just radio stuff but all walks of life.

 

[northern35s]

I don't care if the Queen of England wrote the software and Isaac Newton designed the quarter wave, it ain't as good as a 5/8ths wave.
My mind isn't closed, I've had 2 quarter waves up on my pole and they are on a par with a half wave or maybe just under, my tests were done on the same coax, same pole, same radio with reliable signal reports.
What will be your next claim? Quarter wave is better than a Vector 4000?:bdh:
edit:
Mind you, that is not off the cards because I remember Marconi claiming that his Antron99 was better than a Vector, an Imax 2000, i10K and a Gainmaster. May the misinformation super highway continue...............

I have made no claims in this thread re antenna performance, be that 1/4 or 5/8WL, maybe your closed mind leads you to believe differently?