Base Maco V58 model

[Needle Bender]

Hey guys, I was thinking about what you both might have realized in your real world experiences that gave you the idea there is a problem with A/B comparison testing.

I was checking out my models to see if there was something that I was missing in trying to understand this issue better. I had the though that maybe there was some difference to be noted if we looked at these A99 antenna 36' feet apart from the Azimuth view and to see if the minor skewing noted has some more serious effects that Elevation Plots do not reveal.

These Azimuth plots below show very small and similar differences in the Elevation Plots at the maximum angles for the patterns...but at 0* degrees, where the skewing is noted to occur, the patterns do show a bit more difference in gain and it is a loss. But, I'm still not sure the difference could be noticed just using our radio and even if it could...the difference here still looks pretty small and no where near 1 - 2 S-unit of difference. As you have also told us all the CB and HF signal meters are squirrelly.

Bob, we saw in another video I found showing maybe 1 S-unit difference for sure and another comment saying there was 2 S-units difference...which I would argue was not that apparent to me from the video.

But with that said however, you affirm again there is a difference when A/B testing...more or less stating "...but that is not the way we do it around here."

I think I understand your basic idea and description for how you do your comparison testing and that is fine with me and probably a good idea trying to be more accurate, but you still quarrel the video did it wrong...in spite of the fact they reported similar results to what you are claiming.

If this is the case...then my claim, your claim, NB's claim, and the claim made in the videos are all correct, and we have a winner...everybody wins the argument. A very liberal sign of the times no doubt.

The thing to do would be to erect an antenna, say, an Antron A99 on the A position mast and take readings, both on several local stations receive signal strength and how those stations read you.

Do it during morning, noon, afternoon & evening, and over several days.

Then swap that antenna to the B mast position of equal height & coax and repeat the logging of signal strength both on receive of same test stations and the signal strength they have on you.

Compare.

...ever come slowly to a stop while listening to the FM radio?
Ever hear "Picket fencing" where the station is strong for a second, then fades to weaker and back up as you slowly roll directly toward, or away from, the transmitting tower?

...signal goes up and down as you roll through the 1/4 wave nulls & peaks.

How can you know when test Antenna A is in the same peak or null to any given station as Antenna B?

You can't.

...not to mention how they might interact as a reflector or director for the other one.

 

[bob85]

Eddie i explained years ago what happend when i compared antennas in a field on two 36ft poles then swapped their positions several times and retested,

models only deal with wires their interaction with each other and a very rough guestimation of ground conductivity if you model over earth

in the real world we have all manner of things that effect signal that are not in the model and cannot ever be included in the model

The only proof you would be happy with Eddie is to see it yourself on your equipment,
its VERY easy to make a video that shows whatever i like without any editing or camera tricks,
my locals will say whatever i tell them to say on the video and adjust their power so it all looks convincing,
don't take anything on youtube as proof of anything, laugh at two antenna tests,
its entertainment not science

have a look at spacial diversity antennas Eddie, then tell me two co-located antennas tx and rx the same as each other to all locations,
there may not be a dead balls on method of comparing antennas since you either have to separate the antennas spacially or separate them in time,

my own experience is that unmodulated signals stay fairly constant over time with the odd flutter caused by multipath reflections off passing airplanes summing & cancelling
whereas co-located antennas can have a different winner depending on which same length pole they are mounted on even when mounted in a field not near obstructions in the antennas nearfield.

 

[Marconi]

The thing to do would be to erect an antenna, say, an Antron A99 on the A position mast and take readings, both on several local stations receive signal strength and how those stations read you.

Do it during morning, noon, afternoon & evening, and over several days.

Then swap that antenna to the B mast position of equal height & coax and repeat the logging of signal strength both on receive of same test stations and the signal strength they have on you.

Compare.

NB, I understand the basic ideas you are suggesting for comparing signals using the same mast, feed line, and radio system, but that is not the question I asked you and Bob to explain. I asked for your help in understanding what difference I can expect to see on my signal meter. I have posted my videos and my Signal Reports that I've recorded on paper and it appears to me that you both dismiss, out of hand, what these reports might indicate.

To me, you see issues in my A/B testing that suggest one antenna interferes to such an extent...so as to make my A/B comparisons without value at all. I just want to know how much difference you guys see when you compare your way vs. A/B switching.

I make no claim that all of these signal values I have recorded were done with precision and accurate beyond question...I am a flawed human and I do make mistakes.

I also realize that trying to analyze all the numbers may not be of interest, but they were done randomly as the signals from a select set of buddies came in at any particular time, and they are basically all receive signals. I learned quickly that asking for signal reports from this group of CB buddies was below the dignity of the group and I have talked with for years. I did record others from time to time, but I did that to help balance out the reporting. I also tried to learn as much as possible about what each operator and where their stations were in relationship to my own.

Again, my question is either being ignored because you don't understand my words, or you simply can't explain what difference it might make to the signals I have reported if I did as your suggest rather than doing A/B comparisons.

You both suggest there are shortcomings in A/B testing and IMO that suggests I should see a difference in the signals I have recorded. So, tell me how much of a difference you noticed when you compared A/B testing compared to the method you're suggesting as the only way to compare signals correctly.

...ever come slowly to a stop while listening to the FM radio?
Ever hear "Picket fencing" where the station is strong for a second, then fades to weaker and back up as you slowly roll directly toward, or away from, the transmitting tower?

...signal goes up and down as you roll through the 1/4 wave nulls & peaks.

How can you know when test Antenna A is in the same peak or null to any given station as Antenna B?

You can't.

I probably have noticed what you describe above, but I didn't know what was causing the condition and I sure didn't think about it being called a picket fence effect. To be honest I can't see radio waves and I have no idea what causes any specific condition to occur and I doubt you really know for sure either. I don't include mobile antenna reports in my reporting, so what is the point you are making about picket fencing?

...not to mention how they might interact as a reflector or director for the other one.

I posted a model of two A99 antennas side by side and it does show some shewing effects on the pattern, but here we see how much difference it makes and that does not agree with your suggestion about the pitfalls in A/B testing, because the difference is insignificant. See overlay below.

So, I'm not surprised you ignore the models and signal reports I've posted. You can only make a claim that a model cannot represent what is in the real world, and you are asking me to agree with your claims...and you show no supporting evidence at all...just words. You can't even find a link that discusses these ideas that purports to be anywhere near scientific. I could have posted just words too, but I wanted to try and show some evidence that supported my words.

I can also tell you that what the models shows is pretty much what I've detected in my real world testing...and this is what I have claimed for years...if the antennas are fairly situated with the current maximums even close to the same height. I seldom if ever see any difference in switching antennas when A/B testing on my end, but it does happen now and then.

If I really questioned A/B testing it would be if I saw big differences greater than an >S-unit in the signals on switching between most any of my CB vertical monopole antennas...then I would really wonder why the difference.

I have never said I have never seen a difference, I just don't see the differences and for sure those over 1 S-unit difference.

 

[bob85]

Eddie you are trying to use EZNEC to show two antenna testing is fine and dandy since gain is not effected much with co-located antennas,

I never said gain was notably effected, gain and signal are not the same thing,
you are misusing NEC again to support what you believe,

NEC can't do squat for telling you anything at all about which co-located antenna will produce the strongest rx or tx signal in what direction in the real world of towns and topology because the only part of the real world that can be included in the model is a guess at ground conductivity,

That's like arguing that two "RUN WHAT YOU BRUNG" cars will produce similar times as they have similar horsepower,

NEC is like soldering irons.

 

[Marconi]

Eddie i explained years ago what happend when i compared antennas in a field on two 36ft poles then swapped their positions several times and retested,

Bob, back then I didn't question anything you said. Years later after learning to model a bit...I questioned some of those ideas and I posted what and why I changed my mind, if I did in fact change my mind.

I just presented an argument hoping to explain or explain away what I had been told. At times my recollections were vague, so that too has to be considered. I tried to keep an open mind that I could be convinced either way. In many cases however, all I got was modeling was flawed just like noted in your comments below .

models only deal with wires their interaction with each other and a very rough guestimation of ground conductivity if you model over earth

in the real world we have all manner of things that effect signal that are not in the model and cannot ever be included in the model

You are correct, these models seldom have any environmental objects to interfere with the patterns as we typically imagine/understand happens. Here, however, you admit that your real world experiences validates the claims you make...when in fact all the environmental variables are all in your camp Bob. Thus Ockham's Razor principle comes to mind regarding this issue of disagreement between us.

You also make note about the soil (Earth) conditions and in my models over Eznec's idea of real Earth is truly a variable, but at least it is base on some science and not just pure speculation like it is at your station and mine.

The only proof you would be happy with Eddie is to see it yourself on your equipment,
its VERY easy to make a video that shows whatever i like without any editing or camera tricks,

What is wrong with proof to support one's own ideas? It has never been my desire to be deceptive in the videos I've made and you probably can tell a little of the truth in this claim by the surprise that sometimes showed its ugly side when something in the video obviously didn't work out as I expected or as my words predicted.

All of those videos were as off the cuff and I think such a flaw shows. I don't have the patience to plan evil deeds just to try and prove a point in a video that I can show in some other effective manner. For me, it is easier and more straight forward to say I changed my mind, rather than hang on to a flawed or dubious believe. Some folks never change their minds about anything.

my locals will say whatever i tell them to say on the video and adjust their power so it all looks convincing,

I don't operate that way Bob, I would never tell a buddy to say or post something that I don' believe is true on my behalf.

don't take anything on youtube as proof of anything, laugh at two antenna tests,
its entertainment not science

I'm not claiming to be doing science here and this is entertainment at best, your claiming what you think and telling me I'm wrong.

have a look at spacial diversity antennas Eddie, then tell me two co-located antennas tx and rx the same as each other to all locations,

Why don't you present this idea in support of your thinking here instead of suggesting we read something for our better understanding and missing the point you have in mind. Is that fair enough?

my own experience is that unmodulated signals stay fairly constant over time with the odd flutter caused by multipath reflections off passing airplanes summing & cancelling

I thought watching my meter trying to determine what some guy's maximum signal was using SSB...was a bit boring. Do you think my meter is more error prone than your observations might be with radio signals that nobody can see whether they are bouncing off of an airplane, birds, or smoke in the air?

whereas co-located antennas can have a different winner depending on which same length pole they are mounted on even when mounted in a field not near obstructions in the antennas nearfield.

I have seen winners before but the difference was so small that in the scheme of things it made very little difference just working my radio. See the difference I posted earlier in my overlay of an A99
standing alone and beside each other 36' apart.

I recall Homer telling us recently about his new 5/8 wave with a CC Ringo type tuning ring was able to communicate with another station while a neighbor 4 blocks away with an A99 mounted higher but could not hear. So it can happen, but I never had an antenna that was so bad as to manifest such a terrible performance. I think I suggested Homer go help his neighbor out since he is obviously in the mud.

 

[Marconi]

Eddie you are trying to use EZNEC to show two antenna testing is fine and dandy since gain is not effected much with co-located antennas,

If I said I was talking about gain differences I miss spoke. What I think I said and at least what I meant was the Eznec shows us in the overlays little to no difference in the patterns.

I never said gain was notably effected, gain and signal are not the same thing,

As best I recall you didn't describe anything as the difference. That is what my question to you was all about...what is the difference...if I use A/B testing and you do your testing your way?

NEC is like soldering irons.

I don't get the humor or logic in your words here, but try this in response. How do you explain the value of NEC in light of the fact that LB Cebik used Eznec, a product using NEC engine in virtually every document I ever read where he used modeling as examples for a multitude of features for antennas?

 

[Marconi]

Bob it may surprise you to hear I agree that your way of testing any antenna is probably better served eliminating as many variables as possible. Among other precautions and controls I would figure this is a cardinal rule on any reputable antenna test range.

My question to you and to NB'r is...based on your testing this idea what and how much difference did your comparisons make that demonstrated a difference that mattered just using a radio?

I have records for what I've done to test your idea and I might do some more comparisons for that work, but I can't redo the testing. I have compared several of my antennas standing alone and then took signal readings with another antenna sided beside like I've describe in my setup earlier at 36' apart.

I will follow up either way it develops.

 

[bob85]

Who's we Eddie ?,
its you not we mr doubting tom,

why do you think I should find evidence that supports my claim, are you too lazy to do your own reading ?

How about you find something that supports your mickeymouse tests and misuse of EZNEC,

can you highlight which lines of data in your model represents the local topology and which lines represent obstructions like buildings / trees,
just one line that represents any of the real world things that effect signal will do Eddie.

 

[Marconi]

Bob, you don't seem able to debate an issue without sooner or later getting angry and then personal.

 

[Needle Bender]

Your Question:

NB, I understand the basic ideas you are suggesting for comparing signals using the same mast, feed line, and radio system, but that is not the question I asked you and Bob to explain. I asked for your help in understanding what difference I can expect to see on my signal meter. I have posted my videos and my Signal Reports that I've recorded on paper and it appears to me that you both dismiss, out of hand, what these reports might indicate.

To me, you see issues in my A/B testing that suggest one antenna interferes to such an extent...so as to make my A/B comparisons without value at all. I just want to know how much difference you guys see when you compare your way vs. A/B switching.

I make no claim that all of these signal values I have recorded were done with precision and accurate beyond question...I am a flawed human and I do make mistakes.

I also realize that trying to analyze all the numbers may not be of interest, but they were done randomly as the signals from a select set of buddies came in at any particular time, and they are basically all receive signals. I learned quickly that asking for signal reports from this group of CB buddies was below the dignity of the group and I have talked with for years. I did record others from time to time, but I did that to help balance out the reporting. I also tried to learn as much as possible about what each operator and where their stations were in relationship to my own.

Again, my question is either being ignored because you don't understand my words, or you simply can't explain what difference it might make to the signals I have reported if I did as your suggest rather than doing A/B comparisons.

You both suggest there are shortcomings in A/B testing and IMO that suggests I should see a difference in the signals I have recorded. So, tell me how much of a difference you noticed when you compared A/B testing compared to the method you're suggesting as the only way to compare signals correctly.



I probably have noticed what you describe above, but I didn't know what was causing the condition and I sure didn't think about it being called a picket fence effect. To be honest I can't see radio waves and I have no idea what causes any specific condition to occur and I doubt you really know for sure either. I don't include mobile antenna reports in my reporting, so what is the point you are making about picket fencing?



I posted a model of two A99 antennas side by side and it does show some shewing effects on the pattern, but here we see how much difference it makes and that does not agree with your suggestion about the pitfalls in A/B testing, because the difference is insignificant. See overlay below.

So, I'm not surprised you ignore the models and signal reports I've posted. You can only make a claim that a model cannot represent what is in the real world, and you are asking me to agree with your claims...and you show no supporting evidence at all...just words. You can't even find a link that discusses these ideas that purports to be anywhere near scientific. I could have posted just words too, but I wanted to try and show some evidence that supported my words.

I can also tell you that what the models shows is pretty much what I've detected in my real world testing...and this is what I have claimed for years...if the antennas are fairly situated with the current maximums even close to the same height. I seldom if ever see any difference in switching antennas when A/B testing on my end, but it does happen now and then.

If I really questioned A/B testing it would be if I saw big differences greater than an >S-unit in the signals on switching between most any of my CB vertical monopole antennas...then I would really wonder why the difference.

I have never said I have never seen a difference, I just don't see the differences and for sure those over 1 S-unit difference.

My Answer:

...signal goes up and down as you roll through the 1/4 wave nulls & peaks.

How can you know when test Antenna A is in the same peak or null to any given station as Antenna B?

You can't.

 

[Marconi]

NB. I agree it is impossible for me to tell when test Antenna A is in the same peak or null to any station at Antenna B, and in case you missed my earlier signal reports I do not report that information which you proclaim I can't see or do...when I'm comparing signals either.

So, are you then suggesting, if I only followed the instructions that you and Bob proclaim...as the only way to accurately compare antenna signal reports...everything will be fine, correct, accurate, and then I can also report the peaks, nulls, along with the relative signal strength from an antenna 20 miles away?

Me thinks, you both protest to much!!!

And over such an insignificant issue, and it may be simply because my models results do not agree with your results. Results that you both seem incapable of describing in any measured way...showing a difference that can be compared and considered in thinking about this issue.

I think this is more about egos and ideas regarding modeling than anything else.

Much of what I've heard, almost from the start of my modeling experience, was modeling is junk science and riddled with errors and limitations.

And to put more of a point on it...IMHO this has to do with models that might bring into question sometimes...what others have previously claimed. So, for me this is mostly about ego and self-pride mixed with the pleasures in conversation with others.

 

[bob85]

This is not a debate its you slipping back into doubting Thomas mode again Eddie, we have been over this several times,

The onus is on you to prove what you claim, that co-located antennas in an urban environment rx and tx equally in all directions

I pointed you in the right direction but you can't be arsed to look it up,

where are the words from respected sources that support your ideas ?
Thus far all we have is mickeymouse videos and misuse of NEC,
the youtube vid where you are grunting and gooning at your locals made me realise why they have no interest in helping you test antennas,

your tests are done guerrilla style using unwitting participants who make no effort to provide a stable signal on modes that are up and down like a bridesmaids dress, sometimes while skip is running,

like soldering irons,
I have no issue with EZNEC or other MOM software, they are great tools if the user is competent.

Theres plenty of evidence on here and in the private conversations that you are no longer privvy to that proves i have no issue with EZNEC.

 

[The DB]

...signal goes up and down as you roll through the 1/4 wave nulls & peaks.

I missed this the first time around, but are you saying that the nulls and peaks from a base (or other non-moving) antenna are static in space, or at least traveling slow enough that you can notice the difference by driving through them?


The DB

 

[bob85]

swizzradios made a video that demonstrates why we can see small changes just using our radio,


look what happens to the s-meter when s6 is reduced to s5

i think what NB thinks is him moving along the wave to different voltage nodes causing picket fencing effect is actually multipath summing and cancelling,
the same effect as i see with passing planes,
the reason diversity works and the reason you should test on the same pole/coax

 

[The DB]

i think what NB thinks is him moving along the wave to different voltage nodes causing picket fencing effect is actually multipath summing and cancelling,

This is correct, it is summing from multipath (multiple signal paths for those of less technical persuasion) that creates the picket fencing effect. This typically happens at the far edge of range, and generally at higher frequencies as higher frequency signals are far more reflective in the environment around us than HF signals. Further, the peak points and null points are not necessarily 1/4 wavelength apart, or any specific length as said addition of signals depends on the multiple path lengths the signal took to get to the point in question. Based on said paths, you could just as easily have a much larger or smaller distance where said peaks and nulls happen to line up, and that is assuming a static world. Things moving around, like cars, (or at the right frequencies, people, or even just changing atmospheric conditions) can cause these points to constantly change, even if the antenna is static.

Its just the way he said it made me think he was talking about something other than multipath, as what he said simply doesn't line up with how multipath works. It was like he was talking about something else entirely, so I was curious.


The DB