Regarding antennas, what does counterpoise mean?

[HomerBB]

Well,what I've studied so far is that an antenna(signal) needs something to push off of,namely a counter poise. The antenna is like a race car,the energy being fed it is likened into gas and the counter poise is the tires that are needed to make the whole thing move.

Even if your analogy were workable, the tire would not be the opposing force at all. It would be the ground. The gasoline is fuel, not force. The only force supplied in your analogy is that of the rotation of the tires, and the only thing supplied in opposition is the ground upon they exert their force in order to propel the vehicle forward.

 

[HomerBB]

http://www.worldwidedx.com/attachme...rpoise-mean-counterpoise-vs.-ground-plane.pdf

counterpoise vs. ground plane.pdf

Marconi, I have brought into this post your .pdf model and the graphic.

Two things:

1. I am under the impression that you are limiting your understanding of the counterpoise to a setup as pictured in the graphic. Hopefully not.

2. I think that the comparison model would be more accurate to the experience of a near ground mounted vertical if it was done with a completely surrounding counterpoise network rather than this off center setup under a bent to horizontal antenna with a coil and condenser in it.

It is easy to see why your model has a large off center lobe similar to a vertical dipole side mounted to a metal pole. It would be less a matter of speculation as to whether the gain on the big lobe is due to the effects of the counterpoise or the inherent nature of the horizontal wire.

 

[nav2010]

All antennas need two halves to operate, that is a well proven fact. If you don't give the antenna that other half it will find something to use in its place, be it coax shielding, mast, the roof of your car, ext.

Some people take it a step further by calling anything that makes up this other half a "counterpoise". I believe that this is a misunderstanding that comes from a lack of proper understanding of what the term meant beforehand.

Nicely put, glad you agreed in the end.

 

[Marconi]

counterpoise vs. ground plane.pdf

Marconi, I have brought into this post your .pdf model and the graphic.

Two things:

1. I am under the impression that you are limiting your understanding of the counterpoise to a setup as pictured in the graphic. Hopefully not.

2. I think that the comparison model would be more accurate to the experience of a near ground mounted vertical if it was done with a completely surrounding counterpoise network rather than this off center setup under a bent to horizontal antenna with a coil and condenser in it.

It is easy to see why your model has a large off center lobe similar to a vertical dipole side mounted to a metal pole. It would be less a matter of speculation as to whether the gain on the big lobe is due to the effects of the counterpoise or the inherent nature of the horizontal wire.

Homer, your #1 wasn't my intentions, I choose that image because it was a model of the idea back in the hay days of broadcast, when the term was more popular, the image was captioned Classic Counterpoise, and I think Cebik or W8JI included it in one of their historical accounts for the term.

I was just thinking a modeling demonstration might help simplify what the idea was back then as compared to the ground plane models we see today. A version of the mathematical science was around in those days to calculate antenna patterns and characteristics, but they had to use a slide rule to make the computations. As I read it based on W8JI or Cebik's accounts...this image is sorta the idea as it pertained to broadcast back then. See my earlier post from my thread captioned and noted below: "Does height above Earth effect the common mode current response?" for more reference details below.

Here are the Eznec models of the Classic counterpoise vs. ground plane at various heights I posted earlier.


View attachment 9744


I don't want to get ahead of all the important reading and considering we have ahead of us, but I would like to consider what these models show me.

First off I have a question. Does the "Counterpoise example" model below appear to be a fair representation of the model in Frank C. Jones Radio Handbook for 1937 (p. 39) image for the Classic counterpoise?

If so, it appears quite evident that the "Counterpoise example" model at 27.205 mhz shows an advantage in gain over the ground plane at the same height above Earth. I also note that the Jones article refereed to low frequency AM broadcast considerations, in case that makes some difference.


So, I wonder if the counterpoise ground setup that we see here is actually producing the better gain, as has been suggested, or is this advantage due to some other facts...maybe as per comments by W8JI below?


As per W8JI, we know how horizontal radiators tend to show more isotropic gain than verticals over real Earth, and this is said to be due to the ground effects as noted in this link: Antennas for Receiving and Transmitting

Scroll down to his "Warning..."


I suggest this counterpoise model is possibly showing this increase in gain over the ground plane, because 50% of the radiator is horizontal and we have ground effects to be considered...as noted by W8JI. So, what if this advantage is not because of the superiority of the counterpoise design and capacitive effects we're discussing? Or, what if the difference is small, like I suggested elsewhere?


Consider what might happen if I make the "Counterpoise example" model with a full vertical radiator and compare that to the ground plane...at the same heights.

When I posted this modeling material in my own thread earlier, I made a mistake. I added most of the comments seen here to an older post, and I did not realize it at the time that I was not making a new post.

I think most readers probably missed the post for this reason. So here again, I'm repeating stuff I posted earlier. Maybe this will give some context to what I consider a practical idea for how I might describe the word "counterpoise" compared to back then...and what we might see today. Somebody back then called the image a Classic Counterpoise, not me.

Homer, regarding your #2 comment. I agree, and this is why I did these models comparing the old image idea to a more modern 1/4 wave ground plane. The other day I commented on you mobile idea about the counterpoise. This model your note is irregular is kind of similar to a mobile, and the patterns are also pretty similar. So which is it?

I also agree with your last comment. Maybe this is why the idea of the scientific definition is so vague and has faded from use. Maybe the rejection has everything to do with modern tall broadcast antenna installations, and not so much with high wires strung between two towers, like they probably did back then in broadcast.

If my models here are close enough for government work, and this was the broadcast idea for their antennas back then, can you see with with this modeling demonstration, why the ham world might have thought this Classic Counterpoise idea was superior to adding radials underground or on top of the ground?

This whole philosophical approach to the idea of what the term "counterpoise" means...may just be the brain child of the radio hobby world. LB Cebik was a very smart man, and was a philosopher and writer by trade and education. See some of his credits in this area of his life here: Works by L. B. Cebik - PhilPapers Radio was his avocation, a hobby, does that surprise anyone?

The term "counterpoise" either has an important and special distinction or it doesn't.

 

[Marconi]

I read it, and may need to again. However, so far it seems that VK10D's definition is just another of the myriad of contributions to what he calls "means all things to all"
While I understand his sentiments about it may be best to avoid the use of the term altogether, not unlike Cebik's conclusion, I disagree with him deciding to formulate a new idea (at least that's how I read it) until he is able to identify the original.
To be perfectly honest I fail completely to see him make any connection to the original meaning of the word anywhere in the article. And my position has more or less congealed upon the premise that the only way to know what the true meaning of the word is as it pertains to antenna science is to clarify that original meaning.

I guess his idea sorta gives credence to our efforts to find the true definition or example of what a "counterpoise" really is Homer.

I thought his short comments made some clear and cogent comments for what other's thought about with this term. He also gave us some references, and his conclusion. He said the idea remains unclear, and is probably left alone, unless we can clearly explain how or what we mean when we use the term.

I seem to find some value in several definitions he sited, and my opinion also seems to drift on the subject, but I don't know the answer in words.

This is why I tried to demonstrate an idea with the models I posted, but that went over like a lead balloon.

In this world we live in today I think it is quite common for folks that disagree on any topic...to disregard, out of hand, the comments of others. So, we just go round and around.

Homer, do you remember the story of the Tower of Babel as told in the Bible? I see this world still reeling toward destruction with the experience those people had back then...when God confused their language,

and it ain't gonna' get any better, until he returns.

 

[The DB]

Nicely put, glad you agreed in the end.

I agreed in the beginning. I made statements similar to those in a previous thread on a similar topic.


The DB

 

[The DB]

In this world we live in today I think it is quite common for folks that disagree on any topic...to disregard, out of hand, the comments of others. So, we just go round and around.

I think this perfectly describes where a lot of people are when it comes to the term "counterpoise".


The DB

 

[Wire Dawg]

My counterpoises were huge. One of the NASA antennas that I used to build & maintain was called the discone. The upper section was suspended from 5/8 galvanized steel wires that ran around to top of 8 creosoted poles, each about 80' tall and set in a circular pattern. The multiple-length wires, made out of 3-stranded #12, converged into a bronze disc of 12” dia. that hung about 4’ above the soil. The lower section consisted of several solid copper wires, extending from the center of the structure, out to near the perimeter (a ground screen). The section referred to as the Counterpoise, was at the apex, and consisted of the area & mechanism by which the upper section of the antenna was distanced/ approximated to the ground screen. Ajustment to this gigantic capacitor was accomplished with a series of turnbuckles & an 18” long cylindrical ceramic insulator (humorously nicknamed after donkey’s genitalia), which connected to (while isolating) the upper cone-shaped wire assembly from the bottom ground screen. I’m certain that the same concept or principle of counterpoise can be applied to other/ smaller antennas.

 

[The DB]

Marconi, when it comes to modeling have you tried any other counterpoise models? That diagram may be a classic model of a counterpoise, but it is clearly not the only one. Most books I have show a spiderweb layout for the counterpoise.

This is is an example from Leo Laport's Radio Antenna Engineering. (Figure 1.14)

These are from the Third Edition ARRL Antenna Book dated 1944. (Figure 1219)

I have also seen diagrams where the counterpoise itself almost looks like a spiders web.

To me, any of these layouts with a quarter wave vertical above would also be considered accurate, and I think they would be more common as well. They should also have a much better pattern associated with them.

I just located a .pdf version of the book you used for your diagram, I'll read through it here soon (likely not today though).


The DB

 

[Marconi]

DB until recently, I don't think I've ever even discussed the term "counterpoise." I have read about it and used the term, I'm sure, but I was probably just referring to some radial setup idea or using the word generically, which I tend to think may be what happened originally years ago.

Sometime back I made a model based on my understanding as per Bob85 and Multimode 200 for an antenna they called the SpiderPlane. It looks similar to one of you examples, with the radials extended in a circle, more or less, to make them full 1/4 wavelength at some angle and not straight out.

I seem to remember the antenna was a 1/2 wave vertical monopole similar to an A99. I figured this setup would work about like a shortened radiator with a top hat, and at best it maybe bring the antenna back to work about the same. The model I made did not show a big advantage in gain over the regular antenna used, and that is what I saw in the results. That didn't comport with the reports made on the real antenna, so we never talked much more about it. The idea of a counterpoise never came up either.

 

[Wire Dawg]

Nice picture! It is worth a thousand words. That's the discone that I tried to describe, and that is how they look from a helicopter. While there are many discone antennas, it is not easy to describe the size of the ones that I worked with (lots of land needed, but not as much as the rhombics). Suffice it to say that the coax cable used for these antennas was approximately 3 inches in diameter, had to be air-pressurized, was far away from the control room and often ended behind 20KW transmitters (usually located inside extremely cold buildings). Thanks for the image! A side-view would be very helpful to point to what was referred to as the counterpoise.

 

[HomerBB]

All of your points are well taken.

All of my mobiles to date are verticals where the model you used had a inverted L wire.
As for your model going over like a lead balloon, I have looked it over several times and this is referenced to it. There have not been too many comments in general on any models posted except the CST models, and Eznec as it relates to those. Most of us don't know what we're looking at, I think.
It would still be nice to see how a vertical model compared to other antenna types.
While I may be willing to give a nod to the possibility of AM broadcast stations having used a horizontal wire with counterpoise, I do not believe it was limited in those days to such usage or else the early writings on the subject by Ham operators are meaningless.

 

[The DB]

My counterpoises were huge. One of the NASA antennas that I used to build & maintain was called the discone. The upper section was suspended from 5/8 galvanized steel wires that ran around to top of 8 creosoted poles, each about 80' tall and set in a circular pattern. The multiple-length wires, made out of 3-stranded #12, converged into a bronze disc of 12” dia. that hung about 4’ above the soil. The lower section consisted of several solid copper wires, extending from the center of the structure, out to near the perimeter (a ground screen). The section referred to as the Counterpoise, was at the apex, and consisted of the area & mechanism by which the upper section of the antenna was distanced/ approximated to the ground screen. Ajustment to this gigantic capacitor was accomplished with a series of turnbuckles & an 18” long cylindrical ceramic insulator (humorously nicknamed after donkey’s genitalia), which connected to (while isolating) the upper cone-shaped wire assembly from the bottom ground screen. I’m certain that the same concept or principle of counterpoise can be applied to other/ smaller antennas.

Nice picture! It is worth a thousand words. That's the discone that I tried to describe, and that is how they look from a helicopter. While there are many discone antennas, it is not easy to describe the size of the ones that I worked with (lots of land needed, but not as much as the rhombics). Suffice it to say that the coax cable used for these antennas was approximately 3 inches in diameter, had to be air-pressurized, was far away from the control room and often ended behind 20KW transmitters (usually located inside extremely cold buildings). Thanks for the image! A side-view would be very helpful to point to what was referred to as the counterpoise.

I'm not very familiar with discone antennas, so I am unsure at best. If you are referring to the diagrams that I posted a side view would look like a line as they are capacitive ground systems (counterpoise) for vertical antennas, and thus parallel with the earth itself for the needed capacitance. From what little I know about discone antennas I'm assuming the side view that you are referring to would come up to a point (the cone portion of the discone antenna).

As far as transmitting antennas I was under the impression that it was a rather lossy antenna, although very widebanded, something like a 2:1 SWR to the second harmonic? That being said I also seem to remember that its signal is aimed at the horizon fairly well (not sure how well though in comparison to a vertical antenna).

Note: The info I posted on discone antennas is not from my research, its just info that I have come across over the years and just pulled from memory, which I hope hasn't failed me to much yet...


The DB

 

[Wire Dawg]

DB: I recall that many of the discones were used as receiving antennas, while the rhombics were used to transmit. It's been a long time.... and did not mean to detract from the main subject. Just wanted to describe what I knew as a counterpoise. Thanks.

 

[The DB]

I for one appreciate the input. It is a use of the word that I have not heard before.


The DB