Solarcon A99 Experimental Results and Analysis of Ground Plane Radials

[Bushpilot 593]

Great write up and experiment! Thanks for posting your findings.

 

[arcone]

Just replying to the earlier replies to this post, haven’t had time to read all replies.
I’d like to point out that the ground plane may improve the efficiency of the antenna by reducing ground losses. Can’t believe this was overlooked from the outset. There are other factors here too like a change in radiation angle. Radio is often a chaotic thing, hence why it requires field tests. At least this guy got off his arse and did it and decided to share his findings with you.
Some of you people shouldn’t concentrate so hard on what you think you know but rather think about what you don’t already know.
I wonder what the likes of Hertz, Marconi and Tesla would think.

 

[The DB]

I’d like to point out that the ground plane may improve the efficiency of the antenna by reducing ground losses.

This is true, however, do you know what else improves the efficiency of the antenna by reducing ground losses? Antenna height above the earth. At the half wavelength point above the earth most of the gains in efficiency by reducing ground losses have already happened. While ground plane radials will still have some small effect, the higher the antenna the less of an effect of increased efficiency they will provide. And as a note for context, the op's antenna was already 1/2 wavelength in height.

Can’t believe this was overlooked from the outset.

Considering the people who posted, I highly doubt that this was overlooked. Three years ago when this conversation happened I would have overlooked it, but as seen above, I clearly wouldn't overlook such a thing now as I can speak to it.

There are other factors here too like a change in radiation angle.

Adding radials to an elevated antenna 1/2 wavelength or more high does not change the antennas radiation angle unless you had a common mode currents issue to begin with. Their are several effects said radials will have for an antenna, however, this is not one of them. The op insisted he didn't have such a common mode currents issue, but that is what everything that happened points to, and his stated amount of windings for the choke he used also supports this. When it comes to air wound chokes, more is not better, it needs to be exactly right or it won't work, and can even work against you making such a problem worse. The numbers he gave simply don't add up to a proper choke for the CB band.

Radio is often a chaotic thing, hence why it requires field tests. At least this guy got off his arse and did it and decided to share his findings with you.

It isn't as chaotic as you believe, and outside from the changing conditions for things like DX, radio is not chaotic at all. In the over 150 years of radio, what happens with basic antenna systems (like the ones that are used on the CB band) are actually very well studied, defined, and understood. You can actually go to school and become a broadcast engineer, which wouldn't be possible if radio was as chaotic as you seem to believe.

Some of you people shouldn’t concentrate so hard on what you think you know but rather think about what you don’t already know.

I have been doing just that for years (actually still am as I've never stopped), and I have learned a *LOT* in the process, and a lot of it I have come across in the field or come up with a test/demonstration of my own. I know of others here, many of whom your post has been directed at, that have done the same. Also, those of us who have been actively learning about and seeking more information on antennas for years will consistently give you remarkably similar responses to each other. We may get to said responses differently, or even give very different reasons as to why, yet our responses are still similar.

Not only will I continue to follow the advice you gave, I will recommend you do the same.


The DB

 

[HomerBB]

I haven't gone back and reread all the posts in this thread, either, but I did see my initial response and found it accommodating and encouraging to the OP. I seriously doubt I would use any other tone even if I disagreed, especially as the preponderance of my antenna work/conclusions are empirically driven.
On a short note, I do agree that most of any TVI issues I've encountered personally were diminished or cured by distance from the terra firma. It's been sorta like being less likely to hit a bridge piling the further from it I steer my car. . . Or in the words of Mighty Mouse, "Up, up and away!"

 

[Captain Kilowatt]

This is true, however, do you know what else improves the efficiency of the antenna by reducing ground losses? Antenna height above the earth. At the half wavelength point above the earth most of the gains in efficiency by reducing ground losses have already happened. While ground plane radials will still have some small effect, the higher the antenna the less of an effect of increased efficiency they will provide. And as a note for context, the op's antenna was already 1/2 wavelength in height.



Considering the people who posted, I highly doubt that this was overlooked. The three years ago when this conversation happened I would have overlooked it, but as seen above, I clearly wouldn't overlook such a thing now as I can speak to it.



Adding radials to an elevated antenna 1/2 wavelength or more high does not change the antennas radiation angle unless you had a common mode currents issue to begin with. Their are several effects said radials will have for an antenna, however, this is not one of them. The op insisted he didn't have such a common mode currents issue, but that is what everything that happened points to, and his stated amount of windingsfor the choke he used also supports this. When it comes to air wound chokes, more is not better, it needs to be exactly right or it won't work, and can even work against you making such a problem worse. The numbers he gave simply don't add up to a proper choke for the CB band.



It isn't as chaotic as you believe, and outside from the changing conditions for things like DX, radio is not chaotic at all. In the over 150 years of radio, what happens with basic antenna systems (like the ones that are used on the CB band) are actually very well studied, defined, and understood. You can actually go to school and become a broadcast engineer, which wouldn't be possible if radio was as chaotic as you seem to believe.



I have been doing just that for years (actually still am as I've never stopped), and I have learned a *LOT* in the process, and a lot of it I have come across in the field or come up with a test/demonstration of my own. I know of others here, many of whom your post has been directed at, that have done the same. Also, those of us who have been actively learning about and seeking more information on antennas for years will consistently give you remarkably similar responses to each other. We mat get to said responses differently, or even give very different reasons as to why, yet our responses are still similar.

Not only will I continue to follow the advice you gave, I will recommend you do the same.


The DB

Amen brother on all points.

 

[arcone]

In reply to DB and others,

height above ground will reduce the number of radials required to achieve the same goal in regard to ground losses, but I don't believe a half wavelength is high enough. I would even be inclined to use eight, so I have a different opinion on that one.
So the angle of radiation may have changed by cleaning up the pattern when the radials were mounted. I did not specify this or otherwise.
You mentioned common mode issues and yes you can’t just make up a random coaxial choke or think that more windings is better, it has to be specifically designed for the frequency and type of coax used to be of use at best. I prefer to loop my coax through a certain number of 43 material toroids a certain number of times to achieve a respectable impedance.
When I spoke about chaos, that was in a broad term. The particular operators station, surroundings like terrain and structures, what's in the the ground and where, soil conductivity, the list goes on.
Somehow I don't think you are one of the people that this post was directed at.
The initiator of this discussion (early on in the posts) was given a hard time with some really harsh quick to judge responses, some of them ignorant and narrow minded in my opinion.
Lastly, you are giving me advice on my advice (the same advice)? That kinda doesn't make sense or they cancel each other out or something, ha ha. Or I could say something immature like "I said it first". Well I keep an open mind and experiment myself and ask a lot of questions, do a lot of research but don't take anything as gospel.
I suppose now I will receive an onslaught of replies by readers and then I have to prove myself as some sort of radio academic or a man. I don't think so, I won't, this will only perpetuate whatever the competitive thing is that goes on in these forums at times. I was just reminding people of a couple of fundamentals and for some to keep an open mind and not be so quick to knock somebody.
Jeremy.

 

[The DB]

I could present my argument on the number of radials and height ideas, but I don't think that would benefit this thread as it is. I would have to dig up a document for that anyway, at least the one that got me thinking on said topic. If you want to have a discussion on the whats and whys of what I believe, create a new thread, or start a conversation with me if you are worried about how others will see it. This is a topic that really doesn't get discussed much...

I also prefer using ferrite for chokes, assuming you have an appropriate ferrite type, it just works. Being resistive instead of reactive, it also has a much wider bandwidth than air chokes, as well as if you need more choking you can simply add more ferrite beads... Ferrite chokes are better than air chokes in pretty much every way. It is a pitty that almost no one actually uses them...

The harshness only started when the op was told why he saw the differences that he saw, than dismissed what he was told out of hand while giving evidence that supported that he was dismissing. The discussion, and the part you are complaining about appears, to me at least, to have been brought on by the op. The op clearly didn't help his situation any with how he responded to initial statements, then dismissed the actual reason said change he saw was happening out of hand while giving evidence that supported said dismissed claims.

That recommendation that you have is one that I often give to others and consider words to live by when it comes to understanding antennas, so that is where that statement came from. No negative intentions, just someone who is better at explaining things at a technical level than regular conversation trying to make a joke while offering support for future studies.


The DB

 

[arcone]

I could present my argument on the number of radials and height ideas, but I don't think that would benefit this thread as it is. I would have to dig up a document for that anyway, at least the one that got me thinking on said topic. If you want to have a discussion on the whats and whys of what I believe, create a new thread, or start a conversation with me if you are worried about how others will see it. This is a topic that really doesn't get discussed much...

I also prefer using ferrite for chokes, assuming you have an appropriate ferrite type, it just works. Being resistive instead of reactive, it also has a much wider bandwidth than air chokes, as well as if you need more choking you can simply add more ferrite beads... Ferrite chokes are better than air chokes in pretty much every way. It is a pitty that almost no one actually uses them...

The harshness only started when the op was told why he saw the differences that he saw, than dismissed what he was told out of hand while giving evidence that supported that he was dismissing. The discussion, and the part you are complaining about appears, to me at least, to have been brought on by the op. The op clearly didn't help his situation any with how he responded to initial statements, then dismissed the actual reason said change he saw was happening out of hand while giving evidence that supported said dismissed claims.

That recommendation that you have is one that I often give to others and consider words to live by when it comes to understanding antennas, so that is where that statement came from. No negative intentions, just someone who is better at explaining things at a technical level than regular conversation trying to make a joke while offering support for future studies.


The DB

No worries dB, you seem very knowledgeable, could help me down the track. I appreciate your sincerity and light heartedness.
Better get off this old thread and make a new one. Maybe something on near field and far field.
Bye for now.