Base Maco V58 model

[Marconi]

So you can add in a matching network of some sort with EZNec. Good to know, although I rarely use those anymore.

I use matching when I can get the feature to work simply because I started to suspect lots of folks were likely not considering Eznec results unless they could see a good match. Few that I've seen uses matching in their software model presentations in the literature or on the internet.

IMO. this is regardless of whether matching makes any difference to the reported gain or pattern for the model or not. Just to clarify this...I often find my models might or might not change the gain or pattern when applied to the model. At other times, just adding the physical matching device can cause a pattern change, and then I might see a difference in the performance results or skewing of the pattern. Does this sound too ridiculous to consider? I don't think so. This said, however, is just my opinion and I probably cannot explain the idea any better in words and not leave some with questions, which I always welcome.

Does EZNec have the ability to add in a transmission line? In 4Nec2 I can connect two segments with a transmission line, I can even determine the length of the transmission line overriding the length used simply to connect the two segments.

Yes, but I question my own ideas for its application. I have read all kinds of ideas on this topic, so I'm never sure...even though Eznec handles what I add as values and will scan the model without some error popping up.

Some antennas, such as the Gainmaster, use a piece of coax as a capacitor, and if you can do something like that might be a way of adding in some capacitance. It isn't a feature I have any actual experience with though, just an idea based on something I saw.

I've tried applying some of my matching ideas on the GM and I don't recall much success. The last attempt was an idea to add the physical shorting stub noted for this antenna. Forget the matching features available using Eznec I have not found a fix for matching this one.

That said, I don't believe matching should make any difference in performance results for the GM and if I was able to get my model to show a perfect broad banded match like the specs call for...I would likely still see the same gain and angle.

I have seen this sometimes as well, the problem is I also have experiences where I saw no noticeable difference between said antennas,

I agree and I more often than not see no difference. So I tend to consider the no difference as the best evidence. I think there is also a theory in science that supports this position.

and I have even seen several Maco V5/8's outperform Imax's mounted on the same pole and using the same coax.

I have never tried to compare the Maco V58, but I have several buddies that work those antennas with great success.

I will say that I started seeing consistently better results for the Maco's after I started using field strength meters as part of the equipment used to tune said antennas

I gave up on using Field Strength meters, probably out of ignorance in doing what I was trying to do. I also found out, without thinking, the meters I used all were responding to voltage and not current. Using tools to help understand is great, but you also have to understand what is going on...and I didn't have that understanding.

and I should also add that I do things differently than the directions say as well, so their may be something we are doing different in that regard as well.

I always try and understand the directions before I jaunt off into experimenting or try to test my ideas. Like with antenna models...if I can get them to work and generate results similar to what is published in the specs...then I might start playing around. DB, it is pretty apparent we approach most stuff differently. I just think I follow a normal track.

Now Needle Bender, I am not saying that you are wrong, or even mistaken, I believe that you have experienced exactly what you claim to have experienced, I just have a different set of experiences working with these antennas than you do.

I could not have said it better DB.

 

[Needle Bender]

...Now Needle Bender, I am not saying that you are wrong, or even mistaken, I believe that you have experienced exactly what you claim to have experienced, I just have a different set of experiences working with these antennas than you do.


The DB

I could not have said it better DB.

Boy, you guys better be careful or I might think you imagine that I would be right to infer that you're saying I could get upset at something you would write implying the possibility of a distant chance I could be considered mistaken about not believing I'm wrong about any of this making sense

 

[Marconi]

NB, I didn't exactly say it...I just implied the remarks were OK!...so don't get your hopes up to much.

Like a little China-man once told a troblemaker ---- I try to forgeeeet.

 

[Marconi]

In conclusion NB and Bob, I don't see how anybody just using their radio and paying close attention...can detect the difference needed to support such claims. It all sounds good, but if there is such credible evidence out there supporting these ideas...I would like to see it.

I'm still waiting for some good words, links, or other evidence that shows us proof positive how A/B testing corrupts antenna comparison testing...so as to render it totally inaccurate.

I would think in order for someone to be convincing in their argument or take such a definitive position on this specific subject...there has to be some resounding and clear almost written in stone information out there...that supports such a claim.

I can guess there are dozens of CB ideas out there that try and explain in great detail, demonstrating the pitfalls of comparing two antennas TX/RX signals...using an A/B testing scheme.

So, tell us what you know or show us one of the most significant examples (demonstrations or links with reliable authority) for what happens to antenna receive signals when using A/B testing?

I could be wrong but I think there use to be an image on Sirio's Website showing us their antenna testing facility, or so it was suggested. It was on top of some building as I recall. If this is true maybe they need to be informed about the error of their ways too.

I showed you my Eznec model to help support my idea and we don't see much difference...not even close as one could easily tell just using their radio.

 

[Marconi]

In case you find these A99 antenna setups hard to compare...here is an overlay that I forgot to add earlier. It does show the side by side setup with some minor skewing but it is insignificant at best and would likely not be detectable just using your radio.

Again we don't see much difference. I think if we could see RF patterns from these antenna setups somehow...this overlay pattern is probably pretty close to what we might see.

What do you guys see that is different, or are these ideas just opinions base on your experiences? I basically disagree because, in my opinion, this has not been my experience...to see my vertical CB antennas show significant differences...whether they are, within reason, side by side, or standing alone.

My paper signal reports also seem to support my observations as well and I have reported much the same from the beginning of my comparison efforts. With that said, of course I have seen exceptions but I just considered those as anomalies, due to some conditions I did not understand, and not typical.

 

[HomerBB]

I can't add anything to the modeling as I don't do it, but I can say this ring thing is tough to duplicate and get a good match, or any match as a homebrew. I have used a ringo 1/2 wave belonging to my neighbor that was a 10 meters antenna retuned for 11 meters and could not get a match using the RG8 capacitor that shipped with it. I made a 16.5" long capacitor of RG58 and the match fell right into place. The antenna has a 10" diameter ring. The vertical is set into another tube about 2" at the bottom. No radials as it is a 1/2 wave EFHW. It has a set screw in that bottom tube for tightening it onto the top of a mast (ergo a counterpoise??).
I decided to try to make one. I used a 13" diameter ring like the Cushcraft Ringo antennas have (check cushcraftamateur.com). I tried every imaginable tap point. A wide variety of vertical lengths, and inserting the vertical into the lower tube from 2" to 4" in numerous varieties of configurations. Failed at every turn. Because I was doing this for someone who needed an antenna I removed the ringo matching system, put together a parallel inductor/capacitor network, attached it to the antenna, and within 20 minutes had a matched 1/2 wave EFHW.
I have no doubt the V5/8 model is driving you nuts.
Even my 5/8 with the ring inductor is not stable, it seems. The Spring winds here vary from a sedate 5 MPH to a blustering 40 MPH lately and the flex of the ring above that plate apparently changes my match. I get SWR readings with my inline meter from 1.1:1 to 1.7:1 at different times. I will likely be replacing the ring with a coil inductor. . .

 

[Marconi]

I noticed the CC Ringo did have a tuner hanging down from the bottom of the coil, but I could not tell what it was and I did not read the manual or try to figure out what it was. There was very little to read as I recall.

How was this device connected to what?

Was it shorted section of coax?

Thanks for the heads up Homer. Your surprise was frustration for me. I have not even been able to even follow what DB did to get his model under 2.0:1 SWR. So, again I have given up on trying to match the Maco V58 model. However, I still have a feeling even with a good physical matcher attached and working...the model would not change the performance values very much if at all.

The antenna has a 10" diameter ring. The vertical is set into another tube about 2" at the bottom. No radials as it is a 1/2 wave EFHW. It has a set screw in that bottom tube for tightening it onto the top of a mast (ergo a counterpoise??).

Yes I thought the Ringo was an EFHW, because that is what my .50_11m Wolf is based on with no radials. It has a coil that is 16" inches in diameter with a variable 1" inch between the legs of the coil and the legs are both horizontal.

The capacitor adjustment was meant for convenient fine tuning at the feed point area of the antenna...but it is a weak design and securing the radiator in the insulator is terrible if you ever have to retune the antenna...you will have trouble getting the radiator to move in the insulator. That is because a bolt is used to secure this area and it buggers up the insulator so it will not slide up and down.

I was checking out the ZeroFive Colassal 10K the other day and it uses a similar setup with the radiator down inside the mounting bracket. I looks to be less than 2" inches to me and unless the radiator is double walled in the base...that seems like it is a bit short in overlap. However they do have an out rigger securing device that is supposed to hold the radiator secure in the mast bracket base. It too uses a tubular PVC or Teflon insulator in the top at the base of the radiator so the radiator is floating except for its connetion to the coil.

Is there an tube insulator between your 2" pipe and the radiator?

I decided to try to make one. I used a 13" diameter ring like the Cushcraft Ringo antennas have (check cushcraftamateur.com). I tried every imaginable tap point. A wide variety of vertical lengths, and inserting the vertical into the lower tube from 2" to 4" in numerous varieties of configurations. Failed at every turn.

My Wolf 50_11M has a 72" long base element where the radiator attaches and it is heavy wall for added radiator support. Eddie Chicconni told me without the heavy wall aluminum down there the capacitor being super sensitive to very small adjustments in that area of the antenna...keeps the area from flexing in the wind so the match does not change so much. When I tune that thing I sometimes used 1/16" adjustments and smaller to see a dip on my analyzer. It is very sensitive down there...maybe that is why you had some issues.

Even my 5/8 with the ring inductor is not stable, it seems.

I'll bet it could be due to the radiator not being quite as tight a fit as it needs to be in the mounting bracket base assembly and the wind shows that. IMO, again the capacitor effect in this design is very sensitive and is used for fine tuning.

I hope some of these experiences help you out a bit. You answer some of my frustration with my model.

Good luck with your new project and keep us posted.

 

[HomerBB]

As you can see from the ring I made, and the Ringo antenna, it is a typical parallel L/C matcher. The capacitor (coax open at the far end, not shorted), similar to a gamma match capacitor, the center conductor attached to the upper arm top of the inductor ring, and the braid to the bottom arm bottom of the inductor. The feed line braid to the bottom, and the center conductor tapped into the inductor ring.
Yes, on the homebrew EFHW I had the bottom constructed like the factory model, vertical within a PVC sleeve within a larger tube mount. The inner vertical at no time had contact with the bottom sleeve except through the ring.
My ring is 13" diameter per cushcraft specs, the factory antenna ring is 10" diameter. Inside ring measurements.

 

[Marconi]

Homer, thanks for the description of these setups.

I was thinking the CC Ringo setup with the pig tail wire idea on the bottom leg of the coil served as an inductor of some sort and could be adjusted as to length. I also didn't recall the tap wire feeding the coil being on the top leg however for tuning reactance, with the tap wire tuning for impedance. I thought the black spacer between the legs was some sort of stabilizer. It is sure different from the V58.

What secures the radiator in the top of the mounting bracket on your 5/8 wave antenna or does it just sit in the top of the mount with the coil holding it steady a little?

Is the radiator glued into the insulator and providing enough space above a bolt to help prevent shorting to ground?

These designs sure look like they have very little radiator down inside the pipe. Looks like there is only about and inch of the long radiator down inside the mount also. I see something similar with the Colossal I noted above...considering there is a bolt running all the way thru the mounting tube about an inch below the top.

My Wolf antenna has the insulator and the radiator running down inside the 14" base mounting pipe almost to the 2 bolts that secure the mast to the antenna at the bottom. This setup is secure by two bolts about 1" apart.

There are also 2 bolts near the top that secures the adjustment function but the bolts are very short and only have 3 maybe 4 threads in the think wall pipe, and these bolts mess up the insulator due to wind moving the antenna about and they also can strip out the threads...which in my mind is a no-no idea.

The ZeroFive Colossal out-rigger idea is better, but it too might have some weak points if all the bolts down there don't go all the way thru the pipe at the base.

Some complain that the gamma match on a long vertical element present similar issues with the match in the wind.

Again, my Wolf .64 GP with a gamma deals with this problem by making the 72" bottom part of the radiator out of thick wall aluminum.

 

[Marconi]

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.

 

[HomerBB]

@Marconi
If you look closely again at my ring system you'll see the 3/8" bolt between the upper and lower brackets. That bolt is both a support between the two brackets at the ends of the coil loop and the conductor of the center of my coax capacitor. The braid of thst capaciror is connected only to the bottom bracket. On the CC matcher the black spacer is a support structure, but it has a small threaded screw from the center of the coax capacitor running through the middle of it. Same as my bolt. The center conductor from the feed line pl259 does not make contact with any part of the antenba except with the tap to the ring. The braid is grounded to the bottom bracket.

 

[Marconi]

Well Homer, I would like to be able to tell you I understand the parts you've put together here, to try and duplicate the Ringo, but it's all above my pay grade. I could never model that I don't think.

When I looked close at the Cushcraft page for this antenna I though I was maybe looking at a coaxial pig tail capacitor...where the length determined the capacitance effect but I don't even see that in your application, so maybe I just got a mental block. You know how old folks from Missouri are said to be...don't you live close to Missouri?

So, are you building a 5/8 wave or a 1/2 wave here?

I don't recall having any SWR swing issues with my Wolf .50_11m due to wind or weather, but it was very sensitive to height, and I could not get it to tune low and then raise it up and still have a good match. I figured the higher I went the more feed line was in the air and if the line served as the counterpoise...then these results explained the antenna was not decoupled from the FL.

So, I just ran it with about 1.70:1 SWR and didn't look back. I did talk to Wolf about however but whatever was said back then never pan out.

I even compared and tested it against some other antennas and I recall several local buddies claiming my signal was a bit better with this antenna compared to whatever I had up and running at the time. But soon after, the screw threads in the thick wall mounting bracket stripped out for the bottom leg for the coil, due to wind, and I haven't done anything with it since. I asked Eddie Chicconi if I could send the mount back and if he could weld a thick nut over the hole and fix it like it should be in this case, but he said his shop was shut down.

Just for information see the two bolts near the top and directly below the insulator? One is behind the feed point bracket and the other is to its left. On the left is securing the ground side leg for the coil. The other is securing the weight and twist of the radiator so the capacitor adjustment is secure and fixed as to tune.

Those screws were cut short and were less than a 1/4" inch long. This was because the hole had only 3 threads in the thick wall tubing to connect and hold the radiator fast and secure in place, and hold the ground leg with proper contact for the coil to the mount. These are just dirty shortcut solutions and were not meant for good service IMO.

You could not really tighten these screws because they were seating to the insulator inside...and you sure didn't want them to make physical contact thru the insulator and directly to the radiator or your antenna is directly grounded. This idea buggered up the insulator and prevented subsequent adjustment after a while also.

I'm sure you'll get these antennas working right soon. Just hang in there and keep us posted.

 

[HomerBB]

The first antenna I made was the 5/8 wave I have in the air now. No coax capacitor. It's the one in the thread "5/8 wave at 37 feet".

The second I attempted for a friend was a 1/2 wave, no radials, and a coax pig tail capacitor. I could not get a match with it and switched to a parallel L/C network using the coax pigtail as the capacitor and tapped coil spring ttpe inductor instead of a large rimg. Matched right up.

 

[Marconi]

I could be wrong but I seem to recall asking if you noticed any difference between the coil and the spring coil, but maybe I'm mixing apples and oranges like DB sometime says about me.

Homer, I'm getting to old to remember details, so I better leave this where we are for now...I feel like I'm off track and just rambling.

 

[HomerBB]

Alrighty.
Got a question just shout it out.