Base Maco V58 model

[Marconi]

Do you have any video links that shows the kind of responses you note here?
I would really be interested in seeing such real life reports.

NB I asked you the question above. So, I went looking for someone doing a video comparing a couple of antenna we know, and I found the following from England.

This looks to me to have been done in FM and it makes the meter readings much easier to see. That said the results are pretty much in line with what I almost always see here comparing RX signals on my CB vertical antennas mounted close to the same height at the current maximums...very little difference.

 

[The DB]

Ok, now that you have determined 40.3 picofarads might be close...what do you suggest I do with the information? How would I generally apply this number to Eznec? Do you have any ideas?

When it comes to EZNec I don't know. In 4Nec2 I would simply add a capacitor in the first segment just above the bottom part of the ring. I would also do the feed point a little different, I would actually make a wire between the vertical element and the ring to show the tap, that in itself could change the result some. We had a similar difference with our I-10K/Shockwave models as I recall.


The DB

 

[The DB]

When I put the wire data into 4Nec2, I get tons of warnings and errors, including the entire ring. AGT is also way off, but then, as I said, tons of warnings and errors.

I guess I'll have to make my own model from scratch and see...


The DB

 

[bob85]

Eddie, i agree,
out in the open & properly installed at the same tip height 1/2 waves & 5/8 do perform about the same, in fact a good 1/2wave may have a small advantage at low angles,
problem is nobody makes a quality 1/2wave,

don't take that video as an example of what is typical here in our same mast/coax tests,

 

[The DB]

Here is what I have come up with. I used measurements from my V5000 which is currently in my garage.

I wasn't able to get a perfect match, although I did get it under an SWR of 2. It is the number of wires on the ring that gets me, I just can't get the tap in the spot it needs to be. Also AGT is 1.

And finally the plot, I included a model listed as I-10K, but it more closely resembles the Shockwave antenna, in both cases the radials are at the same height and the ground is the same.

That 0.27 dB difference, you won't notice that.

The Maco isn't skewed as much as the I-10K model, which compared to the Maco has more gain in one direction and less in the other direction. I would put this as a difference in the matching systems, the ring seems to create a more consistent pattern in multiple directions, which I guess is to be expected, not that it was ever enough to notice.

Antenna lengths used, from radials to tip:
Maco: 19 feet 10 inches. This varied from the tuned antenna in my garage some when I did some tuning in 4Nec2, but no more than a few inches. It might have been closer if I could move the tap point closer to a natural match.
I-10K: 22 feet 7 inches.

Hope this helps.


The DB

 

[Marconi]

Eddie, i agree,
out in the open & properly installed at the same tip height 1/2 waves & 5/8 do perform about the same, in fact a good 1/2wave may have a small advantage at low angles,
problem is nobody makes a quality 1/2wave,

don't take that video as an example of what is typical here in our same mast/coax tests,

Bob, I think it is pretty obvious...this guy's results do not agree with what you and NB have reported while comparing your antenna signals.

It may be this guy had his GM mounted in his garden on a 9' mast between a neighborhood full of 3 story homes 30' feet apart, while his A99 was mounted on his roof on a 10' foot mast...he did not say as I recall.

I don't know anything about this video other than what it shows. It just happens to demonstrate similar results to what I see and thus far videos of testing/comparing signals are few and far between. But I'm still looking for other videos as examples, and I will post them regardless of what is report.

I'd love to see a 1 - 2 S-units difference in signals while comparing any CB vertical antennas at similar heights.

I've heard all the words, now I want to see some real results that support all the claims. I also think I've read several notables in the guru antenna world that have reported there is very little real difference between the signals among good working 1/4, 1/2, and 5/8 wave radiators.

IMO the basic difference, installed height is the primary difference among them all.

Check out some of my U-Tube videos. Just click on the link below in my signature area...where I do some hokey south Texas kind of work comparing my antennas. You won't see much of any difference in signals there either.

If anybody out there has different information...how say you?

 

[Marconi]

More antenna comparison videos that indicate differences in signals.

 

[Marconi]

Here is what I have come up with. I used measurements from my V5000 which is currently in my garage.

I wasn't able to get a perfect match, although I did get it under an SWR of 2. It is the number of wires on the ring that gets me, I just can't get the tap in the spot it needs to be. Also AGT is 1.

And finally the plot, I included a model listed as I-10K, but it more closely resembles the Shockwave antenna, in both cases the radials are at the same height and the ground is the same.

That 0.27 dB difference, you won't notice that.

The Maco isn't skewed as much as the I-10K model, which compared to the Maco has more gain in one direction and less in the other direction. I would put this as a difference in the matching systems, the ring seems to create a more consistent pattern in multiple directions, which I guess is to be expected, not that it was ever enough to notice.

Antenna lengths used, from radials to tip:
Maco: 19 feet 10 inches. This varied from the tuned antenna in my garage some when I did some tuning in 4Nec2, but no more than a few inches. It might have been closer if I could move the tap point closer to a natural match.
I-10K: 22 feet 7 inches.

Hope this helps.

The DB

DB, thanks for the details, but I'm still missing something.

My model only has 29 wires, maybe if you posted your wire descriptions I could get close to your model.

BTW I see an insertion object on the wire between the top and the bottom of your coil and according to my model that wire is only about 7" inches long. My model also has a space at the top of wire #7 simulating an insulator.

What is the device and what detail values did you use?

What is the diameter for your coil?

You note that the radiator is measured from radials to tip. Is the radiator continuous or is there an insulator somewhere that I don't see being as the view is looking down at a skewed angle?

I think your radiator length is very close to what it should be for the Maco V58 setup at the middle of the CB band. I would be a happy camper with your match if I could get that close. I have tinkered with my model until I can't see straight sometimes, and I can't even get close to a match...and still keep the radiator short like the specs call for.

Below is my current model with what I did to add the matching wire, source, and loading object. The coil is also larger than specs call for. This model matches but it is not to specs and it fails the AG test. I also added my dimensions including the source and network screen shots.

It is as close as I can get to your model without more dimensions.

 

[The DB]

DB, thanks for the details, but I'm still missing something.

My model only has 29 wires, maybe if you posted you wire descriptions I could get close to your model.

Sure but you will have to wait until I get home for that. It is, however, almost entirely made out of variables, so making it readable might be a trick. I seem to remember their being a file that had the actual wire data somewhere, I may have to dig it up if I can find it.

BTW I see an insertion object on the wire between the top and the bottom of your coil and according to my model that wire is only about 7" inches long. My model also has a space at the top of wire #7 simulating an insulator.

What is the device and what detail values did you use?

That would be a capacitor, and it is near 40 pF, and there is a small amount of resistance in it as well.

What is the diameter for your coil?

Pretty close to 1 foot diameter.

You note that the radiator is measured from radials to tip. Is the radiator continuous or is there an insulator somewhere that I don't see being as the view is looking down at a skewed angle?

The capacitor I mentioned above would include an insulator as capacitors are generally just two plates with an insulator in between. At DC, if it weren't for the coil, both sides of the capacitor would not show a short on a meter.

I can't call it an "open circuit" at RF, but at the same time I can't call it a "short circuit" either. It exists somewhere in between as a part of the matching system of the antenna.

I think your radiator length is very close to what it should be for the Maco V58 setup at the middle of the CB band. I would be a happy camper with your match if I could get that close. I have tinkered with my model until I can't see straight sometimes, and I can't even get close to a match...and still keep the radiator short like the specs call for.

I started with the length of my V5000, and I did tweak it from there some. When tuning this antenna I often have to make some minor adjustments on the radiator length while tuning it. With the model, I can also adjust the capacitor, or the size of the ring, and all three have very similar effects, but on the actual antenna I am limited to the tap point and the length of the radiator.

Below is my current model with what I did to add the matching wire, source, and loading object. The coil is also larger than specs call for. This model matches but it is not to specs and it fails the AG test. I also added my dimensions including the source and network screen shots.

It is as close as I can get to your model without more dimensions.

On your wire layout of the matching area, their is an L next to the feed point on the wire that taps the ring, what does it signify? Is it something with EZNec?


The DB

 

[bob85]

Eddie the videos do show a change,
i can hear those guys from here and see their signals, two of their locals are buddies of mine who are always swapping and changing antennas,
vortex vector sigma4 gainmasters mr coily .64are some they have used,

i could say that's the kind of change we see here BUT it is not because we only test on a single mast using the same coax,

look at where dave has the antennas installed lmao..

 

[Marconi]

Bob I had some problems understanding every word that was said and sometimes it was difficult to see the signals but I could see a difference at times. Trying to be spontaneous trying to do a video...it is not as easy as it might look. I saw a couple of times that I thought the meter didn't look to show what was reported, but stuff happens.

In my drag racing days it was generally said among those participating, "...run what you brung."

So, I guess this is what these guys did making their videos and they probably don't even realize it was all a waste of time and brain power.

 

[Marconi]

The capacitor I mentioned above would include an insulator as capacitors are generally just two plates with an insulator in between. At DC, if it weren't for the coil, both sides of the capacitor would not show a short on a meter.

I'm aware of your description regarding isolation by a capacitor, but it never crossed my mind...I never could see circuits in my minds eye.

On your wire layout of the matching area, their is an L next to the feed point on the wire that taps the ring, what does it signify? Is it something with EZNec?

I used the [L] Network feature in Eznec and it inserted the "L." See the image I posted above...noted as the source and L Network features. It also shows the values I used. The value of 40 picofarads you posted above was close, but I fiddled with the value and as it improved the match for my model at 67 picofarads. I guess the difference is due to the missing dimensions I got wrong in my model above compared to your results.

DB, I'm just flying by the seat of my pants with this tool and cannot explain any of this so a body could understand or make any sense out of the explanation. But it worked for me on the Imax/capacitor you posted a while back...when you helped me get started adding that capacitor to the middle of the Imax. I just took a shot at doing it and it shows a good match. This is not saying it is the right way or the right feature, but it does allow the model to report out a good match. .

How is that for flying blind?

Let me know if I got it all wrong, I'm just trying to understand and learn a little about antennas.

 

[Needle Bender]

I don't consider valid most tests which compare with a switch because the 2 different antennas cannot both simultaneously be on the same mast & location.

The 1 - 1.5 S-unit improvement of a full-size 22.5' or so 5/8 over a Maco V58 which I've witnessed on multiple occasions were at multiple locations owned by multiple different operators on multiple different radios, but almost always analog metered radios were used.

Most of my meter tests are using an Icom IC-756 Pro3, E.F.Johnson Messenger 223, or Icom IC-761/751A analog meters, though similar results were seen on other rigs varying from Uniden Washington to Sears Roadtalker, Cobra 2000GTL, SBE Console II, etc.

"About 1 - 1.5 S-units" is hardly a scientific measurement of dB, nor is it meant to be such, merely a typical real-world occurrence.

...and Marconi, your model of my "...new idea...V58" appears to have a 27 segment by 5.75" long-per-segment ring match, making it around 28" in diameter. Mine was nowhere NEAR that, but about 11.5" - 11.75" in diameter.

 

[The DB]

I used the [L] Network feature in Eznec and it inserted the "L." See the image I posted above...noted as the source and L Network features. It also shows the values I used. The value of 40 picofarads you posted above was close, but I fiddled with the value and as it improved the match for my model at 67 picofarads. I guess the difference is due to the missing dimensions I got wrong in my model above compared to your results.

DB, I'm just flying by the seat of my pants with this tool and cannot explain any of this so a body could understand or make any sense out of the explanation. But it worked for me on the Imax/capacitor you posted a while back...when you helped me get started adding that capacitor to the middle of the Imax. I just took a shot at doing it and it shows a good match. This is not saying it is the right way or the right feature, but it does allow the model to report out a good match. .

How is that for flying blind?

Let me know if I got it all wrong, I'm just trying to understand and learn a little about antennas.

So you can add in a matching network of some sort with EZNec. Good to know, although I rarely use those anymore. If the capacitor was at the feed point on the model that could be a good way to simulate it, unfortunately in this case it isn't as it is on a different wire entirely. I think it was a good idea, but I don't know that it is a direct replacement for having a capacitor where this one is on this antenna, which is not right at the feed point, even if close.

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. 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.

The 1 - 1.5 S-unit improvement of a full-size 22.5' or so 5/8 over a Maco V58 which I've witnessed on multiple occasions were at multiple locations owned by multiple different operators on multiple different radios, but almost always analog metered radios were used.

I have seen this sometimes as well, the problem is I also have experiences where I saw no noticeable difference between said antennas, and I have even seen several Maco V5/8's outperform Imax's mounted on the same pole and using the same coax. 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, 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.

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

 

[Marconi]

...and Marconi, your model of my "...new idea...V58" appears to have a 27 segment by 5.75" long-per-segment ring match, making it around 28" in diameter. Mine was nowhere NEAR that, but about 11.5" - 11.75" in diameter.

NB'r you are mistaken here...the coil diameter is 11.5" inches.

I had to go back and find the model to be sure, Maco V58 model

I do not mind the question at all, but do me a big favor when you have specific questions about a model and give me a link, please. This thread is only about 25 posts long and looking back is not too hard in finding topics in question, but what about threads that are a 100 post long?

I think I remember specifically selecting wire #9 to be displayed in the pattern view...so that you could easily confirm the coil diameter I made.

I used 5.75" inch for wire #9, which is one of the two legs in your 1.75* degree coil design idea. The segment length for the coil I made used 2.24441" inches for the 25 wires in the coil itself.

I don't consider valid most tests which compare with a switch because the 2 different antennas cannot both simultaneously be on the same mast & location.

NB, I think I asked Bob a similar question the other day. I've been in radio a long time, and I've experienced a lot of similar situations that others have reported, but I can't recall ever noticing such a difference by having two antennas relatively close together at 36' feet. How do you guys that claim to know all these worrisome woe's determine what you claim? And, how much difference does it make if what you claim happens when trying to A/B compare two antennas?

Although there could be countless other reasons that can be suggested as to why A/B comparisons will not yield accurate/close enough for government work type results escapes me. I've heard similar stories over the years, but in my real world experiences, I have never been able to notice such disqualifying results.

Below, I made an A99 model with a choke compared to a duplicate A99 setup at 36' away...just to see how much difference it made with these two antennas set 36' feet apart.

I also made a model of the A99 standing alone without a choke as a comparison just to see the currents on this setup without any mitigation and to support my ideas. You will note in the case the model with the choke produces more gain than the model without a choke. So, I conclude such CMC are not constructive in this case.

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.