sigma4 article is online

[Marconi]

Gentlemen, the only collinear effects seen here are due to simple facts, like HyGain and others use to tell us when publishing their advertising for the CB market craze some years ago. It is still going on too. If the definition for collinear simply means a monopole with two current maximums and that is all...so be it. If however a collinear is supposed to produce a doubling of gain over a single dipole then this idea is not applicable to this discussion for the S4 design, unless it can be demonstrated and modeled to show it being feasible.

All 5/8, .625, .64, 3/4, .82, or 7/8 wavelength monopole antennas will produce collinear type dual current maximums on their radiators. Any radiating antenna longer than a 1/2 wavelength will radiate some collinear effect. Problem is, this is not true collinear RF activity like we would see with properly design phased arrays.

The Sigma4 and the New Vector 4000 do a better job of mitigating the associated issues than some other styles, models, and brands however. These longer profiles get you some of that magic height cheaply, and that can be of some advantage for CB operators and something we might even be able to tell and/or measure...just using our radios.

There is no magic activity going on with these antennas as some would have us believe. When they are working right, they tend to follow known and well understood rules of electromagnetic wave theory. There are anomalies in all human endeavors that misguide us in understanding sometimes, and this discussion is likely full of such ancedotal anomalies that are being suggested as true facts and science.

This is nothing more than a rebounding of the old HyGain, Radio Shack, Avanti, Antenna Associates, Solarcon, JoeGunn, and many others in the antenna business...playing old Tin Man tactics from the 60's - 70's. There is nothing new here. It is interesting maybe, but it is all about promotional and advertising gimmicks...that I refer to as mostly commercial puffing in advertising, and nothing more.

Henry's report is basically correct, and exposes some facts, among them that a CST image has been miss applied to support a false narrative about how this particular design works. Don't be fooled by all the mesmerizing and wild claims being made here.

In a common sense way, this design is pretty simply. It is just an end fed 1/2 wave monopole radiator which raises the current maximum up a full 1/4 and more. The logical advantage is regarding the increased height of installation.

This idea is very similar to a 5/8 wave antennas that is also raised up a 1/8 wavelength, being claimed to be the best performing CB monopole available in the science of vertical monopole antennas. Again, just being raised up by 1/8 wavelength over a standard radiator size for a well balanced and center fed 1/4 GP or 1/2 dipole.

In CB world with low watt service...it is all about height of the current maximums, and the effects noted as a result with vertical monopoles. If all these vertical monopole antennas are equal in height at their current maximums...they will generally produce very near the same gain.

You can look at Henry's report on pages 33 -34, where he has produced two graphs that show us an idea for how this particular characteristic in antennas really is with gain for different radiator lengths vs height.

I'm not saying that you should all see the same or even similar results to the science being reported here, because you can see how science is usually looking at factors with antenna design, efficiency, effectiveness, and performance...that are miniscule in differences by comparison...to what we CB radio operators might consider and be able to observe or measure.

So, you mileage may vary.

 

[bob85]

Donald
Im glad you understand the need for balanced conditions at the top of the cone in order to minimise radiation from the cone,

i agree with that idea, it fits antenna / transmission-line theory,

Eddie

All older versions of this antenna, avanti, cte, commtel, tagra, lw150 etc,
have conditions at the top of the cone that are not optimal,
some out of phase radiation from the radiator, and more radiation from the cone than when using a 1/4wave cone that sees an electrical 1/2wave above it,

looking at Cebik's j-pole models shows us what happens with current phase in the cone area when you extend the radiator and cause the cone to radiate more than the small unbalance in an optimised design,

It makes sense that if we start with any of the old style antennas we can make adjustments that will cause more signal at low angles,
just like me and Donald have been telling you guys for years,

like i said earlier, we are not gaining something by utilising collinear gain,
we are minimising what the other designs throw away through poor design,

sirio's upgraded vector looks to be much closer to optimal,

Henry's excellent article explains why the optimised design can do so well in a way i have never seen in any article on cb antennas before.

 

[Marconi]

i am very happy that you and henry HPSD are taking the time to see what eznec+ reports,
the sigma style antenna is not nearly as simple as it looks but it is WELL worth the effort to try to understand how they are best optimised,

keep up the good work guys, we may get to the bottom of this eventually and put the modified sigma where it belongs,
if observed signals can be backed up by accurate plots it leaves little to argue about other than what is the best/most economical way to build a sturdy vector with high power handling

Bob, for months I have been asking for you guys to produce a model for either the S4 or the NV4K that showed some of the high gains that have been reported. Henry's report shows us 2.221 dbi gain for his CST model and close to the same for a couple of other antenna modeling programs.My Eznec FS gain shows to be about the same.

The CST pattern image that Donald posted omitted any indication for gain, but he has suggested the gain is what Sirio has published for the specs on their NV4K, at 4.15 dbi in FS. Where is the model that suggests this increased gain in FS? That would give us something to really crow about if we could produce such evidence.

Saw the thread today so thougth i drop in )

What i think so far...and perhaps already mentioned by some its a long thread already..
One could call it a co-linear since there are two current points on the antenna.

Futhermore the radials are there for the biggest part to profide a normal ohm value one wich we could adjust with a gamma-match.If we would forget the radials and ring the impedance would be very Capacitive -J. The Gain however more or less remains (+/- 0,5dB). (high angle)

The best thing wich comes along with attaching radials is a lower radiation angle.
The 3/4 wave in this case has got a nice low lob and a second lob a bit higher.
Actually it would be great for real dx through F2 and do a good job in with the sproadic E season aswell.
No big mistery..in general radials lower angle and do that for every 1/4 wave (5/8,3/4 etc)

Now...the biggest worrie i have so far is the gain that one can reach (+/-4,2 dBI ) is with a very thin radiator...that migth be the explination why the antennas are always brougth on the market a bit too thin to everyones believe.... ( not a fact!)
each time i enlarge the main radiater gain drops rappidly towards 2 dBi

Intresting antenna so far !

Kindest regards,

Henry

This is interesting to know Henry, but when I mention this idea when I see it...I'm the bad guy that should be ignore, because I'm trying to mislead everybody looking in.

thanks for your input henry,
any work somebody does to try and understand the sigma style antenna is much apreciated by myself,

CEBIK called it a "none apparent colinear array" because he said it was not aparent to most people how they work, you seeing big changes in gain with changes in wire diameter could be the difficulty with trying to get accurate models with nec that he told me about,
i read that sleeve to monopole tube diameter ratios effect that style antennas performance, shockwave is on the right track imho

Bob, this is what I might have noticed if I had the model that showed the big optimized gain we hear about. Thanks for the heads-up.

I didn't even see Henry's chart. As soon as it became clear he was going to contradict 15 years of in field experience, I stopped reading his article. Although if there is a photo of the actual Sigma design antenna he used for testing, I'd love to see this to determine if he fixed the half dozen errors that were obvious enough to spot in the first photo.

Ignoring stuff simply because you might disagree is not very productive Donald. Nobody here is going to ask you to publish any details for your field testing on your business model Donald. We need to get back on message here. This is about the Sigma4 or New Vector 4000 antenna design.

PS: I'm still boggled by the "theory" that one length of mast can produce a 2dbd gain but no other multiple of mast length can detract from the gain? That doesn't even come close to making a bit of sense and sounds like you're talking out of both sides of your mouth to me.

I just posted my evidence how this might happen in post #152. IMO the longer radials on the Vector is the only difference between the models I posted and you can easily see how the current on the mast shifts from constructive to destructive. Beyond that only God knows, but you won't see it unless you open your eyes in this discussion.

ps...and yes....but the sad thing is...
as soon as we have "radiation" from the cone....the antenna will become more a 3/4 wave radiator.
providing higher gain...but upwards...there where we do not want it.

Interesting point Henry. I've said it before...if this design did not cancel the current in the cone area so well...then the 3/4 wave radiator would still be a 3/4 wave radiator with a cloud warming maximum TOA, just like you tell us here.

This is pretty revealing stuff folks.

Thanks Henry.

 

[HomerBB]

I seem to see contradictions in this post . . .

Donald..

are most likely not the complete result of collinear action

We are almost there...Im proud of you thumbs up !

ps...and yes....but the sad thing is...
as soon as we have "radiation" from the cone....the antenna will become more a 3/4 wave radiator.
providing higher gain...but upwards...there where we do not want it.

This antenna does not send its radiation up into the clouds, yet in the previous posts, and in Marconi's post after this, this is not reported to be a 3/4 wave, but a 1/2 wave over a 1/4 wave matching network like the j-pole. Either it is a 3/4 wave, or it is not. Even the models posted in this thread are showing this antenna generates more gain than a 1/2 wave or 5/8 wave. You can't have it both ways.

Under perfect conditions maximum gain would be in the order of 3 dBi or so...and that is without the cone as the radiator can "fully" radiate" as there is no phase shift going on.

If there is no cone, there will be a phase shift on the antenna of this length. Without the cone it will be a cloud burner. With the cone properly tuned to the best center radiator length it generates gain on the order of a 3/4 wavelength antenna toward the horizon. Therefore, the theory that is supposed to be saying it is not a fully radiating antenna from top to bottom including the cone is in fact appearing to be proving it is a 3/4 wavelength fully radiating antenna.

So...in order to have maximum effort from the vector you would need to make the antenna in such a way the cone "sees" a electrical halve wave on top...then max will be send in a 0 degree angle..most beneficial for "distance horizon communication.

Really of to bed now...73s.

That is exactly what has been done by some folks. Others have just put up the antennas out of the box and not done any better than most other antenna types.

There is no magic going on here, just a great construction of what antenna theory says will happen if one builds a 3/4 wavelength antenna that controls the bottom 1/4 wave phase shift and puts the radiation toward the horizon. However, one must remember that the gains reported in the models and in field results depend on this being a 3/4 wavelength antenna mounted at any height and not a 1/2 wave antenna with a fancy mounting bracket on the bottom.

Or so it seems to me. Too many contradictions in this thread for a country boy who always drives east from Fort Smith to Little Rock on I-40. Going west takes me to Oklahoma City. And that is real consistent science.

 

[bob85]

Homer,
Read the thread again m8, take note of when we are talking about freespace gain vs low angle signal strength over other antenna when mounted over real ground,
The vector cannot produce as much gain as a 3/4wave in free space but it will whoop a 3/4wave endfed monopole at low angles over real ground.

 

[Marconi]

Donald
Im glad you understand the need for balanced conditions at the top of the cone in order to minimise radiation from the cone,

i agree with that idea, it fits antenna / transmission-line theory,

Eddie

All older versions of this antenna, avanti, cte, commtel, tagra, lw150 etc,
have conditions at the top of the cone that are not optimal,
some out of phase radiation from the radiator, and more radiation from the cone than when using a 1/4wave cone that sees an electrical 1/2wave above it,

looking at Cebik's j-pole models shows us what happens with current phase in the cone area when you extend the radiator and cause the cone to radiate more than the small unbalance in an optimised design,

It makes sense that if we start with any of the old style antennas we can make adjustments that will cause more signal at low angles,
just like me and Donald have been telling you guys for years,

like i said earlier, we are not gaining something by utilising collinear gain,
we are minimising what the other designs throw away through poor design,

sirio's upgraded vector looks to be much closer to optimal,

Henry's excellent article explains why the optimised design can do so well in a way i have never seen in any article on cb antennas before.

Well Bob, all I have to go by is my Eznec models. I just posted my models here and it shows this idea that the taller radials seem to physically (at least) improve the currents imbalance for the top of Vector cone passing closer to the out of phase change area near the radial hoop and the radiator.

This can't be ignored, and so I talked about it already.

We can physically see this seeming improvement in the model. This also makes the antenna pattern in Free Space show a better gain and much lower angle than Henry's model. I have already asked him about his model in this regard...but with no response. I can't say that is not what I expect either.

I asked him for the file to compare to my model and see what I could learn.

Notice the consequences of the fix that the Vector is supposed to produce with longer radials. Also notice the CMC on the NV4K radiator in my Eznec model where it shows to be destructive now, and out of phase with the top 1/2 wave radiator. On the other hand, the S4 model that shows a worse case issue according to Donald when he talks about where the hoop is relative to the radiator phase cross over area being a possible problem.

Bob, this too may not be so good, but is also being ignored.

This stuff is important to at least consider, and I think Bob, you might be the only one that considers such simple details regarding CMC on the feed line and/or mast that we can see here in the model as important. I might argue this issue is dubious, but in this model...the results are evident and remarkable at the same time.

In the attached models below I think I proved how much of a problem this idea that is supposed to be an improved balance benefit due to longer radials can still caused the model to have issues. Issues that are solved by Isolating the mast by 5" from the antenna in this example I posted for that reason. It is easy just to look the other way and say the old man is nuts, but here I see isolation showing to improve the gain nicely, just like you might tell us in such a situation. IMO, this proves you are right Bob...but nobody want to look at that evidence from me, so be it.

I have another modeling solution for this problem that I've build and tested, that has been mentioned, and discounted without any due consideration by somebody here already, but I don't think I'll post that, right now. I don't want to over burden the conversation with another idea that has already been discounted to the trash.

 

[Shockwave]

We all know a 3/4 wave produces more gain then a halve wave. But sadly the lobs will be pointed more along the ax of the antenna forcing the radiation in the sky there for demolishing the gain where we want it.

We all know that theory can ONLY be applied to radiators that are longer than 1/2 wave and DO NOT effectively eliminate the majority of out of phase currents. It CANNOT be applied to the Sigma where the field on the lower monopole is confined.

Donald.. are most likely not the complete result of collinear action We are almost there...Im proud of you thumbs up

I sense your excitement but let's be careful not to take my statement out of context. I'm simply conceding that I recognize a 1/2 wave directly over a 1/4 wave doesn't produce 2dbd by itself. I've also said the collinear effect allows us to make some use of electronic beamtilt to more effectively focus existing gain on the distant horizon. DB has confirmed this can add up to 1 db in recent models over ground but again was completely ignored exactly like his attempts to model what CMC might look like in this design.

ps...and yes....but the sad thing is... as soon as we have "radiation" from the cone....the antenna will become more a 3/4 wave radiator. providing higher gain...but upwards...there where we do not want it.

This goes right back to my first response. You now assume radiation from the cone must be deconstructive but you just said radiation from the mast (a portion of the same CMC) is constructive enough to add 2dbd. No offense but that's what I mean about talking out of both sides of ones mouth.

Are you forgetting this idea of gain being focused upwards implies all the time spent peaking distant gain in the field was not only done wrong but it's actually producing the complete opposite effect that nearly all users on all bands report? That most extra gain is focused upwards rather than on the distant horizon that allows us to pick stations up that other 1/2 waves could not? That's also what I mean when I say this theory is extremely weak and lacks the credibility of representing the results so many have been reporting for so long.

Marconi, I'm sorry but

Bob said "like i said earlier, we are not gaining something by utilising collinear gain, we are minimising what the other designs throw away through poor design"

I'll ask once again please point out just one of the poor design characteristics you think I'm experiencing regularly with the line of commercial broadcast center fed dipoles?

 

[HomerBB]

@Marconi
This is a photo of my V4k at 36' mount point with a hickory shovel handle between it and the mast providing about 6" of isolation. You should be able to see the coax choke in the photo, too. The radials are right at the 1/4 wave length, so it should be operting as close to your model as a real earth install could be.
This is the antenna that allowed me to talk better than any other monopole antenna mounted at the same tip height.

Your model shows 8 degrees to horizon at 4.34 DBi.

 

[HomerBB]

Bob said "like i said earlier, we are not gaining something by utilising collinear gain, we are minimising what the other designs throw away through poor design"

I'll ask once again please point out just one of the poor design characteristics you think I'm experiencing regularly with the line of commercial broadcast center fed dipoles?

Shockwave, it seems to me that Bob is actually saying the peaked antennas are improving performance/gain because, unlike other poorly designed antennas, the highly tuned antennas use potential that poor designs do not. I believe he is including your antennas among those with better design.

 

[Shockwave]

Shockwave, it seems to me that Bob is actually saying the peaked antennas are improving performance/gain because, unlike other poorly designed antennas, the highly tuned antennas use potential that poor designs do not. I believe he is including your antennas among those with better design.

That makes perfect sense Homer but still begs the question what accounts for consistent improved performance over center fed dipoles without crappy end fed matching networks that I see consistently?

 

[Shockwave]

This is a photo of my V4k at 36' mount point with a hickory shovel handle between it and the mast providing about 6" of isolation. You should be able to see the coax choke in the photo, too. The radials are right at the 1/4 wave length, so it should be operting as close to your model as a real earth install could be. This is the antenna that allowed me to talk better than any other monopole antenna mounted at the same tip height.

Homer, if you believe the theory being presented here you should remove the choke and insulator and get those extra 2dbd hiding in CMC mast radiation.

Bob, it also looks like when you peaked gain to hear distant stations other antennas couldn't, that you missed the possible 2db of extra CMC gain by using the choke and insulator as pictured in your avatar photo. Don't you think that would have been hard to do if this theory were correct and still see improvements?

 

[Shockwave]

Henry, how is it possible that just constructing with simple homemade materials the "11 Meter Macgyver" can see noticeable gain over every other vertical even giving them the advantage of the same tip height? Notice he does it without any need for "the extra 2dbd" in mast CMC radiation too? Does he have some bias or motive to defend 40 pages of theory?

I know the next response is going to be all of his other antennas were deficient in some way. That makes me eager to learn what type of Hi-Tech Dipole do you have access to that seems to produce these impossible to beat reference standards? I've worked with the best and yet to see this.

I've seen more effort to "explain things away" than to explain anything at all. I tried to remain optimistic that we might learn something constructive in this report but against this constant barrage of suggesting what we see is not what we see, not accurate, not for the reasons we think, subject to large CMC variables, all noticed by incompetent people or are all compared to inferior antennas is about as ridiculous as it gets almost 200 posts later.

 

[curlyjo]

@Marconi
This is a photo of my V4k at 36' mount point with a hickory shovel handle between it and the mast providing about 6" of isolation. You should be able to see the coax choke in the photo, too. The radials are right at the 1/4 wave length, so it should be operting as close to your model as a real earth install could be.
This is the antenna that allowed me to talk better than any other monopole antenna mounted at the same tip height.

Your model shows 8 degrees to horizon at 4.34 DBi.

Is your V4k grounded? If so. How? After three years of service the stinger snapped on my LW 150. Going to take the whole thing down and rebuild the radiator with new aluminum and make a RF choke out of coax. Originally my antenna was slid in 1 5/8" top rail for a mast with no choke. It was a solid performer. Now I am thinking of isolating my antenna like like yours and Bob's on my rebuild. Any tips or input is appreciated. 73's

 

[HomerBB]

No, it was not grounded. There are threads in the CB Antenna section about how I built this antenna.
hope you do well with your rebuild.

 

[Henry HPSD]

I recognize a 1/2 wave directly over a 1/4 wave doesn't produce 2dbd by itself.

Great !
So that 5,15 dBI figure and all statements with "equal to 2 stacked dipoles" etc will be removed from you site ....

@ Homer...
You see a lot of contradictions.
All i have told is the truth. please explain where the confusion is.
And we will try to make it more clear.


@ Donald...
Now...Donald you can continu your search for lower angle...(im not going to explain again)....,you can continu everyting else
But why dont you look at the one point where it is possible to find "extra" gain.
It IS perfectly possible for a vertical to have additional gain with "elements" along side.. this because of nearfield mutal coupling.

Now, I have told you....the magnetic near H field current is not the same as antenna current, and it is not.
However, they are related and you can draw conclusions.
(dont start be happy imagining things from the above line )

If you understand that the current is Maximum at the bottom of the cone.
(must be low impedance)
And you know that current radiates....
You know that maximum effort due to mutual coupling should be focussed on the bottom part of the radiator

Do you understand where I am going at ?

You seem to be focused on that i only give 2dB due to different mast lenghts
In that case you missed a lot of things.

And you seem to be focussed on a transmission line that needs to be straigth..
That si not the case there are plenty of applications where they are in an angle..


NOW NEW QUESTION FOR EVERYONE :

The last question wasnt correctly answered by anyone..

New one:
When do we have a situation where we have a current moving though a conductor
which creates a magnetic H field....but NO radiation.

Gammegetter you are not allowed to asnwer hihih
And the open transmission line I have mentioned alllread quite some times

Again...thumbs up and a like !

Hope to have some time...

Kind regards,

H