I'm not personally familiar with what they published for gain figures prior to late 2004 as this is when they started manufacturing for us. I've heard before that these figures were not always accurate. All I can say is I'm happy they are now claiming figures that are obviously true. Other manufacturers should do the same and follow that example.
-
You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
Avanti Sigma4: An alternative view point
- Thread starter bob85
- Start date
I certainly don't see any difference other than the animation and the Vector with two in-phase current lobes vs. the GM that has only one lobe with its center fed 5/8 wave radiator that benefits from its ingenious and maximum full use of the capture area of a 5/8 wave radiator. This is not typical for the end fed 5/8 wave which seems to waste capture area and some RF due to the bottom 1/8 wave section being out of phase.
All the maximum radiation lobes noted on method of moment modeling software produce antenna images showing the primary lobe as a 1/2 wave or portions of the 1/2 wave. I think it's just like ole' Jack the "FreeCell" has always told us...when we got corn'fused.
Personally I believe the big difference in performance we all would hope to see here is due to improvements in "capture area." For me, that seems to be evident among the group of antennas we typically use, the Vector, the Sigma4, the Gain Master, and the 5/8 wave ground plane, and the 1/2 wave, and maybe even in that order of effective gain.
Since I can't explain why my antennas do not seem to indicated the remarkable differences others see, I can only assume that the location is king and the soil and topography differences...rules the success or the lack off success. Personally I think there might be some differences to be noted to be due to good, better, or bad symmetry in design as well. That said however, I think the Sigma4 due to design and length is somewhat superior to all other models thus far produced for CB.
All the maximum radiation lobes noted on method of moment modeling software produce antenna images showing the primary lobe as a 1/2 wave or portions of the 1/2 wave. I think it's just like ole' Jack the "FreeCell" has always told us...when we got corn'fused.
Personally I believe the big difference in performance we all would hope to see here is due to improvements in "capture area." For me, that seems to be evident among the group of antennas we typically use, the Vector, the Sigma4, the Gain Master, and the 5/8 wave ground plane, and the 1/2 wave, and maybe even in that order of effective gain.
Since I can't explain why my antennas do not seem to indicated the remarkable differences others see, I can only assume that the location is king and the soil and topography differences...rules the success or the lack off success. Personally I think there might be some differences to be noted to be due to good, better, or bad symmetry in design as well. That said however, I think the Sigma4 due to design and length is somewhat superior to all other models thus far produced for CB.
im no where near you guys in antenna knowledge ..........
it looks to me like the color pic shows the cone acting kinda like the shield on coax with there being a different signal/polarity on the inside and outside of the coax/basket .
is that right or wrong ?????
Ok 007 I think this answers your question about the CST of the Vecor and the GM look at the numbers posted on the side of both the vector and GM's CST the Vectors clearly has a higher FS radiation numbers than the GM
Exactly the point I was trying to make Shockwave. This could be the real difference that I see, or all of my antennas may just be ill-affected the same...being mounted over very conductive soil like CDX007 suggested, thus making them all appear similar in performance. I prefer to think that may be true to an extent, but instead making the lessor antennas stand up and work like they should, without just benefiting from being installed over poor to very poor soil conditions where the affects of the antennas ground plane is not quite so important.
It's as if no one else even bothered to look at what the colors mean according to the scale on the right. Without looking at the scale or unit of measurement used, the information is lost.
B
BOOTY MONSTER
Guest
i was asking to see if i was on the right track to understanding how the basket becomes a radiating part of the antenna . the colors (phase?) on the outside of the vertical and basket/cone look the same but the inside is different thus my coax analogy .
just trying to get a clue
just trying to get a clue
you know id look at what it meant as soon as i saw it
the scale is in amperes per meter, 1 A/m = 0.012566 Oe ( oersteds )
A/m is the international unit of magnetic field strength.
Hi Bob, OK, could you translate that for me into dB?
I noticed the Vector was peaking at 2.37 A/m but the SGM was peaking at only .173 A/m.
2.37 ÷ .173 = 13.7 times more...?
If this were equivalent to watts, the Vector would be radiating more than 20 times more energy than the SGM.
That would be an increase on the meter of about 3-5 S-units.
I'm not at all familiar with CST so I'd like to know if that is more than simply a difference based on the initial configuration of the program set-up, as in how much input power they told the program it was working with, or something else.
Also, seeing the width of the red/blue in the current peak areas in comparison to the low current areas makes me imagine 'the more the better' as in 'the more width the higher the output'. Is this an incorrect presumption?
I noticed the width of the peak red/blue areas on the still of the Vector full-bloom is only about half of the width which appears at full bloom on the SGM CST.
How is it that this does NOT designate less overall output by comparison, even though the A/m amount is so many times higher?
I apologize in advance for my lack of knowledge in this area.
You are saying the Vector is in full bloom we don't know that , look at the interactive CST of the GM antenna, it shows as the phase changes so does the amplitude of the a/m. To make a valid comparison you would have to know that they were both at "full bloom" as of now you are assuming the Vector shot is taken at full bloom, and if it is, it is clearly showing higher A/m numbers.
As was my suspicion, but now having twice been assured by Shockwave that it IS in full bloom, I am basing my question to him or Bob85 as such.
And yes, that appears so much higher a level of A/m than that of either the SGM or the conventional 5/8 that I have to question why.
Mr. Suburban, I haven't assumed anything about the CST model. I have a working relationship with the staff at this company with everyone from marketing to engineering. I've correspond directly with the man that built the model in CST and it's absolutely shown at a current maxima phase angle.
The better question is why does the Vector show currents in the order of a couple of amps per meter while the GM is at fractions of an amp? I don't think amps per meter easily transfers to gain in db without knowing applied power. I also do not think these models were intended to compare gains as much as they are to show current distribution and phase.
CST is a program that I've never seen until these models were given to me. Therefore I'm not sure exactly how it works. I have to assume that this current is referenced to a particular level of RF drive that has not been shown. I do not know if CST uses a fixed value of power or if it's user selected. These could be the variables.
The better question is why does the Vector show currents in the order of a couple of amps per meter while the GM is at fractions of an amp? I don't think amps per meter easily transfers to gain in db without knowing applied power. I also do not think these models were intended to compare gains as much as they are to show current distribution and phase.
CST is a program that I've never seen until these models were given to me. Therefore I'm not sure exactly how it works. I have to assume that this current is referenced to a particular level of RF drive that has not been shown. I do not know if CST uses a fixed value of power or if it's user selected. These could be the variables.
Looking at the numbers i would also have to assume it is "full bloom" but the GM has an interactive model where you can read the phase in numbers on the bottom while you watch it get larger. Maybe that is all computer mumbo jumbo meant for marketing illustration purposes and isn't really anything that the CST program actually does. I checked out CST but I ain't shelling out the bucks they want for it to see what it does. Im not designing patch antenna, fractals etc so I stick with eznec
While the active version looks impressive it really offers no more useful information then a single snap shot of a maximum current point. Consider the RF as a simple AC sinewave and the antenna just as the load. Current only peaks at the positive crest and the negative crest. I don't understand the desire to see other points at less or no current. What is there to be leaned from seeing this?
Hi Bob, OK, could you translate that for me into dB?
I noticed the Vector was peaking at 2.37 A/m but the SGM was peaking at only .173 A/m.
2.37 ÷ .173 = 13.7 times more...?
If this were equivalent to watts, the Vector would be radiating more than 20 times more energy than the SGM.
That would be an increase on the meter of about 3-5 S-units.
I'm not at all familiar with CST so I'd like to know if that is more than simply a difference based on the initial configuration of the program set-up, as in how much input power they told the program it was working with, or something else.
Also, seeing the width of the red/blue in the current peak areas in comparison to the low current areas makes me imagine 'the more the better' as in 'the more width the higher the output'. Is this an incorrect presumption?
I noticed the width of the peak red/blue areas on the still of the Vector full-bloom is only about half of the width which appears at full bloom on the SGM CST.
How is it that this does NOT designate less overall output by comparison, even though the A/m amount is so many times higher?
I apologize in advance for my lack of knowledge in this area.
Hey guys, of course I can't be sure about CST. I'm not even sure about Eznec. I know enough to be dangerous.
In Eznec there is and elevator control in the Antenna View that controls the appearance of the current distribution magnitude, and is probably for illustration purposes only. You can make the current lines drawn look big or small. We can't assume anything regarding the images and the currents except the actual A/m numbers as fact base on each individual model generated.
I can't explain the differences suggested here, if the differences are in fact accurate and also useful for comparison, which I seriously doubt. We just don't have a full understanding for the meanings, nor the significance of the information we see from two different model's input data.
Usually the current amperage magnitude is a standardize value set within the NEC engine, and I think it is something like 1-3 amps. However, the current values generated are controlled by the number of segments assigned to each wire and that can make the current values just about any amperage/per meter,inch,foot.
Quit looking for the real meaning in pictures.
IMO, comparing the appearance of the pictorial dimensions for two different images in totally unrelated periodicals and/or method of moments modeling is problematic.
Would you like to see a demonstration model? I can make em' look like Marilyn, Twiggie, or Popeye's Olive Oyl.
Last edited:
- No one is chatting at the moment.