Question on the Vector

[bob85]

what are you meaning by pigtail eddie?, its not a term we use over here,
i looked online and the images are patch leads with various connectors which i can only imagine causing impedance discontinuities and internal reflections,

the cone taper seems to me a method of increasing end spacing without proportionally increasing the transmission-line mode impedance.

 

[Marconi]

what are you meaning by pigtail eddie?, its not a term we use over here,
i looked online and the images are patch leads with various connectors which i can only imagine causing impedance discontinuities and internal reflections,

the cone taper seems to me a method of increasing end spacing without proportionally increasing the transmission-line mode impedance.

Bob here is a picture of what I call a pigtail connector that makes a pigtail at the feed point for and antenna.

I site this only as an example of what happens when the proper construction ratio of coax is change, altered, disrupted...it makes the coax start to radiate at that point on and it can disrupt the antenna pattern if it is made too long.

IMO, the way this connector ends up looking is similar to tapered coax you talk about and this cone.

 

[Shockwave]

The "pigtail" radiates because it's no longer shielded and most applications have the exposed conductors far from being parallel.

 

[Marconi]

The "pigtail" radiates because it's no longer shielded and most applications have the exposed conductors far from being parallel.

I agree Donald. At the time when I was convinced I was right in my ideas about how the cone worked, is why I contended the cone was not coaxial in the way it worked. I was saying that y'all were wrong in thinking that the cone was an extension of the coax and that is how it could radiate CMC's on the outside of the cone.

I did not know that Barkley made the statement that Bob mentions above. He asked a question about Barkely's comments, and I was reminded of my thinking and I posted my idea.

 

[bob85]

i can imagine a tiny bit of radiation from the split part of the coax and the outer shield radiating if its connected to an unbalanced load,

 

[Marconi]

i can imagine a tiny bit of radiation from the split part of the coax and the outer shield radiating if its connected to an unbalanced load,

Bob, the radiation will be small for sure if we make the pigtail small, that is what is suggested with the use to keep these connections small.

How bad would RF be if the pigtail was as big as the cone? I was just suggesting the cone is not coaxial, because it does not present the same coaxial ratio like the coax does...this was my point regarding the tapered cone.

 

[bob85]

i would think it depends on the angle and what its terminated with eddie.

 

[Shockwave]

When we connect a quad loop through a 1/4 wave of 75 ohm coax before going into 50 ohm cable, we still consider the 75 ohm section to be coaxial transmission line even though the ratio between conductor diameters has changed. The biggest effect this has is on impedance match shifting higher at the load end but the function as coaxial transmission line remains.

 

[Marconi]

i would think it depends on the angle and what its terminated with eddie.

Bob you're right, this is the nature of coax, it works based on the condition (balance) of the load at its termination. If the load is perfect and the coax is to specs we get no coax radiation in the form of CMC's. However, if the load is a little off of perfect we will get a little CMC radiation, and if the load is way off we will get a lot of radiation due to CMC's. Same with the integrity of the cable issue.

This pigtail idea I used was just an example of what happens to coax when the physical construction ratio of coax is altered, like I see the cone doing. However, IMO these currents on the cone are not CMC's...they are Antenna Mode currents. Thus I cannot consider the cone to be coaxial. It is just a radiator that does not generate a lot of RF.

But, I have claimed this is all a mute point now...because DB's new 4Nec2 model has shown us the kind of gain that Sirio reports for their NV4K, Donald claims in his real world testing, and we see the model suggesting the gain noted as CMC's.

You asked us what does Barkley mean. What do you think Barkley means or is talking about?

Have you read his thesis, "The Open Sleeve, as a Broadband Antenna?"

Here is the link: http://calhoun.nps.edu/bitstream/handle/10945/24797/opensleevebroadb00bark.pdf?sequence=1

 

[bob85]

yes i read barkleys paper that he did in his 11 weeks at sanford research institute on the suggestion of the open sleeve inventor bolljahn and guidance of dr taylor as part of his masters of science in engineering electronics eddie,

when i read barkley and noted his comments of flared radials & skinny radial to monopole diameter ratio i thought it likely that herb had read that too,

you could be right about antenna mode currents eddie,

i can imagine the unbalance at the top of the sleeve causing radiation from the outside of the sleeve with wider spacing as Cebik tells us in his "some j-poles that i have known" article,

its clear that there is not only one current flowing as claimed in the arrl article,

it is clear that Cebik was correct in telling me "there is more going on in the design than is imediately aparent to most people"

im not sure how much radiation, i hope to get a better picture by finding the other articles in barkleys listed bibliography.

 

[Marconi]

Bob, I did a vertical sleeved dipole below to check the tune and how broad band it was vs a simple dipole and found the CFSD had a <2.00:1 bandwidth of 2 mhz vs 1.6 mhz over a simple dipole...so Eznec shows what Barkley was looking for, an increase in bandwidth, with little change in the match. This is why I though Barkley's idea was about matching.

The model produced a minimal change in the resonant match, and a little loss in gain too.

 

[Henry HPSD]

But, I have claimed this is all a mute point now...because DB's new 4Nec2 model has shown us the kind of gain that Sirio reports for their NV4K, Donald claims in his real world testing, and we see the model suggesting the gain noted as CMC's.

No it does not...

As previously mentioned.

 

[bob85]

what does the dipole look like if you make it 3/4wave each leg with 1/4wave sleeves eddie?

henry,
if i lived near you we could compare my homebrew vector to your j-pole hihi,
do you know anything about the software vortex claim shows 3dbd for their majic vector clone?
i smell something you would find in field.

 

[Marconi]

what does the dipole look like if you make it 3/4wave each leg with 1/4wave sleeves eddie?

I don't know what this means, but here is the model with a 3/4 wave radiator.

 

[Henry HPSD]

Bob,

There are only few manufacturers who make antennas because of the joy of making something.

There are many who try to create a hype in order to sell

I perfectly understand one has to make a living..
But i often wonder: if such a antenna manufacturer sees a "bob" and looks them in the eyes...honestly...would he be proud of himself ? would he have "peace" ?

I think many of those need to see a qth say 5000 Km east from them.
And start appricating there is warm water when he looks up he sees a roof.
Suddenly they will realise there is more to this planet.

Educate people, dont start telling lies ....especially if you know better....
But i dont blame them, we all try to crawl up on Maslov his pyramide.