Because I was asked - Best Vertical

[bob85]

eddie, i don't have exact measurements.

 

[Needle Bender]

The CST model is shown with a 1/2 wave top element like the new Vector. This can be determined by noting the model has all radiation currents in a constructive phase. If it were the old 7/8 wave we would see approximately 1/8 wave of the vertical radiator above the cone, out of phase with the rest of the antenna much like we do in a typical 5/8 wave. I don't have access to any old Vector CST models and I'm not aware of any.

The longer length used in the new cone is producing improved performance. Bob and myself both noticed this years before the new Vector came out deviating from the old 94 inch length. This has to do with the fact the cone is not just a 1/4 wave radiator, it must also be positioned correctly so that it covers the bottom 1/4 wave of the vertical. Combine this with the velocity factor between the cone and the vertical and you can quickly see there are several different areas affecting the optimal alignment.

I've found .82 wavelength from the feedpoint to the tip gives the best performance. Bob feels that these lengths can be altered to tailor the angle of radiation to best suit a particular installation. Many would be quick to deny this fact assuming only height above ground could impact TOA. We have a "non apparent collinear" here and with two active elements radiating, beam tilt is possible by altering the phase angle between the two. I don't think that was considered when the antenna was shrunk back down to 3/4 wave.

So have Sirio, with their million dollar testing facility, not produced the Vector at it's finest performance sizing, but one must mod it out to .82 from .75 for superior performance, or are they coming out of the box as .82?
Not being facetious, truly curious, and finding it odd if it's necessary to mod theirs.

 

[HomerBB]

I believe that it has been discussed before to the conclusion that the longer V4k was less strong due to the greater wind loads and the shorter version responded to that. We felt the less expensive route was to use the same tubing for all the production models as opposed to having additional tubing for one antenna. Also, there are other changes they made to the antenna, such as a cone/basket/cage of different dimensions than before. With all the changes the buy it and fly it majority could have a stronger antenna with near parity performance to the old production model without adding significant cost to the price of the antenna. It was/is a win-win for everyone.

Those who fall into the minority of tinkerers would continue to squeeze additional performance out of the antenna at only the cost of personal time and expense, which they are inclined to do with any antenna.

It is likely that virtually all production antennas can be tweaked to some degree for maximum performance gains.
. . . what I think, anyway.

 

[Truck]

Failed Gamma

Has anyone found a cure for the weak gamma match on the Vector 4000? At 1000W pep the gamma match is shorting. The insulator sleeve that slides over the inner rod is burning a hole and causing arcing to the outer gamma housing, not to mention everyone that has failed was full of water.

 

[HomerBB]

Has anyone found a cure for the weak gamma match on the Vector 4000? At 1000W pep the gamma match is shorting. The insulator sleeve that slides over the inner rod is burning a hole and causing arcing to the outer gamma housing, not to mention everyone that has failed was full of water.

Truck,
I've never run that amount of power into my Gamma Match, but I built a larger one that I believe would handle it.

Vector remake Post 25

I wouldn't allow Gamma Match deficiencies on any brand antenna be an ongoing issue as long as I can make one capable of doing the work. I have not had any moisture issues with my homebrew Gammas.
The first thing I'd try with the stock Gamma Match is to replace the tube with one of larger diameter. This tube diameter would be one that was suited to the thicker insulator tubing I'd use around the stock rod. I have used PEX tubing successfully for this insulator.
For the top of the Gamma Match tube I've done several things, but the best is perhaps the simplest. When I've gotten my match where I want it I simply wrap the top of the tube with electrical tape going on up onto the rod. When I'm satisfied with the tape job I use a good quality heat shrink tube over the electrical tape being sure the shrink is longer than the tape wrapping on both the rod and the gamma tube. Usually the shrink will not seal both those diameters effectively, so I have wrapped the electrical tape in a tapering fashion so that I can use a larger sized Heat shrink over the Gamma tube and the tape immediately above the tube, another smaller sized over the end of that heat shrink, and then yet a third smaller size over the upper end of that one. I have a completely sealed Gamma Match.

 

[Marconi]

eddie, i don't have exact measurements.

That's alright Bob. In light of what Shockwave said above, I was just curious.

I recall you posting that your Hybrid was maybe 32' feet tall, and I remember you modified an old Sigma4 radial basket, and added a fourth radial. I seem to remember that you didn't extend the radials out to 107", but I wasn't sure.

I was going to discuss my ideas on the subject again, but as you well know, we could talk until we were blue in the face, and not make a difference or change one mind. Isn't that also about how Cebik saw the subject?

Hardly anybody really reports specifically about the performance of their Vector styled antenna. Do any of your buddies around you that have a New V4k, or have you worked with one? If so, how do think they compare to the Sigma4, an old Vector, or your Hybrid?

 

[bob85]

32ft from hub to tip would be longer than the old style vector eddie,
my hybrid extended avanti vertical with vector 4 radial sleeve ended up shorter than the old vector but longer than the avanti or new style vector.

That's alright Bob. In light of what Shockwave said above, I was just curious.

I recall you posting that your Hybrid was maybe 32' feet tall, and I remember you modified an old Sigma4 radial basket, and added a fourth radial. I seem to remember that you didn't extend the radials out to 107", but I wasn't sure.

I was going to discuss my ideas on the subject again, but as you well know, we could talk until we were blue in the face, and not make a difference or change one mind. Isn't that also about how Cebik saw the subject?

Hardly anybody really reports specifically about the performance of their Vector styled antenna. Do any of your buddies around you that have a New V4k, or have you worked with one? If so, how do think they compare to the Sigma4, an old Vector, or your Hybrid?

 

[Ian1800]

Avanti made some great antennas and were well constructed,
I wonder what they would of came up with today?

 

[Mudfoot]

Avanti made some great antennas and were well constructed,
I wonder what they would of came up with today?

Stronger hubs for the PDL.

 

[Ian1800]

Yes the hub idea for the PDL and Moonraker was good but casting them out of Mazak A low quality alloy wasn’t one of their better moves:thumbdown:
I had some cast out of aluminium and are far better,
then again you always get the spanner monkey that has to tighten everything up till it wont turn any more