Sidebar Sidebar
  • 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.

Vortex antennas


What's the current exchange rate for an English pound? That times 175 for a two element yagi? They are certainly proud of them, aren't they?
- 'Doc
 
Vortex Quasar .64

I took delivery of the Vortex Quasar 64 recently.
Out of the box you are immediately struck by the great build quality.
I tend to take a lot of time building antennas and the Vortex was no exception.
All the joints were waterproofed using C-Seal, a compound I've been using for years. Mounted on a seven foot stub for testing the VSWR was practically 1:1 at the chosen frequency, and when raised up one hundred and twenty foot and tested at the rig end, using a balanced length of coax, the analyser VSWR reading was just a little over 1:1 matching the rigs meter.

I had been using a Sirio Vector 4000 which was reinforced bottom to top, as most know that they are as delicate as Chantilly lace out of the box, and it withstood all that the ferocious storms could throw at it, while factory spec Gain Masters were cracking and splintering and 827's ended up bent into a crescent shape, only the Vector and the Shakespeare NBS remained undamaged.
Anyway, the Vector is an animal for common mode and I wanted to take it down and do some maintenance and borrow the Vortex 1:1 balun isolator. Having taken a lot of readings of local stations over the last week, this gave me the opportunity to do likewise with the Vortex and make comparisons, admittedly being subjective and not at all scientific or professional.

I don't include the Gain Master as the geography of this QTH prevents it from performing as a balanced antenna should, that is, buildings, trees, surrounding hills conspire to badly degrade its performance.
It works superbly well at its owners QTH out in the sticks on the gable wall of a house on a hilltop.
Over the period of five days the Vortex Ugly Stick, as my anti-radio xyl calls it, performed superbly, and was easily on par with the excellent performing Vector, possibly even stealing a narrow victory.
Without professional testing facilities it is impossible for me to definitively choose between the two.
Where the Vortex is a clear winner is the build quality, the materials used and the power handling capability, although the Vector was fitted with a gamma match that bragged about handling 5Kw and had no problem in that area, as for the Gain Master don't even go there unless the stub has been upgraded and modified to cope.
Unlike the Vector the Vortex only has a problem with common mode at QRO power levels, for everyday use at 100-200 watts there is no problem whatsoever, with the Vector, operation without a balun was a non starter, the nature of the beast.
 
davev8 said:
i have not seen them before .....it just make it fair ....as i got quoted $334
shipping for a mako shooting star to the UK
Click to expand...

When I was looking at buying a Hexbeam from the USA it was only about $70 or so shipping.

Shipping from the US to the UK is comparable to shipping from the UK to other EU countries so if you were being quoted $334 its because they didn't want your business.
 
I'm more interested in the 3 port T device with the short stub attached. Is that an integral part of the antenna as installed?
 
I wonder if the CMC problem is due to the SO239 being well above the ground radials, therefore placing the coax above the radials. My understanding is that the coax should connect below the radials so as not to promote CMC?
 
not sure what difference that would make 35s, it would not take much effort to change it and find out,

im just happy we have a sturdy uk made antenna for 1/2 the price or less than what it costs to ship an i-10k or coily over here,

sure i would do it differently but its heading in the right direction with quality materials,
all we have had in the uk cb shops since avanti stopped trading are eurotat antennas made from recycled twin tub lids and monkeymetal that rots faster than a 70's alfa..
 
bob85 said:
not sure what difference that would make 35s, it would not take much effort to change it and find out,

im just happy we have a sturdy uk made antenna for 1/2 the price or less than what it costs to ship an i-10k or coily over here,

sure i would do it differently but its heading in the right direction with quality materials,
all we have had in the uk cb shops since avanti stopped trading are eurotat antennas made from recycled twin tub lids and monkeymetal that rots faster than a 70's alfa..
Click to expand...

Hell fire that's a mighty claim Bob, nothing rots faster than a 70's Alfa :LOL: That said, Sirio is an Italian manufacturer :whistle:

There's no doubting the build quality of Vortex antennas though, Dave Ogg (Oggy) is mighty impressed with his.
 
northern35s said:
I wonder if the CMC problem is due to the SO239 being well above the ground radials, therefore placing the coax above the radials. My understanding is that the coax should connect below the radials so as not to promote CMC?
Click to expand...

35, I can't vouch for either antenna regarding CMC's they might or might not produce, but I read GI0ZGB's comments talking about his Vector and not his new Vortex.

Bob, what is it about the coaxial stub matching setup on the Vortex that makes it seem to you to be less lossy than other impedance transformers?

I recall this is basically what Jay use to say about his trombone tuner on his I-10K. This is not the first time antenna producers have made similar claims regarding their special matching devices. They all seem to claim their idea produces a match with less loss.

Among others, both HyGain and Mosley make similar claims. I've made the claim before that my Starduster design that uses no matching device at all, and I see it produce very good results for me...even though I'm probably one of a very few around that makes such a claim.

Isn't this type of Vortex coaxial stub matcher similar to the Gain Master's stub that produces such a big bandwidth? I guess I was wrong about the bandwidth thing however, because the Vortex paperwork shows it has a <2.0:1 bandwidth of only 1.3 mhz. I think maybe we see here that a symmetrically well balanced design at the feed point is generally always better in some ways and that is what provides the added bandwidth.

I also see that this Vortex model posted producing about the same gain as my models of a similar antenna. The big difference I see beside the matching is the Vortex has the ground plan isolated from the antenna and the ground.

I've also reported for a while now that my Vector model is very sensitive to the height above ground, and that being mounted near a 1/2 wavelength multiple probably will produce a lot of CMC if the antenna is not isolated from the mast and choked well. This same model also shows me if I raised or lower the antenna to some odd 1/4 wave or close the problem of CMC is mitigated nicely. I have not tested this idea specifically with my S4, but over time with numerous installs I have noticed sometimes it is pretty bad and other times it is very good concerning CMC.

So, I think a slight change in height alone might help minimize the problems that some guys report like GI0ZGB did above with his Vector, but the idea really needs to be tested more in the real world to be sure.

I think this effect is very obvious in my models for the Vector.
 
i don't think stub matching is lossy eddie, its mechanical things id change,

i don't have any more cmc issues with my modified sigma than other antennas but i do see the potential with the sigma style antennas, 150ft of my coax lays on the ground so it probably soaks most of it up,

its not height that changes the magnitude of cmc eddie,
its a combination of the electrical length of the mast or coax braid and them been grounded or not grounded that determines common mode impedance/magnitude of cmc on the mast or coax braid,

where do you get the idea that the vortex has isolated radials?
its like a 10k with the trombone swapped for a stub,

i think the gainmaster has good bandwidth because its cleverly put together by folk that know how to work CST.
 

dxChat
Help Users
  • No one is chatting at the moment.


      Top Bottom
      Back