VORTEX Q82 mk2

[Marconi]

Sorry to here about Dave, I'll say a prayer for him.

I just had a thought to go to the Vortex Website again. Dave once told me for the most part the dimensions were there.

I looked again and at the very bottom of the page the primary dimensions are there. It shows the hoop circumference is 94.5" inches, which is 30" inches. I think somebody told me the hoop was 25.5" inches and I got it to 25.6" inches in the model above.

So, the hoop may look smaller but it is not smaller.

I'll make the radials longer and the radiator a bit shorter, then I may have to reset the capacitance at the feed point.

I'll redo my model but I don't expect much difference.

 

[Marconi]

If the bandwidth was wider I would feel better by the model. If the gain was 5.82 dbi like they report I would feel better.

As far as the radiator length, their dimensions note the radiator is 834 cms at 27.500 MHz, so I may have to do the model there and scale the model down or maybe I can just do the math for the radiator and forget using the scaling feature.

 

[bob85]

The specs say the mk2 hoop is 8cm shorter in circumference than the mk1 hoop Eddie,

mk2 radials are 415cm, a shade over 163"
mk2 vertical is shorter at 834cm vs 860cm for the mk1

how fat are your wires? vortex has fat 3 piece radials 20mm 16mm 12.7mm,


https://web.archive.org/web/20160512085758/http://www.vortexantennas.co.uk:80/shop/q82-vertical-11m

http://www.vortexantennas.co.uk/shop/vortex-quasar-q82-mk2/

 

[Marconi]

Well Bob, the model was a surprise to me, so I want to take some more time and see if I missed something.

Here is the Free Space model I started out with so we could see what Exnec says about accuracy.

1. The first page is the control page for Eznec showing the Free Space results for the Average Gain which shows 1.003, very good.

2. The next two pages show a close up and at the bottom each page show the dimensions for the radiator wire #2, and the radial wires #7,8,9,10.

3. The Free Space pattern which is a surprise to me. Does this remind you, a little, of something that you have reported about your Vector Hybrid?

4. SWR curve showing the bandwidth. This too surprised me, but it is what I was watching for in this model as the only real gauge I really have to compare to published reports about models.

5. The Source Data report showing a very good match.

6. Is and overlay comparing my recent model of the New Vector 4K to specs and matched. I didn't expect this, but I don't see the performance reported for this antenna, unless you want to just consider the very nice bandwidth.

To me this wide bandwidth confirms what is reported in the science, if we see more bandwidth we should not expect to see more gain. This is why I had my doubts.

 

[Marconi]

The specs say the mk2 hoop is 8cm shorter in circumference than the mk1 hoop Eddie,

I don't see this in the link which I also have. The dimension I used for the loop is noted as "Basket Loop Length: 240cms in the link. My calculator says that 240cms is 94.5" inches and I followed this math to get the loop diameter 94.5 / 3.1416 = 30" inches.

I never considered to model the older Vortex M1 Q82.

mk2 radials are 415cm, a shade over 163"
mk2 vertical is shorter at 834cm vs 860cm for the mk1

I used 163.036" inches for the radial length.

I started with 328" inches but I had to add length to get lower the frequency. I was thinking their frequency was maybe 27.500 MHz and my model was in the middle of US CB. I ended up at 339" inches and I'm not sure what frequency would equal their model...I use tuning to resolve some of the differences and that is tedious work for me using Eznec.

how fat are your wires? vortex has fat 3 piece radials 20mm 16mm 12.7mm,

I used my Vector model to start and I did not convert all the tubing diameters. I tried to stay as close as I could to the Vector with the tubing diameters, but during the tuning process I did make some changes to the tubing diameter. I should have used segment length to fix those issues, but I got lazy.

The main problem I found was running out of segments. I used all 500 segments allowed me in my version of Exnec and that is why I changed a wire diameter or two at the most.

 

[bob85]

Vortex claim that length for resonance on 27,500,
i imagine using fatter tubes would yield a broader bandwidth, i doubt it would give the increase in gain,

If the radial sleeve has very little radiation making the sigma4 an elevated 1/2wave,
the mk2 Vortex must be an elevated 3/8wave.

i would expect a little lower gain from a 3/8wave, so where is their gain coming from?,

you have them at about the same height, i presume same ground type too,
current maxima is close to the same height with the edge to the older longer vortex,

 

[Marconi]

If the radial sleeve has very little radiation making the sigma4 an elevated 1/2wave,
the mk2 Vortex must be an elevated 3/8wave.

i would expect a little lower gain from a 3/8wave, so where is their gain coming from?,

I have no idea how they get their gain. I smell a Solarcon claim in the wood pile. The Vortek guys use Eznec + and that might make some difference.

you have them at about the same height, i presume same ground type too,
current maxima is close to the same height with the edge to the older longer vortex,

1. Below are two antenna images at about the same location relative to the X and Y coordinates. I expanded the currents a little to make the differences more obvious. The Vector has more currents everywhere. So IMO this suggest more gain.

You could be right that the Vortex looks to be an elevated 3/8 wave, but some of the bottom of the 1/2 looks to be down inside the cone area...and I'm not to sure how that works. It could be wasted currents like the bottom of a 5/8 wave antenna.

2. These two images compare the patterns for my Vector to specs vs. the older Vortex Mark 1 antenna...I think is a knockoff of the Vector 4K. I take this to mean my Vector model is pretty close to right if Vortex is also publishing their model of the M1 showing a similar pattern and gain by the way.​

 

[W2EKG]

Is that considered a J-pole?

 

[Marconi]

W2EKG in response to your question, some folks make the claim including Sirio...who builds the New Vector 4K.

For a long time now I have claimed, but apparently not convincingly, that the bottom cone area of the Sigma4 was basically a tuning device, and the combination of out-of-phase currents in the cone area did not radiate very much in the far field if at all...sorta like the stub area at the bottom of a good working J-Pole.

 

[Marconi]

The ring is a little smaller than the other versions, Fat 3/8wave radials & spreaders make it look smaller than it is.

The specs say the mk2 hoop is 8cm shorter in circumference than the mk1 hoop Eddie,

Bob I still don't see this reference in the specs, but I checked out one of Dave's up-close videos on the Mark 2...and he does say the hoop is smaller in diameter, but doesn't say how much.

On a closer examination, I could see this 1/2" flat-stock was actually 4 pieces with 1"- 2" of overlap at each end for overlapping and bolting the hoop to the insulated bracket. So, I re-did my 30" inch hoop to a 27.56" inch diameter.

I did not consider the exposed material length in my first model above.

mk2 radials are 415cm, a shade over 163"
mk2 vertical is shorter at 834cm vs 860cm for the mk1

My model is very close to these dimensions, but I modeled at 27.205, and that might be a mistake. I also realize, due to your post below, that my wires are all 1/2" inch and very thin. I can't recall why I did this however, I'm usually picky about trying to stay close to the antenna specs for both length and diameter.

how fat are your wires? vortex has fat 3 piece radials 20mm 16mm 12.7mm,

To start with, I made my model at 27.205 using an old model of my NV2K. I don't recall but apparently at some point I was using 1/2" inch for all my wires. So, some of my models for the Vector and this M2 model are abviously off, and might be showing a much lower frequency than planed. However, I have no idea how much this really matters, if at all.

I don't like the way this antenna acts in the wind.

Regardless Bob, unless I can get some better dimensions, I don't think I'll be trying to fix this model again. My Free Space model already has me at my 500 segment limit and I have to add a 36' mast when I set the model over Real Earth. If I make the wire diameters much larger the model might require even more segments in the process of getting a good match at resonance.

Bob, for now I'm convinced that I don't believe this antenna will do what is claimed.

 

[bob85]

The 8cm difference in the loop circumference comes from vortex, i posted links to mk1 & mk2 specs a couple of posts back,

im sure wire diameter does matter in real life & models Eddie, especially with close spaced conductors forming transmission-lines,

it is a pita that they cripple the free & inexpensive versions of eznec with segment limits,

what are you looking at starting @7 minutes that convinces you the mk2 won't do what is claimed ?,
i see a chinajunk s-meter registering local noise, that's normal for chinajunk,
am i missing something ?

The guy Dave is talking to is 25 miles east of me atcf, known him for many years, when he pumps up he's like a local,
he is about 7.5 miles atcf from Dave & using a coily excaliber .64 on a crank up tower.

i don't like how the Q82 mk2 handles in the wind either Eddie, its just a breeze & look at the radials flopping around, should have put the spreader in the right place,

They over engineer in the wrong places, use stauff clamps in stupid places where they are either not required or are a potential disaster,

an ass backwards engineering fugly fat sister version of my favorite antenna.

 

[Marconi]

Well Bob, I did the model at 27.500 MHz in Free Space and got it to working with a fair match (not perfect though). The AG result is close at .973 db, so I quite because my total segments were 499 out of a possible 500, as you will note on the Eznec Control page image below.

I did add an insolated (ISO) mast and assigned it 1 segment and that is as far as I can go without changing the segments and redoing the tuning process all over again. The model shows an non critical error, because the mast only has 1 segment and the segment length is 416" inches long. The minimum length should be no more that 51.503" inches. However, the model still works regardless of the non critical error, IMO that is why it is non critical.

I'm just not sure the full effects, but I doubt if the segments were corrected it would fix the low gain reported.

1. is the Vortex Q82 Mark2 pattern and antenna image at 27.400.

2. is the Free Space model showing the Average Gain results in the Eznec Control Center image.

3. is the Free Space model with two images of the antenna showing the length of the radiator and radials in inches. This also shows us the pattern, gain, angle, and the matching details.

Note: this FS model image that shows wire #7, indicating the length of the radials has the currents turned on...this is why this model does not look like the Vortex model...because they had their current turned off.

4. is the same model as # 3, but is set over Real Earth and includes an isolated mast. Here the currents are turned off to indicate the similarity with the Vortex model. This is also the Ezned model that reports the error I talked about above. Again this is due to the lack of the proper number of segments for this long mast.

IMHO the gist here is, I see a pretty wide bandwidth but not as wide as reported. I also see 38% less gain at 3.63 dbi at 8* degrees rather than the reported gain at 5.82 dbi at 8* degrees.

My next step is to scale this model to 27.205 MHz. To follow later.

 

[Marconi]

what are you looking at starting @7 minutes that convinces you the mk2 won't do what is claimed ?,
i see a chinajunk s-meter registering local noise, that's normal for chinajunk,
am i missing something ?

No Bob, I was wrong...I deleted that comment as soon as I found out I made a mistake in looking at one of Dave's other videos on the Mark 2.

The guy Dave is talking to is 25 miles east of me atcf, known him for many years, when he pumps up he's like a local,
he is about 7.5 miles atcf from Dave & using a coily excaliber .64 on a crank up tower.

I think Dave was claiming in his video MK2 "On Air" Tests that the other guy named Dave was about 20 miles away in his video. If so, then somebody is wrong.

i don't like how the Q82 mk2 handles in the wind either Eddie, its just a breeze & look at the radials flopping around, should have put the spreader in the right place,

According to the Vortex website on the M2 there are two spreader bar setups (basket support bars), one lower and one upper brackets. Do you know if the radial tubes are heavy wall tubing?

In Dave's video "Vortex Q82 MKII Antenna Review.......Part 2" at 2:06 minutes...it looks like the tube might be thick wall and that is at the top of the basket. (https://www.youtube.com/watch?v=pp3MksOZ7u0)
I hope this address works

I scaled my model at 27.500 down to 27.205 using Ezenc scaling feature and it worked great, but it automatically changed all the wires including the mast to a 1/2" inch...except for the mast bracket. Maybe this is why some of my Vector models show most of the tubing as 1/2" inch diameter.

My 27.500 MHz model used 328" inches for the radiator. When I scaled the model it adjusted the radiator to 331.557" inches, and I figured it would be 332" inches using my old trusty slide-rule.

I'll post the model shortly.

 

[bob85]

Yes its all thick wall tube Eddie, as Dave says built like a tank,
did you notice the unequal length radials? broad banding technique ?

That video was taken in Daves back yard so unless the other Dave who lived much closer to me in the 80's & gets along well with us round here has been telling lies about where he moved to Dave is mistaken about the distance,
google earth is handy for looking at distance and terrain between two stations

 

[Marconi]

Yes Bob, I noticed that my AS S4 used 9 sections of tapered tubing, the Siro New Vector 4K uses 7 sections, and the Vortex uses 6 section. I did not know this was a form of broad banding.