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WirelessRudy
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Sextant question antena beam

Thu Jul 04, 2013 12:32 pm

According the brochure http://i.mt.lv/routerboard/files/SextantG-5HPnD.pdf it has 16,8 degrees beam-Width (@ 3dB) in the H-Plane and 22,8 degrees in the E-Plane. ("E" stands for "Elevated"?)

So this means that the Vertical beam is actually bigger than the horizontal? Is this not a bit weird? Should this not be the otherway round?
Usually on directional/sectorial antennas the vertical beam it rather small compared to the horizantal.
Because stations will be found in the more or less same horizontal sector seen from the AP where they can be everywhere around up to 360 degrees (which would than have the need for a omni directional...)

So, am I misinterpreting? Or is it mis printed on the .pdf or is it all correct but is the design of the antenna a bit weird?
(Or am I completely missing the concept here....?
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Re: Sextant question antena beam

Mon Jul 08, 2013 11:10 am

Nobody? pffff...
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Re: Sextant question antena beam

Mon Jul 08, 2013 3:43 pm

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WirelessRudy
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Re: Sextant question antena beam

Mon Jul 08, 2013 3:58 pm

Only partially answers my question.
The most important question is weather the Vertical beam is bigger than the Horizontal. Which would be weird but what would be my conclusion taken from the brochure.
But than again, the brochure's info is too limited....
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Re: Sextant question antena beam

Thu Jul 11, 2013 11:56 pm

Why do you think it's weird ? The antenna PCB is designed this way, that's all. The antenna PCB shape and dipoles determine beamwidth.

Our comparable solution is simetric for example -> http://www.wireless-instruments.com/en/ ... -20hv.html
http://www.wireless-instruments.com/

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WirelessRudy
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Re: Sextant question antena beam

Fri Jul 12, 2013 2:07 am

Why do you think it's weird ? The antenna PCB is designed this way, that's all. The antenna PCB shape and dipoles determine beamwidth.
Well, I wrote this before:
So this means that the Vertical beam is actually bigger than the horizontal? Is this not a bit weird? Should this not be the otherway round?
Usually on directional/sectorial antennas the vertical beam it rather small compared to the horizantal.
That's why.
The PCB is designed a certain way. But the way it is fit depicts the real working panes. Turn the microprint a quarter and you have a different antenna.

So, what is weird; If an antenna has a bigger working beam in the vertical pane than the horizontal than that is weird. Because in the field this is not the usuall usage for an antenna.
But I'm afraid some antenna designers are more busy with producing a new sales item that looks good in the brochure then how it can be used in real deployments.

Like ubnt is selling their Airmax sectors with -6dB pattern reference to show their horizontal working pane where the whole industry works with -3db (more realistic.) (Not to forget the really small vertical pane they work in. Renders them much less useable in high towers or mountain peaks.) But hé, everybody buys them so they must be good......

Or the SXT of MT. Most networks from the pre-mimo era where vertical polorized designed. MT's antenna to be used by many of us to make the transition into the new mimo era had horizontal polorisation as their default. To use them with your still vertical polorized AP antenna you had to fit them 90 degrees angled..... this forum was filled with comments on this. I'd still wonder whoes idea this was....

And now the Sextant with its weird pattern.
Like in the SXT, all they had to do is turning the microprint a quarter and for both there was no issue.
Now I have Sextants that cover only a very small horizontal section while it reaches every ants nest on the mast footing up to the aliens on mars... (hmm, I might be a bit exaggerating, but you might get the point now :? ...)

Why you now compare with your equally distributed pattern antenna is not clear to me. That obviously doesn't have the issue. (You just took the opportunity to show yours isn't it.. :) )
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Re: Sextant question antena beam

Fri Jul 12, 2013 4:38 pm

I have taken a look on the SEXTANT antenna, it's square PCB, I don't detach FR4 from the top to see PTFE laminate underside, but I saw that the fed points of the antenna are on one side of the antenna, that can cause that beams are not simetric.

With the V-Beam wider than H-Beam you are right, it's not ok. But I think there had to some reason of that antenna situated, I don't think MT doesn't know about it, they are professionals from years. As far as I know from my tech. stuff the polarizations in that antenna are quite different.

I show our antenna to show that our product is meeting your expectations regarding beamwidth.
http://www.wireless-instruments.com/

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