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Good vs Bad constellations (yes, the graphs are useful)

Posted: Sun May 31, 2015 7:39 pm
by rebelwireless
Thought I'd show some UBNT AC gear in action and what the constellation patterns are actually useful for.


This is a PTP link with NBE-AC-19
As you can see, one side has tight little patterns while the other side is scattered MUCH more. One unit is tucked down between trees (incursion into second fresnel) and so there is little interference but some typical fresnel incursion issues. The other is up on a hill exposed to more interference.
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This is in a 10Mhz channel. here are speed tests showing the difference between the good constellations and the bad.

The good pattern:
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The messy pattern:
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duplex pattern:
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A couple things of note.
~65Mbps on 10Mhz very nice!
~25Mbps on the 'bad' side in 10Mhz is not that bad.
This link scales almost perfectly with channel width. 125Mbps*45mbps on 20Mhz, ~235Mbps*85Mbos on 40Mhz. The biggest issue with the wide channels is that it's hard to keep the CINR up with the 4x more footprint (40Mhz vs 10Mhz) to get interference.

Notice the 35 vs 30 CINR. This is a VERY good number to use to determine the quality of the link and if you should bump up from the NBE-AC-19 to the PBE-AC-500. Also notice that the higher signal actually has the lower CINR.

Re: Good vs Bad constellations (yes, the graphs are useful)

Posted: Sun May 31, 2015 8:13 pm
by sirhc
Nice write up, thanks!

Been waiting patiently for UNI-I and UNI-II to try some of the gear, just can not use UNI-III.

I would try it immediately if it was backward compatible, Ben told me on Skype the other day they would soon start working on that more aggressively.

Re: Good vs Bad constellations (yes, the graphs are useful)

Posted: Sun May 31, 2015 8:24 pm
by rebelwireless
I should be testing that next week. I really need U-NII-1 for PTP links on the AC gear. Can't afford AF5X everywhere even if I could source them.

I also have a number of micro-pops that I'm running well under DFS EIRP so those will be immediate upgrades for CINR ones U-NII-II is approved. I'm excited to see how the AC gear performs in DFS.