Canopy C/I numbers: ~3dB @ 2 Level FSK, ~10dB @ 4 Level FSK
The 430 series didn't list its C/I. ----- Mike Hammett Intelligent Computing Solutions http://www.ics-il.com On 9/23/2010 6:03 PM, Tom DeReggi wrote: > Marco, > > Be aware of one very important principle when deploying Ubiquiti MIMO.... > > With them, you can NOT disable either of the polarities, both polarities > always hear noise. > In mode 8-15, double the capacity is acheived, each pol with unique data. > Even in Modes 0-7 (single chain), I believe the same signal gets transmitted > across both pols, and listens on both pols for same signal. > The benefit of this is more resilience to multi-path fade, and a theoretical > 3db increase in power on the receive. > The negative of this is that the noise from BOTH polarities is heard. > > So... Lets say Horizontal pol is noise free, but verticle pol is full of > noise. There is no way to steer around the noise on verticle pol. > There is no way to select using Horizontal pol only without the noise of the > verticle antenna heard. > > SO.... How does this apply to Co-existence with Canopy bearby? Well, most > Canopy APs use Verticle polarity only. > Therefore, the Canopies tower will likely use most of the Verticle polarity > channels, and your ubiquitis will likely hear a lot more noise on Verticle > channels. > > If you used equipment that was a single pol design, you'd be able to select > Horizontal pol only, and you'd be able to steer around the Canopy easily. > With Mimo Ubiquiti, you wont have that option anymore. As well, the Canopy > user is locked to 20Mhz channels, and wont be able to make room for you that > way either. So... you should be prepared that you are likely going to be > fighting interference with the Canopy users. The Canopy user will have one > advantage, they'll only need 3db SNR to survive your noise, where you'll > need atleast 8-10db SNR to survive their noise. (Ubiquiti would work better > at 18-25db SNR). > > You will have two advantages though.... One, your Ubiquitis can be set to > 10Mhz channels, adjustable in 5Mhz increasments, to find the holes between > the Canopy's selected channels. Two, the Ubiquitis are higher power. You'll > be able to go up to 24-26dbm at the CPE (depending on modulation), where > Canopy may be limited to 22dbm, and Ubiquiti has more flexible CPE options > to choose higher gain antennas, if needed. > > If the Canopy tower is two miles away, you should be able to carefully > select your channel plan to avoid interference, but noise at your tower will > still be a big concern to avoid. I'd highly recommend that you go all out on > the Ubiquiti Tower, and in addition to using the UBiquiti Antennas, use the > custom third party shields made for them to increase the Front/Back > isolation of the antennas. > > These Ubiquiti Radio are really really sweet. And their wireless dirver > appear to handle noise well. But its still all about the math, and with > Ubiquiti MIMO, it does hear MORE noise, because of the dual pol design. > > Note, if you ever run into trouble where there the Verticle pol noise is to > severe for the AP.... It is possible to select single chain mode 0-7, and > cap the verticle pol antenna port on the radio (disconnect verticle pol > antenna feed), then your radio would just hear on Horizontal pol. (I believe > Chain0 is Horizontal pol, from what we've determined, but you'd need to > confirm that yourself). However, I can not vouge for whether there would be > any long term harm to the radio because of that, meaning whether it would > hurt to operate the radio without an antenna load on the second chain > polarity. But we've operated successfully like that at some sights for a > while. > > Another technique that can help is to point only one 120 degree antenna in > the direction of the Canopy tower. The mentality here is to send the very > least amount of noise and channel usage in their direction. It will be > easier for the Canopy tower to vacate and leave a single channel for your > use, in that direction. Anything you point at them could interfere with > them, and vice versa, so reduce the number of channels pointed to them. Most > ISPs can spare a channel, but cant spare many. So give them a solution for > non-interference, that impacts them the least. They were there first, and > would likely protect their turf, the last thing you want is a noise battle > with a 3db SNR TDD radio. > > The Ubiquiti freq scanner works well, to find the best free channel to use > for each of your sectors. That will come in handy, determining what channels > are being used by the Canopy. > . > Tom DeReggi > RapidDSL& Wireless, Inc > IntAirNet- Fixed Wireless Broadband > > > ----- Original Message ----- > From: "Marco Coelho"<coelh...@gmail.com> > To:<motor...@afmug.org>; "WISPA General List"<wireless@wispa.org> > Sent: Wednesday, September 22, 2010 12:57 PM > Subject: [WISPA] nanostation and canopy towers within 2 miles of each other > > >> I've got a competitor getting ready to light a nanostation based tower >> within 2 miles of one of my Canopy 2.4 towers. What kind of >> interference should I expect? >> >> Listening to this guy, their radios are magic and can shoot through >> trees and over hills. Totally overcoming line of site issues. Is he >> smoking something strange? >> >> Marco >> >> >> -- >> Marco C. Coelho >> Argon Technologies Inc. >> POB 875 >> Greenville, TX 75403-0875 >> 903-455-5036 >> >> >> -------------------------------------------------------------------------------- >> WISPA Wants You! Join today! >> http://signup.wispa.org/ >> -------------------------------------------------------------------------------- >> >> WISPA Wireless List: wireless@wispa.org >> >> Subscribe/Unsubscribe: >> http://lists.wispa.org/mailman/listinfo/wireless >> >> Archives: http://lists.wispa.org/pipermail/wireless/ > > > -------------------------------------------------------------------------------- > WISPA Wants You! Join today! > http://signup.wispa.org/ > -------------------------------------------------------------------------------- > > WISPA Wireless List: wireless@wispa.org > > Subscribe/Unsubscribe: > http://lists.wispa.org/mailman/listinfo/wireless > > Archives: http://lists.wispa.org/pipermail/wireless/ -------------------------------------------------------------------------------- WISPA Wants You! Join today! http://signup.wispa.org/ -------------------------------------------------------------------------------- WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
