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" <[email protected]> To: <[email protected]>; "WISPA General List" <[email protected]> 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! 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