True, but it works the same. Thanks for all the great input. Marco
On Thu, Sep 23, 2010 at 6:59 PM, Faisal Imtiaz <[email protected]> wrote: > Hey Tom, > Great post with great info. have no quams with the info you have presented. > > Just wanted to point it.. that I think you read Marco's email backwards... > > What I understood from Marco's post is that HE is currently operating > the Moto Canopy Tower, and a competitor is getting ready to light up a > Ubiquity tower approx. 2 miles away from his tower. > > :) > > Faisal Imtiaz > Snappy Internet & Telecom > > > On 9/23/2010 7:03 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"<[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! Join today! >>> http://signup.wispa.org/ >>> -------------------------------------------------------------------------------- >>> >>> WISPA Wireless List: [email protected] >>> >>> 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: [email protected] >> >> 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: [email protected] > > Subscribe/Unsubscribe: > http://lists.wispa.org/mailman/listinfo/wireless > > Archives: http://lists.wispa.org/pipermail/wireless/ > -- Marco C. Coelho Argon Technologies Inc. POB 875 Greenville, TX 75403-0875 903-455-5036 -------------------------------------------------------------------------------- WISPA Wants You! 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