The Ubiquiti dual pol antennas have been around for a while now. Has anyone gained any real world testing results regarding difference in performance for MIMO based on which antenna used.
The two Ubiquiti sector types 16/17db versus 19/20db models have signficantly different specs on Cross pol rejection. As well, NanoStation makes a good 45 deg sector, at 14db, (14dbi + 22dbm = Max EIRP 36db for PTMP) with a bit less cross pol rejection than the others. >From past experience, in any MIMO product in general, using PTP, I've observed that maximizing the Cross pol isolation is very advantageous to gain a highest performing links. (so pols dont interfere with each other at high modulations). In general, I'd get numbers like anything less than 35db isolation would result in quality loss. BUT... I've never tested with Ubiquiti yet. So my question here is.... Have people been successful using the smaller 16/17db Sector antennas successfully with MIMO? I can do the math and RF engineering, and I can predict that the larger 19/20 db antenna's have much better cross pol rejection, and combined with the third party shield made for them, to increase Front to Back ratio signficantly, they are an ideal choice for serious cell site deployments. But, for less critical smaller area deployments, I can see the adantage of using the smaller antennas to save space vertically. So just wondering what experience others are having with the 16/17db Ubiquiti Sectors. To be clear, the "gain" of the antenna is NOT my concern here. I interested in whether the Cross Pol rejection is good enough on shorter sector antenna to gain good MIMO quality. Note: short antenna speced at 22db cross pol isolation, whereas taller antenna speced at 28db cross pol. Tom DeReggi RapidDSL & Wireless, Inc IntAirNet- Fixed Wireless Broadband ----- Original Message ----- From: "Butch Evans" <[email protected]> To: "WISPA General List" <[email protected]> Sent: Tuesday, August 10, 2010 6:11 PM Subject: Re: [WISPA] RB1100 > On Tue, 2010-08-10 at 16:48 -0400, Chuck Hogg wrote: >> It's the same. All these distributors "NAME" their gear as their >> own devices. One distributor will support you without the added >> fees, and the other will charge you the fees. It's cheaper at Titan. >> When I owned QuickLink Wireless, it was these types of things that >> separated us from other distributors; how the customer was supported. > > This is exactly the point I was making. Titan is a great company to > work with (this is from my own experience). My company is good to work > with as well, though I didn't mention that. There are several companies > out there that sell this (and other) hardware. The only difference is > the company you end up dealing with. For some, Dennis is their > choice..there is NO "secret sauce" in the routers themselves. > > -- > ******************************************************************** > * Butch Evans * Professional Network Consultation* > * http://www.butchevans.com/ * Network Engineering * > * http://store.wispgear.net/ * Wired or Wireless Networks * > * http://blog.butchevans.com/ * ImageStream, Mikrotik and MORE! * > ******************************************************************** > > > > -------------------------------------------------------------------------------- > 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/
