On Apr 20, 2010, at 12:00 PM, Tom DeReggi wrote: > My point here is that Diversity can make a huge difference, "diversity" is > the differenciator, but that the benefit of diversity can vary dependant on > the Freq used and environment tackling, based on past experience.
Without looking up the math on this, I would speculate that the reason is wavelength. At 3.65 we're about 4' apart. To get the same advantage at 900 MHz I'd willing to bet you might need to be quite a bit further apart-which isn't practical in most cases. I'm not willing to say it scales with wavelength (not without looking at the actual equations that is) but wavelength is going to be a factor in how effective diversity is at any given distance between two antennas. On the other hand, moving the antennas further apart at lower frequencies should be able to re-create the advantage. Chuck > > Tom DeReggi > RapidDSL & Wireless, Inc > IntAirNet- Fixed Wireless Broadband > > > ----- Original Message ----- > From: "Chuck Bartosch" <ch...@clarityconnect.com> > To: "WISPA General List" <wireless@wispa.org> > Sent: Tuesday, April 20, 2010 11:05 AM > Subject: Re: [WISPA] Alvarion 3.65ghz NLOS as good as 900mhz? > > >> We did not find that WiMax in general was better than 900. The key isn't >> WiMax, per se, but diversity antennas. Performance is *helped* by being >> 3.65 WiMax but that alone does NOT obviate the need for 900 in our >> experience. Diversity is key. >> >> Chuck >> >> On Apr 19, 2010, at 9:23 AM, Jeremie Chism wrote: >> >>> I am not using alvarion 3.65 but I am using wimax. I have a couple >>> customers with lower modulation because of non line of site situations >>> and have seen no impact on the entire system in general. "Supposedly" >>> wimax is engineered to handle some of this better than my alvarion 900. >>> >>> Sent from my iPhone >>> >>> On Apr 19, 2010, at 8:15 AM, Rubens Kuhl <rube...@gmail.com> wrote: >>> >>>> That would only be true if the data services are somewhat >>>> purpose-specific and not Internet access. Doing what this vendor told >>>> you would seriously affect aggregate performance of the cell because >>>> of low rate modulation of the NLOS and/or distant customers. >>>> >>>> If you are doing sensor networks or POS connection you will be fine >>>> with all those BPSK/QPSK customers, indeed. >>>> >>>> >>>> Rubens >>>> >>>> >>>> On Mon, Apr 19, 2010 at 10:09 AM, Kurt Fankhauser >>>> <k...@wavelinc.com> wrote: >>>>> Has anyone seen the Alvarion 3.65ghz 802.16e equipment in >>>>> operation? Was >>>>> talking to one vendor that claimed if you run the system in MIMO >>>>> that with >>>>> the diversity you can do NLOS as good as 900mhz and if you get the >>>>> AP on a >>>>> 300ft tower that it starts to "feel" like 700mhz. He claimed the >>>>> NLOS was so >>>>> good that people are ripping out complete old systems of 900mhz and >>>>> 2.4ghz >>>>> and putting in the single system of 3.65ghz to serve their entire >>>>> customer >>>>> base. >>>>> >>>>> >>>>> >>>>> Just wondering if anyone has experience or having seen this >>>>> firsthand. >>>>> >>>>> >>>>> >>>>> Kurt Fankhauser >>>>> WAVELINC >>>>> P.O. Box 126 >>>>> Bucyrus, OH 44820 >>>>> 419-562-6405 >>>>> www.wavelinc.com >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> --- >>>>> --- >>>>> --- >>>>> --- >>>>> -------------------------------------------------------------------- >>>>> 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/ >> >> -------------- >> Chuck Bartosch >> Clarity Connect, Inc. >> 200 Pleasant Grove Road >> Ithaca, NY 14850 >> (607) 257-8268 >> >> "When the stars threw down their spears, >> and water'd heaven with their tears, >> Did He smile, His work to see? >> Did He who made the Lamb make thee?" >> >>> From William Blake's Tiger!, Tiger! >> >> >> >> >> >> -------------------------------------------------------------------------------- >> 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/ -------------- Chuck Bartosch Clarity Connect, Inc. 200 Pleasant Grove Road Ithaca, NY 14850 (607) 257-8268 "When the stars threw down their spears, and water'd heaven with their tears, Did He smile, His work to see? Did He who made the Lamb make thee?" >From William Blake's Tiger!, Tiger! -------------------------------------------------------------------------------- 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/
