http://www.tomshardware.com/reviews/beamforming-wifi-ruckus,2390.html
----- Mike Hammett Intelligent Computing Solutions http://www.ics-il.com -------------------------------------------------- From: "3-dB Networks" <[email protected]> Sent: Monday, November 02, 2009 7:53 AM To: "'WISPA General List'" <[email protected]> Subject: Re: [WISPA] Backhaul Questions > Ruckus Wireless has beamforming (i.e. smart antenna technology)... does it > on a packet by packet basis. But it's a WiFi system (although from what I > understand its being deployed overseas now in Muni-Wifi situations... I > just > proposed to someone using Ubquity Nanostations to them). > > Daniel White > 3-dB Networks > http://www.3dbnetworks.com > > >>-----Original Message----- >>From: [email protected] [mailto:[email protected]] On >>Behalf Of Marlon K. Schafer >>Sent: Sunday, November 01, 2009 2:40 PM >>To: WISPA General List >>Subject: Re: [WISPA] Backhaul Questions >> >>Correction, under the 3 for one rule you can go UP 3 dB in antenna gain >>for every 1 dB of radio transmit power that you go down, but only for >>client side or ptp installations. It STARTS at 30 dB radio and 6dB >>antenna. >> >>So if you have a 30dB radio, it's a 6dB antenna. 29dB radio you can use >>a 9dB antenna. >> >>28-12 >>27-15 >>26-18 >>25-21 >>24-24 >>This is the one that excited me years ago. This meant I could use a >>quarter watt amp, 24dB with a 24dB grid for a ptp link! That'll give >>you a -72dB rssi (54 meg speeds!) at 100 miles! Get this one, -78dB >>rssi at 200 (not a typo, two HUNDRED MILES)! I love big antennas! grin >> >>Again, this is only for 2.4 client side installs (radio only talks to >>ONE other radio). >> >>There is a bit of an exception to this rule based on smart antenna >>technology. One that no one has successfully used (as far as I know). >>Vivato and Nivini tried. We (WISPA) did get the FCC to issue a written >>interpretation of the rules allowing us to use routed AP's as a >>substitute for active beam steering systems (in the end it has the same >>effect). >> >>In theory we COULD ring a building with 24dB grid antennas with 24dB >>radios for a 42 WATT system and still be within the power level rules. >>In reality though, antennas are too "leaky" and you'd be hard pressed to >>avoid massive self inflicted interference. I always wanted to try >>building a system like this though! grin. (disclaimer, it's been a >>while since I studied that part of the rules, the max output power could >>be lower than 42 watts.....) >> >>laters, >>marlon >> >> ----- Original Message ----- >> From: Jack Unger >> To: WISPA General List >> Sent: Sunday, November 01, 2009 12:17 PM >> Subject: Re: [WISPA] Backhaul Questions >> >> >> EIRP is a TRANSMIT number. "Equivalent isotropic RADIATED power". This >>is the radiated power on transmit in dBm leaving the transmit antenna in >>the favored direction compared to the power that would be radiated if 1 >>milliwatt (0 dBm) were fed into a theoretical isotropic antenna that had >>0 dBi (no) gain in any direction. >> >> EIRP = TX power (minus) transmission line loss (plus) antenna gain = >>EIRP >> >> Further, >> >> 2.4 GHz allows more than 6 dBi antennas even with 1-watt radios under >>the "3:1" rule for point-to-point use. This is why CPE can run more than >>+36 dBm because the CPE are effectively point-to-point radios talking to >>only one access point. The AP is NOT a point-to-point radio therefore it >>is limited a maximum EIRP of +36 dBm. >> >> 5.8 GHz allows more than 6 dBi antennas with 1-watt radios for point- >>to-point use. That's how those long 5.8 GHz backhauls can be made to >>work reliably. >> >> jack >> >> >> >> Marlon K. Schafer wrote: >>Yeah. >> >>People all too often forget that eirp is a RECEIVE number not a TRANSMIT >>number. All it takes is big, big ears and you can hear the other end >>from a >>very long ways away. Makes for much less noise in the area too. >> >>I hate the trend toward high power radios with low power antennas. >> >>You guys do realize that 2.4, 900 and 5.8 gig bands limit you to a 6 >>(that's >>S-I-X) dB antenna if you use a 1 watt (30 dB) radio? Base station >>especially. For CPE you can use higher gain cpe antennas on 5 gig and >>still >>be OK within the rules. >> >>But all of these stupid, noisy, wasteful, cpe systems with 1 watt radios >>and >>19dB panels make a mess of your networks. (and mine) >> >>marlon >> >>----- Original Message ----- >>From: "Mike Hammett" <[email protected]> >>To: "WISPA General List" <[email protected]> >>Sent: Saturday, October 31, 2009 10:50 AM >>Subject: Re: [WISPA] Backhaul Questions >> >> >> 30 dB EIRP with a 44 DBi antenna on each side over 73 miles produces - >>75 >>signal. I'll let him say what he did to make it work, but it's >>certainly >>possible. >> >> >>----- >>Mike Hammett >>Intelligent Computing Solutions >>http://www.ics-il.com >> >> >> >> >>From: Bret Clark >>Sent: Saturday, October 31, 2009 11:02 AM >>To: WISPA General List >>Subject: Re: [WISPA] Backhaul Questions >> >> >>Man...what is the EIRP on these links that people are posting high bit >>rates? As someone else stated, gotta wonder if the FCC won't start >>getting >>suspicious at some point. >> >>Travis Johnson wrote: >> 73 miles... and I get 28Mbps total (14Mbps each direction) using a >>20mhz >>channel. >> >> Travis >> >> >> Josh Luthman wrote: >>Travis is getting 28 megs on a really long backhaul - like 58 miles? >> >>You will not see >30. >> >>On 10/31/09, Eric Rogers <[email protected]> wrote: >> Ok guys...Looking for both Mikrotik experience and others. We >>currently >>have a Mikrotik backhaul between each of our towers using NStreme and we >>have been extremely happy with the performance. We recently upgraded a >>tower because we were hitting 15M or so during peak times and was afraid >>it couldn't handle much more. We upgraded that backhaul to a Motorola >>PTP for future capacity. >> >> >> >>The questions: >> >> >> >>MT Gurus: >> >>Each backhaul ranges in distance, each ranges from 3 miles (3 backhauls) >>and the rest are about 12 miles (5 backhauls). Since we have been using >>Mikrotik, I have reliably seen up to 10 Meg, and I am afraid 15 Meg is >>pushing the envelope on a 20 MHz channel. >> >> >> >>How much capacity can I reliably push on a 20 MHz channel using NStreme? >> >> >> >>Other Gurus: >> >>I understand the following are loaded questions, but budget is around >>$1000-3000 range and the capacity needs to be around the 60Meg mark (30 >>each way or without a defined 1:1 guarantee, capability to flex and be >>able to push 30M each way). >> >> >> >>If I start upgrading to larger backhauls on busy links, what type of >>equipment should I look at? >> >>What can support VoIP? >> >>Anything that GPS times for frequency reuse? >> >>Anything work in the 5.4GHz range at a 12 mile distance? >> >> >> >>Eric Rogers >> >>Precision Data Solutions, LLC >> >>(317) 831-3000 x200 >> >> >> >> >> >>------------------------------------------------------------------------ >>-------- >>WISPA Wants You! 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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/ >> >> >> >> >>-- >>Jack Unger - President, Ask-Wi.Com, Inc. >>Author - "Deploying License-Free Wireless WANs" >>Serving the Broadband Wireless Industry Since 1993 >>www.ask-wi.com 818-227-4220 [email protected] >> >>Sent from my Pizzicato PluckString... >> >> >> >> >> >>------------------------------------------------------------------------ >>------ >> >> >> >> >> ---------------------------------------------------------------------- >>---------- >> WISPA Wants You! 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