RE: [WISPA] Licensed Backhaul options

[Charles Wu]

Title: Message

>The Spectra would be around $20k with external antennas. A licensed product is going to be at least that, and probably $5k more. Sit back and actually think for a second about this comparison, and you'll realize that a similarly performing "unlicensed" solution will cost MUCH MORE (and be much riskier) relative to the licensed solution   The main difference is that the spectra requires 30 Mhz of ABSOLUTELY CLEAN SPECTRUM in both the vertical and horizontal polarities (150 Mb "Air Rate" transmits on V-pol & 150 Mb "Air Rate" transmits on H-pol -- cut off 1 polarity, you halve throughput)   In addition, the Rx sensitivity of the Spectra at the 300 Mb data rate (256 QAM) is -59 dB with an output power of +18 (so you'll need HUGE dishes to guarantee the link budget)   So, lets do a "theoretical" path calc / comparison (15 miles)   11 Ghz Licensed Link (100 Mb Full Duplex) Rx Sensitivity: -76 dBm Tx Power: +21 dBm 4' Dish: +39 dBi   Expected RSSI: -42.9 (>30 dB of fade margin = ROCK SOLID LINK =)   5 GHz Spectra Rx Sensitivity: -59 dB Tx Power: +18 6' Dish: +34 dBi   Expected RSSI: -49.4 (~10 dB of fade margin w/ 2' more of each dish)   Then there's all sort of "real-world" performance issues that occur with higher-order modulation schemes and license-exempt operation   -Charles   ------------------------------------------- WiNOG Austin, TX March 13-15, 2006 http://www.winog.com -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Travis Johnson Sent: Friday, March 17, 2006 10:03 PM To: WISPA General List Subject: Re: [WISPA] Licensed Backhaul options Travis Microserv Charles Wu wrote: You don't need licensed to high throughput backhaul. For example, Orthogon's Spectra provides 300Mbps aggregate at a price point generally Less than 45Mbps licensed. Hi Matt, I am curious to see where / what you got those numbers for the Orthogon Spectra? -Charles ------------------------------------------- WiNOG Austin, TX March 13-15, 2006 http://www.winog.com -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Matt Liotta Sent: Thursday, March 16, 2006 1:28 PM To: WISPA General List Subject: Re: [WISPA] Licensed Backhaul options -Matt Bobby Burrow wrote: I'm looking at moving to a licensed solution to increase throughput across one of out backhaul links that spans 5 hops. Distances between hops range anywhere from 7 to 19 miles. We are currently using the dual nstreme Mikrotik solution and it is working very well, however the WRAP/RB532 solutions are only yielding ~25Mb per hop. Can anyone recommend a licensed radio manufacturer that should net us 50Mb-100Mb per hop? Thanks, Bobby Burrow East Texas Rural Net www.etxrn.com

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