The issue will be height. Remember, the longer the link, the taller the freznel zone height requirement will be at the middle of the link.
Tom DeReggi RapidDSL & Wireless, Inc IntAirNet- Fixed Wireless Broadband ----- Original Message ----- From: "Fred Goldstein" <[email protected]> To: "WISPA General List" <[email protected]> Sent: Monday, November 15, 2010 11:14 AM Subject: Re: [WISPA] 90-mile path (was Wireless Digest, Vol 35, Issue 21) > At 11/15/2010 04:06 AM, Akinlolu Ajay-Obe wrote: >>I need to move 155MB internet traffic over 90miles. Fiber will take >>too long and cost too much. Anybody have a solution that will work. >>Power is an issue where repeaters are used. Solar would be the >>preferred option. I also need to manage and distribute bandwidth. Any >>ideas? > > The obvious answer is to build a microwave link; the trick is to find the > path. > > An old rule of thumb is that microwave links in the 6 GHz range are > good for about 30 miles per hop. This is based on needing very high > reliability (telephone company backbone links) even with > weather-related fade. But it is not a hard limit. > > You could theoretically go 90 miles on one hop. The physics are > favorable if the path is direct (mountain to mountain) and doesn't > have extraordinary loss, like rain or trees, or a tropo-ducting event > going on. It takes a large antenna, of course. A 4-foot dish at 5.8 > GHz has a lot of gain! One watt TPO is a lot of ERP. Orthogon, now > part of Motorola, did some moby links that way, including a 100-mile > or so high-speed link in Central America. It beats not being on line > at all, even if it fails 1% of the time (not that it's that > bad). But it's not at all likely to give you 99.99% reliability. > > Since you're in Nigeria, the climate varies quite a bit and what > works in the dryer areas might not works so well in the wetter > ones. But the main trick is to find a path. If you could find a > mountain or tower with real line-of-sight that let you do two 50-mile > paths, and you could put up big dishes, there are radios that can > pump 155 Mbps. Three hops might be easier. But you should spend some > time with a path calculator. > > -- > Fred Goldstein k1io fgoldstein "at" ionary.com > ionary Consulting http://www.ionary.com/ > +1 617 795 2701 > > > > -------------------------------------------------------------------------------- > 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/ > > > ----- > No virus found in this message. > Checked by AVG - www.avg.com > Version: 10.0.1153 / Virus Database: 424/3258 - Release Date: 11/15/10 > -------------------------------------------------------------------------------- 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/
