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: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
