Jim:
The term "multipath" is commonly used to describe the condition wherein a sent signal "arrives" at an antenna through more than one path (by something in addition to or other than a non-obstructed, line-of-sight link). Microwave signals are subject to a number of degradation modes including reflection, diffraction and diffusion-if you apply those terms and physical conditions to light waves, some of the concepts may become clearer than at first blush. I like to explain multipath this way: If you have ever watched analog broadcast TV signals being delivered by an antenna, you have probably seen channels with ghosts (shadows) in the pictures. This occurs when the signal arrives at the antenna both directly and also having been bounced off one or more "reflective" surfaces enroute. The bouncing produces slight delays (among other propagation glitches) forcing the receiver to try to process and display the same information multiple times in each frame. While the effect of this problem is annoying in an analog video environment, it can be 'fatal' in a digital data context. Phase shifts, slightly delayed reception of the same packets, etc. can all "translate" as noise, and can kill the link altogether. Unfortunately there is a lot more to be concerned with in a digital microwave system than signal level alone, even though having too much or too little signal can itself be a show stopper. Signal quality is difficult to quantify without proper equipment but quality problems are no less "deadly" than levels problems. Hope this helps, as quick and dirty as it is. Best, Ted E.J. Hatfield & Company 1-770-209-9236 - Office 1-770-209-9238 - Fax 1-770-560-0736 - Sprint 1-678-457-8411 - Cingular -----Original Message----- From: Jim Stout [mailto:[EMAIL PROTECTED] Sent: Friday, April 13, 2007 10:37 AM To: WISPA General List Subject: Re: [WISPA] Power Lines in the LOS path Marlon, The SL2 is one of the newest radios from Tranzeo. It's part of the CPQ family, but it's a Slim Line (much smaller in size.) Up until this install, they have gone in easy, and run great! Can you explain the "multipath" phenomenon? Thanks, Jim.... Jim Stout LTO Communications, LLC 15701 Henry Andrews Dr Pleasant Hill, MO 64080 (816) 305-1076 - Mobile (816) 497-0033 - Pager -- WISPA Wireless List: [EMAIL PROTECTED] Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
