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Blair, Well, because the 5.180 GHz range is only legal for indoor use in the U.S., your problem could be one of the following. a) The signal over the 1 km indoor path is bouncing off too many interior walls and creating unpredictable multipath effects. Check to see if any new interior walls have been constructed recently and, if so, order them removed immediately. If they are in the "critical path", don't hesitate to immediately knock them down yourself! In the future, plan to cover such long indoor paths with at least 3 hops. b) Somebody moved some large item somewhere in the 1km-long warehouse (or whatever other HUGE building) that you have deployed inside of. That huge moved item (perhaps a large crane or boat) is partially blocking the signal path. The item may be closer to one end of the link thereby causing the lower RSSI at the other end of the link. Walk the path to locate any large objects and have them relocated. c) The building may have become overheated at one end causing the cm9 at that end to overheat and go out of spec causing low transmitter output power. Check the building temperature at the end OPPOSITE the end where the RSSI is low and correct it. d) A bird may have gotten into the building (don't laugh, I've seen it happen before, especially in very large buildings) and built a nest in the feedhorn of one grid antenna thereby introducing 9 dB of attenuation of the signal strength on receive. Visually inspect both antennas and remove any bird nests. Try to humanly trap the bird if at all possible and release it outdoors with a firm verbal command to "go home and don't come back". e) The clear and cold weather outdoors may have caused a buildup of static electricity indoors causing static damage to the front end of the cm9 which is experiencing the RSSI decrease. The chances of this are high especially if you failed to install lightning arrestors on both ends of the indoor link. f) Last but not least (and this is VERY IMPORTANT) - don't even think about trying to figure out what might have happened to cause the RSSI decrease until you go into that warehouse (or whatever that building is) and CHANGE OUT EVERY PIECE OF EQUIPMENT ON BOTH ENDS OF THE LINK. Many, many WISPs have been using this method to "fix" bad links for many years. If so many WISPs are using this ("swap before you stop") method, there must be a very good reason why! Good luck and good birding!! jack Blair Davis wrote: Hi all... -- Jack Unger - President, Ask-Wi.Com, Inc. Serving the Broadband Wireless Industry Since 1993 Cisco Press Author - "Deploying License-Free Wireless WANs" WISPs - Do you know where your customers are? For wireless coverage mapping see http://www.ask-wi.com/mapping FCC Lic. #PG-12-25133 LinkedIn Profile <http://www.linkedin.com/in/jackunger> Phone 818-227-4220 Email <[email protected]> |
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