Inline again :-)
> Behalf Of Jack Unger > > Mac, > > Thanks for replying to my concerns and suggestions. > > Have you tried using 5 to 10 feet of vertical separation between the > antennas rather than mounting them all at the same height? 10 feet of > vertical separation should be enough to prevent one AP transmitter from > overloading another AP receiver. [Mac says:] Now you are talking the "Jack Unger" talk that makes me sit up and take notice :-) I have not tried the vertical separation because it looks so unprofessional (although is a professional move) to have 3 sectors spread out over thirty feet and it also puts 2 of my three sectors at a disadvantage due to the height loss. We cover a lot of rugged territory, conquer (really not very well) massive 90' Oak trees and connect subs as far as 20 miles off these towers. It is a fine idea and one I may have to move to! > > Secondly, single-channel bandpass filters are available which will > provide additional receiver protection from nearby transmitters > operating on non-overlapping frequencies. [Mac says:] That sounds like the way I will go. I appreciate the idea and suggestion. I don't know why I haven't thought of that before. I guess I have never bought or even had need of a bandpass filter till now. Well truth be known it seems I have needed them for years, but didn't realize it till today. > > Finally, higher-priced antennas normally have a higher front-to-back > ratio which increases isolation (minimizes interaction) between the > antennas. A minimum f/b ratio of 30 dBm is recommended. [Mac says:] We have always bought and used PacWireless antennas and thee 16.5dbi 120* VPOL sectors have at least a F/B ratio of 25db. I realize the more you spend the better F/B ratio you get and that is where my original thread started - - looking for some good sectors :-) > > Keep in mind that without dealing with these antenna isolation issues, > you will likely have the same problems using two 180* sector antennas as > you have had using three 120* sector antennas. [ [Mac says:] That is fine advice Jack and I appreciate the fine guidance. You have made me think - - and that may be a dangerous thing. Now - - let me go order some bandpass filters and hang them on one of these troubled tower to see what is gonna happen. I will post back here and let you know my results. Thanks again Jack!! Mac Dearman > > jack > > > Mac Dearman wrote: > > See in line please > > > > > >> Behalf of Jack Unger > >> > >> Mac, > >> > >> Before you discard the idea of using three 120* sectors are you > >> absolutely certain that the "separation" issue is really due to the > >> antennas not being far enough apart? Have you thoroughly looked at > other > >> reasons why there could be interference between three APs like: > > > > > > [Mac says:] > > > > Well Jack - I'd like to think that I have exhausted the other > possibilities > > :-) but I am always willing to listen. > > > >> 1. Using three cards on a single motherboard in one enclosure without > >> sufficient shielding between them. > > > > > > [Mac says:] > > > > All of our sector arrays utilize 3 different enclosures with one radio > to > > the enclosure and then I try to separate the enclosures (and antennas) > as > > far as possible. > > > >> 2. Using three APs that are configured on frequencies that are too > close > >> together and are interfering with each other? > > > > [Mac says:] > > > > Unless we deploy 4 90* sectors we use non overlapping channels (1, 6 & > 11) > > > > > >> I guess what I'm asking is (before you go spend money on antennas that > >> may or may not solve the problem) what equipment are you currently > >> using, how is it configured, and how far apart can you actually get > >> three sector antennas on the 25G tower? > >> > >> jack > > > > [Mac says:] > > > > > > I have come to the conclusion that it is interference from the > backplane of > > the antennas due to not having adequate separation from each other. > These > > small towers (although 180') like Rohn 25G aren't but 12" across - so > you > > wind up with the 3 sectors only 1' apart at their bases. > > > > I wish you had some more ideas :-), but thanks for the thought and the > time! > > > > Mac > > > > > > > > > > > > > > > > > > -- > Jack Unger ([EMAIL PROTECTED]) - President, Ask-Wi.Com, Inc. > FCC License # PG-12-25133 > Serving the Broadband Wireless Industry Since 1993 > Author of the WISP Handbook - "Deploying License-Free Wireless WANs" > True Vendor-Neutral Wireless Consulting-Training-Troubleshooting > FCC Part 15 Certification for Manufacturers and Service Providers > Phone (VoIP Over Broadband Wireless) 818-227-4220 www.ask-wi.com > > > -- > WISPA Wireless List: wireless@wispa.org > > Subscribe/Unsubscribe: > http://lists.wispa.org/mailman/listinfo/wireless > > Archives: http://lists.wispa.org/pipermail/wireless/ -- WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
