I'll take one! How much ? -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Rick Harnish Sent: Friday, May 18, 2007 4:25 PM To: 'WISPA General List' Subject: RE: [WISPA] 180* sector choices
Jack, While we are on this topic, look at the .pdf file and give me your comments on this all in one sector from Pac Wireless? Thanks, Rick Harnish President OnlyInternet Broadband & Wireless, Inc. 260-827-2482 Founding Member of WISPA -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jack Unger Sent: Friday, May 18, 2007 4:18 PM To: WISPA General List Subject: Re: [WISPA] 180* sector choices 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. Secondly, single-channel bandpass filters are available which will provide additional receiver protection from nearby transmitters operating on non-overlapping frequencies. 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. 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. 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: [email protected] Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/ -- WISPA Wireless List: [email protected] Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
