Tom, What you are "probably" seeing is the GPS sync antenna if it's on a cell phone tower. That is what enables them to reuse the same spectrum on all their towers.
Mac > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On > Behalf Of Tom Sharples > Sent: Wednesday, April 23, 2008 11:48 AM > To: WISPA General List > Subject: Re: [WISPA] Sector Placement > > Related question - I've noticed that many multi-sector cell towers have > what > looks like a single vertical bar located midway between adjacent > sectors. I > assume this is some sort of passive tuned element that's been set up to > reduce inter-antenna coupling and interference, but I have been unable > to > find any info on how to design or install these. Anybody out here know? > > Thanks! > > Tom S. > > ----- Original Message ----- > From: "Jack Unger" <[EMAIL PROTECTED]> > To: "WISPA General List" <[email protected]> > Sent: Wednesday, April 23, 2008 8:53 AM > Subject: Re: [WISPA] Sector Placement > > > > Ross, > > > > In general, physically separate them as much as possible. You do not > > want the transmitter signal from one sector to overload the receivers > of > > the other sectors. That is a form of self-interference. If you happen > to > > have a copy of my book handy, you can read more about antenna > separation > > on pages 159 - 165. If you don't have the book, then separate 10 feet > > vertical as a rule of thumb. Other factors such as the amount of > > frequency separation and receiver selectivity also play a part but > > that's more engineering detail than I can address here. But now you > know > > why you should physically separate your antennas. Many people in the > > past have had to move antennas apart to resolve this issue after they > > initially installed them to close. > > > > jack > > > > > > Ross Cornett wrote: > >> Anyone know for a fact if it is worthy to seperate sector antennas > on the > >> same tower. Using 2.4 H Pol 16 db We are readying our 31st tower > >> location and I have been asked why do we seperate the sectors . > Besides > >> the reasonable fact that if you place 3 sectors on a 3 sided tower > at the > >> exact same height, you will never be able to climb over them or at > least > >> with great difficulty. > >> > >> I would like to know first hand examples of anyone having issues or > had > >> to move them apart to resolve any issues. I don't like doing things > >> twice... you advise is greatly appreciated... > >> > >> Ross > >> > >> > >> > >> > _______________________________________________________________________ > ______________________________ > >> Galatians 6:7-8: "Be not deceived; God is not mocked: for whatsoever > a > >> man soweth, that shall he also reap. For he that soweth to his flesh > >> shall of the flesh reap corruption; but he that soweth to the Spirit > >> shall of the Spirit reap life everlasting." > >> > _______________________________________________________________________ > ______________________________ > >> > >> > >> -------------------------------------------------------------------- > ------------ > >> WISPA Wants You! Join today! > >> http://signup.wispa.org/ > >> -------------------------------------------------------------------- > ------------ > >> > >> WISPA Wireless List: [email protected] > >> > >> Subscribe/Unsubscribe: > >> http://lists.wispa.org/mailman/listinfo/wireless > >> > >> Archives: http://lists.wispa.org/pipermail/wireless/ > >> > >> > >> > >> > > > > -- > > Jack Unger - President, Ask-Wi.Com, Inc. > > Serving the Broadband Wireless Industry Since 1993 > > Author of the Cisco Press Book - "Deploying License-Free Wireless > WANs" > > Vendor-Neutral Wireless Training-Design-Troubleshooting-Consulting > > FCC License # PG-12-25133 > > Phone 818-227-4220 Email <[EMAIL PROTECTED]> > > > > > > > > > > > > --------------------------------------------------------------------- > ----------- > > WISPA Wants You! Join today! > > http://signup.wispa.org/ > > --------------------------------------------------------------------- > ----------- > > > > WISPA Wireless List: [email protected] > > > > Subscribe/Unsubscribe: > > http://lists.wispa.org/mailman/listinfo/wireless > > > > Archives: http://lists.wispa.org/pipermail/wireless/ > > > > ----------------------------------------------------------------------- > --------- > WISPA Wants You! Join today! > http://signup.wispa.org/ > ----------------------------------------------------------------------- > --------- > > WISPA Wireless List: [email protected] > > Subscribe/Unsubscribe: > http://lists.wispa.org/mailman/listinfo/wireless > > Archives: http://lists.wispa.org/pipermail/wireless/ -------------------------------------------------------------------------------- WISPA Wants You! Join today! http://signup.wispa.org/ -------------------------------------------------------------------------------- WISPA Wireless List: [email protected] Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
