Right on Dan!
Seems to me that many WISP operators neglect this fact when deploying
multi-sector sites.  They probably don't notice a problem most of the
time because the channels are lightly loaded, but I bet they'd run into
throughput problems if two of more sectors are heavily loaded!

Greg DesBrisay


On Wed, 2003-06-25 at 16:00, Dan Fitzpatrick wrote:
> This sounds about right.  Even with the standard channel separation (1,6 and
> 11 BTW) you will still have some radiated signal in the opposing band. This
> is because the RF filtering in most wi-fi devices isn't all that
> spectacular.  Putting the 2 devices in different polarization planes will
> help some but since one is an omni it will transcieve in the other antenna's
> physical direction anyway.
> 
> One way you make this work would be a band pass filter on each piece of
> hardware.  (Take a look at:
> http://www.rflinx.com/2.4GHz%20Tunable%20Amp-filter.htm )
> 
> In all honesty though unless one or both are transferring data at a rate that
> comes close to saturation there shouldn't be that much of a problem if one
> radio triggers the CD of the other.
> 
> Dan.
> 
> On Wed, Jun 25, 2003 at 05:28:39PM -0500, David Young wrote:
> > On Wed, Jun 25, 2003 at 05:45:48PM -0400, S Woodside wrote:
> > > If they're on non-interfering channels (there are 3 in USA, 1, 7, 11) 
> > > then no problem.
> > 
> >   Let me put this question another way.
> > 
> >   A local WISP puts two radios into each of its routers.  Each radio
> >   attaches to a high-gain antenna: one to an omni, the other to a
> >   patch. They tell me they went to great lengths to achieve great
> >   enough separation of the two radios' signals, lengths that went *way*
> >   beyond tuning the radios to different channels, before one radio would
> >   not routinely activate the other's carrier sense (thus inhibiting
> >   transmissions).
> > 
> >   The lengths that they went to included moving the antennas to different
> >   masts, and crossing their polarization.
> > 
> >   Does anybody know if it is ordinarily so much trouble to isolate
> >   802.11b radios?
> > 
> > Dave
> > 
> > -- 
> > David Young             OJC Technologies
> > [EMAIL PROTECTED]      Urbana, IL * (217) 278-3933
> > --
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