Hey Steve,
Do the metal buildings enter the fresnel zone in the line of sight you
are referring to? If not then yes, go with less beamwidth. If they do
then I don't know if I would go with less beamwidth. If you have a
bunch of metal buildings all around you then they are going to act like
splitters to your signal.
You might experiment by trying an omni directional or an antenna with
like 180deg beamwidth because your signal from the base is going to be
coming from all different directions but then you have multipath to deal
with; but if you are using Tsunami then you are probably using OFDM
which helps combat multipath somewhat. I would try that first or try
aiming your existing client antennas in all possible directions and
polarizations. You might be amazed where your strongest signal comes
from.
Thanks,
Rodney Milam
Infinite Technologies
www.InfinteTech.net
Original Message:
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Message: 1
Date: Fri, 02 Apr 2004 10:23:02 -0600
From: "Steven N. Fettig" <[EMAIL PROTECTED]>
Subject: [BAWUG] Decreas beamwidth via Antenna Style or Increase
Power: Noise Problem
To: [EMAIL PROTECTED]
Message-ID: <[EMAIL PROTECTED]>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Hi All,
I'm having a problem that I simply can't wrap my mind around. I am
setting up a wireless co-op in a small industrial park and am using some
Proxim Tsunami gear for the build (we are a very, very small community
and therefore broadband services are either prohibitively expensive or
non-existent). At the center I have a 15 dBi Omni attached to the AP
and at the end-nodes, I have 15.5 dBi directional patch antennas.
I am having somewhat of a problem with noise and the SNR values going
too low for the QoS I am trying to achieve. One of the installations
has line of site - but between two metal buildings. (In fact, all of
the buildings in the industrial park are metal...) The beam width of
the patch antennas is 25 deg. at -3dBi 45 deg. at -10dBi. I am thinking
of trying out a small parabolic grid antenna with a 16 deg. horizontal
beam width so that I can "fit" between the buildings without so much
reflection. The problem is that if it doesn't work, I'm not sure where
to go. I was thinking of amplifying the signal at the center (if my
calculations are correct, I can go up to 400 mW at the center without
breaking the rules), but I don't know if this is just going to cause
more problems as far as noise is concerned - i.e. if I increase the
power, won't I increase the noise if it is indeed due to
multipath/reflection (which I am assuming it is)? Can anyone offer some
advice in this arena?
Thanks in Advance!
Steve
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