[TowerTalk] Snow and rain attenuation

[Bob Smith]

Hi Dan,


I build wireless ISP for the operators.  As a fast check you might 
get the information
on the radio pwr, receiver gain, antenna gain, etc and plug it into 
the calculator
in the link below and see if you have enough signal from 15miles to 
get you internetl.
Be sure to change the operating frequency  to 5700mhz to do the 
calculations.  I really
don't know if 5.8 is going to give you a signal at 15miles.  However, 
I use 5.8 for PtP links
between mountain tops at 20 miles and get 10mb/s throughput with good 
signals using
a 28dbi grid panel on one end and a 3' dish on the other.  But the 
dish you are using is about
1 meter in diameter.   Why isn't the ISP using 2.4 at that range??

The radio you are describing sounds like a Motorola Canopy System.

http://www.terabeam.com/support/calculations/som.php

hope this helps,

Bob Smith

Robert Smith Consulting
"Wireless Installations -- Government, Businesses & ISP's"
F.C.C. Licensed-Commercial & Amateur Services
A.R.S NA6T
ARRL Life Member
1-707-964-4931 w/answering machine
Fort Bragg, California   95437

"On The Air-Conditioned Mendocino Coast, In REAL Northern California"
No trees were destroyed in the sending of this message.
However, a large number of electrons were terribly inconvenienced.
------------------------------

Message: 7
Date: Mon, 31 Oct 2005 08:28:08 -0800
From: "Dan Hearn" <dhearn at wwnw.net>
Subject: [TowerTalk] Snow and rain attenuation
To: "Towertalk at Contesting.Com" <towertalk at contesting.com>
Message-ID: <ACEGINBFNLHLHJAHIHCPCEMHCGAA.dhearn at wwnw.net>
Content-Type: text/plain;	charset="iso-8859-1"

I have been compelled to use dial up ISP service for some time. Recently a
high speed RF link service has become available. It operates on 5.7ghz. The
ISP transmitter is located on a mountain top at about 15 miles distance and
I have line of sight to it. The operator has recently increased power and
thinks an acceptable signal to my location is available. They are ready to
test for this.
   I am concerned that our frequent snow and rain this winter might result in
unreliable signal levels. The receiver end uses a dish and my experience
with the Dish TV system is that less than an inch of snow on the reflector
kills the signal. The ISP antennas on the mountain top are in a snow
environment all winter for sure. They may have heaters on their antennas to
solve this problem at that end.
   Has anyone had experience in a situation like this? Should I stick with my
dial up?

73, Dan, N5AR