We have a 24 dB directional antenna pointing almost directly (less than 5
degrees) in to an Air radar system transmitting at +26 dBm (if I remember
correct) at 1100 MHz. The distance is about 1.5 km at a foregin location.

This seriously affected the Lucent silver card. By putting a bandpass filter
in between we manage to run this link with almost no measurable disturbance
on the 802.11b link.

The other end of the link is located at the same roof as a 1800 GSM cell. It
does not affect the performance at all.

/Lars

----- Original Message ----- 
From: "Moebius" <[EMAIL PROTECTED]>
To: "'Dirk-Willem van Gulik'" <[EMAIL PROTECTED]>;
<[EMAIL PROTECTED]>
Sent: Wednesday, July 09, 2003 6:37 PM
Subject: RE: [BAWUG] Cell phone arrays and WiFi


Have you used a spectrum analyzer to see if it is in-band interference? If
it is out-of-band, a narrow band-pass filter will make the cell site go buh
bye..

If it is in-band, the cellular guys may need to install a filter.

I have had UHF and VHF systems sitting right next to high power pager
transmitters and with appropriate cavities, you never even knew they were
there..

-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
On Behalf Of Dirk-Willem van Gulik
Sent: Tuesday, July 08, 2003 11:22 PM
To: [EMAIL PROTECTED]
Subject: Re: [BAWUG] Cell phone arrays and WiFi


On Tue, 8 Jul 2003, Gerard J. Cerchio wrote:

> Jennifer Donnelly at Cal Com Systems assures me that
> this cell installation will not affect our 802.11b network at
> all.  Some of our transceivers will be within 50 feet of the
> cellular array.

For what it is worth; at those distances, the European GSM masts in the
1800Mhz frequencies do cause the receivers of most cards to blank out due
to overload when used with for example a simple omni. This is visible as
short burst of no receiption and a very sudden low noise with little
signal.

At www.wirelessleiden.net we are currently experimenting with wave guide
antenna's which have a much narrower range around the 2.2Ghz when we are
deploying near a GSM mast:

The whave guide:
http://www.wirelessleiden.nl/wcl/cgi-bin/moin.cgi/NodeRijnVliet

In the from the two sector GSM antennas, to the back/right the WiFi
antenna:

http://webfolder.wleiden.webweaving.org/Rijn%20en%20Vliet%20-%20July%202003/
Rijn%20en%20Vliet%20-%20July%202003-Pages/Image18.html

We're not quite done testing/deploying here - so we are not quite sure yet
if this solves the problems.

Dw


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