The problem occurs because 802.11b uses direct-sequence spread-spectrum modulation. This technique (in theory) distributes the signal's energy over a wide bandwidth to reduce or eliminate adjacent channel interference. The reality is that DS spread 802.11b signals don't usually interfere with each other--but they will interfere with the X-10 video repeater. The amount of spreading is a function of the "spreading code"; the longer the code the wider the spread. Please see Virginia Tech's "Wireless FAQ" on spread-spectrum:
http://www.cwt.vt.edu/faq/default.htm#sspec I have experimented with the same X-10/802.11b setup and found that even using a spectrum analyzer to determine the frequency of the X-10 and then setting the 802.11b gear as far away as possible did not resolve the problem. It may be that the X-10 gear is simply not well-designed; perhaps a better receiver front-end with better filtering would have helped. Then again it may be that the DS spreading code is not long enough to distribute the signal well, and the interference is truly in-band and non-rejectable. In theory, a better video sender system (based perhaps on digital modulation such as DS spread or FSK) would not be affected. I make no claims that this is true, caveat emptor and all that. Your mileage may vary. ...dtw -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Fred Reinthaler Sent: Friday, September 27, 2002 11:47 AM To: BAWUG Subject: [BAWUG] X10 and 802.11 Hi, I have an "entertainment anywhere" from X10 consisting of a audio/video transmitter and receiver using the 2.4Ghz frequency band. I am also using 802.11b NICs for my home network. The problem is that when using the X10 product for video, every few seconds, interference will occur. There are four different channels the X10 product can be set to (A,B,C or D) but i have no idea to what 802.11 channel this corresponds to and i have tried all four but still am experiencing interference. Now since i am using a specific channel for my wireless network, once the association is made and a connection is established on a certain channel, should the NIC still be trying to scan on other channels? I get the impression that's what XP might be doing so if that is the case, is there a way to change that behaviour? I will have to do some sniffing and analyze some packets in order to confirm this but i thought someone that might have had the same issue could maybe give me a quick answer. thanks, fred -- general wireless list, a bawug thing <http://www.bawug.org/> [un]subscribe: http://lists.bawug.org/mailman/listinfo/wireless -- general wireless list, a bawug thing <http://www.bawug.org/> [un]subscribe: http://lists.bawug.org/mailman/listinfo/wireless
