Effective range varies from house to house with 802.11b. I first noticed the problem at my parent's house which was built around 1911. Plaster walls seems to be a big problem. The plaster is applied to a heavy wire mesh that is an excellent barrier for 2.4 ghz traffic. Spread spectrum phones wipe out my x10 video sender, so they may interfere with 802.11b (I'm just guessing). 802.11b also interferes with the x10, but not on all channels.
Having the access point on the same floor as the remote connections seems to help. Having it in an unobstructed location also improves performance.
All in all, my experience has been poor, but it beats wires!
Greg
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Rio Reciever - 11,700 songs 47g