Like I said, if it goes out on all of your devices at the same time, it's either the "modem" (really most likely a wireless router) or interference. If the owner knows for sure that he is not having any problems, then it is probably interference. I would search for a list on google that lists out devices that run on the 2.4 ghz wireless range and try to eliminate them in your house. I know wireless phones and microwaves among other things will cause problems.