im using channel 11 I think which is outside of the 2.47ghz unregulated band for general use and slightly into the military and emergency service band I believe. You can only use certain channels in certain countries. In fact some wireless equipment ask you to specify your country of operation and will disable the channels that are illegal in your country.
Yeah... if there is a emergency in the local area within the footprint of my wifi setup (which doesnt reach the front of my house). Then there would be a problem.
To be honest I havent checked what channel it is, but I believe I was breaking the law.
WIFI channels are set up so that 3 channels away from each other = the minimum interference. > 3 = interference from the higher up channels, < 3 = more interference from the lower channels. So if his scans come up true, either add 3 to it, or subtract 3 from it.
Also... DECT phones are bastards for screwing up wifi transmission. Make sure your phones are set on an appropriate channel if possible.