I have just 7 metres to router from my box. Only one 20-30cm thin plaster wall behind my box, then router is situated in cellar immediately at bottom of stairs. The door down to the cellar is always open, so i'm sute it's just a setting issue in the box/router, as my signal strength is always a steady 78%.
but now...maybe my luck is in!
pooface... i have just put channel no. in router from 11 to 13...and BINGO! At least for the moment, i've got wi-fi connection working properly straight away. This could be pure coincidence, as occasionally, i do get a connection.
I'll know in a few hours if this has done the trick!
fingers crossed!
thanks!