Ok. Well me and my friend use a lil strategy to help us avoid these promblems.. 1st off u have to know how to change yur wifi signal or w/e the heck its called.
Go to wii menu > wii options > 2nd page > Internet > connection settings > Any empty bar,(may have to clear a space). Then find any Green 2/3 bar connection, then test it.
Fun part, when it asks you to update yur Wii select yes. Dependin on how long it takes yur Wii to realize you have the most updated wii possible depends on yur signal. Ok the beat is like.. Dun dun dun dun.. dun dun dun dun.. dun dun dun.. DING. I believe, soooo, if its about that long then its about medium id say. IF it just beats once then asks u to go back to the wii menu its a really good connection. (I have never d/ced or lagged when this happens, but thats just me..)
Try moving yur Wii little by little.. 1inch can make a huge diffrence in signals.
I honestly dont know if this is a National rule of thumb or im just gettin lucky but me and 2 other friends do this to find nice connections and I have yet to find a flaw. So G/l and dont go owning me cuz it didnt work for u