Here I am sitting on our boat at a marina in the middle of London (well, not quite, near City Airport actually) and I have a TP-Link outdoor WiFi extender that I am running in what they call WISP Client mode to connect to a BT WiFi/Fon hotspot.

It's working OK at the moment - I'm using it to do this, but I'd like some sort of way to decide on which is the best WiFi signal to use.

When I run the TP-Link's 'survey' to see what's out there it reports up to 150 WiFi signals when pointed in certain directions. Obviously I can only use some of these (the BT ones with no security setting in the main) but even then I'm left with quite a choice.

So, is the strongest signal always the best one to use, or will a weaker signal on a quieter channel work better? I chose the one I'm using now because it's on channel 7 and there are very few signals on channel 7. There are however much stronger BT Wifi-Fon signals on channel 1 for example but channel 1 is very crowded.

While I'm at it - how does it work at all when there are many different WiFi signals on the same channel? Is there some sort of time multiplexing going on?

Finally, is it best to avoid channels with *very* strong (unwanted) signals? There's a very expensive 'marina WiFi' system here which has strong signals on two channels, like 20dB or so more than any other signal, is it best to avoid these channels?