[Matth]

I tend to favour 13, unlucky for some, but so long as all kit is, or is set to, proper EU spec, it can do 13. Mind you, the low channels, for me, are unusable - probably Videosender etc., which Wifi tracers using consumer Wifi adpters and/or free software cannot detect.

Stupid arrangement though as the channel is actually 4 wide, so the only true clear to clear is EU spec 1, 5, 9, 13 (allowing 4x 20Mhz channels, or 2x 40MHz wide N150).
Compromise US spec: 1, 4, 7, 11 - with a minimum spacing of 3, so with slight adjacent channel splatter.
The common 3 channel default of 1, 6, 11 is just a bad idea, getting in the way of both better alternatives.

Also, setting the router to enable RDG (Reverse Direction Grant) seems to help, allowing the PC to ACK while the channel still belongs to the router, making the turn around more efficient and less likely to be blocked by other signals.