No need for a shell; just use something like:Once enabled the service, just reboot. Note that iw reg set... takes one or two seconds to change to a different wifi regulation setup.

The wifi "channel" is actually the center frequency - adjacent channels frequencies overlap. This is why most of the commercial wifi access points and routers use either channel 1, or 6, or 11 (and this is why I use 3 in the garage and 13 at home).

Btw I see that XperiaX wifi is even better than Jolla1's - also the WoW (wake-on-wifi) is better, quickly recovering from energy saving modes (no need to try non-default values).